kayg commented

Owner

Owner: "we don't even know if [our multiplexer and mesh] are more performant than NetBird, Tailscale, tmux, Zellij." Performance is priority 1 (D5, D41) and we have never measured against them.

Scope (research only, no product code changes): a reproducible perf kit the orchestrator runs on perf-test-01/02/03 (x86_64, 4 vCPU / 8 GB). Jobs never use the perf VMs.

A. Mesh data plane — infraternal mesh (current dev build, as it ships) vs NetBird vs Tailscale, two network namespaces on one VM, no accounts, no external coordination. Throughput (1 and 8 flows), one-way and RTT latency p50/p99 at 64/512/1400 B, CPU per Gbit/s, RSS per peer idle/load, time to first packet; plus a DE↔IN profile (198 ms RTT netem). Each setup labelled with what it really measures.

B. Terminal multiplexer — infraternal sessions (browser → server → host shim, existing latency gates) vs tmux and Zellij attached in a terminal, plus tmux over SSH with the same delay for a like-for-like case. Keystroke echo p50/p99 local and with 150 ms one-way delay; output throughput (cat 100 MB, yes 10 s) and time until the screen is current; RSS per session at 1/10/50; idle CPU; reattach time; 2% loss.

Deliverable: pinned versions with SHA-256, official static releases, one-command relay archive (x86_64 + aarch64), every case in its own perf-lock hold, before/after machine diff that must be empty, < 45 min on 4 cores; method in research/head-to-head/README.md on branch research-head-to-head. Smoke pass on the build host is labelled "build host, aarch64, not perf evidence".

Owner: "we don't even know if [our multiplexer and mesh] are more performant than NetBird, Tailscale, tmux, Zellij." Performance is priority 1 (D5, D41) and we have never measured against them. **Scope (research only, no product code changes):** a reproducible perf kit the orchestrator runs on perf-test-01/02/03 (x86_64, 4 vCPU / 8 GB). Jobs never use the perf VMs. **A. Mesh data plane** — infraternal mesh (current dev build, as it ships) vs NetBird vs Tailscale, two network namespaces on one VM, no accounts, no external coordination. Throughput (1 and 8 flows), one-way and RTT latency p50/p99 at 64/512/1400 B, CPU per Gbit/s, RSS per peer idle/load, time to first packet; plus a DE↔IN profile (198 ms RTT netem). Each setup labelled with what it really measures. **B. Terminal multiplexer** — infraternal sessions (browser → server → host shim, existing latency gates) vs tmux and Zellij attached in a terminal, plus tmux over SSH with the same delay for a like-for-like case. Keystroke echo p50/p99 local and with 150 ms one-way delay; output throughput (`cat` 100 MB, `yes` 10 s) and time until the screen is current; RSS per session at 1/10/50; idle CPU; reattach time; 2% loss. **Deliverable:** pinned versions with SHA-256, official static releases, one-command relay archive (x86_64 + aarch64), every case in its own perf-lock hold, before/after machine diff that must be empty, < 45 min on 4 cores; method in `research/head-to-head/README.md` on branch `research-head-to-head`. Smoke pass on the build host is labelled "build host, aarch64, not perf evidence".

kayg commented

2026-10-30 16:12:16 +00:00

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Owner

Start: research job, branch research-head-to-head, base a4f15f8f7 (origin/dev). Build host 10by32-02-std (aarch64); kit targets x86_64 perf VMs. Measuring only, no product code changes.

Start: research job, branch `research-head-to-head`, base `a4f15f8f7` (origin/dev). Build host 10by32-02-std (aarch64); kit targets x86_64 perf VMs. Measuring only, no product code changes.

kayg commented

2026-10-30 17:13:43 +00:00

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Paused for the 10by32-02-std reboot. WIP pushed: research-head-to-head @ 78ccce47e744, based on a4f15f8f7.

Machine restored:

Every process I started is stopped: the infraternal server and its __shim children, tmux, Zellij, tailscaled, tscontrol, netbird and netbird-server.
The h2h-* network namespaces, veth/bridge links and netem qdiscs are gone, and so are the /dev/shm/h2h-* directories.
The overlay and sch_netem modules are unloaded again.
In the build-host smoke runs, every case's before/after machine diff is empty, except for two items found and fixed during development: a leftover overlay module, and gcc temp files from other jobs.

Done (kit under research/head-to-head/):

h2h: a single Rust measurement tool for every system. It includes a native infraternal leg-A client that signs up with a software passkey and uses the shipping codec.
A local Tailscale control stack (testcontrol + DERP/STUN, v1.104.4).
NetBird 0.82.0, bootstrapped locally through /api/setup.
Static tmux 3.8 built from pinned sources.
Pinned SHA-256 for every download, and a reproducible build-kit.
run.sh runs each case in its own perf-lock hold and perf.slice scope, with an empty-diff check.

Smoke results (build host, aarch64, not perf evidence): all five mesh cases pass (underlay, infraternal, tailscale, netbird kernel, netbird userspace), and so does term-local for tmux and Zellij.

Finding under investigation: during cat 100MB, the server's browser-route liveness lease ends the infraternal stream with code 1013. The lease probes every 25 ms with a 250 ms floor and retires after twice that. Not yet known whether the native client is late with Pong or the browser would hit the same limit. The next step either way is to re-attach on 1013 the way the web client does.

Next: fix the flood case, smoke term-wan/loss/scale, write the README, build and attach the x86_64 kit with its sha256 and run command.

**Paused for the 10by32-02-std reboot.** WIP pushed: `research-head-to-head` @ `78ccce47e744`, based on `a4f15f8f7`. **Machine restored:** - Every process I started is stopped: the infraternal server and its `__shim` children, tmux, Zellij, tailscaled, tscontrol, netbird and netbird-server. - The `h2h-*` network namespaces, veth/bridge links and netem qdiscs are gone, and so are the `/dev/shm/h2h-*` directories. - The `overlay` and `sch_netem` modules are unloaded again. - In the build-host smoke runs, every case's before/after machine diff is empty, except for two items found and fixed during development: a leftover `overlay` module, and gcc temp files from other jobs. **Done** (kit under `research/head-to-head/`): - `h2h`: a single Rust measurement tool for every system. It includes a native infraternal leg-A client that signs up with a software passkey and uses the shipping codec. - A local Tailscale control stack (testcontrol + DERP/STUN, v1.104.4). - NetBird 0.82.0, bootstrapped locally through `/api/setup`. - Static tmux 3.8 built from pinned sources. - Pinned SHA-256 for every download, and a reproducible `build-kit`. - `run.sh` runs each case in its own perf-lock hold and perf.slice scope, with an empty-diff check. **Smoke results** (build host, aarch64, not perf evidence): all five mesh cases pass (underlay, infraternal, tailscale, netbird kernel, netbird userspace), and so does term-local for tmux and Zellij. **Finding under investigation:** during `cat 100MB`, the server's browser-route liveness lease ends the infraternal stream with code 1013. The lease probes every 25 ms with a 250 ms floor and retires after twice that. Not yet known whether the native client is late with Pong or the browser would hit the same limit. The next step either way is to re-attach on 1013 the way the web client does. **Next:** fix the flood case, smoke term-wan/loss/scale, write the README, build and attach the x86_64 kit with its sha256 and run command.

kayg referenced this issue

2026-10-30 17:36:12 +00:00

Orchestrator handover 2026-10-30: all work paused; mesh-first roadmap; Claude-only #262

kayg commented

2026-10-31 16:12:35 +00:00

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J20 resumed: branch research-head-to-head, base 78ccce47e7. Isolated worktree on control host; builds/tests on claude@infraternal-dev-01-compute01; measurements only on claude@infraternal-perf-01-backup01 through perf-run. Scope: browser 1013 triage, WAN/loss/scale cases, full comparative measurements. No product fix or engine selection.

J20 resumed: branch research-head-to-head, base 78ccce47e744. Isolated worktree on control host; builds/tests on claude@infraternal-dev-01-compute01; measurements only on claude@infraternal-perf-01-backup01 through perf-run. Scope: browser 1013 triage, WAN/loss/scale cases, full comparative measurements. No product fix or engine selection.

kayg commented

2026-10-31 16:17:01 +00:00

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Owner

J20 infrastructure blocker: compute01 became unreachable shortly after starting bounded builds (SSH: ssh: connect to host infraternal-dev-01-compute01 port 22: No route to host). Launched h2h build PID 276702, log /home/claude/worktrees/j20-h2h/build.log; cannot yet establish completion or stop it. Perf VM is reachable, but sudo -n -l grants only infraternal-perf-exec and infraternal-perf-drop-caches; perf-exec explicitly uses --uid=claude --gid=claude. Existing kit needs root for ip netns/netem. No measurement has run and no performance claims are made. Preparing harness changes locally while awaiting restored build access / intended privileged runner.

J20 infrastructure blocker: compute01 became unreachable shortly after starting bounded builds (SSH: `ssh: connect to host infraternal-dev-01-compute01 port 22: No route to host`). Launched h2h build PID 276702, log /home/claude/worktrees/j20-h2h/build.log; cannot yet establish completion or stop it. Perf VM is reachable, but `sudo -n -l` grants only infraternal-perf-exec and infraternal-perf-drop-caches; perf-exec explicitly uses `--uid=claude --gid=claude`. Existing kit needs root for ip netns/netem. No measurement has run and no performance claims are made. Preparing harness changes locally while awaiting restored build access / intended privileged runner.

kayg commented

2026-10-31 16:21:33 +00:00

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Infrastructure update: orchestrator supplied perf-run --root for netns/netem cases. An earlier rootless user-namespace preflight also succeeded, but the actual kit will use the explicitly provided root runner. Compute01 remains down awaiting owner restart. Browser triage build is running on std02 through build-slot (PID 350633, ~/worktrees/j20/build.log); these are functional checks, not perf evidence. Existing term-wan/loss/scale cases are present; adding the missing mesh loss profile and per-case root perf-run driver.

Infrastructure update: orchestrator supplied `perf-run --root` for netns/netem cases. An earlier rootless user-namespace preflight also succeeded, but the actual kit will use the explicitly provided root runner. Compute01 remains down awaiting owner restart. Browser triage build is running on std02 through build-slot (PID 350633, ~/worktrees/j20/build.log); these are functional checks, not perf evidence. Existing term-wan/loss/scale cases are present; adding the missing mesh loss profile and per-case root perf-run driver.

kayg commented

2026-10-31 16:35:56 +00:00

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J20 browser finding (build host std02/aarch64; functional evidence, not perf timing): production Chromium 155.0.8059.79 + production renderer + real server/embedded infraternal agent/shim/PTY reproduced stream 1013 "attachment ended" in 2 of 3 approximately 100 MB cat floods. Run 1: two stream 1013 plus control 1001, 3 replacement sockets; run 2: two stream 1013, 2 replacements; run 3: no close/replacement. Completion marker appeared in all runs, so automatic recovery hides the break. Counts/JSON/screenshots: ~/.cache/codex-scratch/j20/evidence/browser-flood on std02 and control host. The 1013 is distinct from the control liveness 1001. Tracing the attachment queue teardown with temporary content-free diagnostics; no product fix in this research branch.

kayg referenced this issue

2026-10-31 16:39:14 +00:00

Browser terminal flood retires healthy attachments with 1013 and silently reconnects #270

kayg commented

2026-10-31 16:50:02 +00:00

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J20 browser triage is complete: production Chromium reproduces stream 1013 during the ~100 MB cat. The temporary diagnostic build confirms the 256-message embedded output queue fills while the receiver remains open (capacity=0, closed=false); no sequence-gap markers. Details, code path, minimal proposal and 7 diagnostic attachments: #270 (comment) . Temporary product diagnostics have been restored; no product fix here. Separate control-stream 1001 cause remains unconfirmed. The x86 kit is queued through build-slot after the store repair; full perf rows remain pending.

J20 browser triage is complete: production Chromium reproduces stream 1013 during the ~100 MB cat. The temporary diagnostic build confirms the 256-message embedded output queue fills while the receiver remains open (capacity=0, closed=false); no sequence-gap markers. Details, code path, minimal proposal and 7 diagnostic attachments: https://git.kayg.org/kayg/infraternal/issues/270#issuecomment-70910 . Temporary product diagnostics have been restored; no product fix here. Separate control-stream 1001 cause remains unconfirmed. The x86 kit is queued through build-slot after the store repair; full perf rows remain pending.

kayg commented

2026-10-31 18:16:57 +00:00

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J20 perf progress: full mesh LAN/WAN/2%-per-direction-loss workloads completed; corrected terminal WAN SSH fixtures now complete authentication and timing. Private fixture changed to UsePAM yes after its public log explicitly reported User claude not allowed because account is locked; no account/host SSH policy changed. Scale selection now includes detached infraternal shims rather than only server descendants. The invalid original native scale slope will not be published.

Production-browser stream 1013 triage and queue-admission evidence are recorded separately in #270. Corrected native WAN flood again closes 1013.

Required compute01 scripts/verify fast first run exited 1: ctrl_c_in_json_mode_ends_with_an_interrupted_envelope_and_exit_130 panicked with still running after SIGINT. Both static builds, exact size caps, clippy, deny and other Rust gates passed. Complete raw failure is retained; the full gate will rerun after the other branch's gate. This is not a baseline-failure claim or a waived gate.

J20 perf progress: full mesh LAN/WAN/2%-per-direction-loss workloads completed; corrected terminal WAN SSH fixtures now complete authentication and timing. Private fixture changed to `UsePAM yes` after its public log explicitly reported `User claude not allowed because account is locked`; no account/host SSH policy changed. Scale selection now includes detached infraternal shims rather than only server descendants. The invalid original native scale slope will not be published. Production-browser stream 1013 triage and queue-admission evidence are recorded separately in #270. Corrected native WAN flood again closes 1013. Required compute01 `scripts/verify fast` first run exited 1: `ctrl_c_in_json_mode_ends_with_an_interrupted_envelope_and_exit_130` panicked with `still running after SIGINT`. Both static builds, exact size caps, clippy, deny and other Rust gates passed. Complete raw failure is retained; the full gate will rerun after the other branch's gate. This is not a baseline-failure claim or a waived gate.

kayg commented

2026-10-31 18:27:24 +00:00

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Gate failure cause identified: the background/nohup launcher inherited SigIgn: 0000000000000007 (SIGHUP/SIGINT/SIGQUIT ignored) into the gate. infraternal_shim::exit_on_interrupt deliberately preserves an inherited SIG_IGN disposition, so the CLI interruption test's SIGINT was ignored. Both branches failed that same test under this launcher. This is not evidence of a product regression or an origin/dev baseline failure.

The replacement launcher explicitly resets those three dispositions before exec of build-slot/Nix/verify. Both complete scripts/verify fast gates will rerun; no product/test code or timeout is changed. Original logs are retained.

Gate failure cause identified: the background/nohup launcher inherited `SigIgn: 0000000000000007` (SIGHUP/SIGINT/SIGQUIT ignored) into the gate. `infraternal_shim::exit_on_interrupt` deliberately preserves an inherited SIG_IGN disposition, so the CLI interruption test's SIGINT was ignored. Both branches failed that same test under this launcher. This is not evidence of a product regression or an origin/dev baseline failure. The replacement launcher explicitly resets those three dispositions before exec of build-slot/Nix/verify. Both complete `scripts/verify fast` gates will rerun; no product/test code or timeout is changed. Original logs are retained.

kayg commented

2026-10-31 18:43:14 +00:00

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Owner

J20 full x86 head-to-head measurements, built on compute01 through build-slot and measured strictly through perf-run --root on the perf VM. No product fix, foundation choice, merge or deployment.

Method: perf.slice CPUs 1–3, 6 GiB; one full sample per workload. Two endpoint namespaces plus local disposable control. Mesh memory sums both endpoint daemon trees and excludes control; CPU s/Gbit is whole-machine busy time including traffic tools. These are local namespace data-plane tests, not Internet NAT/rendezvous tests. Mesh WAN adds 99 ms in each direction (198 ms RTT); loss adds independent 2% drops per direction. UDP latency uses 300 probes per size. Terminal uses 300 local / 100 network echo samples, ~100.83 MB base64 cat, 10 s local yes, and 20 reattachments. Terminal WAN/loss is 300 ms RTT; flood timeout 180 s. Scale seeds every session via the same 120×40 viewer before detached memory sampling; shells are separate. PSS slope uses 1→50, with no extrapolation beyond 50.

Terminal timing boundary: the native client uses cleartext WebSocket inside the private behind-proxy fixture, excluding TLS termination and browser rendering. SSH rows include encryption/authentication. These rows are backend/viewer-path measurements, not an encrypted end-to-end production ranking. The browser triage below separately uses a TLS front. Native local yes/reattach follow the failed cat on the same session and are not independent fresh-session observations.

Browser triage: production Chromium reproduced stream close 1013. Temporary diagnostics found the 256-message embedded output queue full with receiver still open, then attachment retirement and generic 1013. Separate product issue #270 has evidence and a minimal follow-up proposal; diagnostic instrumentation was removed. A separate 1001 liveness close remains causally unproven. A final screen marker or lower byte count is not proof of lossless transcript delivery: viewport updates and snapshot replacement can coalesce output.

The table combines explicitly selected complete cases: original full run for the four mesh engines, corrected full rerun for underlay/local/WAN/loss, normalized full scale rerun for 1/10/50. combined/provenance.json maps each row to raw directories. Original failed SSH-fixture and invalid native-scale attempts remain in the archive. The SSH fixture auth log identified locked-account rejection with UsePAM=no; the private fixture now uses PAM without changing accounts or host SSH policy.

Interpret nonzero cases honestly: native local cat/yes and the subsequent same-session reattach fail 1013; WAN native cat fails 1013. Tmux-over-SSH loss cat times out at 180 s, then that same session's marker/reattach fails. These are not independent idle-attach failures. Tailscale's diff adds xt_connmark/xt_mark; NetBird kernel adds xt_TCPMSS. The WAN diff is another job creating /tmp/j7-dns-perf.sh. Final cleanup successfully unloaded all three modules, found only the root network namespace, no private work directories and no test qdiscs; final cleanup receipt exit 0. Corrected underlay/local/loss/scale diffs are empty. No host VPN rules were altered.

Kit archive SHA-256: 7498ce8df5842a4f55cb27ef38aa757275b2a1453fa6605c9cc86cdae984cb41 (source 78ccce47e7, binaries unchanged). Harness corrections were overlaid after packaging; attached measured scripts, SHA-256 sums and research source diff preserve them. The early corrected-run manifest still carried the archive run.sh digest because its ./ prefix was missed during refresh; the supplemental hashes identify the actual runner. The final member manifest is corrected. Raw original manifests are retained rather than rewritten.

Required repository gates are queued with corrected launcher signal dispositions. Final branch heads and verbatim gate output will follow.

Head-to-head results: perf VM infraternal-perf-01-backup01, x86_64; perf.slice CPUs 1–3, 6 GiB

infraternal-perf-01-backup01 · Debian GNU/Linux 13 (trixie) · kernel 6.12.113+deb13-amd64 · AMD Ryzen 7 3700X 8-Core Processor · 4 cores · 7880 MiB · load at start 1.07 0.56 0.36

case	exit	seconds	machine diff
mesh-infraternal	0	163	empty
mesh-netbird	3	170	NOT EMPTY
mesh-netbird-userspace	0	162	empty
mesh-tailscale	3	169	NOT EMPTY
mesh-underlay	0	160	empty
term-local	4	77	empty
term-loss	4	690	empty
term-scale	0	286	empty
term-wan	4	427	NOT EMPTY

Failed measurements (error files are retained beside them):

term-local/attach-ix.json.failed
term-local/cat100mb-ix.json.failed
term-local/yes10s-ix.json.failed
term-loss/attach-tmux-ssh.json.failed
term-loss/cat100mb-tmux-ssh.json.failed
term-wan/cat100mb-ix.json.failed

Mesh data plane (a → b, two namespaces, one machine)

system	first packet ms	1 flow Gbit/s	8 flows Gbit/s	CPU s per Gbit (1 / 8)	idle CPU %	RSS idle MiB	RSS peak MiB
underlay	2	32.97	70.61	0.04 / 0.04	0.000	–	–
infraternal	196	3.22	2.88	1.02 / 1.12	0.000	18.1	18.1
tailscale	330	6.15	5.87	0.44 / 0.47	0.133	92.3	107.1
netbird	424	2.48	2.30	1.23 / 1.32	0.200	130.4	130.6
netbird-userspace	271	4.87	4.86	0.51 / 0.57	0.067	138.7	1151.3

Latency, LAN: p50 / p99 ms

system	RTT 64 B	RTT 512 B	RTT 1400 B	one-way 64 B	one-way 1400 B	loss (64/512/1400)
underlay	0.030 / 0.055	0.030 / 0.052	0.030 / 0.052	0.015 / 0.030	0.016 / 0.028	0/0/0
infraternal	0.106 / 0.238	0.104 / 0.166	0.111 / 0.195	0.054 / 0.127	0.058 / 0.108	0/0/0
tailscale	0.176 / 0.228	0.170 / 0.308	0.202 / 0.305	0.089 / 0.130	0.103 / 0.161	0/0/0
netbird	0.100 / 0.160	0.097 / 0.158	0.110 / 0.153	0.053 / 0.090	0.058 / 0.085	0/0/0
netbird-userspace	0.163 / 0.252	0.170 / 0.235	0.188 / 0.264	0.084 / 0.136	0.094 / 0.139	0/0/0

Latency, DE↔IN, 198 ms RTT netem: p50 / p99 ms

system	RTT 64 B	RTT 512 B	RTT 1400 B	one-way 64 B	one-way 1400 B	loss (64/512/1400)
underlay	198.076 / 198.137	198.070 / 198.107	198.074 / 198.119	99.036 / 99.062	99.038 / 99.078	0/0/0
infraternal	198.157 / 198.233	198.178 / 198.309	198.163 / 198.251	99.077 / 99.117	99.078 / 99.130	0/0/0
tailscale	198.222 / 198.340	198.231 / 198.459	198.248 / 198.389	99.106 / 99.165	99.119 / 99.201	0/0/0
netbird	198.169 / 198.259	198.161 / 198.231	198.150 / 198.211	99.079 / 99.127	99.075 / 99.118	0/0/0
netbird-userspace	198.215 / 198.376	198.235 / 198.374	198.249 / 198.392	99.103 / 99.193	99.124 / 99.232	0/0/0

system	1 flow Gbit/s	8 flows Gbit/s
underlay	0.101	0.808
infraternal	0.098	0.781
tailscale	0.098	0.778
netbird	0.098	0.779
netbird-userspace	0.098	0.779

Latency, 198 ms RTT, independent 2% loss per direction: p50 / p99 ms

system	RTT 64 B	RTT 512 B	RTT 1400 B	one-way 64 B	one-way 1400 B	loss (64/512/1400)
underlay	198.066 / 198.105	198.068 / 198.118	198.055 / 198.114	99.031 / 99.065	99.019 / 99.050	11/11/11
infraternal	198.166 / 198.256	198.177 / 198.306	198.147 / 198.214	99.073 / 99.121	99.071 / 99.108	13/13/18
tailscale	198.451 / 200.162	198.322 / 200.777	198.347 / 203.548	99.186 / 100.385	99.147 / 103.119	14/13/22
netbird	198.165 / 198.291	198.192 / 198.310	198.159 / 198.219	99.079 / 99.145	99.076 / 99.110	8/15/17
netbird-userspace	198.225 / 198.412	198.221 / 198.397	198.260 / 198.409	99.109 / 99.249	99.116 / 99.236	9/11/19

system	1 flow Gbit/s	8 flows Gbit/s
underlay	0.047	0.452
infraternal	0.038	0.315
tailscale	0.054	0.382
netbird	0.038	0.259
netbird-userspace	0.054	0.406

Terminal, local viewer

viewer	echo p50 / p99 ms	cat 100 MB: s to marker at viewer	bytes to viewer	yes 10 s: lag s	reattach p50 / p99 ms
infraternal	0.64 / 0.96	–	–	–	–
tmux	0.17 / 0.30	3.88	106818822	0.00	3.82 / 4.56
Zellij	11.61 / 11.91	4.57	2218019	0.02	79.25 / 81.93

Terminal, 150 ms one-way (300 ms RTT)

viewer	echo p50 / p99 ms	cat 100 MB: s to marker at viewer	bytes to viewer	yes 10 s: lag s	reattach p50 / p99 ms
infraternal	300.77 / 301.04	–	–	–	1202.91 / 1204.92
tmux over SSH	309.70 / 533.04	6.89	5464126	–	3374.00 / 3378.49
Zellij over SSH	315.90 / 383.12	7.85	2230658	–	3473.71 / 3476.81
plain SSH (no multiplexer)	304.93 / 391.50	36.00	101667458	–	–

Terminal, 150 ms one-way + 2 % loss

viewer	echo p50 / p99 ms	cat 100 MB: s to marker at viewer	bytes to viewer	yes 10 s: lag s	reattach p50 / p99 ms
infraternal	300.72 / 661.64	9.07	9566396	–	1203.30 / 2219.79
tmux over SSH	332.83 / 676.31	–	–	–	–
Zellij over SSH	339.90 / 866.79	8.20	2268087	–	3771.30 / 4564.99
plain SSH (no multiplexer)	355.63 / 807.77	67.29	101667460	–	–

Terminal sessions at scale (host side; shells counted separately)

system	PSS MiB at 1 / 10 / 50	per extra session MiB (1→50)	RSS MiB at 50	shells PSS MiB at 50	idle CPU % detached / 1 viewer	viewer keepalives /s
infraternal	18.8 / 29.4 / 74.9	1.14	215.5	118.2	0.050 / 0.767	36.9
tmux	2.5 / 2.6 / 3.0	0.01	3.0	118.2	0.000 / 0.000	0.0
Zellij	75.4 / 457.0 / 2139.3	42.12	3753.5	114.8	1.400 / 1.267	0.0

J20 full x86 head-to-head measurements, built on compute01 through build-slot and measured strictly through `perf-run --root` on the perf VM. No product fix, foundation choice, merge or deployment. Method: perf.slice CPUs 1–3, 6 GiB; one full sample per workload. Two endpoint namespaces plus local disposable control. Mesh memory sums both endpoint daemon trees and excludes control; CPU s/Gbit is whole-machine busy time including traffic tools. These are local namespace data-plane tests, not Internet NAT/rendezvous tests. Mesh WAN adds 99 ms in each direction (198 ms RTT); loss adds independent 2% drops per direction. UDP latency uses 300 probes per size. Terminal uses 300 local / 100 network echo samples, ~100.83 MB base64 cat, 10 s local yes, and 20 reattachments. Terminal WAN/loss is 300 ms RTT; flood timeout 180 s. Scale seeds every session via the same 120×40 viewer before detached memory sampling; shells are separate. PSS slope uses 1→50, with no extrapolation beyond 50. Terminal timing boundary: the native client uses cleartext WebSocket inside the private behind-proxy fixture, excluding TLS termination and browser rendering. SSH rows include encryption/authentication. These rows are backend/viewer-path measurements, not an encrypted end-to-end production ranking. The browser triage below separately uses a TLS front. Native local yes/reattach follow the failed cat on the same session and are not independent fresh-session observations. Browser triage: production Chromium reproduced stream close 1013. Temporary diagnostics found the 256-message embedded output queue full with receiver still open, then attachment retirement and generic 1013. Separate product issue #270 has evidence and a minimal follow-up proposal; diagnostic instrumentation was removed. A separate 1001 liveness close remains causally unproven. A final screen marker or lower byte count is not proof of lossless transcript delivery: viewport updates and snapshot replacement can coalesce output. The table combines explicitly selected complete cases: original full run for the four mesh engines, corrected full rerun for underlay/local/WAN/loss, normalized full scale rerun for 1/10/50. `combined/provenance.json` maps each row to raw directories. Original failed SSH-fixture and invalid native-scale attempts remain in the archive. The SSH fixture auth log identified locked-account rejection with UsePAM=no; the private fixture now uses PAM without changing accounts or host SSH policy. Interpret nonzero cases honestly: native local cat/yes and the subsequent same-session reattach fail 1013; WAN native cat fails 1013. Tmux-over-SSH loss cat times out at 180 s, then that same session's marker/reattach fails. These are not independent idle-attach failures. Tailscale's diff adds xt_connmark/xt_mark; NetBird kernel adds xt_TCPMSS. The WAN diff is another job creating /tmp/j7-dns-perf.sh. Final cleanup successfully unloaded all three modules, found only the root network namespace, no private work directories and no test qdiscs; final cleanup receipt exit 0. Corrected underlay/local/loss/scale diffs are empty. No host VPN rules were altered. Kit archive SHA-256: `7498ce8df5842a4f55cb27ef38aa757275b2a1453fa6605c9cc86cdae984cb41` (source 78ccce47e744, binaries unchanged). Harness corrections were overlaid after packaging; attached measured scripts, SHA-256 sums and research source diff preserve them. The early corrected-run manifest still carried the archive run.sh digest because its ./ prefix was missed during refresh; the supplemental hashes identify the actual runner. The final member manifest is corrected. Raw original manifests are retained rather than rewritten. Required repository gates are queued with corrected launcher signal dispositions. Final branch heads and verbatim gate output will follow. # Head-to-head results: perf VM infraternal-perf-01-backup01, x86_64; perf.slice CPUs 1–3, 6 GiB infraternal-perf-01-backup01 · Debian GNU/Linux 13 (trixie) · kernel 6.12.113+deb13-amd64 · AMD Ryzen 7 3700X 8-Core Processor · 4 cores · 7880 MiB · load at start 1.07 0.56 0.36 | case | exit | seconds | machine diff | |---|---|---|---| | mesh-infraternal | 0 | 163 | empty | | mesh-netbird | 3 | 170 | NOT EMPTY | | mesh-netbird-userspace | 0 | 162 | empty | | mesh-tailscale | 3 | 169 | NOT EMPTY | | mesh-underlay | 0 | 160 | empty | | term-local | 4 | 77 | empty | | term-loss | 4 | 690 | empty | | term-scale | 0 | 286 | empty | | term-wan | 4 | 427 | NOT EMPTY | Failed measurements (error files are retained beside them): - `term-local/attach-ix.json.failed` - `term-local/cat100mb-ix.json.failed` - `term-local/yes10s-ix.json.failed` - `term-loss/attach-tmux-ssh.json.failed` - `term-loss/cat100mb-tmux-ssh.json.failed` - `term-wan/cat100mb-ix.json.failed` ## Mesh data plane (a → b, two namespaces, one machine) | system | first packet ms | 1 flow Gbit/s | 8 flows Gbit/s | CPU s per Gbit (1 / 8) | idle CPU % | RSS idle MiB | RSS peak MiB | |---|---|---|---|---|---|---|---| | underlay | 2 | 32.97 | 70.61 | 0.04 / 0.04 | 0.000 | – | – | | infraternal | 196 | 3.22 | 2.88 | 1.02 / 1.12 | 0.000 | 18.1 | 18.1 | | tailscale | 330 | 6.15 | 5.87 | 0.44 / 0.47 | 0.133 | 92.3 | 107.1 | | netbird | 424 | 2.48 | 2.30 | 1.23 / 1.32 | 0.200 | 130.4 | 130.6 | | netbird-userspace | 271 | 4.87 | 4.86 | 0.51 / 0.57 | 0.067 | 138.7 | 1151.3 | ### Latency, LAN: p50 / p99 ms | system | RTT 64 B | RTT 512 B | RTT 1400 B | one-way 64 B | one-way 1400 B | loss (64/512/1400) | |---|---|---|---|---|---|---| | underlay | 0.030 / 0.055 | 0.030 / 0.052 | 0.030 / 0.052 | 0.015 / 0.030 | 0.016 / 0.028 | 0/0/0 | | infraternal | 0.106 / 0.238 | 0.104 / 0.166 | 0.111 / 0.195 | 0.054 / 0.127 | 0.058 / 0.108 | 0/0/0 | | tailscale | 0.176 / 0.228 | 0.170 / 0.308 | 0.202 / 0.305 | 0.089 / 0.130 | 0.103 / 0.161 | 0/0/0 | | netbird | 0.100 / 0.160 | 0.097 / 0.158 | 0.110 / 0.153 | 0.053 / 0.090 | 0.058 / 0.085 | 0/0/0 | | netbird-userspace | 0.163 / 0.252 | 0.170 / 0.235 | 0.188 / 0.264 | 0.084 / 0.136 | 0.094 / 0.139 | 0/0/0 | ### Latency, DE↔IN, 198 ms RTT netem: p50 / p99 ms | system | RTT 64 B | RTT 512 B | RTT 1400 B | one-way 64 B | one-way 1400 B | loss (64/512/1400) | |---|---|---|---|---|---|---| | underlay | 198.076 / 198.137 | 198.070 / 198.107 | 198.074 / 198.119 | 99.036 / 99.062 | 99.038 / 99.078 | 0/0/0 | | infraternal | 198.157 / 198.233 | 198.178 / 198.309 | 198.163 / 198.251 | 99.077 / 99.117 | 99.078 / 99.130 | 0/0/0 | | tailscale | 198.222 / 198.340 | 198.231 / 198.459 | 198.248 / 198.389 | 99.106 / 99.165 | 99.119 / 99.201 | 0/0/0 | | netbird | 198.169 / 198.259 | 198.161 / 198.231 | 198.150 / 198.211 | 99.079 / 99.127 | 99.075 / 99.118 | 0/0/0 | | netbird-userspace | 198.215 / 198.376 | 198.235 / 198.374 | 198.249 / 198.392 | 99.103 / 99.193 | 99.124 / 99.232 | 0/0/0 | | system | 1 flow Gbit/s | 8 flows Gbit/s | |---|---|---| | underlay | 0.101 | 0.808 | | infraternal | 0.098 | 0.781 | | tailscale | 0.098 | 0.778 | | netbird | 0.098 | 0.779 | | netbird-userspace | 0.098 | 0.779 | ### Latency, 198 ms RTT, independent 2% loss per direction: p50 / p99 ms | system | RTT 64 B | RTT 512 B | RTT 1400 B | one-way 64 B | one-way 1400 B | loss (64/512/1400) | |---|---|---|---|---|---|---| | underlay | 198.066 / 198.105 | 198.068 / 198.118 | 198.055 / 198.114 | 99.031 / 99.065 | 99.019 / 99.050 | 11/11/11 | | infraternal | 198.166 / 198.256 | 198.177 / 198.306 | 198.147 / 198.214 | 99.073 / 99.121 | 99.071 / 99.108 | 13/13/18 | | tailscale | 198.451 / 200.162 | 198.322 / 200.777 | 198.347 / 203.548 | 99.186 / 100.385 | 99.147 / 103.119 | 14/13/22 | | netbird | 198.165 / 198.291 | 198.192 / 198.310 | 198.159 / 198.219 | 99.079 / 99.145 | 99.076 / 99.110 | 8/15/17 | | netbird-userspace | 198.225 / 198.412 | 198.221 / 198.397 | 198.260 / 198.409 | 99.109 / 99.249 | 99.116 / 99.236 | 9/11/19 | | system | 1 flow Gbit/s | 8 flows Gbit/s | |---|---|---| | underlay | 0.047 | 0.452 | | infraternal | 0.038 | 0.315 | | tailscale | 0.054 | 0.382 | | netbird | 0.038 | 0.259 | | netbird-userspace | 0.054 | 0.406 | ## Terminal, local viewer | viewer | echo p50 / p99 ms | cat 100 MB: s to marker at viewer | bytes to viewer | yes 10 s: lag s | reattach p50 / p99 ms | |---|---|---|---|---|---| | infraternal | 0.64 / 0.96 | – | – | – | – | | tmux | 0.17 / 0.30 | 3.88 | 106818822 | 0.00 | 3.82 / 4.56 | | Zellij | 11.61 / 11.91 | 4.57 | 2218019 | 0.02 | 79.25 / 81.93 | ## Terminal, 150 ms one-way (300 ms RTT) | viewer | echo p50 / p99 ms | cat 100 MB: s to marker at viewer | bytes to viewer | yes 10 s: lag s | reattach p50 / p99 ms | |---|---|---|---|---|---| | infraternal | 300.77 / 301.04 | – | – | – | 1202.91 / 1204.92 | | tmux over SSH | 309.70 / 533.04 | 6.89 | 5464126 | – | 3374.00 / 3378.49 | | Zellij over SSH | 315.90 / 383.12 | 7.85 | 2230658 | – | 3473.71 / 3476.81 | | plain SSH (no multiplexer) | 304.93 / 391.50 | 36.00 | 101667458 | – | – | ## Terminal, 150 ms one-way + 2 % loss | viewer | echo p50 / p99 ms | cat 100 MB: s to marker at viewer | bytes to viewer | yes 10 s: lag s | reattach p50 / p99 ms | |---|---|---|---|---|---| | infraternal | 300.72 / 661.64 | 9.07 | 9566396 | – | 1203.30 / 2219.79 | | tmux over SSH | 332.83 / 676.31 | – | – | – | – | | Zellij over SSH | 339.90 / 866.79 | 8.20 | 2268087 | – | 3771.30 / 4564.99 | | plain SSH (no multiplexer) | 355.63 / 807.77 | 67.29 | 101667460 | – | – | ## Terminal sessions at scale (host side; shells counted separately) | system | PSS MiB at 1 / 10 / 50 | per extra session MiB (1→50) | RSS MiB at 50 | shells PSS MiB at 50 | idle CPU % detached / 1 viewer | viewer keepalives /s | |---|---|---|---|---|---|---| | infraternal | 18.8 / 29.4 / 74.9 | 1.14 | 215.5 | 118.2 | 0.050 / 0.767 | 36.9 | | tmux | 2.5 / 2.6 / 3.0 | 0.01 | 3.0 | 118.2 | 0.000 / 0.000 | 0.0 | | Zellij | 75.4 / 457.0 / 2139.3 | 42.12 | 3753.5 | 114.8 | 1.400 / 1.267 | 0.0 |

h2h-raw-evidence.zip

5.3 MiB

kayg commented

2026-10-31 18:55:53 +00:00

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Per-peer view of the mesh RSS figures in the full table (two endpoint trees, coordination excluded):

Mesh	Mean RSS per peer idle MiB	Mean RSS per peer at sampled LAN peak MiB
infraternal	9.04	9.04
Tailscale	46.16	53.57
NetBird kernel	65.19	65.28
NetBird userspace	69.35	575.64

These are the aggregate two-peer figures divided by two, not the worst individual peer. The peak column is the mean at the sampled aggregate LAN RSS peak across the 1/8-flow runs; it does not claim that both peers reach their individual peaks simultaneously. The raw per-process memory lists remain in the attached JSON.

The selected full case durations total 2,304 seconds (38.4 minutes), excluding wrapper overhead, shared-lock waits and diagnostic/retry attempts; this is not a claim that the combined provenance table came from a single uninterrupted suite.

Per-peer view of the mesh RSS figures in the full table (two endpoint trees, coordination excluded): | Mesh | Mean RSS per peer idle MiB | Mean RSS per peer at sampled LAN peak MiB | |---|---:|---:| | infraternal | 9.04 | 9.04 | | Tailscale | 46.16 | 53.57 | | NetBird kernel | 65.19 | 65.28 | | NetBird userspace | 69.35 | 575.64 | These are the aggregate two-peer figures divided by two, not the worst individual peer. The peak column is the mean at the sampled aggregate LAN RSS peak across the 1/8-flow runs; it does not claim that both peers reach their individual peaks simultaneously. The raw per-process memory lists remain in the attached JSON. The selected full case durations total 2,304 seconds (38.4 minutes), excluding wrapper overhead, shared-lock waits and diagnostic/retry attempts; this is not a claim that the combined provenance table came from a single uninterrupted suite.

kayg commented

2026-10-31 19:03:01 +00:00

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The existing CLI interruption test passes when launched with SIGINT's default disposition restored. This used the already-built test executable, with no compilation or repository change:

running 1 test
test ctrl_c_in_json_mode_ends_with_an_interrupted_envelope_and_exit_130 ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 16 filtered out; finished in 0.84s

This confirms the background-launcher diagnosis. Both complete fast gates remain queued through build-slot; this focused check does not replace them.

The existing CLI interruption test passes when launched with SIGINT's default disposition restored. This used the already-built test executable, with no compilation or repository change: ```text running 1 test test ctrl_c_in_json_mode_ends_with_an_interrupted_envelope_and_exit_130 ... ok test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 16 filtered out; finished in 0.84s ``` This confirms the background-launcher diagnosis. Both complete fast gates remain queued through build-slot; this focused check does not replace them.

kayg commented

2026-10-31 19:25:46 +00:00

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Terminal timing boundary, explicit for interpreting the comparison: the existing native h2h client opens ws:// on the private server fixture configured behind a proxy. Its timing rows exclude TLS termination and browser rendering. The SSH rows include SSH encryption/authentication; their reattach handshakes are therefore a different transport stack. These measurements establish backend/viewer-path behavior, not an encrypted end-to-end production ranking. The separate production-Chromium 1013 triage does use a TLS front and the real renderer. README now states this boundary explicitly.

Also, native local yes/reattach follow the failed cat on the same session; retain those failures as a sequence, not independent fresh-session conclusions. Larger UDP datagrams may fragment inside a tunnel, so whole-probe loss can exceed the 3.96% unfragmented RTT drop exposure from independent 2% per direction.

Terminal timing boundary, explicit for interpreting the comparison: the existing native `h2h` client opens `ws://` on the private server fixture configured behind a proxy. Its timing rows exclude TLS termination and browser rendering. The SSH rows include SSH encryption/authentication; their reattach handshakes are therefore a different transport stack. These measurements establish backend/viewer-path behavior, not an encrypted end-to-end production ranking. The separate production-Chromium 1013 triage does use a TLS front and the real renderer. README now states this boundary explicitly. Also, native local yes/reattach follow the failed cat on the same session; retain those failures as a sequence, not independent fresh-session conclusions. Larger UDP datagrams may fragment inside a tunnel, so whole-probe loss can exceed the 3.96% unfragmented RTT drop exposure from independent 2% per direction.

kayg commented

2026-10-31 19:31:22 +00:00

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J20 scheduling blocker: all measurements, comparisons, browser triage, source checks and perf cleanup are complete. The corrected full fast gates and final archive repack are waiting through the mandatory compute01 build-slot helper. Current queued PID: 2045649; log: ~/.cache/codex-scratch/j20/verify-both-signal-reset.log. This launcher alone has waited over 30 minutes; all four slot holders have changed while it has remained queued. The helper polls locks and has no FIFO queue.

Orchestrator scheduling help is needed if a prompt handoff is required: reserve a slot for this already-queued command. I am leaving it queued and will finish the two gates, final packages, commits and authorized branch pushes once it acquires a slot. No product work or perf run remains, and no gate is waived. The earlier focused SIGINT test passes with the launcher correction; the two complete gates still need to run.

J20 scheduling blocker: all measurements, comparisons, browser triage, source checks and perf cleanup are complete. The corrected full fast gates and final archive repack are waiting through the mandatory compute01 build-slot helper. Current queued PID: 2045649; log: ~/.cache/codex-scratch/j20/verify-both-signal-reset.log. This launcher alone has waited over 30 minutes; all four slot holders have changed while it has remained queued. The helper polls locks and has no FIFO queue. Orchestrator scheduling help is needed if a prompt handoff is required: reserve a slot for this already-queued command. I am leaving it queued and will finish the two gates, final packages, commits and authorized branch pushes once it acquires a slot. No product work or perf run remains, and no gate is waived. The earlier focused SIGINT test passes with the launcher correction; the two complete gates still need to run.

kayg commented

2026-10-31 20:01:27 +00:00

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J20 acquired compute01 slot 4. Full run now passes the CLI SIGINT test, confirming the launcher correction. The next existing replay-size fixture failed before product startup: fixture_state('rr257') rejects its default/fallback Unix-socket path at 109 bytes once host PIDs have seven digits.

The helper already supports INFRATERNAL_AGENT_TEST_STATE_ROOT / INFRATERNAL_TEST_STATE_ROOT. Final complete gates use a fresh short /tmp/j20.XXXXXX root through those variables, removed on exit. Repository/product/test code is unchanged. Both full gates will rerun inside the same held build slot, so this will not re-enter the unfair queue. Original attempts are retained; no gate is waived. Final authoritative logs are verify-fast-short-root.log and .exit under each branch's J20 cache.

J20 acquired compute01 slot 4. Full run now passes the CLI SIGINT test, confirming the launcher correction. The next existing replay-size fixture failed before product startup: `fixture_state('rr257')` rejects its default/fallback Unix-socket path at 109 bytes once host PIDs have seven digits. The helper already supports `INFRATERNAL_AGENT_TEST_STATE_ROOT` / `INFRATERNAL_TEST_STATE_ROOT`. Final complete gates use a fresh short `/tmp/j20.XXXXXX` root through those variables, removed on exit. Repository/product/test code is unchanged. Both full gates will rerun inside the same held build slot, so this will not re-enter the unfair queue. Original attempts are retained; no gate is waived. Final authoritative logs are `verify-fast-short-root.log` and `.exit` under each branch's J20 cache.

kayg commented

2026-10-31 20:23:27 +00:00

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J20 measurements and raw evidence are complete; research source is now preserved on the named branch as a WIP commit pending the final fast gate. No product code or verification code changed.

Both static target builds pass at the checked-in size caps. Full Rust gate attempts exposed fixture-environment requirements: the default fallback socket path reaches 109 bytes with seven-digit host PIDs; configuring /tmp fixes that length but is unsuitable for restart fixtures (world-writable ancestor admission refusal and cross-device hard links). The next full run uses a fresh short 0700 directory directly in claude's home, on the same filesystem as the test binary. Failed logs will be attached with the final run. No gate is waived.

The branches' non-research workspace trees are identical. The final gate runs unchanged scripts/verify fast in the h2h canonical worktree with both research slices present; provenance records both source manifests and common workspace hash. This is one shared full workspace gate, not two independent passes. Individual standalone kits already have separate build/perf evidence.

compute01 logs: ~/.cache/codex-scratch/j20/verify-common-home-coordinator.log, verify-fast-common.log, and retained verify-fast-common-tmp-root.log. The retry is queued through build-slot. Remaining: final gate, final kit manifest/binary identity checks, replace WIP history with atomic commits and post final heads/output. No perf/browser background jobs remain.

J20 measurements and raw evidence are complete; research source is now preserved on the named branch as a WIP commit pending the final fast gate. No product code or verification code changed. Both static target builds pass at the checked-in size caps. Full Rust gate attempts exposed fixture-environment requirements: the default fallback socket path reaches 109 bytes with seven-digit host PIDs; configuring `/tmp` fixes that length but is unsuitable for restart fixtures (world-writable ancestor admission refusal and cross-device hard links). The next full run uses a fresh short 0700 directory directly in claude's home, on the same filesystem as the test binary. Failed logs will be attached with the final run. No gate is waived. The branches' non-research workspace trees are identical. The final gate runs unchanged `scripts/verify fast` in the h2h canonical worktree with both research slices present; provenance records both source manifests and common workspace hash. This is one shared full workspace gate, not two independent passes. Individual standalone kits already have separate build/perf evidence. compute01 logs: `~/.cache/codex-scratch/j20/verify-common-home-coordinator.log`, `verify-fast-common.log`, and retained `verify-fast-common-tmp-root.log`. The retry is queued through build-slot. Remaining: final gate, final kit manifest/binary identity checks, replace WIP history with atomic commits and post final heads/output. No perf/browser background jobs remain.

kayg commented

2026-10-31 20:52:31 +00:00

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J20 final-gate retry has waited over 30 minutes for compute01 build-slot (coordinator PID 3109436; ~/.cache/codex-scratch/j20/verify-common-home-coordinator.log). All four slots have active builds from other jobs; no J20 process retains a stale slot. No gate was bypassed.

Research is preserved at WIP heads research-head-to-head 9c29e5b75d and research-reverse-proxy ccdc7e6376. No source changes since that push. Two relevant restart checks executed in the existing workspace test binary under Nix with a private home root: each reports 1 passed; 0 failed. The full gate remains outstanding. Measurements/raw evidence are complete; perf/browser workloads are stopped and cleaned. The finished std02 target cache is removed per the brief.

J20 final-gate retry has waited over 30 minutes for compute01 build-slot (coordinator PID 3109436; `~/.cache/codex-scratch/j20/verify-common-home-coordinator.log`). All four slots have active builds from other jobs; no J20 process retains a stale slot. No gate was bypassed. Research is preserved at WIP heads `research-head-to-head` 9c29e5b75d87e1fa2f9692f6d8329de2b05028f5 and `research-reverse-proxy` ccdc7e6376836a3307cd81c504e30434d38a55fc. No source changes since that push. Two relevant restart checks executed in the existing workspace test binary under Nix with a private home root: each reports `1 passed; 0 failed`. The full gate remains outstanding. Measurements/raw evidence are complete; perf/browser workloads are stopped and cleaned. The finished std02 target cache is removed per the brief.

kayg commented

2026-10-31 21:22:36 +00:00

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J20 final verification is blocked on compute01 capacity: coordinator PID 3109436 has waited over an hour in build-slot. Log remains ~/.cache/codex-scratch/j20/verify-common-home-coordinator.log; no slot has been acquired. The queued command will run automatically if one becomes free. If the orchestrator can reserve the next slot for this final cached gate, that would unblock completion. No other job has been interrupted and no gate has been bypassed.

No source changes since the pushed WIP heads 9c29e5b75 (#260) and ccdc7e637 (#261). Browser triage, x86 kit builds, full perf tables/raw bundles and perf/browser cleanup are complete. Both static targets passed at their caps. Private-home-root focused restart checks each executed one test and passed. Remaining work is the full shared gate, final manifest/binary identity packaging, atomic commit finalization and final head/output comments. This is not a completed-gate claim.

J20 final verification is blocked on compute01 capacity: coordinator PID 3109436 has waited over an hour in build-slot. Log remains `~/.cache/codex-scratch/j20/verify-common-home-coordinator.log`; no slot has been acquired. The queued command will run automatically if one becomes free. If the orchestrator can reserve the next slot for this final cached gate, that would unblock completion. No other job has been interrupted and no gate has been bypassed. No source changes since the pushed WIP heads 9c29e5b75 (#260) and ccdc7e637 (#261). Browser triage, x86 kit builds, full perf tables/raw bundles and perf/browser cleanup are complete. Both static targets passed at their caps. Private-home-root focused restart checks each executed one test and passed. Remaining work is the full shared gate, final manifest/binary identity packaging, atomic commit finalization and final head/output comments. This is not a completed-gate claim.

kayg referenced this issue

2026-10-31 21:22:36 +00:00

Reverse proxy on every client: embeddable engine candidates, measured (D316) #261

kayg commented

2026-10-31 21:48:22 +00:00

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J20 finished and pushed research-head-to-head at ad8eb0c318 (browser reproduction commit c42c3f103; WAN/loss/scale harness and write-up commit ad8eb0c31).

Full results, selected-run provenance and raw bundle: #260 (comment); per-peer memory supplement: #260 (comment). Full namespace cases ran through perf-run --root; failures are preserved. Production Chromium confirmed the embedded output-queue retirement bug in #270; no product fix is included. Native terminal timings use cleartext private WS and exclude TLS/browser rendering, while SSH legs include encryption/authentication; they are not an encrypted production end-to-end ranking. Local native reattach follows the failed flood on the same session.

Final h2h kit SHA-256: 29ef9a04d41262d4167d18029b29ede6ccc2d5577f4409ebe5f958deb0b42ec8.

Final verification ran unchanged scripts/verify fast through compute01 build-slot with jobs/threads limited to four, both research slices present, and a fresh private short home-directory fixture root. The branches have identical workspace tree entries outside research/ (SHA-256 f2adf3aefe5585f305a67e14ecacbe13c99f9f3dd822aa71e57f44ab6bb01418). This is one shared full workspace gate, not two independent passes. The attached bundle records both baseline heads, every research file hash, and proof that both final commits exactly match those tested sources. Individual standalone builds and perf evidence are separate.

Earlier failed attempts and launchers are retained in the bundle: inherited ignored SIGINT, an overlong default socket path, and an unsuitable /tmp fixture root. The final run changed only the supported fixture-root environment; no product/test/gate code was changed or test skipped. Static sizes are exactly 21,431,472 B x86_64 and 19,605,896 B aarch64 (both delta +0).

Verbatim final gate output excerpt (full output and exit file attached):

+---------------------------+--------------+
| Rust gate                 | Result       |
+---------------------------+--------------+
| fmt                       | PASS         |
| VT native fmt             | PASS         |
| CLI plugin compile-out    | PASS         |
| clippy                    | PASS         |
| SSH runtime test helper   | PASS         |
| real-binary fixture paths | PASS         |
| test                      | PASS         |
| SSH inode reuse fixture   | PASS         |
| shim process-per-user     | PASS         |
| cargo-deny                | PASS         |
| static builds             | PASS         |
+---------------------------+--------------+

 39 pass
 0 fail
 50325 expect() calls
Ran 39 tests across 10 files. [7.68s]
J20 common final gate exit=0

Final kits are on compute01 under ~/.cache/codex-scratch/j20/{h2h,rproxy}/final-kits/ and copied to perf VM ~/j20/final-kits/; both destination SHA-256 checks report OK. Their names retain the original baseline heads; SOURCE_DIFF.patch and the attached final-commit provenance identify the final harness sources. All 19 measured executables are byte-identical to the original measured kits; manifests verified. Build caches on compute01/std02 are removed, the temporary source union is removed, and no J20 background build/browser/perf work remains. Perf namespaces/qdiscs and modules were cleaned; original cleanup diffs remain in the measurement evidence.

J20 finished and pushed `research-head-to-head` at **ad8eb0c3183ea36214987980e2c0421a70460825** (browser reproduction commit c42c3f103; WAN/loss/scale harness and write-up commit ad8eb0c31). Full results, selected-run provenance and raw bundle: https://git.kayg.org/kayg/infraternal/issues/260#issuecomment-71257; per-peer memory supplement: https://git.kayg.org/kayg/infraternal/issues/260#issuecomment-71291. Full namespace cases ran through `perf-run --root`; failures are preserved. Production Chromium confirmed the embedded output-queue retirement bug in #270; no product fix is included. Native terminal timings use cleartext private WS and exclude TLS/browser rendering, while SSH legs include encryption/authentication; they are not an encrypted production end-to-end ranking. Local native reattach follows the failed flood on the same session. Final h2h kit SHA-256: `29ef9a04d41262d4167d18029b29ede6ccc2d5577f4409ebe5f958deb0b42ec8`. Final verification ran unchanged `scripts/verify fast` through compute01 build-slot with jobs/threads limited to four, both research slices present, and a fresh private short home-directory fixture root. The branches have identical workspace tree entries outside `research/` (SHA-256 `f2adf3aefe5585f305a67e14ecacbe13c99f9f3dd822aa71e57f44ab6bb01418`). This is **one shared full workspace gate**, not two independent passes. The attached bundle records both baseline heads, every research file hash, and proof that both final commits exactly match those tested sources. Individual standalone builds and perf evidence are separate. Earlier failed attempts and launchers are retained in the bundle: inherited ignored SIGINT, an overlong default socket path, and an unsuitable `/tmp` fixture root. The final run changed only the supported fixture-root environment; no product/test/gate code was changed or test skipped. Static sizes are exactly 21,431,472 B x86_64 and 19,605,896 B aarch64 (both delta +0). Verbatim final gate output excerpt (full output and exit file attached): ```text +---------------------------+--------------+ | Rust gate | Result | +---------------------------+--------------+ | fmt | PASS | | VT native fmt | PASS | | CLI plugin compile-out | PASS | | clippy | PASS | | SSH runtime test helper | PASS | | real-binary fixture paths | PASS | | test | PASS | | SSH inode reuse fixture | PASS | | shim process-per-user | PASS | | cargo-deny | PASS | | static builds | PASS | +---------------------------+--------------+ 39 pass 0 fail 50325 expect() calls Ran 39 tests across 10 files. [7.68s] J20 common final gate exit=0 ``` Final kits are on compute01 under `~/.cache/codex-scratch/j20/{h2h,rproxy}/final-kits/` and copied to perf VM `~/j20/final-kits/`; both destination SHA-256 checks report OK. Their names retain the original baseline heads; `SOURCE_DIFF.patch` and the attached final-commit provenance identify the final harness sources. All 19 measured executables are byte-identical to the original measured kits; manifests verified. Build caches on compute01/std02 are removed, the temporary source union is removed, and no J20 background build/browser/perf work remains. Perf namespaces/qdiscs and modules were cleaned; original cleanup diffs remain in the measurement evidence.

j20-final-gates.zip

256 KiB

kayg referenced this issue

2026-10-31 21:48:39 +00:00

Browser terminal flood retires healthy attachments with 1013 and silently reconnects #270

kayg referenced this issue

2026-11-01 01:59:02 +00:00

Browser terminal flood retires healthy attachments with 1013 and silently reconnects #270

kayg commented

2026-11-01 07:48:51 +00:00

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J50 started. Isolated branch mesh-datapath-perf starts at h2h harness commit ad8eb0c3183ea36214987980e2c0421a70460825. No product code changed yet. Next: reproduce mesh-infraternal on the perf VM with perf-run --root, identify the shipped mesh data path and collect syscall/profile evidence, then prototype up to two isolated changes if the measurements support them.

J50 started. Isolated branch `mesh-datapath-perf` starts at h2h harness commit `ad8eb0c3183ea36214987980e2c0421a70460825`. No product code changed yet. Next: reproduce `mesh-infraternal` on the perf VM with `perf-run --root`, identify the shipped mesh data path and collect syscall/profile evidence, then prototype up to two isolated changes if the measurements support them.

kayg commented

2026-11-01 07:55:29 +00:00

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J50 finding: reproduced mesh-infraternal from the checksum-verified J20 kit via perf-run --root. On infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X; perf.slice CPUs 1–3, 6 GiB), the 163 s run exited 0 with an empty machine diff. LAN was 2.81 / 2.43 Gbit/s at 1 / 8 flows and 1.18 / 1.34 CPU-s/Gbit; first packet was 203 ms; aggregate two-daemon RSS was 20.1 MiB (PSS 13.8 MiB) and daemon CPU stayed at 0 during transfer. The run reports 2.2% CPU steal, so these single-run values need a same-window comparison/repeat. The kit README and mesh_ix.py say this exercises the shipping kernel WireGuard + nftables path; D313 direct-path discovery and relay changes are excluded. Next: profile the loaded stacks and compare syscall/offload behavior.

J50 finding: reproduced `mesh-infraternal` from the checksum-verified J20 kit via `perf-run --root`. On infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X; perf.slice CPUs 1–3, 6 GiB), the 163 s run exited 0 with an empty machine diff. LAN was 2.81 / 2.43 Gbit/s at 1 / 8 flows and 1.18 / 1.34 CPU-s/Gbit; first packet was 203 ms; aggregate two-daemon RSS was 20.1 MiB (PSS 13.8 MiB) and daemon CPU stayed at 0 during transfer. The run reports 2.2% CPU steal, so these single-run values need a same-window comparison/repeat. The kit README and `mesh_ix.py` say this exercises the shipping kernel WireGuard + nftables path; D313 direct-path discovery and relay changes are excluded. Next: profile the loaded stacks and compare syscall/offload behavior.

kayg commented

2026-11-01 08:09:23 +00:00

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J50 instrumentation setup finding: the assigned perf VM has no installed perf command, and perf-run itself completes normally. I did not install system packages. I downloaded Debian's kernel-matched linux-perf 6.12.113-1 and its missing runtime libraries into ~/.cache/codex-scratch/j50/perf-package and perf-tools; the package SHA-256 is recorded in perf-package/SHA256SUMS. The user-local launcher works under the required runner: perf-run --root ... -- perf stat -a -C 1-3 -e cycles,instructions -- sleep 1 exited 0, reported 33,188,367 cycles and 9,374,490 instructions, with 1 steal jiffy in 420 total. Next: collect focused kernel/userspace profiles and offload/syscall evidence for infraternal and Tailscale.

J50 instrumentation setup finding: the assigned perf VM has no installed `perf` command, and `perf-run` itself completes normally. I did not install system packages. I downloaded Debian's kernel-matched `linux-perf 6.12.113-1` and its missing runtime libraries into `~/.cache/codex-scratch/j50/perf-package` and `perf-tools`; the package SHA-256 is recorded in `perf-package/SHA256SUMS`. The user-local launcher works under the required runner: `perf-run --root ... -- perf stat -a -C 1-3 -e cycles,instructions -- sleep 1` exited 0, reported 33,188,367 cycles and 9,374,490 instructions, with 1 steal jiffy in 420 total. Next: collect focused kernel/userspace profiles and offload/syscall evidence for infraternal and Tailscale.

kayg commented

2026-11-01 08:39:29 +00:00

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Owner

J50 finding: the exact mesh-infraternal h2h case uses the Linux kernel WireGuard + nftables data plane. mesh_ix.py starts the shipping infraternal agent binary at both endpoints and applies the production coordinator's config; its local socket pair is only the coordinator control channel. It does not use GotaTun and does not exercise D313 discovery, the seam-C discovery socket, or the relay. The measured path is the kernel data-plane side that seam C preserves.

On the perf VM, the captured infraternal0 state was MTU 1380, numtxqueues=1, numrxqueues=1, qdisc=noqueue; TSO, GSO, GRO, and tx-udp-segmentation were reported on by ethtool. Each endpoint's infraternal process had two threads. The h2h sender uses one thread per TCP flow and write_all blocks of 128 KiB; the watched infraternal daemons used 0 CPU seconds during each 10-second LAN throughput sample. This points the cycle investigation at the kernel/network path and test traffic processes, not per-packet work in the Rust daemon.

The instrumented perf record run produced 2.49 / 2.35 Gbit/s and 1.26 / 1.38 whole-machine CPU-s/Gbit for 1 / 8 flows. These are profiler-run values, not a clean comparison; perf sampling and host contention are present. The kit marked the before/after machine diff non-empty: a separate NetBird process exited during the case, and perf created root .debug/.build-id entries. The case removed its own namespaces. Raw capture: /home/claude/.cache/codex-scratch/j50/profiles/results/infraternal/mesh-infraternal/ (path-state.txt, perf-1-flow.data, perf-8-flow.data, machine-diff.txt); outer receipt: /home/claude/.cache/codex-scratch/j50/profiles/receipts/perf-run-20261101T092750-119825.{before,after}.txt.

Next: compare Tailscale TUN/offload state and perf stacks, then collect syscall counts without using instrumented throughput as a performance result.

J50 finding: the exact `mesh-infraternal` h2h case uses the Linux kernel WireGuard + nftables data plane. `mesh_ix.py` starts the shipping `infraternal agent` binary at both endpoints and applies the production coordinator's config; its local socket pair is only the coordinator control channel. It does not use GotaTun and does not exercise D313 discovery, the seam-C discovery socket, or the relay. The measured path is the kernel data-plane side that seam C preserves. On the perf VM, the captured `infraternal0` state was MTU 1380, `numtxqueues=1`, `numrxqueues=1`, `qdisc=noqueue`; TSO, GSO, GRO, and `tx-udp-segmentation` were reported on by `ethtool`. Each endpoint's `infraternal` process had two threads. The h2h sender uses one thread per TCP flow and `write_all` blocks of 128 KiB; the watched infraternal daemons used 0 CPU seconds during each 10-second LAN throughput sample. This points the cycle investigation at the kernel/network path and test traffic processes, not per-packet work in the Rust daemon. The instrumented `perf record` run produced 2.49 / 2.35 Gbit/s and 1.26 / 1.38 whole-machine CPU-s/Gbit for 1 / 8 flows. These are profiler-run values, not a clean comparison; perf sampling and host contention are present. The kit marked the before/after machine diff non-empty: a separate NetBird process exited during the case, and perf created root `.debug/.build-id` entries. The case removed its own namespaces. Raw capture: `/home/claude/.cache/codex-scratch/j50/profiles/results/infraternal/mesh-infraternal/` (`path-state.txt`, `perf-1-flow.data`, `perf-8-flow.data`, `machine-diff.txt`); outer receipt: `/home/claude/.cache/codex-scratch/j50/profiles/receipts/perf-run-20261101T092750-119825.{before,after}.txt`. Next: compare Tailscale TUN/offload state and perf stacks, then collect syscall counts without using instrumented throughput as a performance result.

kayg commented

2026-11-01 08:54:24 +00:00

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J50 harness correction: the perf VM's final kit archive is h2h-kit-x86_64-78ccce47e744-j20-final.tar.gz (its extracted SOURCE_COMMIT is 78ccce47), not the requested ad8eb0c31. Comparing the kit changes shows that ad8 adds the independent 2% loss phase to the mesh case and updates the runner to cooperate with an outer perf-run lock. The existing J50 path-state and profiles still identify the LAN data path, but their timing is diagnostic evidence from the older archive. Next: build the exact ad8 kit on compute01, copy it to the perf VM, rerun the selected cases through perf-run --root, and collect syscall counts. No product source changed.

J50 harness correction: the perf VM's final kit archive is `h2h-kit-x86_64-78ccce47e744-j20-final.tar.gz` (its extracted `SOURCE_COMMIT` is `78ccce47`), not the requested `ad8eb0c31`. Comparing the kit changes shows that ad8 adds the independent 2% loss phase to the mesh case and updates the runner to cooperate with an outer `perf-run` lock. The existing J50 path-state and profiles still identify the LAN data path, but their timing is diagnostic evidence from the older archive. Next: build the exact ad8 kit on compute01, copy it to the perf VM, rerun the selected cases through `perf-run --root`, and collect syscall counts. No product source changed.

kayg commented

2026-11-01 08:55:31 +00:00

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Correction to my previous comment: SOURCE_COMMIT=78ccce47 is the archive's base commit label. The final J20 kit includes SOURCE_DIFF.patch; I compared SHA-256 for its cases/mesh.sh, run.sh, and lib/report.py against the source at ad8eb0c31, and all three match exactly (including the loss phase and external-lock handling). The extracted j50-h2h kit has the same hashes. No rebuild is needed; the existing J50 reproduction and profiles used the requested harness code.

Correction to my previous comment: `SOURCE_COMMIT=78ccce47` is the archive's base commit label. The final J20 kit includes `SOURCE_DIFF.patch`; I compared SHA-256 for its `cases/mesh.sh`, `run.sh`, and `lib/report.py` against the source at `ad8eb0c31`, and all three match exactly (including the loss phase and external-lock handling). The extracted `j50-h2h` kit has the same hashes. No rebuild is needed; the existing J50 reproduction and profiles used the requested harness code.

kayg commented

2026-11-01 09:18:11 +00:00

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J50 bottleneck analysis

The mesh-infraternal h2h case uses Linux kernel WireGuard plus nftables. mesh_ix.py starts the shipping infraternal agent binary at both endpoints and applies the production coordinator fixture. Its local socket pair is control traffic only. The bulk path does not use GotaTun, D313 discovery, the seam-C discovery socket, or a relay. It measures the direct kernel data path that D313 preserves. The final kit’s mesh.sh, run.sh, and report.py hashes match the J20 head at ad8eb0c31, despite its archive label being based at 78ccce47.

Comparison and confidence

J20’s clean, uninstrumented h2h comparison on the same perf VM is the performance baseline (method and raw bundle):

Path	Throughput, 1 / 8 flows	Whole-machine CPU-s/Gbit, 1 / 8 flows	Aggregate RSS, 1 / 8 flows
infraternal	3.22 / 2.88 Gbit/s	1.02 / 1.12	18.1 MiB
Tailscale	6.15 / 5.87 Gbit/s	0.44 / 0.47	92.3 / 107.1 MiB

To beat those Tailscale results, infraternal needs more than 1.91× / 2.04× throughput and about 57% / 58% less CPU per Gbit. CPU includes the traffic tools. The underlay measured 33/70 Gbit/s, so it was not the ceiling. The current memory lead is large: 18.1 MiB versus at least 92.3 MiB in these cases.

J50’s uninstrumented repeat reached 2.81 / 2.43 Gbit/s with 2.2% CPU steal, so it is not a clean replacement baseline. The perf record run reached 2.49 / 2.35 Gbit/s and 1.26 / 1.38 CPU-s/Gbit, and had a non-empty machine diff (another NetBird process exited and perf created .debug/.build-id entries). I use that run to locate call paths only, not to rank throughput.

Where the sampled work goes

Infraternal’s infraternal0 was MTU 1380, one TX/RX queue, noqueue; TSO, GSO, GRO, and tx-udp-segmentation were reported enabled. The two infraternal daemons had two threads each and used 0 CPU during the 10-second transfer samples. The h2h sender has one thread per TCP flow and writes 128 KiB blocks.
Infraternal perf stacks are in kernel WireGuard TX workers, UDP send/receive, and softirq/NAPI processing. In the one-flow profile, the WireGuard TX worker path accounts for 7.34% of sampled child cycles; net_rx_action is 4.39%. Encryption/decryption workers are about 2.2% / 2.9%; the ChaCha20-Poly1305 symbols themselves are about 1.8% / 1.5%. These call-graph percentages overlap. Crypto is not large enough to explain a 2× gap.
The prominent infraternal recvfrom stack ends at tcp_recvmsg; it is the h2h TCP receiver, not a userspace WireGuard packet receive. The shipping daemon is not processing bulk packets. Kernel WireGuard runs its packet workers outside those two daemon threads.
Tailscale’s captured interface was a TUN with vnet_hdr on, MTU 1280, one queue, fq; GSO/GRO and UDP segmentation features were enabled. Its perf stack shows RoutineSequentialReceiver → processInboundContainer → TUN write, plus handleGRO/tcpGRO, GSOSplit, and AVX2 checksumming. The profile also shows sendmmsg and recvmmsg; these batch socket operations reduce syscall overhead. It still crosses user/kernel boundaries and has copy/checksum work, so this is not a zero-copy path.
Offload flags show capability, not that every packet used it. The TUN profile shows GRO/GSO processing, but our captures do not prove how many packets were batched or whether UDP_SEGMENT ancillary data was used.
Full-case syscall-only traces (not throughput measurements) counted 867,887 calls for infraternal, including 422,368 recvfrom and 89,935 sendto, with no sendmmsg or recvmmsg. Tailscale counted 3,819,002 calls, including 686,908 sendmmsg, 768,060 recvmmsg, and 693,388 writev. These totals include the LAN/WAN/loss phases and harness/control work; they are not normalized per packet, and sendmmsg calls may carry multiple messages.

This matches the public engineering details in Surpassing 10Gb/s with Tailscale, Enhance UDP Throughput for QUIC and HTTP/3 on Linux, and We’re making Tailscale faster. The posts describe Linux UDP batching and TUN GSO/GRO work; the last also reports roughly 5% gains for some buffer-reuse/queue changes. That smaller optimization alone cannot close this measured gap.

Ranked changes and decision boundary

Owner decision — revisit D163 only as a measured Linux dataplane experiment. Decide whether to test a userspace TUN path with batched UDP and vnet-header GSO/GRO against the current kernel path. The observed Tailscale result is the reference opportunity (about 1.9–2.0× throughput), not a promised gain. Require >6.15 / 5.87 Gbit/s and <0.44 / 0.47 CPU-s/Gbit, while keeping aggregate RSS below 92.3 MiB to preserve the memory lead. D313 direct traffic remains in the kernel until the owner approves and evidence supports a different choice. D316 path finding is control-plane work and is not on this bulk path.
Implementation after that decision — batch and reuse buffers in the selected userspace path. Measure sendmmsg/recvmmsg, TUN GSO/GRO, queue bounds, RSS, and CPU/Gbit separately. Tailscale reports around 5% for some buffer/queue changes; J50 did not isolate or measure an infraternal gain. This is implementation work, but it depends on the owner’s engine decision.
If D163 stays kernel — first measure actual offload/batching and worker scaling, then tune one variable at a time. The flags are enabled but not proof of active UDP segmentation. Expected gain is currently unquantified; the profile does not show that the single netdev queue is the limiter. Do not treat a queue-count change as a fix without an A/B.
Low priority — MTU and crypto tuning. Moving MTU 1380 to 1420 could reduce inner packet count by at most about 2.9% if the path allows it; Tailscale is already faster at MTU 1280. ChaCha symbols account for only a few percent of sampled cycles, so crypto work cannot close the gap.

No prototype was made: the only high-upside candidate crosses the D163 Linux engine decision, while the cheap knobs have low or unmeasured upside. Seam B was within roughly 3–10% of kernel in #220; seam A used about 2× CPU/Gbit. This is not a relay-branch change, and J49’s #220 work was left untouched. No target directories were created; none were present in this worktree or the J50 perf scratch paths.

J50 finish: branch mesh-datapath-perf, head ad8eb0c3183ea36214987980e2c0421a70460825; no code changed, gate not applicable.

## J50 bottleneck analysis **The `mesh-infraternal` h2h case uses Linux kernel WireGuard plus nftables.** `mesh_ix.py` starts the shipping infraternal agent binary at both endpoints and applies the production coordinator fixture. Its local socket pair is control traffic only. The bulk path does not use GotaTun, D313 discovery, the seam-C discovery socket, or a relay. It measures the direct kernel data path that D313 preserves. The final kit’s `mesh.sh`, `run.sh`, and `report.py` hashes match the J20 head at `ad8eb0c31`, despite its archive label being based at `78ccce47`. ### Comparison and confidence J20’s clean, uninstrumented h2h comparison on the same perf VM is the performance baseline ([method and raw bundle](https://git.kayg.org/kayg/infraternal/issues/260#issuecomment-71257)): | Path | Throughput, 1 / 8 flows | Whole-machine CPU-s/Gbit, 1 / 8 flows | Aggregate RSS, 1 / 8 flows | |---|---:|---:|---:| | infraternal | 3.22 / 2.88 Gbit/s | 1.02 / 1.12 | 18.1 MiB | | Tailscale | 6.15 / 5.87 Gbit/s | 0.44 / 0.47 | 92.3 / 107.1 MiB | To beat those Tailscale results, infraternal needs more than 1.91× / 2.04× throughput and about 57% / 58% less CPU per Gbit. CPU includes the traffic tools. The underlay measured 33/70 Gbit/s, so it was not the ceiling. The current memory lead is large: 18.1 MiB versus at least 92.3 MiB in these cases. J50’s uninstrumented repeat reached 2.81 / 2.43 Gbit/s with 2.2% CPU steal, so it is not a clean replacement baseline. The `perf record` run reached 2.49 / 2.35 Gbit/s and 1.26 / 1.38 CPU-s/Gbit, and had a non-empty machine diff (another NetBird process exited and perf created `.debug/.build-id` entries). I use that run to locate call paths only, not to rank throughput. ### Where the sampled work goes - Infraternal’s `infraternal0` was MTU 1380, one TX/RX queue, `noqueue`; TSO, GSO, GRO, and `tx-udp-segmentation` were reported enabled. The two infraternal daemons had two threads each and used 0 CPU during the 10-second transfer samples. The h2h sender has one thread per TCP flow and writes 128 KiB blocks. - Infraternal perf stacks are in kernel WireGuard TX workers, UDP send/receive, and softirq/NAPI processing. In the one-flow profile, the WireGuard TX worker path accounts for 7.34% of sampled child cycles; `net_rx_action` is 4.39%. Encryption/decryption workers are about 2.2% / 2.9%; the ChaCha20-Poly1305 symbols themselves are about 1.8% / 1.5%. These call-graph percentages overlap. Crypto is not large enough to explain a 2× gap. - The prominent infraternal `recvfrom` stack ends at `tcp_recvmsg`; it is the h2h TCP receiver, not a userspace WireGuard packet receive. The shipping daemon is not processing bulk packets. Kernel WireGuard runs its packet workers outside those two daemon threads. - Tailscale’s captured interface was a TUN with `vnet_hdr on`, MTU 1280, one queue, `fq`; GSO/GRO and UDP segmentation features were enabled. Its perf stack shows `RoutineSequentialReceiver → processInboundContainer → TUN write`, plus `handleGRO`/`tcpGRO`, `GSOSplit`, and AVX2 checksumming. The profile also shows `sendmmsg` and `recvmmsg`; these batch socket operations reduce syscall overhead. It still crosses user/kernel boundaries and has copy/checksum work, so this is not a zero-copy path. - Offload flags show capability, not that every packet used it. The TUN profile shows GRO/GSO processing, but our captures do not prove how many packets were batched or whether `UDP_SEGMENT` ancillary data was used. - Full-case syscall-only traces (not throughput measurements) counted 867,887 calls for infraternal, including 422,368 `recvfrom` and 89,935 `sendto`, with no `sendmmsg` or `recvmmsg`. Tailscale counted 3,819,002 calls, including 686,908 `sendmmsg`, 768,060 `recvmmsg`, and 693,388 `writev`. These totals include the LAN/WAN/loss phases and harness/control work; they are not normalized per packet, and `sendmmsg` calls may carry multiple messages. This matches the public engineering details in [Surpassing 10Gb/s with Tailscale](https://tailscale.com/blog/more-throughput), [Enhance UDP Throughput for QUIC and HTTP/3 on Linux](https://tailscale.com/blog/quic-udp-throughput), and [We’re making Tailscale faster](https://tailscale.com/blog/making-tailscale-faster). The posts describe Linux UDP batching and TUN GSO/GRO work; the last also reports roughly 5% gains for some buffer-reuse/queue changes. That smaller optimization alone cannot close this measured gap. ### Ranked changes and decision boundary 1. **Owner decision — revisit D163 only as a measured Linux dataplane experiment.** Decide whether to test a userspace TUN path with batched UDP and vnet-header GSO/GRO against the current kernel path. The observed Tailscale result is the reference opportunity (about 1.9–2.0× throughput), not a promised gain. Require >6.15 / 5.87 Gbit/s and <0.44 / 0.47 CPU-s/Gbit, while keeping aggregate RSS below 92.3 MiB to preserve the memory lead. D313 direct traffic remains in the kernel until the owner approves and evidence supports a different choice. D316 path finding is control-plane work and is not on this bulk path. 2. **Implementation after that decision — batch and reuse buffers in the selected userspace path.** Measure `sendmmsg`/`recvmmsg`, TUN GSO/GRO, queue bounds, RSS, and CPU/Gbit separately. Tailscale reports around 5% for some buffer/queue changes; J50 did not isolate or measure an infraternal gain. This is implementation work, but it depends on the owner’s engine decision. 3. **If D163 stays kernel — first measure actual offload/batching and worker scaling, then tune one variable at a time.** The flags are enabled but not proof of active UDP segmentation. Expected gain is currently unquantified; the profile does not show that the single netdev queue is the limiter. Do not treat a queue-count change as a fix without an A/B. 4. **Low priority — MTU and crypto tuning.** Moving MTU 1380 to 1420 could reduce inner packet count by at most about 2.9% if the path allows it; Tailscale is already faster at MTU 1280. ChaCha symbols account for only a few percent of sampled cycles, so crypto work cannot close the gap. No prototype was made: the only high-upside candidate crosses the D163 Linux engine decision, while the cheap knobs have low or unmeasured upside. Seam B was within roughly 3–10% of kernel in #220; seam A used about 2× CPU/Gbit. This is not a relay-branch change, and J49’s #220 work was left untouched. No target directories were created; none were present in this worktree or the J50 perf scratch paths. **J50 finish:** branch `mesh-datapath-perf`, head `ad8eb0c3183ea36214987980e2c0421a70460825`; no code changed, gate not applicable.

j50-bottleneck-evidence-2026-11-01.tar.gz

161 KiB

kayg commented

2026-11-01 09:18:36 +00:00

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Owner

J50 finished on branch mesh-datapath-perf, head SHA ad8eb0c3183ea36214987980e2c0421a70460825.

Analysis and ranked recommendations: J50 bottleneck analysis. Evidence bundle is attached there.

no code changed, gate not applicable

No target directories were created or found in the J50 worktree or perf scratch paths. No product code or relay branch was changed; no prototype was made because the high-upside option requires the D163 owner decision.

J50 finished on branch `mesh-datapath-perf`, head SHA `ad8eb0c3183ea36214987980e2c0421a70460825`. Analysis and ranked recommendations: [J50 bottleneck analysis](https://git.kayg.org/kayg/infraternal/issues/260#issuecomment-72607). Evidence bundle is attached there. no code changed, gate not applicable No target directories were created or found in the J50 worktree or perf scratch paths. No product code or relay branch was changed; no prototype was made because the high-upside option requires the D163 owner decision.

kayg commented

2026-11-01 09:34:20 +00:00

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Start: R4 userspace WireGuard measurement. Branch , based on origin/dev , carrying the h2h harness from J50 head . Measure-only: D163 remains the owner decision; no product dataplane changes. I will build on compute01 through build-slot, run all perf cases only on infraternal-perf-01-backup01 through perf-run --root, compare kernel/Tailscale in the same session, then record evidence and cleanup here.

kayg commented

2026-11-01 09:34:36 +00:00

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Correction to my start note: branch research-userspace-wg is based on origin/dev SHA 65a48d3835. It carries the h2h harness from J50 head ad8eb0c318.

Correction to my start note: branch research-userspace-wg is based on origin/dev SHA 65a48d3835e85f4f976178e1e490c9b4fba46b27. It carries the h2h harness from J50 head ad8eb0c3183ea36214987980e2c0421a70460825.

kayg commented

2026-11-01 09:49:00 +00:00

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Finding: GotaTun v0.10.2 already batches Linux UDP with sendmmsg/recvmmsg and enables UDP GRO. The release does not implement UDP send GSO or TUN IFF_VNET_HDR/TUNSETOFFLOAD. Upstream GSO PR #170 is outside v0.10.2 and conflicts with its current socket code; TUN TSO PR #10 is an older draft. I will measure the release as-is and estimate the offload port separately. D163 remains unchanged. Evidence: github.com/mullvad/gotatun@1d46b779f5 and https://github.com/mullvad/gotatun/pull/170, https://github.com/mullvad/gotatun/pull/10.

Finding: GotaTun v0.10.2 already batches Linux UDP with sendmmsg/recvmmsg and enables UDP GRO. The release does not implement UDP send GSO or TUN IFF_VNET_HDR/TUNSETOFFLOAD. Upstream GSO PR #170 is outside v0.10.2 and conflicts with its current socket code; TUN TSO PR #10 is an older draft. I will measure the release as-is and estimate the offload port separately. D163 remains unchanged. Evidence: https://github.com/mullvad/gotatun/tree/1d46b779f5e0743f30a13cc2c325b8114b901fb9 and https://github.com/mullvad/gotatun/pull/170, https://github.com/mullvad/gotatun/pull/10.

kayg commented

2026-11-01 09:56:07 +00:00

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Architecture finding: the userspace benchmark is an isolated dataplane candidate. D313 keeps direct peers on the kernel WireGuard socket; seam C uses that same port for probes. J49 relays ciphertext by pointing a peer endpoint at a loopback shim, then reinjects received ciphertext through that socket. GotaTun v0.10.2 can be measured as a standalone tunnel, but adopting it on Linux needs a new direct-path socket seam and a relay adapter. This is a compatibility cost, not a measured runtime result. Evidence: https://git.kayg.org/kayg/infraternal/src/branch/research-userspace-wg/DECISIONS.md and https://git.kayg.org/kayg/infraternal/src/branch/mesh-relay-220/contracts/mesh-relay.md.

kayg commented

2026-11-01 09:57:05 +00:00

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R4 progress: added GotaTun v0.10.2 to the h2h kit with a pinned source archive, UAPI setup helper and 64-byte latency probes during 1/8-flow transfers. The harness records LAN, 198 ms RTT and 2%-per-direction loss alongside fresh kernel and Tailscale cases in one perf-all invocation. Commit 9c0a9cb50 is pushed to research-userspace-wg. Next: build via build-slot on compute01, then run the selected mesh cases via perf-run --root on the perf VM. Build log/target: /home/claude/.cache/codex-scratch/r4-userspace-wg/{build.log,target}.

R4 progress: added GotaTun v0.10.2 to the h2h kit with a pinned source archive, UAPI setup helper and 64-byte latency probes during 1/8-flow transfers. The harness records LAN, 198 ms RTT and 2%-per-direction loss alongside fresh kernel and Tailscale cases in one perf-all invocation. Commit 9c0a9cb50 is pushed to research-userspace-wg. Next: build via build-slot on compute01, then run the selected mesh cases via perf-run --root on the perf VM. Build log/target: /home/claude/.cache/codex-scratch/r4-userspace-wg/{build.log,target}.

kayg commented

2026-11-01 09:59:19 +00:00

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Finding: GotaTun v0.10.2 has the same Linux sendmmsg/recvmmsg and UDP GRO foundation as the requested batching path, but not UDP send GSO or TUN virtual-header offload. Upstream PR #170 remains open, adds a large Linux-only UDP_SEGMENT path with fallback, and explicitly excludes TUN work; its discussion questions whether socket GSO helps while TUN I/O remains the bottleneck. PR #10 for TUN TSO is still a draft. Existing BoringTun rows in research/mesh-engines used a different five-run harness under load averages around 29–35, so I will not present them as same-run h2h results. Source evidence: https://github.com/mullvad/gotatun/pull/170, https://github.com/mullvad/gotatun/pull/10, https://tailscale.com/blog/throughput-improvements, https://tailscale.com/blog/more-throughput. The compute01 build is waiting at build-slot position 10; log/target remain /home/claude/.cache/codex-scratch/r4-userspace-wg/{build.log,target}.

kayg commented

2026-11-01 10:12:17 +00:00

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R4 progress: research-userspace-wg is at 33897fe15, based on origin/dev 65a48d3835e85f4f976178e1e490c9b4fba46b27.

Finding: BoringTun CLI v0.5.2 exposes the standard Linux foreground interface and UAPI configuration path, so it fits the same isolated h2h fixture without a second harness. The pinned CLI defaults to four workers and TUN multi-queue; that difference is recorded in the case metadata for interpretation. Source/docs: https://github.com/cloudflare/boringtun/tree/boringtun-cli-0.5.2 .

The updated kit build is queued through compute01 build-slot as PID 1901677; its log is /home/claude/.cache/codex-scratch/r4-userspace-wg/build.log. Next: finish the build, then run one perf-all.sh invocation for underlay, kernel infraternal, Tailscale, GotaTun, and BoringTun through perf-run --root on the perf VM. No product code or decision changed.

R4 progress: `research-userspace-wg` is at `33897fe15`, based on `origin/dev` `65a48d3835e85f4f976178e1e490c9b4fba46b27`. Finding: BoringTun CLI v0.5.2 exposes the standard Linux foreground interface and UAPI configuration path, so it fits the same isolated h2h fixture without a second harness. The pinned CLI defaults to four workers and TUN multi-queue; that difference is recorded in the case metadata for interpretation. Source/docs: https://github.com/cloudflare/boringtun/tree/boringtun-cli-0.5.2 . The updated kit build is queued through compute01 `build-slot` as PID `1901677`; its log is `/home/claude/.cache/codex-scratch/r4-userspace-wg/build.log`. Next: finish the build, then run one `perf-all.sh` invocation for underlay, kernel infraternal, Tailscale, GotaTun, and BoringTun through `perf-run --root` on the perf VM. No product code or decision changed.

kayg commented

2026-11-01 10:16:27 +00:00

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R4 progress: research-userspace-wg is now at d2f12f07c, based on origin/dev 65a48d3835e85f4f976178e1e490c9b4fba46b27.

Harness finding: the report generator had an explicit mesh-engine list, so the new BoringTun case would have run but been omitted from summary.md. Added it to the report list; the run output now includes BoringTun alongside kernel WG, Tailscale, and GotaTun.

Option 2 scope estimate: pinned GotaTun already uses Linux sendmmsg/recvmmsg and UDP GRO; v0.10.2 lacks UDP send GSO and TUN virtual-header offloads. Upstream's Linux UDP GSO PR #170 is open and adds 757 lines across two files, with eligibility checks and fallback; its author reports large local-VM gains but explicitly limits them to that setup: https://github.com/mullvad/gotatun/pull/170 . The TUN TSO PR #10 remains a draft, adds 814 lines across five files, and currently shows CI failures: https://github.com/mullvad/gotatun/pull/10 . My estimate is 1–3 engineering days for a GSO-only prototype and same-harness measurement, then roughly 1–2 weeks to combine UDP GSO with Linux vnet-header TSO/GRO, safe fallbacks, and correctness coverage. This is scope estimation, not a performance result; no engine fork is included in this measurement-only branch.

The approved build is still waiting in compute01 build-slot as PID 1901677; log remains /home/claude/.cache/codex-scratch/r4-userspace-wg/build.log.

R4 progress: `research-userspace-wg` is now at `d2f12f07c`, based on `origin/dev` `65a48d3835e85f4f976178e1e490c9b4fba46b27`. Harness finding: the report generator had an explicit mesh-engine list, so the new BoringTun case would have run but been omitted from `summary.md`. Added it to the report list; the run output now includes BoringTun alongside kernel WG, Tailscale, and GotaTun. Option 2 scope estimate: pinned GotaTun already uses Linux `sendmmsg`/`recvmmsg` and UDP GRO; v0.10.2 lacks UDP send GSO and TUN virtual-header offloads. Upstream's Linux UDP GSO PR #170 is open and adds 757 lines across two files, with eligibility checks and fallback; its author reports large local-VM gains but explicitly limits them to that setup: https://github.com/mullvad/gotatun/pull/170 . The TUN TSO PR #10 remains a draft, adds 814 lines across five files, and currently shows CI failures: https://github.com/mullvad/gotatun/pull/10 . My estimate is 1–3 engineering days for a GSO-only prototype and same-harness measurement, then roughly 1–2 weeks to combine UDP GSO with Linux vnet-header TSO/GRO, safe fallbacks, and correctness coverage. This is scope estimation, not a performance result; no engine fork is included in this measurement-only branch. The approved build is still waiting in compute01 `build-slot` as PID `1901677`; log remains `/home/claude/.cache/codex-scratch/r4-userspace-wg/build.log`.

kayg commented

2026-11-01 10:57:09 +00:00

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Crash-safety note for the queued build: its only retained Rust target is /home/claude/.cache/codex-scratch/r4-userspace-wg/target. The build remains queued as PID 1901677; the log is /home/claude/.cache/codex-scratch/r4-userspace-wg/build.log. I will remove the target after the kit and raw evidence are copied off the VMs.

Crash-safety note for the queued build: its only retained Rust target is `/home/claude/.cache/codex-scratch/r4-userspace-wg/target`. The build remains queued as PID `1901677`; the log is `/home/claude/.cache/codex-scratch/r4-userspace-wg/build.log`. I will remove the target after the kit and raw evidence are copied off the VMs.

kayg commented

2026-11-01 10:58:00 +00:00

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R4 queue update on research-userspace-wg @ d2f12f07c: the x86_64 kit build has been waiting in compute01 build-slot for about an hour. Its log still reports all four slots busy; PID 1901677 remains queued. No benchmark has started. Log: /home/claude/.cache/codex-scratch/r4-userspace-wg/build.log; the only build target is /home/claude/.cache/codex-scratch/r4-userspace-wg/target. Next: finish this build, run the selected cases in one perf VM session, and report the results. No product changes; gate not applicable.

R4 queue update on `research-userspace-wg` @ `d2f12f07c`: the x86_64 kit build has been waiting in compute01 `build-slot` for about an hour. Its log still reports all four slots busy; PID `1901677` remains queued. No benchmark has started. Log: `/home/claude/.cache/codex-scratch/r4-userspace-wg/build.log`; the only build target is `/home/claude/.cache/codex-scratch/r4-userspace-wg/target`. Next: finish this build, run the selected cases in one perf VM session, and report the results. No product changes; gate not applicable.

kayg commented

2026-11-01 11:02:47 +00:00

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R4 measurement start: branch , based on ; harness head . The x86_64 head-to-head kit build is running on compute01 (build-slot PID 1901677, admitted to slot 3/4 at 12:00:12 local). Log: ; sole target: . Once the archive is complete, I will copy and checksum-verify it on the perf VM, then run kernel WG, Tailscale and selected userspace cases in one invocation, with each case using .

kayg commented

2026-11-01 11:03:10 +00:00

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Correction to the start update: branch research-userspace-wg, based on 65a48d3835, harness head d2f12f07c. The x86_64 head-to-head kit build is running on compute01 (build-slot PID 1901677, admitted to slot 3/4 at 12:00:12 local). Log: /home/claude/.cache/codex-scratch/r4-userspace-wg/build.log; sole target: /home/claude/.cache/codex-scratch/r4-userspace-wg/target. After the archive is complete I will checksum-verify it on the perf VM and run kernel WG, Tailscale and selected userspace cases in one perf-all.sh invocation, with every case using perf-run --root.

Correction to the start update: branch research-userspace-wg, based on 65a48d3835e85f4f976178e1e490c9b4fba46b27, harness head d2f12f07c. The x86_64 head-to-head kit build is running on compute01 (build-slot PID 1901677, admitted to slot 3/4 at 12:00:12 local). Log: /home/claude/.cache/codex-scratch/r4-userspace-wg/build.log; sole target: /home/claude/.cache/codex-scratch/r4-userspace-wg/target. After the archive is complete I will checksum-verify it on the perf VM and run kernel WG, Tailscale and selected userspace cases in one perf-all.sh invocation, with every case using perf-run --root.

kayg commented

2026-11-01 11:10:42 +00:00

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R4 progress: compute01 is still compiling the head-to-head kit at d2f12f07c. The Rust workspace build is active (target currently 2.2 GiB); GotaTun/BoringTun packaging has not started yet. The perf VM is idle for this run and has 84 GiB free. No benchmark case has run; I will start the single perf-all invocation after archive checksum and manifest verification.

R4 progress: compute01 is still compiling the head-to-head kit at d2f12f07c. The Rust workspace build is active (target currently 2.2 GiB); GotaTun/BoringTun packaging has not started yet. The perf VM is idle for this run and has 84 GiB free. No benchmark case has run; I will start the single perf-all invocation after archive checksum and manifest verification.

kayg commented

2026-11-01 11:13:22 +00:00

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Research finding: the kit pins GotaTun commit 1d46b779f5e0743f30a13cc2c325b8114b901fb9, release 0.10.2 (2026-10-20). At that exact revision LICENSE is MPL-2.0 and includes the “Incompatible With Secondary Licenses” notice. This run uses the standalone CLI as an independent process; direct product library integration with our AGPL-3.0-only code needs an explicit license-boundary review. D169’s macOS selection does not by itself resolve that question for Linux. Evidence: github.com/mullvad/gotatun@1d46b779f5 and github.com/mullvad/gotatun@1d46b779f5/LICENSE.

Research finding: the kit pins GotaTun commit 1d46b779f5e0743f30a13cc2c325b8114b901fb9, release 0.10.2 (2026-10-20). At that exact revision LICENSE is MPL-2.0 and includes the “Incompatible With Secondary Licenses” notice. This run uses the standalone CLI as an independent process; direct product library integration with our AGPL-3.0-only code needs an explicit license-boundary review. D169’s macOS selection does not by itself resolve that question for Linux. Evidence: https://github.com/mullvad/gotatun/commit/1d46b779f5e0743f30a13cc2c325b8114b901fb9 and https://github.com/mullvad/gotatun/blob/1d46b779f5e0743f30a13cc2c325b8114b901fb9/LICENSE.

kayg commented

2026-11-01 11:19:35 +00:00

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Build finding and fix: the first attempt stopped at build-kit line 63 with go: command not found. The README requires Go and Bison in the Nix dev shell, but the flake omitted both; build-slot only executes the supplied command. Commit 4f84c8005 adds Go and Bison from the locked nixpkgs input to the research branch shell. On compute01, nix develop now resolves Go 1.26.10 and Bison 3.8.2. I am resuming the cached kit build through that shell and build-slot; no perf case has run yet.

Build finding and fix: the first attempt stopped at build-kit line 63 with `go: command not found`. The README requires Go and Bison in the Nix dev shell, but the flake omitted both; build-slot only executes the supplied command. Commit 4f84c8005 adds Go and Bison from the locked nixpkgs input to the research branch shell. On compute01, `nix develop` now resolves Go 1.26.10 and Bison 3.8.2. I am resuming the cached kit build through that shell and build-slot; no perf case has run yet.

kayg commented

2026-11-01 11:20:14 +00:00

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Build update: the corrected Nix-shell check passed on compute01 (Go 1.26.10, Bison 3.8.2). The cached kit rebuild is waiting in build-slot at queue position 16 with all four slots busy; the fair queue is intact. No perf case has run yet.

kayg commented

2026-11-01 11:23:06 +00:00

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Correction to my license finding: I mistook the standard Exhibit B text included in the MPL-2.0 license document for a repository-specific incompatibility notice. That text alone does not show that GotaTun is marked incompatible with secondary licenses, and I withdraw that claim. D169 already records GotaTun as MPL-2.0 and chooses a project-owned macOS adapter. The measurement uses its independent CLI, so it does not establish adapter or Linux product-integration fit; no new license blocker is concluded here.

kayg commented

2026-11-01 11:36:32 +00:00

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Build-slot wait finding: the queue has grown from 17 to 19 ticket files while Rust/Zig build processes occupy the four slots. Compute01 still has 79 GiB free, above the 25 GiB threshold, so storage is not the current cause. The one R4 build request remains queued; no perf case has run.

kayg commented

2026-11-01 12:00:35 +00:00

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Build-slot remains the blocker: queue count is now 21 ticket files, four CPU-heavy build processes are active, and compute01 has 68 GiB free. The single R4 rebuild is still queued through the required path; no perf case has run and I am not building or measuring on another host.

kayg commented

2026-11-01 12:11:33 +00:00

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Compute contention update: build-slot queue count is 35 and free disk is 34 GiB, 9 GiB above its 25 GiB minimum. The R4 rebuild remains queued, and I am keeping it on the documented fair build-slot path. No perf measurements have started.

kayg commented

2026-11-01 12:16:32 +00:00

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Compute contention update: the shared build-slot queue has grown to 42 ticket files; compute01 currently has 51 GiB free, above the 25 GiB minimum. The R4 request remains queued through build-slot and no perf measurement has started.

kayg commented

2026-11-01 18:30:52 +00:00

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R4b start: research only, no product decision (D163 remains an owner choice), no repo code changes. Reusing R4/J20 kit and the same perf VM pair/session; builds, if needed, go through build-slot on a dev VM, and all measurements go through perf-run on the perf VM. Plan: (1) recover pinned R4 binaries and harness and verify test comparability; (2) check current upstream UDP/TUN batching support for GotaTun 0.10.2, BoringTun 0.5.2, and wireguard-go; (3) run current kernel WireGuard, both Rust candidates, wireguard-go, and tailscaled if it fits, for single/multi-stream throughput, loaded p50/p99 latency, CPU/Gbit, and RSS at 1/1,000 peers; (4) attach the table and raw logs and ask the owner which trade-offs to choose. Estimate: 2.5 hours, assuming the recovered binaries and harness run on the pinned perf VM. No new harness or infrastructure is in scope.

kayg commented

2026-11-01 18:37:31 +00:00

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R4b recovery finding: the completed x86_64 kit is on compute01 at /home/claude/.cache/codex-scratch/r4-userspace-wg/out/h2h-kit-x86_64-4f84c800570b.tar.gz. Its SHA-256 verifies as 060bb8edd6284b14698a5918e0fe75ca18f507643e327a408b0063e7c5088763 (source head 4f84c80057); it contains GotaTun 0.10.2, BoringTun CLI 0.5.2, tailscaled 1.104.4, and the existing 1/8-flow latency/throughput harness. The perf VM is Debian 13 x86_64, kernel 6.12.113, idle at preflight. Finding: the kit has neither a wireguard-go binary nor a 1,000-peer scale fixture; the perf image has no wg utility. I will build the pinned wireguard-go reference and minimal WG CLI via build-slot, extend only the disposable research kit, and keep all measured cases under perf-run. Upstream status check: GotaTun PR #170 (Linux UDP GSO) remains open; PR #10 (TUN TSO) remains open/draft. Evidence: https://github.com/mullvad/gotatun/pull/170 and https://github.com/mullvad/gotatun/pull/10.

R4b recovery finding: the completed x86_64 kit is on compute01 at /home/claude/.cache/codex-scratch/r4-userspace-wg/out/h2h-kit-x86_64-4f84c800570b.tar.gz. Its SHA-256 verifies as 060bb8edd6284b14698a5918e0fe75ca18f507643e327a408b0063e7c5088763 (source head 4f84c800570b); it contains GotaTun 0.10.2, BoringTun CLI 0.5.2, tailscaled 1.104.4, and the existing 1/8-flow latency/throughput harness. The perf VM is Debian 13 x86_64, kernel 6.12.113, idle at preflight. Finding: the kit has neither a wireguard-go binary nor a 1,000-peer scale fixture; the perf image has no wg utility. I will build the pinned wireguard-go reference and minimal WG CLI via build-slot, extend only the disposable research kit, and keep all measured cases under perf-run. Upstream status check: GotaTun PR #170 (Linux UDP GSO) remains open; PR #10 (TUN TSO) remains open/draft. Evidence: https://github.com/mullvad/gotatun/pull/170 and https://github.com/mullvad/gotatun/pull/10.

kayg commented

2026-11-01 18:51:22 +00:00

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R4b upstream offload finding (source checked 2026-11-01; no performance result implied)

implementation	UDP batching / offload in pinned source	TUN offload in pinned source	patch estimate
GotaTun 0.10.2 (`1d46b779f5e0743f30a13cc2c325b8114b901fb9`)	Linux `sendmmsg`/`recvmmsg` and UDP GRO are present; no UDP send GSO (`UDP_SEGMENT`).	No `IFF_VNET_HDR` / `TUNSETOFFLOAD` path.	GSO-only prototype: roughly 1–3 engineering days; adding TUN vnet-header TSO/GRO with safe fallbacks and correctness coverage: roughly 1–2 weeks.
BoringTun CLI 0.5.2 (`boringtun-cli-0.5.2`)	Socket code uses per-packet `sendto`/`recvfrom` and `send`/`recv`; no mmsg or UDP GSO/GRO. Its default multi-queue mode is concurrency, not batched I/O.	TUN uses `IFF_TUN	IFF_NO_PI
wireguard-go (`b3bc704ef0ee21a36298601a9e1e5ff90377ac52`)	Linux batch I/O plus UDP GRO/GSO (`UDP_GRO` / `UDP_SEGMENT`) are present.	`IFF_VNET_HDR` and `TUNSETOFFLOAD` are present; optional UDP TUN GSO is enabled when the kernel supports it (Linux 6.2+).	Already implemented in this reference.

Evidence: GotaTun Linux UDP source, GotaTun UDP GSO PR #170 (open, 757 additions / 27 deletions across 2 files), GotaTun TUN TSO PR #10 (open draft, 814 additions / 6 deletions across 5 files), BoringTun UDP source, BoringTun Linux TUN source, wireguard-go Linux GSO source, wireguard-go Linux TUN source.

Next: measure the pinned candidates as-is against the same kernel WireGuard and Tailscale cases. D163 remains kayg's choice.

R4b upstream offload finding (source checked 2026-11-01; no performance result implied) | implementation | UDP batching / offload in pinned source | TUN offload in pinned source | patch estimate | |---|---|---|---| | GotaTun 0.10.2 (`1d46b779f5e0743f30a13cc2c325b8114b901fb9`) | Linux `sendmmsg`/`recvmmsg` and UDP GRO are present; no UDP send GSO (`UDP_SEGMENT`). | No `IFF_VNET_HDR` / `TUNSETOFFLOAD` path. | GSO-only prototype: roughly 1–3 engineering days; adding TUN vnet-header TSO/GRO with safe fallbacks and correctness coverage: roughly 1–2 weeks. | | BoringTun CLI 0.5.2 (`boringtun-cli-0.5.2`) | Socket code uses per-packet `sendto`/`recvfrom` and `send`/`recv`; no mmsg or UDP GSO/GRO. Its default multi-queue mode is concurrency, not batched I/O. | TUN uses `IFF_TUN | IFF_NO_PI | IFF_MULTI_QUEUE`, with per-packet read/write; no `IFF_VNET_HDR` or `TUNSETOFFLOAD`. | Roughly 2–3 engineering weeks for Linux UDP batching/GSO/GRO plus TUN vnet-header support, fallback paths, and correctness tests; estimate only. | | wireguard-go (`b3bc704ef0ee21a36298601a9e1e5ff90377ac52`) | Linux batch I/O plus UDP GRO/GSO (`UDP_GRO` / `UDP_SEGMENT`) are present. | `IFF_VNET_HDR` and `TUNSETOFFLOAD` are present; optional UDP TUN GSO is enabled when the kernel supports it (Linux 6.2+). | Already implemented in this reference. | Evidence: [GotaTun Linux UDP source](https://github.com/mullvad/gotatun/blob/1d46b779f5e0743f30a13cc2c325b8114b901fb9/gotatun/src/udp/socket/linux.rs), [GotaTun UDP GSO PR #170](https://github.com/mullvad/gotatun/pull/170) (open, 757 additions / 27 deletions across 2 files), [GotaTun TUN TSO PR #10](https://github.com/mullvad/gotatun/pull/10) (open draft, 814 additions / 6 deletions across 5 files), [BoringTun UDP source](https://github.com/cloudflare/boringtun/blob/boringtun-cli-0.5.2/boringtun/src/device/udp_unix.rs), [BoringTun Linux TUN source](https://github.com/cloudflare/boringtun/blob/boringtun-cli-0.5.2/boringtun/src/device/tun_linux.rs), [wireguard-go Linux GSO source](https://github.com/WireGuard/wireguard-go/blob/b3bc704ef0ee21a36298601a9e1e5ff90377ac52/conn/gso_linux.go), [wireguard-go Linux TUN source](https://github.com/WireGuard/wireguard-go/blob/b3bc704ef0ee21a36298601a9e1e5ff90377ac52/tun/tun_linux.go). Next: measure the pinned candidates as-is against the same kernel WireGuard and Tailscale cases. D163 remains kayg's choice.

kayg commented

2026-11-01 18:55:41 +00:00

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R4b build preflight finding: the first queued reference command would fail because compute01's plain PATH has no go. I cancelled that queued PID before admission, retained its queue-only log as build-reference.plain-path.log, and relaunched the same pinned build through build-slot with the R4 worktree's locked Nix dev shell (which provides Go and make). Corrected build is queued as PID 3554641 at position 3; no build slot or perf run has started for it yet.

R4b build preflight finding: the first queued reference command would fail because compute01's plain PATH has no `go`. I cancelled that queued PID before admission, retained its queue-only log as `build-reference.plain-path.log`, and relaunched the same pinned build through `build-slot` with the R4 worktree's locked Nix dev shell (which provides Go and make). Corrected build is queued as PID 3554641 at position 3; no build slot or perf run has started for it yet.

kayg commented

2026-11-01 18:59:27 +00:00

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R4b build-toolchain correction: I also cancelled the first Nix-wrapped queue entry before admission because its nested bash -lc could reset the dev-shell PATH. The current request calls the build script directly inside the pinned R4 shell, which declares Go and Bison; build-slot PID 3627155 is queued at position 4. The two cancelled attempts never acquired a build slot and produced no measurement or binary.

R4b build-toolchain correction: I also cancelled the first Nix-wrapped queue entry before admission because its nested `bash -lc` could reset the dev-shell PATH. The current request calls the build script directly inside the pinned R4 shell, which declares Go and Bison; `build-slot` PID 3627155 is queued at position 4. The two cancelled attempts never acquired a build slot and produced no measurement or binary.

kayg commented

2026-11-01 19:03:39 +00:00

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R4b queue update: dev02's queue expanded between its status check and dispatch, so I cancelled the dev02 request before admission and removed the temporary worktree. No build ran there. The corrected request is back on compute01 as PID 3650889, queue position 5, with 50 GiB free (above the 25 GiB floor). It runs the build script directly inside the Go-enabled pinned R4 Nix shell; no build or perf measurement has started yet.

kayg commented

2026-11-01 19:06:34 +00:00

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R4b scale-memory method check: the one-peer RSS used the 15-second idle measurement, while the initial 1,000-peer snapshot followed the traffic profiles after only a two-second pause. I added an idle-1000 15-second idle interval before mem-1000 for kernel and userspace WireGuard, so both RSS snapshots use the same idle window. Throughput and latency profiles are unchanged. The updated perf-kit harness checksum is b1e3f8e9a6e3e2a4021c2e1f9f9c63558d9f50af40904e2e3d3c7a0ab4ed4b6e (cases/mesh.sh); extension manifest checksum is 886f311d4741d3c00546ae5993f5ba8d9a41040d2fe7110ec8bd282195809e94. No perf run has started.

R4b scale-memory method check: the one-peer RSS used the 15-second idle measurement, while the initial 1,000-peer snapshot followed the traffic profiles after only a two-second pause. I added an `idle-1000` 15-second idle interval before `mem-1000` for kernel and userspace WireGuard, so both RSS snapshots use the same idle window. Throughput and latency profiles are unchanged. The updated perf-kit harness checksum is `b1e3f8e9a6e3e2a4021c2e1f9f9c63558d9f50af40904e2e3d3c7a0ab4ed4b6e` (`cases/mesh.sh`); extension manifest checksum is `886f311d4741d3c00546ae5993f5ba8d9a41040d2fe7110ec8bd282195809e94`. No perf run has started.

kayg commented

2026-11-01 19:11:33 +00:00

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R4b build-slot wait: the latest compute01 status is unchanged, with all four slots busy, four queued jobs ahead of this job (position 5), and 48 GiB free above the 25 GiB floor. Corrected reference build PID 3650889 is still queued; the script has not started and the perf VM remains idle. I am waiting on the required shared queue so the six-case comparison can stay in one perf-all session.

kayg commented

2026-11-01 19:18:12 +00:00

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R4b queue progress: one older compute01 ticket cleared. PID 3650889 is now fourth in line (three queued jobs ahead); all four slots remain busy and 45 GiB is free. The corrected Nix-wrapped command is still waiting; no reference binary or perf result yet.

kayg commented

2026-11-01 19:19:29 +00:00

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R4b queue progress: a compute01 slot opened and the oldest waiter was admitted. PID 3650889 is now second in line (one queued job ahead), with 44 GiB free; no reference build has started yet.

kayg commented

2026-11-01 19:23:25 +00:00

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R4b queue progress: the previous first waiter has been admitted to slot 1. PID 3650889 is now first in line on compute01, with 43 GiB free; waiting for the next slot before building the pinned wireguard-go and wireguard-tools binaries.

kayg commented

2026-11-01 19:27:48 +00:00

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R4b queue progress: the ticket ahead of PID 3650889 cleared. Our build is now first in line, with all four compute01 slots still busy and 41 GiB free. The build process remains a waiter; no reference binary or benchmark yet.

kayg commented

2026-11-01 19:41:10 +00:00

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R4b reference build completed on compute01 through build-slot slot 3. Pinned sources: wireguard-go b3bc704ef0ee21a36298601a9e1e5ff90377ac52; wireguard-tools a998407747005ea7e4e0258d96f105c97241e1d3. SHA-256: wireguard-go 26f64ade377d0336ad1b50839c26992976422dac99c11b72f40763ebe469d952; wg 610861327870fd1a66296aad1df57194e0e5036c69b086944764f6bc7138ed04. Both are installed in the R4b kit, with provenance in R4B_REFERENCE_MANIFEST.txt.

The binaries use the pinned Nix glibc loader; the perf VM has that store path and ldd resolved their runtime dependencies. wg --help exits 0. wireguard-go does not accept -h as a help flag (it emits its standard kernel-support banner and exits 1), so functional daemon startup will be validated by the mesh case. The R4b overlay checksums verify; no repository code changed.

R4b reference build completed on compute01 through build-slot slot 3. Pinned sources: wireguard-go `b3bc704ef0ee21a36298601a9e1e5ff90377ac52`; wireguard-tools `a998407747005ea7e4e0258d96f105c97241e1d3`. SHA-256: wireguard-go `26f64ade377d0336ad1b50839c26992976422dac99c11b72f40763ebe469d952`; `wg` `610861327870fd1a66296aad1df57194e0e5036c69b086944764f6bc7138ed04`. Both are installed in the R4b kit, with provenance in `R4B_REFERENCE_MANIFEST.txt`. The binaries use the pinned Nix glibc loader; the perf VM has that store path and `ldd` resolved their runtime dependencies. `wg --help` exits 0. wireguard-go does not accept `-h` as a help flag (it emits its standard kernel-support banner and exits 1), so functional daemon startup will be validated by the mesh case. The R4b overlay checksums verify; no repository code changed.

kayg commented

2026-11-01 19:42:53 +00:00

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R4b measurement start: one perf-all.sh invocation is running on infraternal-perf-01-backup01 for mesh-underlay, mesh-infraternal, mesh-tailscale, mesh-gotatun, mesh-boringtun, and mesh-wireguard-go. Each case is launched through perf-run --root; the first underlay case is in perf.slice on CPUs 1–3 with the 6 GiB cap. Results/logs: /home/claude/j20/r4b/h2h-kit/results/20261101T194210Z and r4b-perf-all.log. No case results are complete yet.

R4b measurement start: one `perf-all.sh` invocation is running on infraternal-perf-01-backup01 for `mesh-underlay`, `mesh-infraternal`, `mesh-tailscale`, `mesh-gotatun`, `mesh-boringtun`, and `mesh-wireguard-go`. Each case is launched through `perf-run --root`; the first underlay case is in `perf.slice` on CPUs 1–3 with the 6 GiB cap. Results/logs: `/home/claude/j20/r4b/h2h-kit/results/20261101T194210Z` and `r4b-perf-all.log`. No case results are complete yet.

kayg commented

2026-11-01 19:54:49 +00:00

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R4b runner finding (no performance claim from the failed candidate cases)

The first combined perf-all run completed the underlay, kernel WireGuard (mesh-infraternal), and Tailscale cases (exit 0; each machine diff empty). GotaTun, BoringTun, and wireguard-go each stopped during setup after 21 seconds; their machine diffs were also empty. GotaTun and BoringTun both reported NULL from getlogin: the detached perf-run --root launcher has no login TTY, and both CLI privilege-drop paths call getlogin(). Their upstream-supported WG_SUDO=1 skips that startup path. wireguard-go exited on its built-in Linux kernel WireGuard warning; its upstream WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD=1 option explicitly permits the userspace daemon.

I will apply these three per-process environment overrides only in the disposable measurement harness and rerun all cases in one perf-all invocation, with every case still using perf-run --root. The failed first-pass logs remain in /home/claude/j20/r4b/h2h-kit/results/20261101T194210Z and will be retained separately from the successful comparison.

Source references: github.com/mullvad/gotatun@1d46b779f5/gotatun-cli/src/unix/drop_privileges.rs ; github.com/mullvad/gotatun@1d46b779f5/gotatun-cli/src/unix/mod.rs ; https://github.com/cloudflare/boringtun/blob/boringtun-cli-0.5.2/boringtun-cli/src/main.rs ; https://git.zx2c4.com/wireguard-go/tree/main.go?id=b3bc704ef0ee21a36298601a9e1e5ff90377ac52

R4b runner finding (no performance claim from the failed candidate cases) The first combined `perf-all` run completed the underlay, kernel WireGuard (`mesh-infraternal`), and Tailscale cases (exit 0; each machine diff empty). GotaTun, BoringTun, and wireguard-go each stopped during setup after 21 seconds; their machine diffs were also empty. GotaTun and BoringTun both reported `NULL from getlogin`: the detached `perf-run --root` launcher has no login TTY, and both CLI privilege-drop paths call `getlogin()`. Their upstream-supported `WG_SUDO=1` skips that startup path. wireguard-go exited on its built-in Linux kernel WireGuard warning; its upstream `WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD=1` option explicitly permits the userspace daemon. I will apply these three per-process environment overrides only in the disposable measurement harness and rerun all cases in one `perf-all` invocation, with every case still using `perf-run --root`. The failed first-pass logs remain in `/home/claude/j20/r4b/h2h-kit/results/20261101T194210Z` and will be retained separately from the successful comparison. Source references: https://github.com/mullvad/gotatun/blob/1d46b779f5e0743f30a13cc2c325b8114b901fb9/gotatun-cli/src/unix/drop_privileges.rs ; https://github.com/mullvad/gotatun/blob/1d46b779f5e0743f30a13cc2c325b8114b901fb9/gotatun-cli/src/unix/mod.rs ; https://github.com/cloudflare/boringtun/blob/boringtun-cli-0.5.2/boringtun-cli/src/main.rs ; https://git.zx2c4.com/wireguard-go/tree/main.go?id=b3bc704ef0ee21a36298601a9e1e5ff90377ac52

kayg commented

2026-11-01 19:57:17 +00:00

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R4b corrected comparison started on the perf VM as one perf-all invocation (PID 169371). The only runner changes are the upstream-supported per-process overrides identified above: WG_SUDO=1 for both Rust CLI daemons and WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD=1 for wireguard-go. Candidate binaries and workloads are unchanged. The harness diff SHA-256 is 09149489592f60b23619c05f90b75b29679c478676ff6ab6a7d592e6c4bd0e5b.

Live log: /home/claude/j20/r4b/h2h-kit/r4b-perf-all-rerun.log
Results: /home/claude/j20/r4b/h2h-kit/results/20261101T195701Z

R4b corrected comparison started on the perf VM as one `perf-all` invocation (PID `169371`). The only runner changes are the upstream-supported per-process overrides identified above: `WG_SUDO=1` for both Rust CLI daemons and `WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD=1` for wireguard-go. Candidate binaries and workloads are unchanged. The harness diff SHA-256 is `09149489592f60b23619c05f90b75b29679c478676ff6ab6a7d592e6c4bd0e5b`. Live log: `/home/claude/j20/r4b/h2h-kit/r4b-perf-all-rerun.log` Results: `/home/claude/j20/r4b/h2h-kit/results/20261101T195701Z`

kayg commented

2026-11-01 20:12:25 +00:00

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R4b setup finding (no userspace performance data yet)

In the corrected sweep, mesh-gotatun, mesh-boringtun, and mesh-wireguard-go each exit 1 after 21 seconds while waiting for the wgA UAPI socket. Their machine diffs are empty. GotaTun and BoringTun have empty captured daemon-log tails; wireguard-go's captured tail is only a terminal glyph. The per-process WG_SUDO=1 and kernel-module override are present in the harness. These are setup failures, not throughput results.

Next I am adding startup-only diagnostics to the disposable harness to capture process state, mount namespace, and UAPI path visibility, then I will rerun the affected cases under perf-run --root. The completed underlay, kernel WireGuard, and Tailscale rows remain available; no Rust or Go candidate measurements are valid yet.

R4b setup finding (no userspace performance data yet) In the corrected sweep, `mesh-gotatun`, `mesh-boringtun`, and `mesh-wireguard-go` each exit 1 after 21 seconds while waiting for the `wgA` UAPI socket. Their machine diffs are empty. GotaTun and BoringTun have empty captured daemon-log tails; wireguard-go's captured tail is only a terminal glyph. The per-process `WG_SUDO=1` and kernel-module override are present in the harness. These are setup failures, not throughput results. Next I am adding startup-only diagnostics to the disposable harness to capture process state, mount namespace, and UAPI path visibility, then I will rerun the affected cases under `perf-run --root`. The completed underlay, kernel WireGuard, and Tailscale rows remain available; no Rust or Go candidate measurements are valid yet.

kayg commented

2026-11-01 20:15:32 +00:00

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R4b setup root cause found

The startup diagnostic shows the PID stored in GOTA_A_PID is a Bash wrapper (comm=bash) in mount namespace mnt:[4026531841]; the namespace holder is in mnt:[4026532716]. The harness later uses the stored PID with nsenter -m both to check the UAPI socket and to configure the device. It therefore enters the wrapper's mount namespace instead of the daemon's private one, so the /var/run/wireguard socket is not visible. This explains the same 21-second UAPI wait failure for all three userspace implementations; the privilege overrides were not the cause.

I will add exec before nsenter in the disposable sandboxed wrapper so its tracked PID becomes the daemon process, verify GotaTun with one perf-run --root case, then rerun the full comparison on the same perf VM. No product code is involved.

R4b setup root cause found The startup diagnostic shows the PID stored in `GOTA_A_PID` is a Bash wrapper (`comm=bash`) in mount namespace `mnt:[4026531841]`; the namespace holder is in `mnt:[4026532716]`. The harness later uses the stored PID with `nsenter -m` both to check the UAPI socket and to configure the device. It therefore enters the wrapper's mount namespace instead of the daemon's private one, so the `/var/run/wireguard` socket is not visible. This explains the same 21-second UAPI wait failure for all three userspace implementations; the privilege overrides were not the cause. I will add `exec` before `nsenter` in the disposable `sandboxed` wrapper so its tracked PID becomes the daemon process, verify GotaTun with one `perf-run --root` case, then rerun the full comparison on the same perf VM. No product code is involved.

kayg commented

2026-11-01 20:17:54 +00:00

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R4b startup correction verified

After adding exec before nsenter in the disposable sandboxed wrapper, the GotaTun startup smoke completed successfully: first packet 275 ms, 2.02 Gbit/s single-flow and 2.06 Gbit/s eight-flow over the shortened smoke intervals, 58 s total, empty machine diff. These smoke numbers are diagnostic only and will not be used in the comparison table. The result also confirms the tracked PIDs now name the GotaTun daemons.

I restored the case script after its one-run diagnostic instrumentation. Next I am running the six requested systems in one corrected perf-all invocation on the same perf VM, with all cases still under perf-run --root; the full table will use only that run.

R4b startup correction verified After adding `exec` before `nsenter` in the disposable `sandboxed` wrapper, the GotaTun startup smoke completed successfully: first packet 275 ms, 2.02 Gbit/s single-flow and 2.06 Gbit/s eight-flow over the shortened smoke intervals, 58 s total, empty machine diff. These smoke numbers are diagnostic only and will not be used in the comparison table. The result also confirms the tracked PIDs now name the GotaTun daemons. I restored the case script after its one-run diagnostic instrumentation. Next I am running the six requested systems in one corrected `perf-all` invocation on the same perf VM, with all cases still under `perf-run --root`; the full table will use only that run.

kayg commented

2026-11-01 20:35:22 +00:00

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Correction to the earlier R4b wireguard-go setup note

The pinned commit b3bc704ef0ee21a36298601a9e1e5ff90377ac52 does not check WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD. Its main.go uses WG_PROCESS_FOREGROUND=1 (ENV_WG_PROCESS_FOREGROUND) to suppress the Linux kernel-support warning and select foreground mode. The harness set the wrong variable, which is why the warning remained and the UAPI socket never appeared. Source: github.com/WireGuard/wireguard-go@b3bc704ef0/main.go

I will replace the harness-only environment variable with the pinned source's supported one and rerun the missing wireguard-go case through perf-run --root into the existing comparison results directory. No wireguard-go source or product code changes.

Correction to the earlier R4b wireguard-go setup note The pinned commit `b3bc704ef0ee21a36298601a9e1e5ff90377ac52` does not check `WG_I_PREFER_BUGGY_USERSPACE_TO_POLISHED_KMOD`. Its `main.go` uses `WG_PROCESS_FOREGROUND=1` (`ENV_WG_PROCESS_FOREGROUND`) to suppress the Linux kernel-support warning and select foreground mode. The harness set the wrong variable, which is why the warning remained and the UAPI socket never appeared. Source: https://github.com/WireGuard/wireguard-go/blob/b3bc704ef0ee21a36298601a9e1e5ff90377ac52/main.go I will replace the harness-only environment variable with the pinned source's supported one and rerun the missing wireguard-go case through `perf-run --root` into the existing comparison results directory. No wireguard-go source or product code changes.

kayg commented

2026-11-01 20:47:43 +00:00

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R4b: Linux WireGuard data-plane results

Answer: the offload-enabled wireguard-go reference reaches Tailscale-like throughput and exceeds the current kernel path here. The pinned GotaTun and BoringTun CLIs do not close the gap as shipped. Since these are different implementations, this is not a before/after experiment that attributes wireguard-go's lead to batching alone.

All final cases exited 0 with empty machine diffs. They used infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), perf.slice CPUs 1–3 with a 6 GiB cap. The five-case sweep covered underlay, kernel WireGuard, Tailscale, GotaTun and BoringTun; wireguard-go was rerun after correcting its pinned commit's foreground variable, in a separate perf-run --root hold on the same VM and into the same result set. No run remains pending. Each row is one run per workload; p99 is calculated over that run’s probe samples, not across repeated runs.

Data plane	Throughput, 1 / 8 TCP flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT 64 B p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB, both endpoints)
Infraternal, kernel WireGuard	3.27 / 2.82	1.01 / 1.13	0.99 / 3.35; 3.04 / 4.45	18.1 / 18.1
Tailscale 1.104.4 (`tailscaled`)	4.85 / 5.28	0.52 / 0.49	3.40 / 10.04; 7.91 / 16.05	90.8 / n/a¹
GotaTun 0.10.2	1.71 / 1.78	1.36 / 1.37	2.26 / 7.02; 5.41 / 12.22	9.7 / 105.5
BoringTun 0.5.2	1.28 / 2.03	1.07 / 1.11	0.09 / 3.01; 1.78 / 7.14	7.7 / 43.3
wireguard-go, pinned commit	5.23 / 4.98	0.47 / 0.54	2.24 / 6.36; 8.50 / 17.52	31.2 / 1,116.7

CPU is whole-machine busy time, including traffic tools. RSS sums both endpoint daemons and descendants, excluding coordination. The 1,000-peer snapshots used the same 15-second idle interval as the one-peer snapshots. The kernel row is process RSS and excludes in-kernel WireGuard peer-state memory; the perf-scope memory-accounting snapshots for that state are in the archive. wireguard-go also retained 1,026.4 MiB peak RSS after traffic. ¹ The two-node Tailscale testcontrol fixture does not support 1,000 peers.

Linux batching and offload status

Engine	Current support in pinned source	Estimated work to add missing paths
GotaTun 0.10.2	`sendmmsg`/`recvmmsg` and UDP GRO; no UDP send GSO or TUN `IFF_VNET_HDR` / `TUNSETOFFLOAD`.	UDP GSO: about 1–3 engineering days. TUN vnet-header TSO/GRO, fallback paths and correctness coverage: about 1–2 weeks.
BoringTun CLI 0.5.2	Per-packet UDP and TUN I/O; no mmsg, UDP GSO/GRO or TUN vnet-header offloads. Its multi-queue mode is concurrency, not batching.	About 2–3 engineering weeks for UDP batching/GSO/GRO, TUN vnet-header support, fallbacks and correctness coverage.
wireguard-go at `b3bc704ef0ee21a36298601a9e1e5ff90377ac52`	Linux batch I/O, UDP GRO/GSO, and TUN vnet-header/offloads are present. UDP TUN GSO is enabled where supported (Linux 6.2+).	Already implemented in this reference.
Kernel WireGuard	Kernel data plane; no userspace offload patch required for this comparison.	n/a

Sources checked 2026-11-01: GotaTun Linux UDP, GotaTun UDP GSO PR #170 (open), GotaTun TUN TSO PR #10 (open draft), BoringTun UDP, BoringTun Linux TUN, wireguard-go Linux GSO, wireguard-go Linux TUN.

The raw result JSON, environment and machine-diff records, perf-run receipts, runner overlays and logs are attached as r4b-evidence-final-20261101.tar.gz (SHA-256 f04609aedc73758f0e0c2abb91b57f54ca0c0fd82dc8add174495f46545b71bd). No repo code changed; the fast gate is not applicable.

Given the throughput, memory and loaded-tail trade-offs, kayg: would you like a bounded GotaTun GSO/TUN-offload prototype measured before revisiting Linux D163, or should the current kernel-WireGuard Linux path remain the baseline? D163 remains your decision.

## R4b: Linux WireGuard data-plane results **Answer:** the offload-enabled wireguard-go reference reaches Tailscale-like throughput and exceeds the current kernel path here. The pinned GotaTun and BoringTun CLIs do not close the gap as shipped. Since these are different implementations, this is not a before/after experiment that attributes wireguard-go's lead to batching alone. All final cases exited 0 with empty machine diffs. They used infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), perf.slice CPUs 1–3 with a 6 GiB cap. The five-case sweep covered underlay, kernel WireGuard, Tailscale, GotaTun and BoringTun; wireguard-go was rerun after correcting its pinned commit's foreground variable, in a separate `perf-run --root` hold on the same VM and into the same result set. No run remains pending. Each row is one run per workload; p99 is calculated over that run’s probe samples, not across repeated runs. | Data plane | Throughput, 1 / 8 TCP flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT 64 B p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB, both endpoints) | |---|---:|---:|---:|---:| | Infraternal, kernel WireGuard | 3.27 / 2.82 | 1.01 / 1.13 | 0.99 / 3.35; 3.04 / 4.45 | 18.1 / 18.1 | | Tailscale 1.104.4 (`tailscaled`) | 4.85 / 5.28 | 0.52 / 0.49 | 3.40 / 10.04; 7.91 / 16.05 | 90.8 / n/a¹ | | GotaTun 0.10.2 | 1.71 / 1.78 | 1.36 / 1.37 | 2.26 / 7.02; 5.41 / 12.22 | 9.7 / 105.5 | | BoringTun 0.5.2 | 1.28 / 2.03 | 1.07 / 1.11 | 0.09 / 3.01; 1.78 / 7.14 | 7.7 / 43.3 | | wireguard-go, pinned commit | 5.23 / 4.98 | 0.47 / 0.54 | 2.24 / 6.36; 8.50 / 17.52 | 31.2 / 1,116.7 | CPU is whole-machine busy time, including traffic tools. RSS sums both endpoint daemons and descendants, excluding coordination. The 1,000-peer snapshots used the same 15-second idle interval as the one-peer snapshots. The kernel row is process RSS and excludes in-kernel WireGuard peer-state memory; the perf-scope memory-accounting snapshots for that state are in the archive. wireguard-go also retained 1,026.4 MiB peak RSS after traffic. ¹ The two-node Tailscale testcontrol fixture does not support 1,000 peers. ### Linux batching and offload status | Engine | Current support in pinned source | Estimated work to add missing paths | |---|---|---| | GotaTun 0.10.2 | `sendmmsg`/`recvmmsg` and UDP GRO; no UDP send GSO or TUN `IFF_VNET_HDR` / `TUNSETOFFLOAD`. | UDP GSO: about 1–3 engineering days. TUN vnet-header TSO/GRO, fallback paths and correctness coverage: about 1–2 weeks. | | BoringTun CLI 0.5.2 | Per-packet UDP and TUN I/O; no mmsg, UDP GSO/GRO or TUN vnet-header offloads. Its multi-queue mode is concurrency, not batching. | About 2–3 engineering weeks for UDP batching/GSO/GRO, TUN vnet-header support, fallbacks and correctness coverage. | | wireguard-go at `b3bc704ef0ee21a36298601a9e1e5ff90377ac52` | Linux batch I/O, UDP GRO/GSO, and TUN vnet-header/offloads are present. UDP TUN GSO is enabled where supported (Linux 6.2+). | Already implemented in this reference. | | Kernel WireGuard | Kernel data plane; no userspace offload patch required for this comparison. | n/a | Sources checked 2026-11-01: [GotaTun Linux UDP](https://github.com/mullvad/gotatun/blob/1d46b779f5e0743f30a13cc2c325b8114b901fb9/gotatun/src/udp/socket/linux.rs), [GotaTun UDP GSO PR #170](https://github.com/mullvad/gotatun/pull/170) (open), [GotaTun TUN TSO PR #10](https://github.com/mullvad/gotatun/pull/10) (open draft), [BoringTun UDP](https://github.com/cloudflare/boringtun/blob/boringtun-cli-0.5.2/boringtun/src/device/udp_unix.rs), [BoringTun Linux TUN](https://github.com/cloudflare/boringtun/blob/boringtun-cli-0.5.2/boringtun/src/device/tun_linux.rs), [wireguard-go Linux GSO](https://github.com/WireGuard/wireguard-go/blob/b3bc704ef0ee21a36298601a9e1e5ff90377ac52/conn/gso_linux.go), [wireguard-go Linux TUN](https://github.com/WireGuard/wireguard-go/blob/b3bc704ef0ee21a36298601a9e1e5ff90377ac52/tun/tun_linux.go). The raw result JSON, environment and machine-diff records, `perf-run` receipts, runner overlays and logs are attached as `r4b-evidence-final-20261101.tar.gz` (SHA-256 `f04609aedc73758f0e0c2abb91b57f54ca0c0fd82dc8add174495f46545b71bd`). No repo code changed; the fast gate is not applicable. Given the throughput, memory and loaded-tail trade-offs, kayg: would you like a bounded GotaTun GSO/TUN-offload prototype measured before revisiting Linux D163, or should the current kernel-WireGuard Linux path remain the baseline? D163 remains your decision.

r4b-evidence-final-20261101.tar.gz

1.3 MiB

kayg commented

2026-11-02 04:35:22 +00:00

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Owner decision (kayg, 2026-11-02) on D163: keep kernel WireGuard as the Linux baseline now. Work toward GotaTun matching or beating wireguard-go throughput at far less memory (Linux UDP GSO/GRO + TUN offloads, upstream-first via GotaTun PRs #170/#10, fork only as needed), so one engine can serve every platform. Switch Linux only when measured better. J88 is prototyping and measuring.

Owner decision (kayg, 2026-11-02) on D163: **keep kernel WireGuard as the Linux baseline now.** Work toward GotaTun matching or beating wireguard-go throughput at far less memory (Linux UDP GSO/GRO + TUN offloads, upstream-first via GotaTun PRs #170/#10, fork only as needed), so one engine can serve every platform. Switch Linux only when measured better. J88 is prototyping and measuring.

kayg commented

2026-11-02 04:39:06 +00:00

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Owner

J88 start: fork https://github.com/kaygdotorg/gotatun, branch j88-linux-offloads, based on upstream GotaTun main 2a867b3f322d95dc08043498d34eb91fb4266590. No infraternal product integration. D163 remains unchanged: kernel WireGuard is the Linux baseline; D169 records GotaTun as the userspace engine and MPL-2.0.

Plan:

Check GotaTun's license and inspect PR #170 and PR #10 against pinned 0.10.2 and current upstream main; record the chosen base and upstream commit references.
Port UDP send GSO while retaining GRO and the existing fallback; build and check it on a dev VM.
Add TUN IFF_VNET_HDR plus TUNSETOFFLOAD TSO/GRO from PR #10 where it applies, with fallback and focused correctness coverage; build and check it on a dev VM.
Reuse the R4b harness, build artifacts off the perf VM, and run a single controlled perf-run sweep on infraternal-perf-01-backup01 for kernel WireGuard, wireguard-go, and GotaTun before/after the full patch. Capture 1/8-flow throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, environment diff, and raw logs.
Push the fork branch; post the final table, raw logs, remaining work estimate, and owner question on next steps here.

Estimate: 5–8 engineering days: 1–2 for UDP GSO and its checks, 3–5 for TUN offloads and fallback correctness, and 1 for the controlled measurement and report. The earlier R4b estimate of 1–2 weeks was for production-grade TUN support; this job stays a prototype. If either upstream patch does not port cleanly, I will report the evidence and revised estimate before expanding scope.

J88 start: fork https://github.com/kaygdotorg/gotatun, branch `j88-linux-offloads`, based on upstream GotaTun main `2a867b3f322d95dc08043498d34eb91fb4266590`. No infraternal product integration. D163 remains unchanged: kernel WireGuard is the Linux baseline; D169 records GotaTun as the userspace engine and MPL-2.0. Plan: 1. Check GotaTun's license and inspect PR #170 and PR #10 against pinned 0.10.2 and current upstream main; record the chosen base and upstream commit references. 2. Port UDP send GSO while retaining GRO and the existing fallback; build and check it on a dev VM. 3. Add TUN `IFF_VNET_HDR` plus `TUNSETOFFLOAD` TSO/GRO from PR #10 where it applies, with fallback and focused correctness coverage; build and check it on a dev VM. 4. Reuse the R4b harness, build artifacts off the perf VM, and run a single controlled `perf-run` sweep on `infraternal-perf-01-backup01` for kernel WireGuard, wireguard-go, and GotaTun before/after the full patch. Capture 1/8-flow throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, environment diff, and raw logs. 5. Push the fork branch; post the final table, raw logs, remaining work estimate, and owner question on next steps here. Estimate: 5–8 engineering days: 1–2 for UDP GSO and its checks, 3–5 for TUN offloads and fallback correctness, and 1 for the controlled measurement and report. The earlier R4b estimate of 1–2 weeks was for production-grade TUN support; this job stays a prototype. If either upstream patch does not port cleanly, I will report the evidence and revised estimate before expanding scope.

kayg commented

2026-11-02 04:40:26 +00:00

Author

Owner

J88 upstream applicability finding: GotaTun is MPL-2.0 (confirmed by upstream LICENSE metadata). PR #170 is open (head 2c4f97e9598a8f5fb64ab7c2e7083ac3ebfa20e4); PR #10 is open/draft (head bfd9f0d2f87d2716270c674d91321a241b61f534). git apply --check fails for both PR patches on both pinned v0.10.2 (1d46b779f5e0743f30a13cc2c325b8114b901fb9) and current main (2a867b3f322d95dc08043498d34eb91fb4266590): #170 conflicts at gotatun/src/udp/socket/mod.rs:11; #10 conflicts at gotatun/src/packet/ipv4/mod.rs:461. I reset the not-yet-pushed j88-linux-offloads branch to the exact v0.10.2 tag so its before/after numbers isolate the patches against R4b's GotaTun baseline. I will port the narrow Linux paths while retaining upstream commit references for a later upstream submission.

Revised estimate: 8–12 engineering days: 2–3 for UDP GSO adaptation and checks, 5–7 for TUN vnet-header TSO/GRO with safe fallback/correctness coverage, 1–2 for the controlled perf sweep and report. The first estimate assumed clean application of the upstream patches. Scope remains this prototype and measurement only; no infraternal product integration.

J88 upstream applicability finding: GotaTun is MPL-2.0 (confirmed by upstream `LICENSE` metadata). PR #170 is open (head `2c4f97e9598a8f5fb64ab7c2e7083ac3ebfa20e4`); PR #10 is open/draft (head `bfd9f0d2f87d2716270c674d91321a241b61f534`). `git apply --check` fails for both PR patches on both pinned v0.10.2 (`1d46b779f5e0743f30a13cc2c325b8114b901fb9`) and current main (`2a867b3f322d95dc08043498d34eb91fb4266590`): #170 conflicts at `gotatun/src/udp/socket/mod.rs:11`; #10 conflicts at `gotatun/src/packet/ipv4/mod.rs:461`. I reset the not-yet-pushed `j88-linux-offloads` branch to the exact v0.10.2 tag so its before/after numbers isolate the patches against R4b's GotaTun baseline. I will port the narrow Linux paths while retaining upstream commit references for a later upstream submission. Revised estimate: 8–12 engineering days: 2–3 for UDP GSO adaptation and checks, 5–7 for TUN vnet-header TSO/GRO with safe fallback/correctness coverage, 1–2 for the controlled perf sweep and report. The first estimate assumed clean application of the upstream patches. Scope remains this prototype and measurement only; no infraternal product integration.

kayg commented

2026-11-02 04:45:18 +00:00

Author

Owner

Additional source review: the pinned v0.10.2 UDP receive path already enables UDP GRO and splits UdpGroSegments into original packets; I will preserve and exercise that path. PR #10 is still draft and its TUN changes are not safe to transplant unchanged: the receive path unwraps vnet-header parsing, has a todo! fallback, and its test ends in panic!(); its segmenter also leaves gso_size header semantics unresolved in a TODO. I will keep offloads opt-in/fallback-safe and validate untrusted TUN metadata before segmentation.

License check: LICENSE, workspace Cargo metadata, and crate SPDX headers say MPL-2.0. flake.nix package metadata says BSD-3-Clause. I will not change this unrelated metadata in the prototype; please reconcile it before any distribution or product integration. This does not alter the current job estimate or scope.

Additional source review: the pinned v0.10.2 UDP receive path already enables UDP GRO and splits `UdpGroSegments` into original packets; I will preserve and exercise that path. PR #10 is still draft and its TUN changes are not safe to transplant unchanged: the receive path unwraps vnet-header parsing, has a `todo!` fallback, and its test ends in `panic!()`; its segmenter also leaves `gso_size` header semantics unresolved in a TODO. I will keep offloads opt-in/fallback-safe and validate untrusted TUN metadata before segmentation. License check: `LICENSE`, workspace Cargo metadata, and crate SPDX headers say MPL-2.0. `flake.nix` package metadata says BSD-3-Clause. I will not change this unrelated metadata in the prototype; please reconcile it before any distribution or product integration. This does not alter the current job estimate or scope.

kayg commented

2026-11-02 04:47:02 +00:00

Author

Owner

J88 plan update per owner direction. Work stays on kaygdotorg/gotatun branch j88-linux-offloads, currently based on GotaTun v0.10.2 (1d46b779f5e0743f30a13cc2c325b8114b901fb9). I will apply upstream PR #170 and #10 commits as the starting patches, resolve conflicts on this pinned baseline, keep their commit references, and make no upstream contributions.

Checks and bug hunt:

UDP GSO/GRO: equal and mixed segment sizes, short tail, zero-length datagrams, 64-segment and IPv4/IPv6 size limits, destination changes, packet ordering, coalesced receive, and unsupported-kernel fallback.
TUN vnet header: TSO/GRO parsing and fallback when IFF_VNET_HDR or TUNSETOFFLOAD is unsupported; malformed metadata, checksums, IPv4/IPv6, TCP options, MTU/fragmentation boundaries, and mixed offload/non-offload peers.
Run loss and reordering cases through the same harness; verify no packet loss/duplication beyond injected loss and record per-peer RSS at 1 and 1,000 peers.
Build/check on a dev VM. On the perf VM only, run one perf-run sweep using the R4b harness for kernel WireGuard, wireguard-go, GotaTun v0.10.2, and patched GotaTun. Report 1/8-flow throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, environment diffs, and raw logs.

Estimate remains 8–12 engineering days: 2–3 for UDP GSO/GRO integration and cases, 5–7 for TUN offloads/fallback and edge coverage, 1–2 for the perf sweep and report. Kernel WireGuard remains the Linux baseline pending the owner's next decision. I will post the table, raw logs, fork branch, remaining-work estimate, and next-step question on #260; no upstream PR, comment, or issue until the owner discusses it.

J88 plan update per owner direction. Work stays on `kaygdotorg/gotatun` branch `j88-linux-offloads`, currently based on GotaTun v0.10.2 (`1d46b779f5e0743f30a13cc2c325b8114b901fb9`). I will apply upstream PR #170 and #10 commits as the starting patches, resolve conflicts on this pinned baseline, keep their commit references, and make no upstream contributions. Checks and bug hunt: - UDP GSO/GRO: equal and mixed segment sizes, short tail, zero-length datagrams, 64-segment and IPv4/IPv6 size limits, destination changes, packet ordering, coalesced receive, and unsupported-kernel fallback. - TUN vnet header: TSO/GRO parsing and fallback when `IFF_VNET_HDR` or `TUNSETOFFLOAD` is unsupported; malformed metadata, checksums, IPv4/IPv6, TCP options, MTU/fragmentation boundaries, and mixed offload/non-offload peers. - Run loss and reordering cases through the same harness; verify no packet loss/duplication beyond injected loss and record per-peer RSS at 1 and 1,000 peers. - Build/check on a dev VM. On the perf VM only, run one `perf-run` sweep using the R4b harness for kernel WireGuard, wireguard-go, GotaTun v0.10.2, and patched GotaTun. Report 1/8-flow throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, environment diffs, and raw logs. Estimate remains 8–12 engineering days: 2–3 for UDP GSO/GRO integration and cases, 5–7 for TUN offloads/fallback and edge coverage, 1–2 for the perf sweep and report. Kernel WireGuard remains the Linux baseline pending the owner's next decision. I will post the table, raw logs, fork branch, remaining-work estimate, and next-step question on #260; no upstream PR, comment, or issue until the owner discusses it.

kayg commented

2026-11-02 04:54:48 +00:00

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Owner

J88 progress: upstream PR #170 is now the base for the first fork commit, adapted to retain v0.10.2's dual-stack socket API and existing GRO receive path. The fork branch is j88-linux-offloads at WIP head ea10c84; it is pushed to https://github.com/kaygdotorg/gotatun/tree/j88-linux-offloads. No upstream contribution was made.

TDD evidence: the first cargo invocation selected no socket feature and stopped in an unrelated integration target; rerun with --features socket reached our GSO test and failed on the expected missing UdpGsoBatch/plan_udp_gso_batches symbols. The implementation is now applied, but the green run is waiting for build capacity. Latest build-slot --status: compute01 has 23 GiB free (below the 25 GiB floor); dev02 has 8 GiB. No build is queued and no run is pending. Next: compile/test the GSO patch when a slot and disk floor are available, then apply PR #10 and run the full bug-hunt matrix.

J88 progress: upstream PR #170 is now the base for the first fork commit, adapted to retain v0.10.2's dual-stack socket API and existing GRO receive path. The fork branch is `j88-linux-offloads` at WIP head `ea10c84`; it is pushed to https://github.com/kaygdotorg/gotatun/tree/j88-linux-offloads. No upstream contribution was made. TDD evidence: the first cargo invocation selected no `socket` feature and stopped in an unrelated integration target; rerun with `--features socket` reached our GSO test and failed on the expected missing `UdpGsoBatch`/`plan_udp_gso_batches` symbols. The implementation is now applied, but the green run is waiting for build capacity. Latest `build-slot --status`: compute01 has 23 GiB free (below the 25 GiB floor); dev02 has 8 GiB. No build is queued and no run is pending. Next: compile/test the GSO patch when a slot and disk floor are available, then apply PR #10 and run the full bug-hunt matrix.

kayg commented

2026-11-02 05:07:43 +00:00

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Owner

J88 test harness finding: the focused TSO test compiled on compute01, but Cargo did not execute it. The upstream .cargo/config.toml sets the Unix target runner to sudo -E; the noninteractive claude account cannot use that runner, so the test exited before reaching any assertion. This is an environment issue, not a passing or failing packet test. I will rerun the test binary directly (without changing the source config), then continue the TUN metadata and fallback cases.

J88 test harness finding: the focused TSO test compiled on compute01, but Cargo did not execute it. The upstream `.cargo/config.toml` sets the Unix target runner to `sudo -E`; the noninteractive `claude` account cannot use that runner, so the test exited before reaching any assertion. This is an environment issue, not a passing or failing packet test. I will rerun the test binary directly (without changing the source config), then continue the TUN metadata and fallback cases.

kayg commented

2026-11-02 05:08:48 +00:00

Author

Owner

J88 TUN test finding: direct execution of the compiled test binary reached the new regression test and failed as intended. With a 10-byte TCP payload MSS and 4 bytes of TCP options, the current segmenter panics with gso_size (10) must be greater than the length of the IP/TCP headers (44). Linux virtio gso_size is the TCP payload MSS, so this patch subtracts headers incorrectly. I will fix the segment length semantics and validate checksums/options in the passing test before expanding malformed-header coverage.

J88 TUN test finding: direct execution of the compiled test binary reached the new regression test and failed as intended. With a 10-byte TCP payload MSS and 4 bytes of TCP options, the current segmenter panics with `gso_size (10) must be greater than the length of the IP/TCP headers (44)`. Linux virtio `gso_size` is the TCP payload MSS, so this patch subtracts headers incorrectly. I will fix the segment length semantics and validate checksums/options in the passing test before expanding malformed-header coverage.

kayg commented

2026-11-02 05:39:00 +00:00

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Owner

J88 finding (fork branch j88-linux-offloads, HEAD ea10c84; TUN work is uncommitted):

A dev VM test using a valid IPv4 TCP frame with IHL=6, four bytes of IP options, csum_start=24, gso_size=10, and a 26-byte payload fails with InvalidData: invalid TCPv4 checksum metadata. The current TUN parser hard-codes csum_start == 20, so the PR #10 port rejects this valid options-bearing TSO frame before segmentation. The test was run on compute01 with nix develop and the env target runner; it compiled and reached the assertion path. I will use the actual IPv4 header length, preserve options, and verify per-segment lengths/checksums before the perf sweep. No perf run has started, and no upstream PR/comment/issue was made.

J88 finding (fork branch `j88-linux-offloads`, HEAD `ea10c84`; TUN work is uncommitted): A dev VM test using a valid IPv4 TCP frame with IHL=6, four bytes of IP options, `csum_start=24`, `gso_size=10`, and a 26-byte payload fails with `InvalidData: invalid TCPv4 checksum metadata`. The current TUN parser hard-codes `csum_start == 20`, so the PR #10 port rejects this valid options-bearing TSO frame before segmentation. The test was run on compute01 with `nix develop` and the `env` target runner; it compiled and reached the assertion path. I will use the actual IPv4 header length, preserve options, and verify per-segment lengths/checksums before the perf sweep. No perf run has started, and no upstream PR/comment/issue was made.

kayg commented

2026-11-02 06:02:24 +00:00

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Owner

J88 correctness progress:

The UDP send test now checks distinct payload contents and ordering across equal segments and a short tail, and a forced GSO-disabled run covers the plain-send fallback including a zero-length datagram.
Review of the UDP GRO receive path found that segmentation did not explicitly use recvmmsg's returned byte count. I bounded splitting to that length and now reject truncated data/control messages. The new regression first failed to compile because the helper did not exist, then passed after the change.
Current verification on compute01: cargo fmt --all -- --check passed; the full GotaTun library suite passed 85/85 with tun,socket,ring.

Next: commit and push the fork branch, build the release CLI on compute01, then run the paired correctness and performance cases through perf-run on the perf VM. No upstream PRs, comments, or issues have been made.

J88 correctness progress: - The UDP send test now checks distinct payload contents and ordering across equal segments and a short tail, and a forced GSO-disabled run covers the plain-send fallback including a zero-length datagram. - Review of the UDP GRO receive path found that segmentation did not explicitly use `recvmmsg`'s returned byte count. I bounded splitting to that length and now reject truncated data/control messages. The new regression first failed to compile because the helper did not exist, then passed after the change. - Current verification on compute01: `cargo fmt --all -- --check` passed; the full GotaTun library suite passed **85/85** with `tun,socket,ring`. Next: commit and push the fork branch, build the release CLI on compute01, then run the paired correctness and performance cases through `perf-run` on the perf VM. No upstream PRs, comments, or issues have been made.

kayg commented

2026-11-02 07:08:32 +00:00

Author

Owner

J88 result: Linux UDP GSO/GRO and TUN TSO/GRO prototype

Fork branch: j88-linux-offloads, head 8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38. Based on GotaTun v0.10.2 (1d46b779f5e0743f30a13cc2c325b8114b901fb9), with upstream PR #170/#10 heads retained in the commits and evidence. No upstream PR, issue or comment was made. D163 and D169 are unchanged.

Measurements used the same R4b kit and perf VM (infraternal-perf-01-backup01, Debian 13, kernel 6.12.113, Ryzen 7 3700X), through perf-run --root, perf.slice CPUs 1–3, 6 GiB. CPU is whole-machine busy time, including traffic tools; RSS sums both endpoint daemons. Each workload is one sample. The corrected GotaTun rows below are from the follow-up result session; kernel WireGuard and wireguard-go controls are from the first full sweep. Kernel WireGuard and wireguard-go before/after aliases use byte-identical binaries; only GotaTun changed.

Engine	TCP throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	LAN loaded RTT 64 B p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB, both endpoints)
Kernel WireGuard control A	2.94 / 2.77	1.10 / 1.15	0.985 / 1.698; 3.089 / 4.288	20.1 / 20.1
Kernel WireGuard control B	3.33 / 2.83	1.01 / 1.14	0.992 / 2.178; 3.013 / 4.343	20.1 / 20.1
wireguard-go control A	5.01 / 4.85	0.49 / 0.55	2.888 / 57.743; 8.346 / 107.175	30.9 / 1,117.4
wireguard-go control B	5.35 / 5.04	0.48 / 0.54	2.348 / 6.809; 8.665 / 17.120	29.3 / 1,050.3
GotaTun v0.10.2	1.87 / 1.97	1.26 / 1.33	2.307 / 5.889; 6.027 / 13.414	9.7 / 106.6
GotaTun patched	2.97 / 2.56	0.79 / 0.99	2.007 / 5.372; 6.366 / 11.804	9.8 / 110.4
GotaTun mixed baseline/patched peers	1.74 / 1.59	1.30 / 1.39	2.139 / 5.419; 4.645 / 12.163	9.9 / 104.5

The patch raises GotaTun throughput by 59% at 1 flow and 30% at 8 flows versus its same-session baseline. It reaches 56% / 51% of wireguard-go’s throughput and does not meet the throughput target. The wireguard-go control A loaded p99 contains a single-sample outlier; control B and R4b are near 6–17 ms.

At 1,000 peers per endpoint, patched GotaTun uses 110.4 MiB versus 1,050.3 MiB for wireguard-go (10.5%). Incremental RSS is about 0.050 MiB per peer for GotaTun and 0.511 MiB for wireguard-go, so the per-peer and 1,000-peer memory target is met. At one peer, total RSS is 9.8 versus 29.3 MiB (33%); that does not meet a one-fifth total-RSS interpretation. Kernel WireGuard’s process RSS excludes kernel peer-state memory.

Bug-hunt coverage and results:

UDP GSO/GRO tests cover distinct payload ordering, equal segments, short tails, zero-length fallback, destination/family and IPv4/IPv6 size limits, batch limits, GRO returned-length bounds and truncated records.
TUN tests cover vnet-header fallback, failed TUNSETOFFLOAD, partial checksums, malformed metadata, TCPv4/v6 segmentation, IPv4 options, 1,500-byte MTU boundaries and rejection of fragmented TCP GSO metadata. Perf VM used Linux 6.12; unsupported ioctl behavior is covered by focused fallback tests (IFF_VNET_HDR retry seam and ioctl failure on /dev/null), not a second kernel without TUN offload.
The corrected mixed-peer run has exit 0, empty machine diff and no failed measurements. With 198 ms RTT and 25% correlated reordering, all 300 probes per size arrived for each GotaTun variant. TCP throughput fell to 0.003 / 0.015 Gbit/s at 1 / 8 flows for patched and mixed peers, similar to baseline’s 0.003 / 0.016. The R4b mesh fixture is IPv4; IPv6 is covered by library tests.
The first full sweep’s mixed case caught only a changing /root/.cache/nix/sentry/*.run cache entry in its machine diff and exited 3. The corrected follow-up mixed case exited 0 with an empty diff. The first sweep also exposed that the reorder flag was not forwarded through the wrapper; the follow-up explicitly passed it. Both runs and diffs are retained in the archive.

Verification on compute01: cargo fmt --all -- --check and git diff --check passed; cargo test --lib --features "tun,socket,ring" reported 86/86 passed. Release CLI SHA-256: ffc73a610f1be5625cd22ddfec9b2f0955f49bc61c42bb5ad64cb893b7d3be9a. No infraternal product source changed, so scripts/verify fast is not applicable.

GotaTun is MPL-2.0 per LICENSE, Cargo metadata and crate SPDX. flake.nix says BSD-3-Clause; reconcile that mismatch before distribution or product integration.

Raw JSON, per-case logs, machine snapshots/diffs, perf-run receipts, overlay patches and provenance are attached as j88-evidence-20261102.tar.gz (SHA-256 8056be6c3db07ab9a4b2cc1739f0020286585f03bd34a3caf370be7cec91a779).

Remaining estimate toward the throughput target:

Profile crypto, syscall, batching and TUN costs to select the next bottleneck: 1–2 days.
Implement and test a focused throughput-tuning pass against the remaining 44% / 49% gap: 3–5 days.
Exercise a real kernel without TUN offload, dynamic MTU/fragmentation and IPv6 extension/fragment cases: 2–3 days.
Repeat the paired perf matrix with multiple samples and scale checks: 1–2 days.
If one-fifth means total RSS at one peer, reduce fixed process overhead: 1–2 more days.

Owner question: should the next fork-only lane profile and tune GotaTun throughput while leaving upstream contributions parked for your review? Also, should the memory target mean total RSS at one peer or per-peer/1,000-peer memory? Current results meet the latter and miss the former.

## J88 result: Linux UDP GSO/GRO and TUN TSO/GRO prototype Fork branch: [`j88-linux-offloads`](https://github.com/kaygdotorg/gotatun/tree/j88-linux-offloads), head `8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38`. Based on GotaTun v0.10.2 (`1d46b779f5e0743f30a13cc2c325b8114b901fb9`), with upstream PR #170/#10 heads retained in the commits and evidence. No upstream PR, issue or comment was made. D163 and D169 are unchanged. Measurements used the same R4b kit and perf VM (`infraternal-perf-01-backup01`, Debian 13, kernel 6.12.113, Ryzen 7 3700X), through `perf-run --root`, perf.slice CPUs 1–3, 6 GiB. CPU is whole-machine busy time, including traffic tools; RSS sums both endpoint daemons. Each workload is one sample. The corrected GotaTun rows below are from the follow-up result session; kernel WireGuard and wireguard-go controls are from the first full sweep. Kernel WireGuard and wireguard-go before/after aliases use byte-identical binaries; only GotaTun changed. | Engine | TCP throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | LAN loaded RTT 64 B p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB, both endpoints) | |---|---:|---:|---:|---:| | Kernel WireGuard control A | 2.94 / 2.77 | 1.10 / 1.15 | 0.985 / 1.698; 3.089 / 4.288 | 20.1 / 20.1 | | Kernel WireGuard control B | 3.33 / 2.83 | 1.01 / 1.14 | 0.992 / 2.178; 3.013 / 4.343 | 20.1 / 20.1 | | wireguard-go control A | 5.01 / 4.85 | 0.49 / 0.55 | 2.888 / 57.743; 8.346 / 107.175 | 30.9 / 1,117.4 | | wireguard-go control B | 5.35 / 5.04 | 0.48 / 0.54 | 2.348 / 6.809; 8.665 / 17.120 | 29.3 / 1,050.3 | | GotaTun v0.10.2 | 1.87 / 1.97 | 1.26 / 1.33 | 2.307 / 5.889; 6.027 / 13.414 | 9.7 / 106.6 | | GotaTun patched | 2.97 / 2.56 | 0.79 / 0.99 | 2.007 / 5.372; 6.366 / 11.804 | 9.8 / 110.4 | | GotaTun mixed baseline/patched peers | 1.74 / 1.59 | 1.30 / 1.39 | 2.139 / 5.419; 4.645 / 12.163 | 9.9 / 104.5 | The patch raises GotaTun throughput by 59% at 1 flow and 30% at 8 flows versus its same-session baseline. It reaches 56% / 51% of wireguard-go’s throughput and does not meet the throughput target. The wireguard-go control A loaded p99 contains a single-sample outlier; control B and R4b are near 6–17 ms. At 1,000 peers per endpoint, patched GotaTun uses 110.4 MiB versus 1,050.3 MiB for wireguard-go (10.5%). Incremental RSS is about 0.050 MiB per peer for GotaTun and 0.511 MiB for wireguard-go, so the per-peer and 1,000-peer memory target is met. At one peer, total RSS is 9.8 versus 29.3 MiB (33%); that does not meet a one-fifth total-RSS interpretation. Kernel WireGuard’s process RSS excludes kernel peer-state memory. Bug-hunt coverage and results: - UDP GSO/GRO tests cover distinct payload ordering, equal segments, short tails, zero-length fallback, destination/family and IPv4/IPv6 size limits, batch limits, GRO returned-length bounds and truncated records. - TUN tests cover vnet-header fallback, failed `TUNSETOFFLOAD`, partial checksums, malformed metadata, TCPv4/v6 segmentation, IPv4 options, 1,500-byte MTU boundaries and rejection of fragmented TCP GSO metadata. Perf VM used Linux 6.12; unsupported ioctl behavior is covered by focused fallback tests (`IFF_VNET_HDR` retry seam and ioctl failure on `/dev/null`), not a second kernel without TUN offload. - The corrected mixed-peer run has exit 0, empty machine diff and no failed measurements. With 198 ms RTT and 25% correlated reordering, all 300 probes per size arrived for each GotaTun variant. TCP throughput fell to 0.003 / 0.015 Gbit/s at 1 / 8 flows for patched and mixed peers, similar to baseline’s 0.003 / 0.016. The R4b mesh fixture is IPv4; IPv6 is covered by library tests. - The first full sweep’s mixed case caught only a changing `/root/.cache/nix/sentry/*.run` cache entry in its machine diff and exited 3. The corrected follow-up mixed case exited 0 with an empty diff. The first sweep also exposed that the reorder flag was not forwarded through the wrapper; the follow-up explicitly passed it. Both runs and diffs are retained in the archive. Verification on compute01: `cargo fmt --all -- --check` and `git diff --check` passed; `cargo test --lib --features "tun,socket,ring"` reported 86/86 passed. Release CLI SHA-256: `ffc73a610f1be5625cd22ddfec9b2f0955f49bc61c42bb5ad64cb893b7d3be9a`. No infraternal product source changed, so `scripts/verify fast` is not applicable. GotaTun is MPL-2.0 per LICENSE, Cargo metadata and crate SPDX. `flake.nix` says BSD-3-Clause; reconcile that mismatch before distribution or product integration. Raw JSON, per-case logs, machine snapshots/diffs, perf-run receipts, overlay patches and provenance are attached as `j88-evidence-20261102.tar.gz` (SHA-256 `8056be6c3db07ab9a4b2cc1739f0020286585f03bd34a3caf370be7cec91a779`). Remaining estimate toward the throughput target: - Profile crypto, syscall, batching and TUN costs to select the next bottleneck: 1–2 days. - Implement and test a focused throughput-tuning pass against the remaining 44% / 49% gap: 3–5 days. - Exercise a real kernel without TUN offload, dynamic MTU/fragmentation and IPv6 extension/fragment cases: 2–3 days. - Repeat the paired perf matrix with multiple samples and scale checks: 1–2 days. - If one-fifth means total RSS at one peer, reduce fixed process overhead: 1–2 more days. Owner question: should the next fork-only lane profile and tune GotaTun throughput while leaving upstream contributions parked for your review? Also, should the memory target mean total RSS at one peer or per-peer/1,000-peer memory? Current results meet the latter and miss the former.

j88-evidence-20261102.tar.gz

2.4 MiB

kayg commented

2026-11-02 07:14:52 +00:00

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Owner

Owner decisions (kayg, 2026-11-02) on J88's results: the public fork (github.com/kaygdotorg/gotatun, branch j88-linux-offloads) is fine; keep tuning in the fork; still no upstream contribution until reviewed. Memory target: as low as kernel WireGuard, measured fairly (in-kernel peer state, not just process RSS). Throughput target unchanged: at least wireguard-go.

Owner decisions (kayg, 2026-11-02) on J88's results: the public fork (github.com/kaygdotorg/gotatun, branch j88-linux-offloads) is fine; **keep tuning** in the fork; still no upstream contribution until reviewed. Memory target: **as low as kernel WireGuard**, measured fairly (in-kernel peer state, not just process RSS). Throughput target unchanged: at least wireguard-go.

kayg commented

2026-11-02 07:16:55 +00:00

Author

Owner

J88 follow-up plan (owner direction, 2026-11-02)

Start: fork branch j88-linux-offloads, head/base 8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38. The branch is pushed and clean. Work remains in the fork; no upstream PRs, issues or comments.

Set the memory target from kernel WireGuard. On the perf VM, use the R4b two-netns harness and perf-run --root to measure kernel WireGuard at 1 and 1,000 peers per endpoint. Capture process RSS plus before/after memory-cgroup kernel statistics and /proc/slabinfo deltas for WireGuard peer state, allowedips and relevant kmalloc/slab caches. Repeat quiet snapshots, preserve machine diffs and separate fixed memory from per-peer growth. Re-run the same 1/1,000 measurements for GotaTun and wireguard-go so the table is directly comparable. This measured kernel figure becomes the GotaTun memory target.
Profile throughput on the perf VM. Build profiling-capable release artifacts on a dev VM. Under perf-run --root, collect perf stat and perf record/flamegraphs for GotaTun baseline, patched GotaTun and wireguard-go at 1/8 flows. Attribute crypto batching, copies, syscalls per packet and thread scheduling. Profiling runs are separate from timing samples; final throughput stays on the existing R4b harness.
Tune one bottleneck and memory use in the fork. Follow profile evidence to reduce per-peer buffers/queues/timers/maps with lazy, shared or pooled state where safe; also check fixed one-peer RSS. Make one bounded throughput optimization pass based on measured hot stacks. Keep changes small and preserve fallbacks.
Run the edge matrix and paired measurement again. Cover loss and reordering, MTU changes and fragmentation boundaries, mixed baseline/patched peers, forced unsupported IFF_VNET_HDR/TUNSETOFFLOAD, IPv4/IPv6 and checksums, plus memory at 1/1,000. Keep kernel WireGuard and wireguard-go controls. Post the same results table after each meaningful stage, now with measured kernel peer-state memory and per-peer deltas.
Record licensing exactly. Check every GotaTun LICENSE* file, Cargo SPDX metadata and flake.nix; post the exact license text/metadata discrepancy to this issue for the owner.

Estimate: 10–17 engineering days: kernel memory baseline 1–2; profile 1–2; memory and fixed-RSS investigation/tuning 3–5; one throughput tuning pass 3–5; edge matrix and repeat measurements 2–3; license/reporting 0.5. This excludes any wider redesign or upstream contribution, which remains parked for owner discussion. I will stop and report before expanding beyond this scope.

## J88 follow-up plan (owner direction, 2026-11-02) Start: fork branch `j88-linux-offloads`, head/base `8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38`. The branch is pushed and clean. Work remains in the fork; no upstream PRs, issues or comments. 1. **Set the memory target from kernel WireGuard.** On the perf VM, use the R4b two-netns harness and `perf-run --root` to measure kernel WireGuard at 1 and 1,000 peers per endpoint. Capture process RSS plus before/after memory-cgroup kernel statistics and `/proc/slabinfo` deltas for WireGuard peer state, allowedips and relevant kmalloc/slab caches. Repeat quiet snapshots, preserve machine diffs and separate fixed memory from per-peer growth. Re-run the same 1/1,000 measurements for GotaTun and wireguard-go so the table is directly comparable. This measured kernel figure becomes the GotaTun memory target. 2. **Profile throughput on the perf VM.** Build profiling-capable release artifacts on a dev VM. Under `perf-run --root`, collect `perf stat` and `perf record`/flamegraphs for GotaTun baseline, patched GotaTun and wireguard-go at 1/8 flows. Attribute crypto batching, copies, syscalls per packet and thread scheduling. Profiling runs are separate from timing samples; final throughput stays on the existing R4b harness. 3. **Tune one bottleneck and memory use in the fork.** Follow profile evidence to reduce per-peer buffers/queues/timers/maps with lazy, shared or pooled state where safe; also check fixed one-peer RSS. Make one bounded throughput optimization pass based on measured hot stacks. Keep changes small and preserve fallbacks. 4. **Run the edge matrix and paired measurement again.** Cover loss and reordering, MTU changes and fragmentation boundaries, mixed baseline/patched peers, forced unsupported `IFF_VNET_HDR`/`TUNSETOFFLOAD`, IPv4/IPv6 and checksums, plus memory at 1/1,000. Keep kernel WireGuard and wireguard-go controls. Post the same results table after each meaningful stage, now with measured kernel peer-state memory and per-peer deltas. 5. **Record licensing exactly.** Check every GotaTun `LICENSE*` file, Cargo SPDX metadata and `flake.nix`; post the exact license text/metadata discrepancy to this issue for the owner. Estimate: **10–17 engineering days**: kernel memory baseline 1–2; profile 1–2; memory and fixed-RSS investigation/tuning 3–5; one throughput tuning pass 3–5; edge matrix and repeat measurements 2–3; license/reporting 0.5. This excludes any wider redesign or upstream contribution, which remains parked for owner discussion. I will stop and report before expanding beyond this scope.

kayg commented

2026-11-02 07:18:07 +00:00

Author

Owner

J88 license check (owner follow-up)

At branch j88-linux-offloads (8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38):

Root LICENSE begins exactly Mozilla Public License Version 2.0; root Cargo.toml says license = "MPL-2.0", and gotatun / gotatun-cli inherit that workspace value.
LICENSE-CLOUDFLARE begins Copyright (c) 2019 Cloudflare, Inc. All rights reserved. It grants redistribution and use in source and binary forms under three conditions, followed by the standard warranty/liability disclaimer. This is a separate license notice in the tree.
flake.nix package metadata says license = lib.licenses.bsd3, i.e. BSD 3-Clause.

The project-level LICENSE and Cargo metadata identify MPL-2.0, while the Nix package metadata identifies BSD-3-Clause. The separate Cloudflare notice is not the root project license. No license metadata was changed in the fork; please decide the intended Nix package license before product integration or distribution.

## J88 license check (owner follow-up) At branch `j88-linux-offloads` (`8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38`): - Root `LICENSE` begins exactly `Mozilla Public License Version 2.0`; root `Cargo.toml` says `license = "MPL-2.0"`, and `gotatun` / `gotatun-cli` inherit that workspace value. - `LICENSE-CLOUDFLARE` begins `Copyright (c) 2019 Cloudflare, Inc. All rights reserved.` It grants redistribution and use in source and binary forms under three conditions, followed by the standard warranty/liability disclaimer. This is a separate license notice in the tree. - `flake.nix` package metadata says `license = lib.licenses.bsd3`, i.e. BSD 3-Clause. The project-level LICENSE and Cargo metadata identify MPL-2.0, while the Nix package metadata identifies BSD-3-Clause. The separate Cloudflare notice is not the root project license. No license metadata was changed in the fork; please decide the intended Nix package license before product integration or distribution.

kayg commented

2026-11-02 07:27:04 +00:00

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Owner

J88 memory-accounting finding: R4b records cgroup snapshots in D=$H2H_RUN/$SYSTEM, but run.sh removes H2H_RUN after each case. The attached R4b archive also has no retained memcg-one.txt or memcg-1000.txt. I will capture fresh cgroup and /proc/slabinfo snapshots directly under the per-case results directory in a disposable copy of the same harness; no measurement has started yet.

J88 memory-accounting finding: R4b records cgroup snapshots in `D=$H2H_RUN/$SYSTEM`, but `run.sh` removes `H2H_RUN` after each case. The attached R4b archive also has no retained `memcg-one.txt` or `memcg-1000.txt`. I will capture fresh cgroup and `/proc/slabinfo` snapshots directly under the per-case results directory in a disposable copy of the same harness; no measurement has started yet.

kayg commented

2026-11-02 08:15:09 +00:00

Author

Owner

J88 kernel-memory baseline and profile preparation (2026-11-02)

Three repeats of a disposable R4b case ran under perf-run --root on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113). Each case used the same two-netns setup, then configured one peer with no AllowedIPs, 1,000 peers with no AllowedIPs, and 1,000 peers with one IPv4 /32 each. All three exited 0 with empty machine diffs. Process RSS stayed flat for the kernel case at about 20.1 MiB across both endpoints.

The full table below uses the same R4b sweep and timings already reported. Added columns show process RSS growth per configured peer and the newly measured kernel peer-state target. Userspace RSS deltas divide the two-endpoint 1-to-1,000 change by 1,998 added peers.

Engine	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT 64 B p50/p99, 1 / 8 flows (ms)	Process RSS, 1 / 1,000 peers (MiB)	Incremental process RSS per peer	Kernel peer-state target per peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.59 KiB at 1 peer; 1.65 KiB at 1,000 peers
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun v0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun patched	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun mixed	1.90 / 1.83	1.22 / 1.36	2.261 / 5.648; 5.255 / 11.814	9.9 / 108.1	50.3 KiB	n/a

Kernel accounting: /sys/kernel/slab/wg_peer reports 1,552 bytes per peer object (21 objects per 8-page slab). /sys/kernel/slab/allowedips_node reports 72 bytes per node (56 objects per page); the cache is aliased with the global vmap_area cache. Across the three repeats, adding 2,000 /32 routes increased that cache by 3,756–4,046 objects (median 3,809), or about 1.90 nodes and 137 bytes per route. That gives about 1.65 KiB of peer plus route objects per configured peer at 1,000 peers per endpoint, 3.22 MiB for 2,000 peers total. Slab page capacity rounds this to about 3.27 MiB. At one peer per endpoint, one /32 each is about 1.59 KiB per peer (3.17 KiB total).

The cgroup kernel/slab counters did not account for these shared caches consistently: their deltas were far below the slab-object sizes. Global wg_peer active-object deltas also had background churn, so the target uses the measured object sizes plus the repeated AllowedIP cache delta. Raw per-stage cgroup, slab, RSS and machine snapshots are attached in kernel-memory-isolation-20261102.tar.gz (SHA-256 ded7d7b56a73218c65ad81a62b2066773ffd3ac2ee2a85ea150b0ee43bc5f505).

GotaTun patched currently uses about 30.6 times the kernel peer-state memory per peer (50.5 KiB versus 1.65 KiB), so matching this target requires roughly a 96.7% reduction in its incremental peer memory. Its throughput remains 55% / 53% of wireguard-go at 1 / 8 flows. Next: build profiling artifacts on a dev VM, then profile the baseline and patched GotaTun plus wireguard-go under perf-run before selecting a single bounded tuning pass.

## J88 kernel-memory baseline and profile preparation (2026-11-02) Three repeats of a disposable R4b case ran under `perf-run --root` on `infraternal-perf-01-backup01` (Debian 13, kernel 6.12.113). Each case used the same two-netns setup, then configured one peer with no AllowedIPs, 1,000 peers with no AllowedIPs, and 1,000 peers with one IPv4 `/32` each. All three exited 0 with empty machine diffs. Process RSS stayed flat for the kernel case at about 20.1 MiB across both endpoints. The full table below uses the same R4b sweep and timings already reported. Added columns show process RSS growth per configured peer and the newly measured kernel peer-state target. Userspace RSS deltas divide the two-endpoint 1-to-1,000 change by 1,998 added peers. | Engine | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT 64 B p50/p99, 1 / 8 flows (ms) | Process RSS, 1 / 1,000 peers (MiB) | Incremental process RSS per peer | Kernel peer-state target per peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.59 KiB at 1 peer; 1.65 KiB at 1,000 peers | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun v0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun patched | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun mixed | 1.90 / 1.83 | 1.22 / 1.36 | 2.261 / 5.648; 5.255 / 11.814 | 9.9 / 108.1 | 50.3 KiB | n/a | Kernel accounting: `/sys/kernel/slab/wg_peer` reports 1,552 bytes per peer object (21 objects per 8-page slab). `/sys/kernel/slab/allowedips_node` reports 72 bytes per node (56 objects per page); the cache is aliased with the global `vmap_area` cache. Across the three repeats, adding 2,000 `/32` routes increased that cache by 3,756–4,046 objects (median 3,809), or about 1.90 nodes and 137 bytes per route. That gives about 1.65 KiB of peer plus route objects per configured peer at 1,000 peers per endpoint, 3.22 MiB for 2,000 peers total. Slab page capacity rounds this to about 3.27 MiB. At one peer per endpoint, one `/32` each is about 1.59 KiB per peer (3.17 KiB total). The cgroup `kernel`/`slab` counters did not account for these shared caches consistently: their deltas were far below the slab-object sizes. Global `wg_peer` active-object deltas also had background churn, so the target uses the measured object sizes plus the repeated AllowedIP cache delta. Raw per-stage cgroup, slab, RSS and machine snapshots are attached in `kernel-memory-isolation-20261102.tar.gz` (SHA-256 `ded7d7b56a73218c65ad81a62b2066773ffd3ac2ee2a85ea150b0ee43bc5f505`). GotaTun patched currently uses about 30.6 times the kernel peer-state memory per peer (50.5 KiB versus 1.65 KiB), so matching this target requires roughly a 96.7% reduction in its incremental peer memory. Its throughput remains 55% / 53% of wireguard-go at 1 / 8 flows. Next: build profiling artifacts on a dev VM, then profile the baseline and patched GotaTun plus wireguard-go under `perf-run` before selecting a single bounded tuning pass.

kernel-memory-isolation-20261102.tar.gz

684 KiB

kayg commented

2026-11-02 08:29:24 +00:00

Author

Owner

J88 memory target update (owner decision, 2026-11-02)

The owner set the incremental memory target at ≤5 KiB per peer at 1,000 peers, with the measured kernel WireGuard baseline (about 1.65 KiB per peer) as the reference to approach. This supersedes the earlier implied requirement to match the kernel exactly. GotaTun patched is currently about 50.5 KiB per added peer, so it needs roughly a 90% reduction to meet the target.

Next steps remain profile first, then a bounded memory pass: identify per-peer buffers, queues, maps and task/timer state; share or pool those allocations, keep only peer essentials, use a shared timer wheel, and avoid per-peer threads or task stacks. I will not widen the design beyond this approach unless the profile shows it is required; if so, I will stop and report the measured reason and estimate before expanding. Throughput remains ≥ wireguard-go. The existing 10–17 engineering-day estimate still covers profile, one bounded memory/throughput pass, edge matrix, repeat measurements and report; any larger redesign is excluded.

## J88 memory target update (owner decision, 2026-11-02) The owner set the incremental memory target at **≤5 KiB per peer at 1,000 peers**, with the measured kernel WireGuard baseline (about 1.65 KiB per peer) as the reference to approach. This supersedes the earlier implied requirement to match the kernel exactly. GotaTun patched is currently about 50.5 KiB per added peer, so it needs roughly a 90% reduction to meet the target. Next steps remain profile first, then a bounded memory pass: identify per-peer buffers, queues, maps and task/timer state; share or pool those allocations, keep only peer essentials, use a shared timer wheel, and avoid per-peer threads or task stacks. I will not widen the design beyond this approach unless the profile shows it is required; if so, I will stop and report the measured reason and estimate before expanding. Throughput remains ≥ wireguard-go. The existing 10–17 engineering-day estimate still covers profile, one bounded memory/throughput pass, edge matrix, repeat measurements and report; any larger redesign is excluded.

kayg commented

2026-11-02 08:48:30 +00:00

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Owner

J88 profile setup finding

The first shortened profile-harness case stopped before traffic or sampling. GotaTun could not start; env reported No such file or directory for the patched binary. The R4b machine diff was empty, and the case recorded no throughput or profile data.

Root cause: the debug-symbol binaries built on the dev VM request the Nix glibc 2.40 loader at /nix/store/xx7cm72qy2c0643cm1ipngd87aqwkcdp-glibc-2.40-66/lib/ld-linux-x86-64.so.2, which is absent on the perf VM. The existing R4b GotaTun binary requests its glibc 2.44 loader, which is present. No GotaTun source changed.

I will copy the exact debug-binary runtime libraries into this job's perf scratch area and invoke them through that loader via wrappers in the isolated profile harness. This leaves the perf VM system and the original R4b kit unchanged. I will repeat the shortened profile case before capturing the full GotaTun baseline, patched, and wireguard-go 1/8-flow profiles.

## J88 profile setup finding The first shortened profile-harness case stopped before traffic or sampling. GotaTun could not start; `env` reported `No such file or directory` for the patched binary. The R4b machine diff was empty, and the case recorded no throughput or profile data. Root cause: the debug-symbol binaries built on the dev VM request the Nix glibc 2.40 loader at `/nix/store/xx7cm72qy2c0643cm1ipngd87aqwkcdp-glibc-2.40-66/lib/ld-linux-x86-64.so.2`, which is absent on the perf VM. The existing R4b GotaTun binary requests its glibc 2.44 loader, which is present. No GotaTun source changed. I will copy the exact debug-binary runtime libraries into this job's perf scratch area and invoke them through that loader via wrappers in the isolated profile harness. This leaves the perf VM system and the original R4b kit unchanged. I will repeat the shortened profile case before capturing the full GotaTun baseline, patched, and wireguard-go 1/8-flow profiles.

kayg commented

2026-11-02 09:00:19 +00:00

Author

Owner

J88 profile smoke finding

After switching the isolated harness to the copied runtime loader, the shortened patched-GotaTun case completed its R4b workloads and generated both 1-flow and 8-flow perf.data, text reports, syscall counters, thread snapshots, and FlameGraph SVGs. The profiling hooks themselves report profile_rc=0; each endpoint had four threads in this smoke run. These shortened numbers are diagnostic only and are not throughput evidence.

The harness case exited 3 because perf wrote new build-id and symbol-cache entries under /root/.debug. Inspection of the full machine diff found no changes outside that cache. I will set HOME for every perf subprocess to a cache directory under this job's results tree and remove only the .debug paths introduced by this smoke run. Then I will repeat the smoke and require an empty machine diff before the full profiles.

## J88 profile smoke finding After switching the isolated harness to the copied runtime loader, the shortened patched-GotaTun case completed its R4b workloads and generated both 1-flow and 8-flow `perf.data`, text reports, syscall counters, thread snapshots, and FlameGraph SVGs. The profiling hooks themselves report `profile_rc=0`; each endpoint had four threads in this smoke run. These shortened numbers are diagnostic only and are not throughput evidence. The harness case exited 3 because `perf` wrote new build-id and symbol-cache entries under `/root/.debug`. Inspection of the full machine diff found no changes outside that cache. I will set `HOME` for every perf subprocess to a cache directory under this job's results tree and remove only the `.debug` paths introduced by this smoke run. Then I will repeat the smoke and require an empty machine diff before the full profiles.

kayg commented

2026-11-02 09:11:01 +00:00

Author

Owner

J88 progress: profile smoke is clean

The shortened R4b profile case for patched GotaTun (mesh-gotatun-after, --smoke) now exits 0 with an empty machine diff. It generated perf.data, a text report and FlameGraph SVG for both 1 and 8 flows, plus task-clock/cycle/instruction/cache/context-switch/syscall counts and thread snapshots. The smoke showed four threads per endpoint. Its 2-second throughput figures are diagnostic only and are not comparable to the full R4b rows below. The build-id cache now stays under the harness results directory. Full 10-second LAN profiles for GotaTun v0.10.2, patched GotaTun and wireguard-go are next.

Engine	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT 64 B p50/p99, 1 / 8 flows (ms)	Process RSS, 1 / 1,000 peers (MiB)	Incremental RSS per peer	Kernel peer state per peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.59 KiB at 1 peer; 1.65 KiB at 1,000
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun v0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun patched	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun mixed peers	1.90 / 1.83	1.22 / 1.36	2.261 / 5.648; 5.255 / 11.814	9.9 / 108.1	50.3 KiB	n/a

The memory target remains ≤5 KiB incremental per peer at 1,000 peers, approaching the measured kernel reference of 1.65 KiB. The patched GotaTun profile and smoke used the existing fork head 8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38; the fork branch itself is unchanged by this profiling setup.

## J88 progress: profile smoke is clean The shortened R4b profile case for patched GotaTun (`mesh-gotatun-after`, `--smoke`) now exits 0 with an empty machine diff. It generated `perf.data`, a text report and FlameGraph SVG for both 1 and 8 flows, plus task-clock/cycle/instruction/cache/context-switch/syscall counts and thread snapshots. The smoke showed four threads per endpoint. Its 2-second throughput figures are diagnostic only and are not comparable to the full R4b rows below. The build-id cache now stays under the harness results directory. Full 10-second LAN profiles for GotaTun v0.10.2, patched GotaTun and wireguard-go are next. | Engine | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT 64 B p50/p99, 1 / 8 flows (ms) | Process RSS, 1 / 1,000 peers (MiB) | Incremental RSS per peer | Kernel peer state per peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.59 KiB at 1 peer; 1.65 KiB at 1,000 | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun v0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun patched | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun mixed peers | 1.90 / 1.83 | 1.22 / 1.36 | 2.261 / 5.648; 5.255 / 11.814 | 9.9 / 108.1 | 50.3 KiB | n/a | The memory target remains ≤5 KiB incremental per peer at 1,000 peers, approaching the measured kernel reference of 1.65 KiB. The patched GotaTun profile and smoke used the existing fork head `8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38`; the fork branch itself is unchanged by this profiling setup.

kayg commented

2026-11-02 09:32:19 +00:00

Author

Owner

J88 progress: full perf profiles complete

The R4b cases mesh-gotatun-before, mesh-gotatun-after, and mesh-wireguard-go-before completed in one perf-run --root hold on infraternal-perf-01-backup01. Each took 184–193 s, exited 0, and had an empty machine diff. Full WAN/loss and 1,000-peer snapshots also ran; CPU profiles cover both 10-second LAN throughput samples at 1 and 8 flows.

Comparable R4b table

These are the existing un-instrumented R4b rows. The profile figures below are diagnostic and do not replace them.

Engine	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS per peer	Kernel peer state per peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.59 KiB at 1 peer; 1.65 KiB at 1,000
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun v0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun patched	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun mixed baseline/patched	1.90 / 1.83	1.22 / 1.36	2.261 / 5.648; 5.255 / 11.814	9.9 / 108.1	50.3 KiB	n/a

The GotaTun patched row remains at 55% / 53% of wireguard-go throughput, and 50.5 KiB per added peer is 10× the ≤5 KiB target.

Instrumented LAN profile (diagnostic only)

Engine	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT 64 B p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)
wireguard-go	2.77 / 2.75	0.98 / 0.99	4.818 / 43.755; 12.422 / 29.355	27.1 / 987.2
GotaTun v0.10.2	1.24 / 1.07	2.04 / 2.48	3.474 / 10.140; 7.728 / 19.720	9.2 / 102.7
GotaTun patched	1.65 / 1.42	1.49 / 1.81	3.385 / 11.014; 8.260 / 23.914	9.6 / 103.3

Profile findings

Before the patch, the main sampled leaves were UDP sendmmsg (17–18%), epoll_wait (17–18%), TUN tun_get_user (about 11%), and ChaCha20-Poly1305 seal/open (about 4% / 3% each). After the GSO/TSO patch, sendmmsg fell to 5–5.5% and recvmmsg to 1.5–1.7%; epoll_wait remained 16–19%, TUN reads 15–17%, and AEAD seal/open 4–6% each. memmove was 0.8–2.2%.
The instrumented raw sys_enter totals for 1 / 8 flows were 3.30m / 3.19m (baseline GotaTun), 2.59m / 2.56m (patched GotaTun), and 0.59m / 0.68m (wireguard-go). TUN packet counters count GSO/GRO aggregates differently, so dividing these totals by those counters is not an apples-to-apples syscall-per-packet comparison. The profiles show the remaining cost in the per-packet TUN, UDP, and async I/O path rather than a crypto-dominated stack.
GotaTun ran four OS threads per endpoint in both profiles (main plus three Tokio workers); wireguard-go used 11 per endpoint at 1 flow and 12–13 at 8 flows. GotaTun has one device timer task that iterates peers, not a task per peer.
The profiles do not indicate a need for a wider runtime redesign. I will stay within the requested shared/pool memory and packet-I/O scope while tracing the 50 KiB peer growth to specific retained allocations.

Raw R4b JSON, machine snapshots/diffs, receipts, perf.data, symbolized folded stacks, reports, counters, thread snapshots, and FlameGraph SVGs are attached. They are also retained under /home/claude/j20/r4b/j88-memory-20261102/profile-harness/results/profile-full-20261102T091159Z on the perf VM.

## J88 progress: full perf profiles complete The R4b cases `mesh-gotatun-before`, `mesh-gotatun-after`, and `mesh-wireguard-go-before` completed in one `perf-run --root` hold on `infraternal-perf-01-backup01`. Each took 184–193 s, exited 0, and had an empty machine diff. Full WAN/loss and 1,000-peer snapshots also ran; CPU profiles cover both 10-second LAN throughput samples at 1 and 8 flows. ### Comparable R4b table These are the existing un-instrumented R4b rows. The profile figures below are diagnostic and do not replace them. | Engine | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS per peer | Kernel peer state per peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.59 KiB at 1 peer; 1.65 KiB at 1,000 | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun v0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun patched | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun mixed baseline/patched | 1.90 / 1.83 | 1.22 / 1.36 | 2.261 / 5.648; 5.255 / 11.814 | 9.9 / 108.1 | 50.3 KiB | n/a | The GotaTun patched row remains at 55% / 53% of wireguard-go throughput, and 50.5 KiB per added peer is 10× the ≤5 KiB target. ### Instrumented LAN profile (diagnostic only) | Engine | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT 64 B p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | |---|---:|---:|---:|---:| | wireguard-go | 2.77 / 2.75 | 0.98 / 0.99 | 4.818 / 43.755; 12.422 / 29.355 | 27.1 / 987.2 | | GotaTun v0.10.2 | 1.24 / 1.07 | 2.04 / 2.48 | 3.474 / 10.140; 7.728 / 19.720 | 9.2 / 102.7 | | GotaTun patched | 1.65 / 1.42 | 1.49 / 1.81 | 3.385 / 11.014; 8.260 / 23.914 | 9.6 / 103.3 | ### Profile findings - Before the patch, the main sampled leaves were UDP `sendmmsg` (17–18%), `epoll_wait` (17–18%), TUN `tun_get_user` (about 11%), and ChaCha20-Poly1305 seal/open (about 4% / 3% each). After the GSO/TSO patch, `sendmmsg` fell to 5–5.5% and `recvmmsg` to 1.5–1.7%; `epoll_wait` remained 16–19%, TUN reads 15–17%, and AEAD seal/open 4–6% each. `memmove` was 0.8–2.2%. - The instrumented raw `sys_enter` totals for 1 / 8 flows were 3.30m / 3.19m (baseline GotaTun), 2.59m / 2.56m (patched GotaTun), and 0.59m / 0.68m (wireguard-go). TUN packet counters count GSO/GRO aggregates differently, so dividing these totals by those counters is not an apples-to-apples syscall-per-packet comparison. The profiles show the remaining cost in the per-packet TUN, UDP, and async I/O path rather than a crypto-dominated stack. - GotaTun ran four OS threads per endpoint in both profiles (main plus three Tokio workers); wireguard-go used 11 per endpoint at 1 flow and 12–13 at 8 flows. GotaTun has one device timer task that iterates peers, not a task per peer. - The profiles do not indicate a need for a wider runtime redesign. I will stay within the requested shared/pool memory and packet-I/O scope while tracing the 50 KiB peer growth to specific retained allocations. Raw R4b JSON, machine snapshots/diffs, receipts, `perf.data`, symbolized folded stacks, reports, counters, thread snapshots, and FlameGraph SVGs are attached. They are also retained under `/home/claude/j20/r4b/j88-memory-20261102/profile-harness/results/profile-full-20261102T091159Z` on the perf VM.

profile-full-20261102T091159Z-evidence.tar.gz

15 MiB

kayg commented

2026-11-02 09:39:14 +00:00

Author

Owner

J88 next slice: trace the 50 KiB peer growth

Owner memory target: ≤5 KiB incremental per peer at 1,000 peers, approaching the measured kernel WireGuard state of 1.65 KiB. Throughput target remains ≥ wireguard-go. I will stay in the public fork branch j88-linux-offloads; no upstream PRs, comments or issues, and no product integration.

Plan and test matrix

Inventory retained GotaTun allocations at 1 and 1,000 peers. Attribute the per-peer delta across the peer object, session/replay state, AllowedIPs map, queues/buffers, and async tasks; compare type sizes with observed RSS/PSS and allocator/slab evidence. The current profile shows one shared device timer and device-wide lazy packet pool, so I will not introduce a runtime redesign.
Use the allocation evidence to select one bounded memory change, if it can address measured retained bytes. Add a failing regression test first; keep peer packet ordering/replay and mixed-peer behavior intact. Build and run focused tests on a dev VM.
Break-it matrix: loss and reordering; MTU/fragmentation boundaries; IPv4 and IPv6; mixed patched/unpatched peers; supported and forced unsupported IFF_VNET_HDR/TUNSETOFFLOAD; peer memory at 1 and 1,000. Preserve each raw result and machine diff.
Re-run the same R4b harness on the perf VM via perf-run --root, in one held tool call: kernel WireGuard, wireguard-go, GotaTun baseline and patched at 1/8 flows, CPU/Gbit, loaded p50/p99, RSS at 1/1,000, plus the measured 1.65 KiB kernel peer-state reference. Keep diagnostic profiles separate from timing runs.
Post the same table and evidence after each meaningful step; push only the fork branch when the change is verified.

Estimate from current profile

Allocation attribution and proposed byte budget: 0.5–1 engineering day.
One bounded memory pass and focused regression tests: 1–2 days.
Throughput tuning from the already captured flamegraphs: 2–4 days, only if a single measured bottleneck supports a focused change.
Edge matrix and paired perf table: 1–2 days.
Evidence, final table and fork push: 0.5 day.

Total remaining estimate: 5–9 engineering days, subject to the memory attribution. If measured allocation sources show that ≤5 KiB requires a wider redesign than shared/pooled buffers and compact per-peer state, I will stop with the measured breakdown and revised estimate before expanding scope.

## J88 next slice: trace the 50 KiB peer growth Owner memory target: ≤5 KiB incremental per peer at 1,000 peers, approaching the measured kernel WireGuard state of 1.65 KiB. Throughput target remains ≥ wireguard-go. I will stay in the public fork branch `j88-linux-offloads`; no upstream PRs, comments or issues, and no product integration. ### Plan and test matrix 1. Inventory retained GotaTun allocations at 1 and 1,000 peers. Attribute the per-peer delta across the peer object, session/replay state, AllowedIPs map, queues/buffers, and async tasks; compare type sizes with observed RSS/PSS and allocator/slab evidence. The current profile shows one shared device timer and device-wide lazy packet pool, so I will not introduce a runtime redesign. 2. Use the allocation evidence to select one bounded memory change, if it can address measured retained bytes. Add a failing regression test first; keep peer packet ordering/replay and mixed-peer behavior intact. Build and run focused tests on a dev VM. 3. Break-it matrix: loss and reordering; MTU/fragmentation boundaries; IPv4 and IPv6; mixed patched/unpatched peers; supported and forced unsupported `IFF_VNET_HDR`/`TUNSETOFFLOAD`; peer memory at 1 and 1,000. Preserve each raw result and machine diff. 4. Re-run the same R4b harness on the perf VM via `perf-run --root`, in one held tool call: kernel WireGuard, wireguard-go, GotaTun baseline and patched at 1/8 flows, CPU/Gbit, loaded p50/p99, RSS at 1/1,000, plus the measured 1.65 KiB kernel peer-state reference. Keep diagnostic profiles separate from timing runs. 5. Post the same table and evidence after each meaningful step; push only the fork branch when the change is verified. ### Estimate from current profile - Allocation attribution and proposed byte budget: 0.5–1 engineering day. - One bounded memory pass and focused regression tests: 1–2 days. - Throughput tuning from the already captured flamegraphs: 2–4 days, only if a single measured bottleneck supports a focused change. - Edge matrix and paired perf table: 1–2 days. - Evidence, final table and fork push: 0.5 day. Total remaining estimate: 5–9 engineering days, subject to the memory attribution. If measured allocation sources show that ≤5 KiB requires a wider redesign than shared/pooled buffers and compact per-peer state, I will stop with the measured breakdown and revised estimate before expanding scope.

kayg commented

2026-11-02 09:47:37 +00:00

Author

Owner

J88 progress: first retained-allocation lead

The first source-level allocation audit found a duplicate per-peer AllowedIPs trie. The device already keeps one shared trie for packet routing; each PeerState also constructs a private IPv4/IPv6 IpNetworkTable used for listing and rebuilding routes. The pinned treebitmap constructor eagerly allocates 32-entry freelists in 36 buckets for that table: 4,608 bytes of freelist payload per peer, before allocator overhead, even with one /32. A compact per-peer Vec<IpNetwork> appears to preserve the listing/update need while keeping the shared route trie. This is an upper-bound source estimate, not yet an observed RSS saving.

That finding alone can explain only about 4.6 KiB of the current 50.5 KiB/peer slope; the remainder is still unexplained. I have made no code change and will not widen the design based on this partial attribution.

Same R4b comparison table

Engine	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS per peer	Kernel peer state per peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.59 KiB at 1 peer; 1.65 KiB at 1,000
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun v0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun patched	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun mixed	1.90 / 1.83	1.22 / 1.36	2.261 / 5.648; 5.255 / 11.814	9.9 / 108.1	50.3 KiB	n/a

Build-capacity block

I checked both dev VMs before the next layout probe/build. Compute01 has 11 GiB free (25 GiB floor); dev02 has 1 GiB free and all three slots busy. I did not queue or start a build. No perf run or other background work is pending. Next: wait for a VM to meet the existing floor, then measure the in-memory type sizes and allocation contribution before selecting a test-first optimization.

Estimate to finish the remaining allocation attribution: 0.5–1 day after a compliant dev slot is available. The broader 5–9 day estimate from the plan comment remains unchanged.

## J88 progress: first retained-allocation lead The first source-level allocation audit found a duplicate per-peer AllowedIPs trie. The device already keeps one shared trie for packet routing; each `PeerState` also constructs a private IPv4/IPv6 `IpNetworkTable` used for listing and rebuilding routes. The pinned treebitmap constructor eagerly allocates 32-entry freelists in 36 buckets for that table: 4,608 bytes of freelist payload per peer, before allocator overhead, even with one `/32`. A compact per-peer `Vec<IpNetwork>` appears to preserve the listing/update need while keeping the shared route trie. This is an upper-bound source estimate, not yet an observed RSS saving. That finding alone can explain only about 4.6 KiB of the current 50.5 KiB/peer slope; the remainder is still unexplained. I have made no code change and will not widen the design based on this partial attribution. ### Same R4b comparison table | Engine | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS per peer | Kernel peer state per peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.59 KiB at 1 peer; 1.65 KiB at 1,000 | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun v0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun patched | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun mixed | 1.90 / 1.83 | 1.22 / 1.36 | 2.261 / 5.648; 5.255 / 11.814 | 9.9 / 108.1 | 50.3 KiB | n/a | ### Build-capacity block I checked both dev VMs before the next layout probe/build. Compute01 has 11 GiB free (25 GiB floor); dev02 has 1 GiB free and all three slots busy. I did not queue or start a build. No perf run or other background work is pending. Next: wait for a VM to meet the existing floor, then measure the in-memory type sizes and allocation contribution before selecting a test-first optimization. Estimate to finish the remaining allocation attribution: 0.5–1 day after a compliant dev slot is available. The broader 5–9 day estimate from the plan comment remains unchanged.

kayg commented

2026-11-02 09:50:20 +00:00

Author

Owner

J88 estimate correction

Correction to the aggregate estimate in my preceding plan comment: 5–9 days covered the near-term work items but understated the owner-approved remaining memory and throughput work. With the kernel memory baseline and throughput flamegraphs now complete, the remaining estimate is about 8.5–13.5 engineering days, assuming compliant dev build capacity returns:

finish source/allocator attribution and reduce peer/fixed memory: 3–5 days;
one bounded throughput tuning pass: 3–5 days;
correctness edge matrix plus paired R4b measurements: 2–3 days;
final evidence and report: 0.5 day.

The newly identified duplicate AllowedIPs trie accounts for 4.6 KiB of freelist payload plus about 1.7 KiB of embedded bucket structures per peer before allocator rounding. Even removing that structure would cover only roughly 12% of the current 50.5 KiB RSS slope; it is not yet a code change or a target result. The rest still needs attribution. The 10–17 day owner estimate remains consistent with this corrected remaining range plus the profiling and kernel-baseline work already completed.

## J88 estimate correction Correction to the aggregate estimate in my preceding plan comment: 5–9 days covered the near-term work items but understated the owner-approved remaining memory and throughput work. With the kernel memory baseline and throughput flamegraphs now complete, the remaining estimate is **about 8.5–13.5 engineering days**, assuming compliant dev build capacity returns: - finish source/allocator attribution and reduce peer/fixed memory: 3–5 days; - one bounded throughput tuning pass: 3–5 days; - correctness edge matrix plus paired R4b measurements: 2–3 days; - final evidence and report: 0.5 day. The newly identified duplicate AllowedIPs trie accounts for 4.6 KiB of freelist payload plus about 1.7 KiB of embedded bucket structures per peer before allocator rounding. Even removing that structure would cover only roughly 12% of the current 50.5 KiB RSS slope; it is not yet a code change or a target result. The rest still needs attribution. The 10–17 day owner estimate remains consistent with this corrected remaining range plus the profiling and kernel-baseline work already completed.

kayg commented

2026-11-02 09:56:11 +00:00

Author

Owner

J88 memory attribution progress

No code changed. The fork remains clean at j88-linux-offloads / 8c17cb1. Compute01 is available for builds (one free slot, 42 GiB free); all profiling and comparative measurements remain on the perf VM through perf-run.

Source-level allocation findings

Structure	Current evidence	Status
Per-peer AllowedIPs	Each `PeerState` constructs a private `IpNetworkTable`, while `DeviceState` already owns the shared routing trie. The treebitmap constructor reserves 4,608 bytes of freelist payload plus about 1.7 KiB of embedded bucket structures per private table before allocator rounding.	Candidate saving ~6.3 KiB/peer; source estimate only.
Tunn sessions	Every `Tunn` embeds `[Option<Session>; 8]`. Each session contains a 1,024-byte replay bitmap, so the ring reserves at least 8 KiB inside every peer even before a handshake.	Candidate for lazy session storage; exact type layout and active-session impact still to measure.
Packet pools and async tasks	Connection setup creates one device-wide lazy packet pool; the device uses shared I/O/timer tasks. There is no per-peer task or task stack in the default device path.	Already shared; no redesign indicated by the throughput profile.
Remaining RSS slope	The two source candidates explain only part of the measured 50.5 KiB/peer patched slope.	Unattributed; no change selected.

Same R4b comparison table

Engine	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS per peer	Kernel peer state per peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.59 KiB at 1 peer; 1.65 KiB at 1,000
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun v0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun patched	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun mixed	1.90 / 1.83	1.22 / 1.36	2.261 / 5.648; 5.255 / 11.814	9.9 / 108.1	50.3 KiB	n/a

The patched GotaTun row is 55% / 53% of wireguard-go throughput and remains 10.1× the ≤5 KiB/peer target. No new perf run has been started.

Licence record for owner

GotaTun's root LICENSE is the Mozilla Public License Version 2.0. LICENSE-CLOUDFLARE contains the BSD 3-Clause redistribution terms for Cloudflare-attributed code. The flake package metadata currently declares lib.licenses.bsd3; that does not match the repository's main MPL-2.0 licence declaration. D169 records GotaTun as MPL-2.0. I have not changed either licence file or the flake.

Estimate

The remaining estimate stays 8.5–13.5 engineering days: finish allocation attribution and bounded memory changes (3–5d), one profile-driven throughput tuning pass (3–5d), edge matrix and paired R4b measurements (2–3d), and final evidence (0.5d). Next: obtain exact type sizes and allocator-level retained bytes, then choose at most a bounded test-first change supported by those numbers.

## J88 memory attribution progress No code changed. The fork remains clean at `j88-linux-offloads` / `8c17cb1`. Compute01 is available for builds (one free slot, 42 GiB free); all profiling and comparative measurements remain on the perf VM through `perf-run`. ### Source-level allocation findings | Structure | Current evidence | Status | |---|---|---| | Per-peer AllowedIPs | Each `PeerState` constructs a private `IpNetworkTable`, while `DeviceState` already owns the shared routing trie. The treebitmap constructor reserves 4,608 bytes of freelist payload plus about 1.7 KiB of embedded bucket structures per private table before allocator rounding. | Candidate saving ~6.3 KiB/peer; source estimate only. | | Tunn sessions | Every `Tunn` embeds `[Option<Session>; 8]`. Each session contains a 1,024-byte replay bitmap, so the ring reserves at least 8 KiB inside every peer even before a handshake. | Candidate for lazy session storage; exact type layout and active-session impact still to measure. | | Packet pools and async tasks | Connection setup creates one device-wide lazy packet pool; the device uses shared I/O/timer tasks. There is no per-peer task or task stack in the default device path. | Already shared; no redesign indicated by the throughput profile. | | Remaining RSS slope | The two source candidates explain only part of the measured 50.5 KiB/peer patched slope. | Unattributed; no change selected. | ### Same R4b comparison table | Engine | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS per peer | Kernel peer state per peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.59 KiB at 1 peer; 1.65 KiB at 1,000 | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun v0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun patched | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun mixed | 1.90 / 1.83 | 1.22 / 1.36 | 2.261 / 5.648; 5.255 / 11.814 | 9.9 / 108.1 | 50.3 KiB | n/a | The patched GotaTun row is 55% / 53% of wireguard-go throughput and remains 10.1× the ≤5 KiB/peer target. No new perf run has been started. ### Licence record for owner GotaTun's root `LICENSE` is the Mozilla Public License Version 2.0. `LICENSE-CLOUDFLARE` contains the BSD 3-Clause redistribution terms for Cloudflare-attributed code. The flake package metadata currently declares `lib.licenses.bsd3`; that does not match the repository's main MPL-2.0 licence declaration. D169 records GotaTun as MPL-2.0. I have not changed either licence file or the flake. ### Estimate The remaining estimate stays **8.5–13.5 engineering days**: finish allocation attribution and bounded memory changes (3–5d), one profile-driven throughput tuning pass (3–5d), edge matrix and paired R4b measurements (2–3d), and final evidence (0.5d). Next: obtain exact type sizes and allocator-level retained bytes, then choose at most a bounded test-first change supported by those numbers.

kayg commented

2026-11-02 10:05:16 +00:00

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J88 progress: x86 type layout measured

The pinned GotaTun crate compiled on compute01 with Rust -Zprint-type-sizes (exit 0); log: ~/.cache/codex-scratch/j88-memory/crate-layout.log. No code changed.

Retained structure	x86_64 layout	Per-peer interpretation
`PeerState`	12,368 B	Includes the `Tunn`, private AllowedIPs table object, endpoint and watch sender.
`Tunn`	10,560 B	Includes an inline session ring, handshake, timers, RNG, and empty queue header.
`[Option<Session>; 8]`	9,024 B	All slots occupy space before any handshake; each `Session` is 1,128 B, of which 1,040 B is the replay validator.
Private `IpNetworkTable<()>`	1,760 B inline	The current constructor also allocates about 4,608 B of per-table freelist payload.
Device packet pool / I/O tasks	device-shared	One lazy pool and shared connection tasks; no per-peer packet queue allocation or task stack in the inert-peer case.

The two memory candidates total about 15.3 KiB/peer before allocator rounding: lazy session storage can avoid the 9,024-byte empty ring, and replacing the duplicate per-peer trie with compact route state can avoid its 1,760-byte table plus about 4,608 bytes of freelists. Against the measured 50.5 KiB/peer RSS slope, about 35.2 KiB/peer is still unaccounted for. These are layout/source estimates, not measured RSS savings. I have not started either change.

Same R4b comparison table

Engine	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS per peer	Kernel peer state per peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.59 KiB at 1 peer; 1.65 KiB at 1,000
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun v0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun patched	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun mixed	1.90 / 1.83	1.22 / 1.36	2.261 / 5.648; 5.255 / 11.814	9.9 / 108.1	50.3 KiB	n/a

Next: use an allocation-level profile of the same inert 1/1,000-peer setup to locate the remaining RSS slope. The x86 source layout alone is not enough to select a change that can approach the ≤5 KiB target. Current remaining estimate stays 8.5–13.5 engineering days; attribution is still in progress.

## J88 progress: x86 type layout measured The pinned GotaTun crate compiled on compute01 with Rust `-Zprint-type-sizes` (exit 0); log: `~/.cache/codex-scratch/j88-memory/crate-layout.log`. No code changed. | Retained structure | x86_64 layout | Per-peer interpretation | |---|---:|---| | `PeerState` | 12,368 B | Includes the `Tunn`, private AllowedIPs table object, endpoint and watch sender. | | `Tunn` | 10,560 B | Includes an inline session ring, handshake, timers, RNG, and empty queue header. | | `[Option<Session>; 8]` | 9,024 B | All slots occupy space before any handshake; each `Session` is 1,128 B, of which 1,040 B is the replay validator. | | Private `IpNetworkTable<()>` | 1,760 B inline | The current constructor also allocates about 4,608 B of per-table freelist payload. | | Device packet pool / I/O tasks | device-shared | One lazy pool and shared connection tasks; no per-peer packet queue allocation or task stack in the inert-peer case. | The two memory candidates total about 15.3 KiB/peer before allocator rounding: lazy session storage can avoid the 9,024-byte empty ring, and replacing the duplicate per-peer trie with compact route state can avoid its 1,760-byte table plus about 4,608 bytes of freelists. Against the measured 50.5 KiB/peer RSS slope, about 35.2 KiB/peer is still unaccounted for. These are layout/source estimates, not measured RSS savings. I have not started either change. ### Same R4b comparison table | Engine | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS per peer | Kernel peer state per peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.59 KiB at 1 peer; 1.65 KiB at 1,000 | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun v0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun patched | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun mixed | 1.90 / 1.83 | 1.22 / 1.36 | 2.261 / 5.648; 5.255 / 11.814 | 9.9 / 108.1 | 50.3 KiB | n/a | Next: use an allocation-level profile of the same inert 1/1,000-peer setup to locate the remaining RSS slope. The x86 source layout alone is not enough to select a change that can approach the ≤5 KiB target. Current remaining estimate stays 8.5–13.5 engineering days; attribution is still in progress.

kayg commented

2026-11-02 10:09:35 +00:00

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J88 progress: RSS includes a large THP-backed component

The existing R4b sample separates process RSS from cgroup memory. At 1,000 peers per endpoint, the two GotaTun processes together reported RSS 111,188 KiB and PSS 106,736 KiB. Their cgroup reported 107,393,024 bytes anonymous memory, including 46,137,344 bytes of anon_thp; at one peer the cgroup reported 3,432,448 bytes anonymous and zero anon_thp. This makes transparent huge-page-backed anonymous memory a likely contributor to the unexplained RSS slope; cgroup stats do not yet attribute those pages to individual processes.

The GotaTun CLI has existing jemalloc and mimalloc feature options in addition to the current system allocator. Next bounded profile: build both variants on a compliant dev slot and compare them in the R4b harness on the perf VM, first for per-peer memory and then throughput/loaded latency if either materially improves memory. No allocator choice is being made here.

Same R4b comparison table

Engine	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS per peer	Kernel peer state per peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.59 KiB at 1 peer; 1.65 KiB at 1,000
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun v0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun patched	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun mixed	1.90 / 1.83	1.22 / 1.36	2.261 / 5.648; 5.255 / 11.814	9.9 / 108.1	50.3 KiB	n/a

Build-capacity block

Before the allocator builds, I checked both dev VMs. Compute01 has 16 GiB free, below the required 25 GiB floor, though it has free slots. Dev02 has 84 GiB free but no free slot. I did not queue a build or start another perf run. The fork remains clean at j88-linux-offloads / 8c17cb1; no build or run is pending.

The remaining estimate is unchanged at 8.5–13.5 engineering days. Once compliant x86 build capacity returns, I will build the two existing allocator variants and profile them through perf-run.

## J88 progress: RSS includes a large THP-backed component The existing R4b sample separates process RSS from cgroup memory. At 1,000 peers per endpoint, the two GotaTun processes together reported RSS 111,188 KiB and PSS 106,736 KiB. Their cgroup reported 107,393,024 bytes anonymous memory, including 46,137,344 bytes of `anon_thp`; at one peer the cgroup reported 3,432,448 bytes anonymous and zero `anon_thp`. This makes transparent huge-page-backed anonymous memory a likely contributor to the unexplained RSS slope; cgroup stats do not yet attribute those pages to individual processes. The GotaTun CLI has existing `jemalloc` and `mimalloc` feature options in addition to the current system allocator. Next bounded profile: build both variants on a compliant dev slot and compare them in the R4b harness on the perf VM, first for per-peer memory and then throughput/loaded latency if either materially improves memory. No allocator choice is being made here. ### Same R4b comparison table | Engine | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS per peer | Kernel peer state per peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.59 KiB at 1 peer; 1.65 KiB at 1,000 | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun v0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun patched | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun mixed | 1.90 / 1.83 | 1.22 / 1.36 | 2.261 / 5.648; 5.255 / 11.814 | 9.9 / 108.1 | 50.3 KiB | n/a | ### Build-capacity block Before the allocator builds, I checked both dev VMs. Compute01 has 16 GiB free, below the required 25 GiB floor, though it has free slots. Dev02 has 84 GiB free but no free slot. I did not queue a build or start another perf run. The fork remains clean at `j88-linux-offloads` / `8c17cb1`; no build or run is pending. The remaining estimate is unchanged at **8.5–13.5 engineering days**. Once compliant x86 build capacity returns, I will build the two existing allocator variants and profile them through `perf-run`.

kayg commented

2026-11-02 10:20:14 +00:00

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J88 allocator probe: arena limit is a small, uncertain win

Two paired R4b GotaTun runs completed through perf-run --root on the perf VM, each with exit 0 and machine diff: empty. The only variable was glibc's existing system allocator setting (MALLOC_ARENA_MAX=1 versus the default). The raw JSON, logs, summaries, environment captures, and diffs are attached to this comment.

Same R4b comparison table

Engine / allocator	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS per peer	Kernel peer state
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB at 1,000
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun patched, prior R4b	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun patched, glibc default, paired run	3.06 / 2.59	0.78 / 0.97	2.005 / 5.901; 5.873 / 11.558	10.0 / 109.9	~51.2 KiB	n/a
GotaTun patched, `MALLOC_ARENA_MAX=1`	3.01 / 2.56	0.79 / 0.98	1.881 / 37.176; 6.222 / 13.340	9.9 / 105.2	~48.8 KiB	n/a

The arena limit saves about 2.4 KiB per peer in this pair, far short of the ≤5 KiB goal. Throughput is 1–2% lower; loaded latency is mixed, and the one-flow p99 outlier needs caution. The cgroup still reports 46.1 MiB anon_thp with the limit, versus 48.2 MiB with the default. This doesn't explain the full RSS slope or justify choosing the allocator setting. It is a diagnostic result only.

Raw archive SHA-256: 65990f1362158b7ace16d4d0fe5c1bc0e191610defd046afcb6f0c0281f50115; archive has both run directories and all per-case outputs.

Next: profile the existing jemalloc/mimalloc builds when a compliant x86 dev slot is available; then continue the retained-allocation attribution. The last capacity check had compute01 at 15 GiB free (below floor) and dev02 with no free slot. No build is queued; no code changed.

## J88 allocator probe: arena limit is a small, uncertain win Two paired R4b GotaTun runs completed through `perf-run --root` on the perf VM, each with exit 0 and `machine diff: empty`. The only variable was glibc's existing system allocator setting (`MALLOC_ARENA_MAX=1` versus the default). The raw JSON, logs, summaries, environment captures, and diffs are attached to this comment. ### Same R4b comparison table | Engine / allocator | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS per peer | Kernel peer state | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB at 1,000 | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun patched, prior R4b | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun patched, glibc default, paired run | 3.06 / 2.59 | 0.78 / 0.97 | 2.005 / 5.901; 5.873 / 11.558 | 10.0 / 109.9 | ~51.2 KiB | n/a | | GotaTun patched, `MALLOC_ARENA_MAX=1` | 3.01 / 2.56 | 0.79 / 0.98 | 1.881 / 37.176; 6.222 / 13.340 | 9.9 / 105.2 | ~48.8 KiB | n/a | The arena limit saves about 2.4 KiB per peer in this pair, far short of the ≤5 KiB goal. Throughput is 1–2% lower; loaded latency is mixed, and the one-flow p99 outlier needs caution. The cgroup still reports 46.1 MiB `anon_thp` with the limit, versus 48.2 MiB with the default. This doesn't explain the full RSS slope or justify choosing the allocator setting. It is a diagnostic result only. Raw archive SHA-256: `65990f1362158b7ace16d4d0fe5c1bc0e191610defd046afcb6f0c0281f50115`; archive has both run directories and all per-case outputs. Next: profile the existing jemalloc/mimalloc builds when a compliant x86 dev slot is available; then continue the retained-allocation attribution. The last capacity check had compute01 at 15 GiB free (below floor) and dev02 with no free slot. No build is queued; no code changed.

j88-allocator-arena-r4b-20261102.tar.gz

470 KiB

kayg commented

2026-11-02 11:01:26 +00:00

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J88 progress: allocator probe result and THP-first plan

Two full mesh-gotatun cases ran on the R4b perf VM under perf-run --root, using the same patched GotaTun binary from fork commit 8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38 (SHA-256 ffc73a610f1be5625cd22ddfec9b2f0955f49bc61c42bb5ad64cb893b7d3be9a). The glibc case and the mimalloc LD_PRELOAD case each took 180 s, exited 0, and had an empty machine diff. These are one sample each; the previously reported kernel WireGuard and wireguard-go controls are from the earlier R4b sweep.

Process RSS sums both endpoints. Incremental RSS divides the 1-to-1,000-peer change by 1,998 added peers. The mimalloc row is a diagnostic preload, not the Cargo mimalloc feature.

Engine / allocator	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS per peer	Kernel peer state per peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB at 1,000
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun v0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun patched, prior R4b	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun patched, paired glibc	2.65 / 2.26	0.91 / 1.11	2.199 / 35.548; 6.249 / 15.053	9.9 / 107.6	50.0 KiB	n/a
GotaTun patched, mimalloc preload	2.57 / 2.33	0.90 / 1.09	2.507 / 54.391; 6.428 / 13.598	40.2 / 152.5	57.6 KiB	n/a

Mimalloc preload increased one-peer RSS by 30.3 MiB and the 1,000-peer slope by about 7.6 KiB per peer; throughput was similar and the one-flow loaded p99 was noisy. I will not carry that preload forward. The available jemalloc shared library did not interpose: loader traces showed GotaTun's malloc/free/calloc/realloc calls binding to glibc. A jemalloc Cargo-feature build has not been measured.

Next steps

Disable THP at the Linux process entry with PR_SET_THP_DISABLE, following the #24 shim precedent. Add a focused test that checks THP_enabled in /proc/self/status; unsupported kernels must continue to run. In the disposable R4b copy, preserve cgroup memory.stat at 1 and 1,000 peers so the next paired run quantifies anon_thp as well as RSS/PSS. The existing case currently deletes its /dev/shm snapshots during cleanup.
If that measurement confirms the THP contribution, keep this as a separate commit and report its table row.
Next, make the session ring lazy and replace the duplicate per-peer AllowedIPs trie with compact route state, one bounded change at a time. Keep the device-wide routing trie, packet ordering/replay, UAPI updates, and shared I/O/timer tasks unchanged; run focused handshake/rekey and IPv4/IPv6 tests before each memory measurement.
Continue the profile-led throughput pass and remaining offload edge matrix. Stop and report measured numbers before any wider design change.

Remaining estimate

THP guard, regression coverage, and paired memory measurement: 0.5–1 day.
Lazy session ring and handshake/rekey coverage: 1.5–2.5 days.
Compact per-peer AllowedIPs state and update/listing coverage: 1–2 days.
Attribute the remaining per-peer and fixed RSS after those cuts: 1–2 days.
One profile-driven throughput tuning pass toward wireguard-go: 3–5 days.
Loss/reordering, MTU/fragmentation, mixed offload, unsupported-kernel and IPv4/IPv6 matrix; repeat paired measurements: 2–3 days.
Final evidence and report: 0.5–1 day.

Total remaining estimate: about 10–17 engineering days. Throughput remains below wireguard-go and memory remains above the ≤5 KiB per-peer target. Raw logs, JSON, receipts, machine diffs, loader traces and the disposable harness copy are attached.

## J88 progress: allocator probe result and THP-first plan Two full `mesh-gotatun` cases ran on the R4b perf VM under `perf-run --root`, using the same patched GotaTun binary from fork commit `8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38` (SHA-256 `ffc73a610f1be5625cd22ddfec9b2f0955f49bc61c42bb5ad64cb893b7d3be9a`). The glibc case and the mimalloc `LD_PRELOAD` case each took 180 s, exited 0, and had an empty machine diff. These are one sample each; the previously reported kernel WireGuard and wireguard-go controls are from the earlier R4b sweep. Process RSS sums both endpoints. Incremental RSS divides the 1-to-1,000-peer change by 1,998 added peers. The `mimalloc` row is a diagnostic preload, not the Cargo `mimalloc` feature. | Engine / allocator | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS per peer | Kernel peer state per peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB at 1,000 | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun v0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun patched, prior R4b | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun patched, paired glibc | 2.65 / 2.26 | 0.91 / 1.11 | 2.199 / 35.548; 6.249 / 15.053 | 9.9 / 107.6 | 50.0 KiB | n/a | | GotaTun patched, mimalloc preload | 2.57 / 2.33 | 0.90 / 1.09 | 2.507 / 54.391; 6.428 / 13.598 | 40.2 / 152.5 | 57.6 KiB | n/a | Mimalloc preload increased one-peer RSS by 30.3 MiB and the 1,000-peer slope by about 7.6 KiB per peer; throughput was similar and the one-flow loaded p99 was noisy. I will not carry that preload forward. The available jemalloc shared library did not interpose: loader traces showed GotaTun's malloc/free/calloc/realloc calls binding to glibc. A jemalloc Cargo-feature build has not been measured. ### Next steps 1. Disable THP at the Linux process entry with `PR_SET_THP_DISABLE`, following the #24 shim precedent. Add a focused test that checks `THP_enabled` in `/proc/self/status`; unsupported kernels must continue to run. In the disposable R4b copy, preserve cgroup `memory.stat` at 1 and 1,000 peers so the next paired run quantifies `anon_thp` as well as RSS/PSS. The existing case currently deletes its `/dev/shm` snapshots during cleanup. 2. If that measurement confirms the THP contribution, keep this as a separate commit and report its table row. 3. Next, make the session ring lazy and replace the duplicate per-peer AllowedIPs trie with compact route state, one bounded change at a time. Keep the device-wide routing trie, packet ordering/replay, UAPI updates, and shared I/O/timer tasks unchanged; run focused handshake/rekey and IPv4/IPv6 tests before each memory measurement. 4. Continue the profile-led throughput pass and remaining offload edge matrix. Stop and report measured numbers before any wider design change. ### Remaining estimate - THP guard, regression coverage, and paired memory measurement: 0.5–1 day. - Lazy session ring and handshake/rekey coverage: 1.5–2.5 days. - Compact per-peer AllowedIPs state and update/listing coverage: 1–2 days. - Attribute the remaining per-peer and fixed RSS after those cuts: 1–2 days. - One profile-driven throughput tuning pass toward wireguard-go: 3–5 days. - Loss/reordering, MTU/fragmentation, mixed offload, unsupported-kernel and IPv4/IPv6 matrix; repeat paired measurements: 2–3 days. - Final evidence and report: 0.5–1 day. Total remaining estimate: about 10–17 engineering days. Throughput remains below wireguard-go and memory remains above the ≤5 KiB per-peer target. Raw logs, JSON, receipts, machine diffs, loader traces and the disposable harness copy are attached.

j88-allocator-preload-r4b-20261102.tar.gz

506 KiB

kayg commented

2026-11-02 11:06:22 +00:00

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J88 continuation start (2026-11-02)

Branch: j88-linux-offloads
Starting head / base for this continuation: 8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38 (clean; no source edits since the plan in comment 74641).

The plan and 10–17 engineering day estimate are in comment 74641. I will execute it in the public GotaTun fork only, in this order:

Add best-effort Linux PR_SET_THP_DISABLE at process entry, with a regression check and safe behavior when the kernel rejects the option. Measure the same R4b mesh-gotatun case before and after, preserving cgroup memory.stat at 1 and 1,000 peers so anon_thp is visible.
Make the eight-slot Noise session ring lazy, then measure as a separate step with handshake/rekey/replay coverage.
Remove the duplicate per-peer AllowedIPs trie while keeping the device routing trie, then measure separately with route update/list and IPv4/IPv6 coverage.
Continue the profile-led throughput pass, then run the break-it matrix: loss/reordering, MTU/fragmentation, mixed offload peers, kernels without TUN offload, IPv4/IPv6, and peer-memory scaling. Wider redesign stops for an owner review with numbers.

Each step will report the R4b table fields: 1/8-flow throughput, CPU-s/Gbit, loaded RTT p50/p99, RSS at 1/1,000 peers, incremental RSS per peer, kernel peer-state figure, and cgroup THP bytes where applicable. Build/test only on a dev VM; measurements only through perf-run on the perf VM. No upstream PRs, issues, or comments.

J88 continuation start (2026-11-02) Branch: `j88-linux-offloads` Starting head / base for this continuation: `8c17cb1abe9b4cd8b7661dcce7d62d6d47552e38` (clean; no source edits since the plan in comment 74641). The plan and 10–17 engineering day estimate are in comment 74641. I will execute it in the public GotaTun fork only, in this order: 1. Add best-effort Linux `PR_SET_THP_DISABLE` at process entry, with a regression check and safe behavior when the kernel rejects the option. Measure the same R4b `mesh-gotatun` case before and after, preserving cgroup `memory.stat` at 1 and 1,000 peers so `anon_thp` is visible. 2. Make the eight-slot Noise session ring lazy, then measure as a separate step with handshake/rekey/replay coverage. 3. Remove the duplicate per-peer AllowedIPs trie while keeping the device routing trie, then measure separately with route update/list and IPv4/IPv6 coverage. 4. Continue the profile-led throughput pass, then run the break-it matrix: loss/reordering, MTU/fragmentation, mixed offload peers, kernels without TUN offload, IPv4/IPv6, and peer-memory scaling. Wider redesign stops for an owner review with numbers. Each step will report the R4b table fields: 1/8-flow throughput, CPU-s/Gbit, loaded RTT p50/p99, RSS at 1/1,000 peers, incremental RSS per peer, kernel peer-state figure, and cgroup THP bytes where applicable. Build/test only on a dev VM; measurements only through `perf-run` on the perf VM. No upstream PRs, issues, or comments.

kayg commented

2026-11-02 11:22:30 +00:00

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THP implementation / build-control finding

On compute01, the focused child-process test passes and observes THP_enabled: 0 after PR_SET_THP_DISABLE. The release candidate built successfully (SHA-256 737b54288395ae87fcb87e9b0f4dc5bdc83f23aea44c7e194c450c4527a75677).

I have not run a perf case yet. The existing R4b gotatun-after-8c17cb1 binary links to Nix glibc 2.44, while the new candidate links to glibc 2.40 and that runtime path is absent on the perf VM. I will rebuild the unmodified 8c17cb1 baseline and use the candidate under the same GotaTun flake/toolchain, then record both processes' /proc/<pid>/status THP_enabled and preserve memory.stat at 1 and 1,000 peers. This keeps the paired memory comparison controlled.

The code diff is limited to the Linux CLI startup call and gotatun-cli/src/thp.rs; no upstream or infraternal product changes.

## THP implementation / build-control finding On compute01, the focused child-process test passes and observes `THP_enabled: 0` after `PR_SET_THP_DISABLE`. The release candidate built successfully (SHA-256 `737b54288395ae87fcb87e9b0f4dc5bdc83f23aea44c7e194c450c4527a75677`). I have not run a perf case yet. The existing R4b `gotatun-after-8c17cb1` binary links to Nix glibc 2.44, while the new candidate links to glibc 2.40 and that runtime path is absent on the perf VM. I will rebuild the unmodified `8c17cb1` baseline and use the candidate under the same GotaTun flake/toolchain, then record both processes' `/proc/<pid>/status` `THP_enabled` and preserve `memory.stat` at 1 and 1,000 peers. This keeps the paired memory comparison controlled. The code diff is limited to the Linux CLI startup call and `gotatun-cli/src/thp.rs`; no upstream or infraternal product changes.

kayg commented

2026-11-02 11:26:12 +00:00

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THP step code progress

Commit 8db98bd (perf: disable THP on Linux CLI startup (#260)) is pushed on j88-linux-offloads. It applies PR_SET_THP_DISABLE before the Unix CLI starts; a rejected prctl is non-fatal. The focused child-process test passed on compute01 and observed THP_enabled: 0. Release build: exit 0, candidate SHA-256 737b54288395ae87fcb87e9b0f4dc5bdc83f23aea44c7e194c450c4527a75677.

No perf case has run yet. To keep the THP before/after comparison matched, I need to rebuild the unmodified 8c17cb1 source with the same GotaTun flake/toolchain. Compute01 currently has only 18 GiB free, below the 25 GiB build-slot floor; dev02 has free slots but is aarch64 and cannot produce the perf VM's x86 binary. I have not queued a build. The disposable R4b harness copy is prepared with persistent memory.stat and per-process THP_enabled captures.

## THP step code progress Commit `8db98bd` (`perf: disable THP on Linux CLI startup (#260)`) is pushed on `j88-linux-offloads`. It applies `PR_SET_THP_DISABLE` before the Unix CLI starts; a rejected `prctl` is non-fatal. The focused child-process test passed on compute01 and observed `THP_enabled: 0`. Release build: exit 0, candidate SHA-256 `737b54288395ae87fcb87e9b0f4dc5bdc83f23aea44c7e194c450c4527a75677`. No perf case has run yet. To keep the THP before/after comparison matched, I need to rebuild the unmodified `8c17cb1` source with the same GotaTun flake/toolchain. Compute01 currently has only 18 GiB free, below the 25 GiB build-slot floor; dev02 has free slots but is aarch64 and cannot produce the perf VM's x86 binary. I have not queued a build. The disposable R4b harness copy is prepared with persistent `memory.stat` and per-process `THP_enabled` captures.

kayg commented

2026-11-02 11:39:28 +00:00

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J88 continuation plan (2026-11-02), from the already-pushed THP commit 8db98bd2b0d00b253de80553c9882e4116b069b5 on j88-linux-offloads.

Rebuild the unchanged 8c17cb1 baseline with the candidate's exact GotaTun flake/toolchain so the perf VM can run both. Use the prepared R4b copy to capture /proc/<pid>/status THP_enabled, RSS/PSS, and cgroup memory.stat (anon_thp) at 1 and 1,000 peers. Compare this with the THP-disabled candidate as a separate row.
Keep the memory work bounded and one change per step: make the eight-slot Noise session ring lazy, then remove the duplicate per-peer AllowedIPs trie while retaining the device routing trie. Run handshake/rekey/replay coverage before the first change and route update/list plus IPv4/IPv6 coverage before the second; measure each step in the same R4b table.
Use the perf VM flamegraph/profile to justify any throughput tuning. Then finish the loss/reordering, MTU/fragmentation, mixed-offload, unsupported-TUN-offload, IPv4/IPv6, and 1/1,000-peer matrix. If the two approved structural cuts and profile do not justify reaching the ≤5 KiB/peer goal, stop before wider redesign and report the measured attribution for owner review.
Build and run functional checks on a dev VM only; run measurements only through perf-run on the perf VM, with each measurement batch blocking to completion in a single tool invocation. Keep upstream contribution parked.

Estimate remains 10–17 engineering days: THP paired run 0.5–1d; lazy sessions 1.5–2.5d; route-state cut 1–2d; remaining memory attribution 1–2d; profile-led throughput work 3–5d; edge matrix and paired measurements 2–3d; final evidence 0.5–1d. Current measured baseline remains the R4b table in comment 73644, augmented by the corrected same-session J88 rows in comment 74344 and memory accounting in comments 74560–74570. No perf claim is made for THP until the paired run completes.

J88 continuation plan (2026-11-02), from the already-pushed THP commit `8db98bd2b0d00b253de80553c9882e4116b069b5` on `j88-linux-offloads`. 1. Rebuild the unchanged `8c17cb1` baseline with the candidate's exact GotaTun flake/toolchain so the perf VM can run both. Use the prepared R4b copy to capture `/proc/<pid>/status` `THP_enabled`, RSS/PSS, and cgroup `memory.stat` (`anon_thp`) at 1 and 1,000 peers. Compare this with the THP-disabled candidate as a separate row. 2. Keep the memory work bounded and one change per step: make the eight-slot Noise session ring lazy, then remove the duplicate per-peer AllowedIPs trie while retaining the device routing trie. Run handshake/rekey/replay coverage before the first change and route update/list plus IPv4/IPv6 coverage before the second; measure each step in the same R4b table. 3. Use the perf VM flamegraph/profile to justify any throughput tuning. Then finish the loss/reordering, MTU/fragmentation, mixed-offload, unsupported-TUN-offload, IPv4/IPv6, and 1/1,000-peer matrix. If the two approved structural cuts and profile do not justify reaching the ≤5 KiB/peer goal, stop before wider redesign and report the measured attribution for owner review. 4. Build and run functional checks on a dev VM only; run measurements only through `perf-run` on the perf VM, with each measurement batch blocking to completion in a single tool invocation. Keep upstream contribution parked. Estimate remains 10–17 engineering days: THP paired run 0.5–1d; lazy sessions 1.5–2.5d; route-state cut 1–2d; remaining memory attribution 1–2d; profile-led throughput work 3–5d; edge matrix and paired measurements 2–3d; final evidence 0.5–1d. Current measured baseline remains the R4b table in comment 73644, augmented by the corrected same-session J88 rows in comment 74344 and memory accounting in comments 74560–74570. No perf claim is made for THP until the paired run completes.

kayg commented

2026-11-02 11:40:44 +00:00

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J88 progress: the fork is clean at 8db98bd2b0d00b253de80553c9882e4116b069b5. No build or perf run is pending. I checked both dev VM build slots before attempting the matched THP baseline build: compute01 has 12 GiB free (below the required 25 GiB floor); dev02 has 27 GiB free, is aarch64, and has queued build work. I have not queued a build or started a perf case. I will continue source review on the two bounded memory cuts and retry the x86 build when compliant capacity is available.

Current same-session R4b comparison (THP step still unmeasured)

Engine	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS/peer	Kernel peer state/peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB at 1,000
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun v0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun offloads, before THP change	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun offloads + THP disabled	pending matched run

The offload build reaches 55% / 53% of wireguard-go throughput and is 10.1× the ≤5 KiB/peer target. Its existing 46.1 MiB cgroup anon_thp observation at 1,000 peers is suggestive, not yet attributable to the THP startup setting. The next measurement remains a matched rebuild of the unchanged 8c17cb1 baseline and the THP candidate under the same toolchain, preserving cgroup memory.stat and each process's THP_enabled field. Reference rows are from R4b/J88 prior runs (comments 73644, 74344, and 74560–74570), not new measurements in this continuation.

J88 progress: the fork is clean at `8db98bd2b0d00b253de80553c9882e4116b069b5`. No build or perf run is pending. I checked both dev VM build slots before attempting the matched THP baseline build: compute01 has 12 GiB free (below the required 25 GiB floor); dev02 has 27 GiB free, is aarch64, and has queued build work. I have not queued a build or started a perf case. I will continue source review on the two bounded memory cuts and retry the x86 build when compliant capacity is available. ### Current same-session R4b comparison (THP step still unmeasured) | Engine | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS/peer | Kernel peer state/peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB at 1,000 | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun v0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun offloads, before THP change | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun offloads + THP disabled | pending matched run | | | | | | The offload build reaches 55% / 53% of wireguard-go throughput and is 10.1× the ≤5 KiB/peer target. Its existing 46.1 MiB cgroup `anon_thp` observation at 1,000 peers is suggestive, not yet attributable to the THP startup setting. The next measurement remains a matched rebuild of the unchanged `8c17cb1` baseline and the THP candidate under the same toolchain, preserving cgroup `memory.stat` and each process's `THP_enabled` field. Reference rows are from R4b/J88 prior runs (comments 73644, 74344, and 74560–74570), not new measurements in this continuation.

kayg commented

2026-11-02 12:20:56 +00:00

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J88 progress: paired THP measurement

The matched R4b GotaTun case ran on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), perf.slice CPUs 1–3 with a 6 GiB cap. Both 180-second cases exited 0 with empty machine diffs. The control is fork commit 8c17cb1 (THP enabled); the candidate is 8db98bd (THP disabled). THP_enabled was 1 on both control processes and 0 on both candidate processes.

RSS sums the two endpoint daemons. Incremental RSS divides the 1-to-1,000-peer change by 1,998 added peers. The kernel state figure is the measured in-kernel peer-state accounting from the prior R4b/J88 isolation, not the kernel daemon's process RSS.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS / peer	Kernel peer state / peer	cgroup anon_thp at 1 / 1,000 peers
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB	n/a
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a	n/a
GotaTun 0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a	n/a
GotaTun offloads, prior R4b sample	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a	n/a
GotaTun offloads, paired THP-on control	3.15 / 2.80	0.79 / 0.98	1.878 / 6.861; 6.577 / 12.159	9.6 / 109.7	51.3 KiB	n/a	0 / 62 MiB
GotaTun offloads + THP disabled	2.99 / 2.44	0.82 / 1.00	2.177 / 5.580; 6.324 / 14.234	9.5 / 68.4	30.2 KiB	n/a	0 / 0

At 1,000 peers, THP disablement reduced RSS by 41.3 MiB and the incremental slope by 21.1 KiB per peer. cgroup anon_thp fell from 65,011,712 bytes to zero. One-peer RSS was unchanged within 0.1 MiB. This is still about 6× the ≤5 KiB/peer target. Throughput and latency are one sample per variant; treat their differences as noisy, not causal.

Raw paired result archive SHA-256: 0bd560129f9c9da459c70bf1334bd782dac660b86903084eea0cbc561c9445ad (attached). Next bounded cut: lazy allocation of the eight-slot Noise session ring, then a separate same-harness measurement.

## J88 progress: paired THP measurement The matched R4b GotaTun case ran on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), perf.slice CPUs 1–3 with a 6 GiB cap. Both 180-second cases exited 0 with empty machine diffs. The control is fork commit `8c17cb1` (THP enabled); the candidate is `8db98bd` (THP disabled). `THP_enabled` was 1 on both control processes and 0 on both candidate processes. RSS sums the two endpoint daemons. Incremental RSS divides the 1-to-1,000-peer change by 1,998 added peers. The kernel state figure is the measured in-kernel peer-state accounting from the prior R4b/J88 isolation, not the kernel daemon's process RSS. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS / peer | Kernel peer state / peer | cgroup anon_thp at 1 / 1,000 peers | |---|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | n/a | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | n/a | | GotaTun 0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | n/a | | GotaTun offloads, prior R4b sample | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | n/a | | GotaTun offloads, paired THP-on control | 3.15 / 2.80 | 0.79 / 0.98 | 1.878 / 6.861; 6.577 / 12.159 | 9.6 / 109.7 | 51.3 KiB | n/a | 0 / 62 MiB | | GotaTun offloads + THP disabled | 2.99 / 2.44 | 0.82 / 1.00 | 2.177 / 5.580; 6.324 / 14.234 | 9.5 / 68.4 | 30.2 KiB | n/a | 0 / 0 | At 1,000 peers, THP disablement reduced RSS by 41.3 MiB and the incremental slope by 21.1 KiB per peer. cgroup `anon_thp` fell from 65,011,712 bytes to zero. One-peer RSS was unchanged within 0.1 MiB. This is still about 6× the ≤5 KiB/peer target. Throughput and latency are one sample per variant; treat their differences as noisy, not causal. Raw paired result archive SHA-256: `0bd560129f9c9da459c70bf1334bd782dac660b86903084eea0cbc561c9445ad` (attached). Next bounded cut: lazy allocation of the eight-slot Noise session ring, then a separate same-harness measurement.

j88-thp-paired-results.tar.gz

453 KiB

kayg commented

2026-11-02 12:57:04 +00:00

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Owner direction (kayg, 2026-11-02): prove GotaTun stable and crunch the throughput/latency/memory numbers in the fork first, then switch Linux to it. No product integration yet. The owner also noted the payoff: with a userspace engine, all mesh packets pass through our process, so connections to the node's own mesh IP (SSH :22, proxy :80/:443) can be terminated in-process. No host port conflict and no NAT redirect are needed; on NetBird (kernel WireGuard) the OS stack sees them first, hence the 22 → 22022 juggling. Qualification targets before switching: throughput ≥ kernel WireGuard at 1 and 8 flows, loaded p99 within kernel ± a small margin, ≤ 5 KB per peer, plus the edge-case matrix.

Owner direction (kayg, 2026-11-02): **prove GotaTun stable and crunch the throughput/latency/memory numbers in the fork first, then switch Linux to it.** No product integration yet. The owner also noted the payoff: with a userspace engine, all mesh packets pass through our process, so connections to the node's own mesh IP (SSH :22, proxy :80/:443) can be terminated in-process. No host port conflict and no NAT redirect are needed; on NetBird (kernel WireGuard) the OS stack sees them first, hence the 22 → 22022 juggling. Qualification targets before switching: throughput ≥ kernel WireGuard at 1 and 8 flows, loaded p99 within kernel ± a small margin, ≤ 5 KB per peer, plus the edge-case matrix.

kayg referenced this issue

2026-11-02 12:57:04 +00:00

Mesh: SSH over the mesh (D197 M1, D235) #221

kayg commented

2026-11-02 12:59:05 +00:00

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Owner

Owner decision (kayg, 2026-11-02) on D163: the Linux mesh data plane switches to GotaTun now, using our fork, and improvements keep shipping from it. Owner: "using kernel wireguard right now is a path backward, let's directly use gotatun and keep shipping improvements. our own app would become a nice dogfood."

One engine on every platform (macOS is already GotaTun, D169). A userspace engine lets mesh SSH (:22) and publish (:80/:443) on the node's own mesh IP be answered in-process, with no host port conflicts or redirects (#221 S4, #281).
Source: our fork github.com/kaygdotorg/gotatun, pinned by commit (currently the offloads plus THP-off line). Performance work (J88) continues there and is pulled in by bumping the pin.
Kernel WireGuard becomes a fallback only if needed during the transition; GotaTun is the default.
To be recorded as a DECISIONS amendment to D163 with this date.

**Owner decision (kayg, 2026-11-02) on D163: the Linux mesh data plane switches to GotaTun now, using our fork, and improvements keep shipping from it.** Owner: "using kernel wireguard right now is a path backward, let's directly use gotatun and keep shipping improvements. our own app would become a nice dogfood." - One engine on every platform (macOS is already GotaTun, D169). A userspace engine lets mesh SSH (:22) and publish (:80/:443) on the node's own mesh IP be answered in-process, with no host port conflicts or redirects (#221 S4, #281). - Source: our fork github.com/kaygdotorg/gotatun, pinned by commit (currently the offloads plus THP-off line). Performance work (J88) continues there and is pulled in by bumping the pin. - Kernel WireGuard becomes a fallback only if needed during the transition; GotaTun is the default. - To be recorded as a DECISIONS amendment to D163 with this date.

kayg commented

2026-11-02 13:03:22 +00:00

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J103 start: branch mesh-gotatun-linux, based on origin/dev at 17d282a187611c85aca4058fac161268454c5b8d. I checked both Linux build queues before scheduling any work: compute01 has four occupied slots and one queued build; dev-02 has two occupied slots and queued work, with disk above the 25 GiB floor.

Plan:

Reuse the existing mesh data-plane boundary and the macOS GotaTun adapter structure; add a Linux GotaTun TUN engine with offloads, coordinator peer keys/allowed IPs, and the existing relay and rotation hooks. Keep kernel WireGuard selectable per node as a transition fallback; make GotaTun the Linux default. Disable THP in the engine process.
Preserve the D228 C rootless limit: TUN creation needs CAP_NET_ADMIN; rootless mode remains own-traffic only and does not gain a host tunnel promise. Keep a clean future in-process service hook for #221 S4/#281 without adding interception now.
Pin github.com/kaygdotorg/gotatun to the J88 offloads + THP-off commit 8db98bd2b0d00b253de80553c9882e4116b069b5; check deny.toml/MPL-2.0, record the fork LICENSE vs flake.nix mismatch, and amend D163.
Add/run namespace direct and relay byte-exact e2e coverage, failover/rebound, rotation overlap, and run R4b throughput/latency/memory comparisons against kernel WireGuard on the perf VM. Then run the repo gate on a dev VM and push this branch.

Estimate: 5–8 engineering days, mostly Linux engine integration and the full e2e/perf matrix. Estimate assumes the J88 commit builds against the existing workspace toolchain and the VM/perf queues have capacity; I will report any concrete blocker with evidence.

J103 start: branch `mesh-gotatun-linux`, based on `origin/dev` at `17d282a187611c85aca4058fac161268454c5b8d`. I checked both Linux build queues before scheduling any work: compute01 has four occupied slots and one queued build; dev-02 has two occupied slots and queued work, with disk above the 25 GiB floor. Plan: 1. Reuse the existing mesh data-plane boundary and the macOS GotaTun adapter structure; add a Linux GotaTun TUN engine with offloads, coordinator peer keys/allowed IPs, and the existing relay and rotation hooks. Keep kernel WireGuard selectable per node as a transition fallback; make GotaTun the Linux default. Disable THP in the engine process. 2. Preserve the D228 C rootless limit: TUN creation needs `CAP_NET_ADMIN`; rootless mode remains own-traffic only and does not gain a host tunnel promise. Keep a clean future in-process service hook for #221 S4/#281 without adding interception now. 3. Pin `github.com/kaygdotorg/gotatun` to the J88 offloads + THP-off commit `8db98bd2b0d00b253de80553c9882e4116b069b5`; check `deny.toml`/MPL-2.0, record the fork LICENSE vs flake.nix mismatch, and amend D163. 4. Add/run namespace direct and relay byte-exact e2e coverage, failover/rebound, rotation overlap, and run R4b throughput/latency/memory comparisons against kernel WireGuard on the perf VM. Then run the repo gate on a dev VM and push this branch. Estimate: 5–8 engineering days, mostly Linux engine integration and the full e2e/perf matrix. Estimate assumes the J88 commit builds against the existing workspace toolchain and the VM/perf queues have capacity; I will report any concrete blocker with evidence.

kayg commented

2026-11-02 13:15:04 +00:00

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J103 findings with source evidence:

deny.toml already allows MPL-2.0; the fork's workspace manifest and LICENSE both identify MPL-2.0, so no new license allowlist entry is needed for that license. The packaged infraternal binary is still labeled AGPL-3.0-only in nix/package.nix (the flake's package metadata). That does not describe the fork's MPL-2.0 source license; recording the mismatch here per the owner decision, without changing license metadata in this job.
origin/dev has the Linux kernel adapter (crates/plugins/mesh/src/wireguard.rs) and the #220 relay shim (relay_path.rs), but no macOS node adapter file. The D169 macOS adapter structure is available in the recorded source snapshot 34b341bc2 (crates/plugins/mesh/src/macos_node.rs): GotaTun DeviceBuilder, custom packet I/O traits, peer mapping from coordinator config, and an isolated worker/runtime.
The fork's current J88 branch head is 77109e5f (lazy peer session ring), but there are no GitHub check runs and no test result recorded for that commit yet. 8db98bd2b0d00b253de80553c9882e4116b069b5 is the last J88 commit with reported build and focused THP-test evidence and includes the tested offload commit 8c17cb1; this is the pin for J103.
D228 rootless mode only covers infraternal agent traffic; other host programs use the local proxy. Creating a Linux TUN requires CAP_NET_ADMIN. D313 seam C currently keeps direct traffic in kernel WireGuard; today's owner decision on D163 supersedes that engine choice while keeping the #220 relay protocol/handoff unchanged.

J103 findings with source evidence: - `deny.toml` already allows `MPL-2.0`; the fork's workspace manifest and `LICENSE` both identify MPL-2.0, so no new license allowlist entry is needed for that license. The packaged infraternal binary is still labeled `AGPL-3.0-only` in `nix/package.nix` (the flake's package metadata). That does not describe the fork's MPL-2.0 source license; recording the mismatch here per the owner decision, without changing license metadata in this job. - `origin/dev` has the Linux kernel adapter (`crates/plugins/mesh/src/wireguard.rs`) and the #220 relay shim (`relay_path.rs`), but no macOS node adapter file. The D169 macOS adapter structure is available in the recorded source snapshot `34b341bc2` (`crates/plugins/mesh/src/macos_node.rs`): GotaTun `DeviceBuilder`, custom packet I/O traits, peer mapping from coordinator config, and an isolated worker/runtime. - The fork's current J88 branch head is `77109e5f` (lazy peer session ring), but there are no GitHub check runs and no test result recorded for that commit yet. `8db98bd2b0d00b253de80553c9882e4116b069b5` is the last J88 commit with reported build and focused THP-test evidence and includes the tested offload commit `8c17cb1`; this is the pin for J103. - D228 rootless mode only covers infraternal agent traffic; other host programs use the local proxy. Creating a Linux TUN requires `CAP_NET_ADMIN`. D313 seam C currently keeps direct traffic in kernel WireGuard; today's owner decision on D163 supersedes that engine choice while keeping the #220 relay protocol/handoff unchanged.

kayg commented

2026-11-02 14:06:35 +00:00

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Owner

J88 progress: lazy session ring measurement (2026-11-02)

The same R4b harness case ran against fork commit 77109e5f on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), through perf-run --root, CPUs 1–3, 6 GiB. It exited 0 in 181 seconds with an empty machine diff. Each row is one run; traffic and memory include both endpoint processes. The peer-scale case configured 1,000 peers at each endpoint.

Engine / step	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS per peer	Kernel peer state / peer	cgroup anon_thp at 1 / 1,000 peers
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB	n/a
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a	n/a
GotaTun 0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a	n/a
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a	n/a
GotaTun offloads, paired THP-on control	3.15 / 2.80	0.79 / 0.98	1.878 / 6.861; 6.577 / 12.159	9.6 / 109.7	51.3 KiB	n/a	0 / 62 MiB
GotaTun offloads + THP disabled	2.99 / 2.44	0.82 / 1.00	2.177 / 5.580; 6.324 / 14.234	9.5 / 68.4	30.2 KiB	n/a	0 / 0
GotaTun offloads + THP disabled + lazy session ring	3.04 / 2.54	0.81 / 1.00	2.050 / 5.124; 6.564 / 13.579	9.6 / 52.3	21.9 KiB	n/a	0 / 0

At one and 1,000 peers, cgroup anon_thp was zero; the two processes reported THP_enabled: 0. RSS at one peer was 9,780 KiB and at 1,000 peers 53,512 KiB. The incremental slope is (53,512 - 9,780) / 1,998 = 21.9 KiB per added peer. Against the paired THP-off run, the lazy ring lowered the 1,000-peer RSS by 16.1 MiB and the incremental slope by 8.3 KiB per peer. One-peer RSS was effectively unchanged. These are single samples, so small throughput and latency differences are noisy.

The current row remains at 54% / 51% of wireguard-go throughput and 4.4× the ≤5 KiB/peer goal (about 13.3× the measured 1.65 KiB kernel peer-state figure). At 1,000 peers, GotaTun total RSS is 4.9% of wireguard-go; its one-peer fixed RSS is 38% of wireguard-go. The next bounded cut is removing the duplicate per-peer AllowedIPs trie and freelists while retaining the device routing trie and compact per-peer route list, with route update/list and IPv4/IPv6 regression coverage. Estimate: 1–2 engineering days for that cut and its focused verification, followed by the same-harness measurement.

Raw run logs and JSON, cgroup memory snapshots, THP status, machine diff and perf-run receipts are attached as j88-lazy-ring-20261102.tar.gz (SHA-256 731fc70b1e16110b01dad975f08847ce739d9dbcce966cae103b46abb91871c4). Machine process snapshots are omitted from the attachment.

## J88 progress: lazy session ring measurement (2026-11-02) The same R4b harness case ran against fork commit `77109e5f` on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), through `perf-run --root`, CPUs 1–3, 6 GiB. It exited 0 in 181 seconds with an empty machine diff. Each row is one run; traffic and memory include both endpoint processes. The peer-scale case configured 1,000 peers at each endpoint. | Engine / step | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS per peer | Kernel peer state / peer | cgroup anon_thp at 1 / 1,000 peers | |---|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | n/a | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | n/a | | GotaTun 0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | n/a | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | n/a | | GotaTun offloads, paired THP-on control | 3.15 / 2.80 | 0.79 / 0.98 | 1.878 / 6.861; 6.577 / 12.159 | 9.6 / 109.7 | 51.3 KiB | n/a | 0 / 62 MiB | | GotaTun offloads + THP disabled | 2.99 / 2.44 | 0.82 / 1.00 | 2.177 / 5.580; 6.324 / 14.234 | 9.5 / 68.4 | 30.2 KiB | n/a | 0 / 0 | | GotaTun offloads + THP disabled + lazy session ring | 3.04 / 2.54 | 0.81 / 1.00 | 2.050 / 5.124; 6.564 / 13.579 | 9.6 / 52.3 | 21.9 KiB | n/a | 0 / 0 | At one and 1,000 peers, cgroup `anon_thp` was zero; the two processes reported `THP_enabled: 0`. RSS at one peer was 9,780 KiB and at 1,000 peers 53,512 KiB. The incremental slope is `(53,512 - 9,780) / 1,998 = 21.9 KiB per added peer`. Against the paired THP-off run, the lazy ring lowered the 1,000-peer RSS by 16.1 MiB and the incremental slope by 8.3 KiB per peer. One-peer RSS was effectively unchanged. These are single samples, so small throughput and latency differences are noisy. The current row remains at 54% / 51% of wireguard-go throughput and 4.4× the ≤5 KiB/peer goal (about 13.3× the measured 1.65 KiB kernel peer-state figure). At 1,000 peers, GotaTun total RSS is 4.9% of wireguard-go; its one-peer fixed RSS is 38% of wireguard-go. The next bounded cut is removing the duplicate per-peer AllowedIPs trie and freelists while retaining the device routing trie and compact per-peer route list, with route update/list and IPv4/IPv6 regression coverage. Estimate: 1–2 engineering days for that cut and its focused verification, followed by the same-harness measurement. Raw run logs and JSON, cgroup memory snapshots, THP status, machine diff and perf-run receipts are attached as `j88-lazy-ring-20261102.tar.gz` (SHA-256 `731fc70b1e16110b01dad975f08847ce739d9dbcce966cae103b46abb91871c4`). Machine process snapshots are omitted from the attachment.

j88-lazy-ring-20261102.tar.gz

9.9 KiB

kayg commented

2026-11-02 14:19:35 +00:00

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J88 source finding: remaining duplicate route state

At branch `j88-linux-offloads` / `77109e5f`, the test-first x86_64 layout guard measured `PeerState` at 3,360 inline bytes after the lazy session-ring cut. The current `PeerState` still contains its own `AllowedIps<()>`; `DeviceState` already owns the routing trie used for packet lookup. The earlier source audit measured about 1,760 bytes inline plus roughly 4,608 bytes of per-table freelist payload for the duplicate per-peer trie (comments 74560 and 74567).

The new IPv4/IPv6 characterization test passed before the change: replacing the peer's routes keeps canonical networks in the peer listing and routes both families through the device trie. The size guard fails as expected at 3,360 bytes. Next: keep peer route metadata as a sorted, normalized, unique `Vec`, remove only the peer-local trie, and rerun the same tests plus the GotaTun library suite.

## J88 source finding: remaining duplicate route state At branch \`j88-linux-offloads\` / \`77109e5f\`, the test-first x86_64 layout guard measured \`PeerState\` at 3,360 inline bytes after the lazy session-ring cut. The current \`PeerState\` still contains its own \`AllowedIps<()>\`; \`DeviceState\` already owns the routing trie used for packet lookup. The earlier source audit measured about 1,760 bytes inline plus roughly 4,608 bytes of per-table freelist payload for the duplicate per-peer trie (comments 74560 and 74567). The new IPv4/IPv6 characterization test passed before the change: replacing the peer's routes keeps canonical networks in the peer listing and routes both families through the device trie. The size guard fails as expected at 3,360 bytes. Next: keep peer route metadata as a sorted, normalized, unique \`Vec<IpNetwork>\`, remove only the peer-local trie, and rerun the same tests plus the GotaTun library suite.

kayg commented

2026-11-02 14:29:44 +00:00

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J88 progress: compact peer route state (2026-11-02)

Fork commit `823133f828d8805f5ea17139f623395cc5cf7afa` is pushed on `j88-linux-offloads`. It removes the peer-local trie, keeps a canonical sorted unique `Vec` for configuration listings, and retains `DeviceState`'s shared routing trie for packet lookup. Route replacement/listing checks cover duplicate canonical networks and both IPv4 and IPv6.

Verification on compute01:

Test-first layout guard: 3,360 inline bytes before the change (RED), below 2 KiB after (GREEN).
IPv4/IPv6 route update, listing, and shared-trie lookup test: passed.
Full GotaTun library test binary: 118 passed, 7 ignored.
`cargo fmt --all -- --check`: passed.
Release CLI build: exit 0.

This commit is pin-ready on fork tests for J103 to consume. Its same-R4b perf row is still pending; I will report throughput, CPU, loaded RTT p50/p99, RSS at 1/1,000 peers, and incremental KiB/peer after the perf VM run.

License record for owner

The root `LICENSE` says “Mozilla Public License Version 2.0”; the root Cargo workspace declares `MPL-2.0`. `LICENSE-CLOUDFLARE` contains BSD 3-Clause redistribution terms for Cloudflare-attributed code. The GotaTun `flake.nix` package metadata declares `lib.licenses.bsd3`, which does not match the root MPL-2.0 declaration. D169 records GotaTun as MPL-2.0. No license file or metadata was changed.

## J88 progress: compact peer route state (2026-11-02) Fork commit \`823133f828d8805f5ea17139f623395cc5cf7afa\` is pushed on \`j88-linux-offloads\`. It removes the peer-local trie, keeps a canonical sorted unique \`Vec<IpNetwork>\` for configuration listings, and retains \`DeviceState\`'s shared routing trie for packet lookup. Route replacement/listing checks cover duplicate canonical networks and both IPv4 and IPv6. Verification on compute01: - Test-first layout guard: 3,360 inline bytes before the change (RED), below 2 KiB after (GREEN). - IPv4/IPv6 route update, listing, and shared-trie lookup test: passed. - Full GotaTun library test binary: 118 passed, 7 ignored. - \`cargo fmt --all -- --check\`: passed. - Release CLI build: exit 0. This commit is **pin-ready on fork tests** for J103 to consume. Its same-R4b perf row is still pending; I will report throughput, CPU, loaded RTT p50/p99, RSS at 1/1,000 peers, and incremental KiB/peer after the perf VM run. ### License record for owner The root \`LICENSE\` says “Mozilla Public License Version 2.0”; the root Cargo workspace declares \`MPL-2.0\`. \`LICENSE-CLOUDFLARE\` contains BSD 3-Clause redistribution terms for Cloudflare-attributed code. The GotaTun \`flake.nix\` package metadata declares \`lib.licenses.bsd3\`, which does not match the root MPL-2.0 declaration. D169 records GotaTun as MPL-2.0. No license file or metadata was changed.

kayg commented

2026-11-02 14:34:14 +00:00

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J88 latency plan, continuing fork branch j88-linux-offloads at 823133f828d8805f5ea17139f623395cc5cf7afa (duplicate-trie cut; fork tests reported green; its perf row is pending).

Reproduce the same R4b loaded RTT64 1-flow p50/p99 baseline on the perf VM, then profile the 1-flow and 8-flow packet paths. Attribute queueing across UDP GSO/GRO and TUN TSO/GRO batch sizes/delay, worker hand-offs, channel capacities/backpressure, syscall/packet counts, and scheduling. First check the harness and source for existing trace points; use reversible, task-local profiling/instrumentation if the VM lacks suitable tools.
Pick one source-supported queueing hypothesis at a time, add a focused regression/functional check, and make the smallest fork-only change. Preserve correctness for packet ordering, loss/reordering, MTU boundaries, IPv4/IPv6, and offload/non-offload compatibility. Do not broaden into a redesign; stop with evidence if this needs a larger architecture change.
Measure each step with the same R4b case and report the full table: kernel WireGuard, wireguard-go, GotaTun baseline, route-trie cut, and each latency step; 1/8-flow throughput, CPU s/Gbit, loaded RTT64 p50/p99, RSS at 1/1,000 peers, incremental RSS/peer, and kernel peer-state bytes. Preserve raw logs and machine-diff receipts. Compare repeated samples where runtime permits; each batch runs via perf-run and blocks to completion in one tool call.
Run fork tests and build gates for each code commit, push the fork branch, and mark a commit pin-ready only after those checks are green. No product integration and no upstream PR, issue, or comment.

Estimate: 2–4 engineering days for matched profiling, one or two bounded latency hypotheses, fork verification, and paired R4b rows; add 1–2 days if source attribution requires custom instrumentation or the first cut exposes a correctness regression. Remaining broader offload edge matrix and final qualification remain tracked separately.

J88 latency plan, continuing fork branch `j88-linux-offloads` at `823133f828d8805f5ea17139f623395cc5cf7afa` (duplicate-trie cut; fork tests reported green; its perf row is pending). 1. Reproduce the same R4b loaded RTT64 1-flow p50/p99 baseline on the perf VM, then profile the 1-flow and 8-flow packet paths. Attribute queueing across UDP GSO/GRO and TUN TSO/GRO batch sizes/delay, worker hand-offs, channel capacities/backpressure, syscall/packet counts, and scheduling. First check the harness and source for existing trace points; use reversible, task-local profiling/instrumentation if the VM lacks suitable tools. 2. Pick one source-supported queueing hypothesis at a time, add a focused regression/functional check, and make the smallest fork-only change. Preserve correctness for packet ordering, loss/reordering, MTU boundaries, IPv4/IPv6, and offload/non-offload compatibility. Do not broaden into a redesign; stop with evidence if this needs a larger architecture change. 3. Measure each step with the same R4b case and report the full table: kernel WireGuard, wireguard-go, GotaTun baseline, route-trie cut, and each latency step; 1/8-flow throughput, CPU s/Gbit, loaded RTT64 p50/p99, RSS at 1/1,000 peers, incremental RSS/peer, and kernel peer-state bytes. Preserve raw logs and machine-diff receipts. Compare repeated samples where runtime permits; each batch runs via `perf-run` and blocks to completion in one tool call. 4. Run fork tests and build gates for each code commit, push the fork branch, and mark a commit pin-ready only after those checks are green. No product integration and no upstream PR, issue, or comment. Estimate: 2–4 engineering days for matched profiling, one or two bounded latency hypotheses, fork verification, and paired R4b rows; add 1–2 days if source attribution requires custom instrumentation or the first cut exposes a correctness regression. Remaining broader offload edge matrix and final qualification remain tracked separately.

kayg commented

2026-11-02 14:44:18 +00:00

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Finding with source evidence: crates/plugins/mesh/src/relay_path.rs:235-245 binds the loopback shim and installs its endpoint through wireguard::Client::new()?.endpoint. With GotaTun as the default, that handoff must update the GotaTun peer while keeping the loopback socket and QUIC DATAGRAM relay flow intact. I am adding an endpoint-setter seam around the existing handoff.

Finding with source evidence: `crates/plugins/mesh/src/relay_path.rs:235-245` binds the loopback shim and installs its endpoint through `wireguard::Client::new()?.endpoint`. With GotaTun as the default, that handoff must update the GotaTun peer while keeping the loopback socket and QUIC DATAGRAM relay flow intact. I am adding an endpoint-setter seam around the existing handoff.

kayg commented

2026-11-02 15:04:34 +00:00

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J88 latency continuation starting on branch j88-linux-offloads, base 823133f828d8805f5ea17139f623395cc5cf7afa (duplicate-trie cut; fork tests reported green, same-R4b row pending). The latency plan and 2–4 day estimate are already posted above. I will run the route-cut R4b case first, then profile the loaded 1-flow path for batch sizes, queue residence/backpressure, worker hand-offs and syscalls. I will make one evidence-backed latency change at a time, keep 1/8-flow throughput and the existing edge coverage, run fork gates on a dev VM, and publish each measured row here. No product integration or upstream contribution.

J88 latency continuation starting on branch `j88-linux-offloads`, base `823133f828d8805f5ea17139f623395cc5cf7afa` (duplicate-trie cut; fork tests reported green, same-R4b row pending). The latency plan and 2–4 day estimate are already posted above. I will run the route-cut R4b case first, then profile the loaded 1-flow path for batch sizes, queue residence/backpressure, worker hand-offs and syscalls. I will make one evidence-backed latency change at a time, keep 1/8-flow throughput and the existing edge coverage, run fork gates on a dev VM, and publish each measured row here. No product integration or upstream contribution.

kayg commented

2026-11-02 15:13:00 +00:00

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J103 continuation: I resumed the existing mesh-gotatun-linux worktree and rebased it onto current origin/dev (294042b56daac3d4ab2289508b7f8a6ddb0b24a4).

Pin update from the initial plan: the public j88-linux-offloads head is now 823133f828d8805f5ea17139f623395cc5cf7afa. The recorded fork verification for that exact commit is 118 tests passed, 7 ignored, cargo fmt --all -- --check passed, and a release CLI build exited 0. It includes UDP GSO/TUN TSO-GRO offloads and THP-off. I will pin this tested head, replacing the earlier 8db98bd pin. Its matching R4b row is still pending, so I will keep the earlier paired rows clearly labelled and measure the selected pin against kernel WireGuard before claiming a J103 result.

Queue check before builds: compute01 is full; its queued release build is from J80, so I left it untouched. dev-02 has one free slot and 129 GiB free, and will be used for J103 builds/tests. The license allowlist already contains MPL-2.0; the branch only needs the explicit allow-git entry for the fork under unknown-git = "deny".

J103 continuation: I resumed the existing `mesh-gotatun-linux` worktree and rebased it onto current `origin/dev` (`294042b56daac3d4ab2289508b7f8a6ddb0b24a4`). Pin update from the initial plan: the public `j88-linux-offloads` head is now `823133f828d8805f5ea17139f623395cc5cf7afa`. The recorded fork verification for that exact commit is 118 tests passed, 7 ignored, `cargo fmt --all -- --check` passed, and a release CLI build exited 0. It includes UDP GSO/TUN TSO-GRO offloads and THP-off. I will pin this tested head, replacing the earlier `8db98bd` pin. Its matching R4b row is still pending, so I will keep the earlier paired rows clearly labelled and measure the selected pin against kernel WireGuard before claiming a J103 result. Queue check before builds: compute01 is full; its queued release build is from J80, so I left it untouched. dev-02 has one free slot and 129 GiB free, and will be used for J103 builds/tests. The license allowlist already contains MPL-2.0; the branch only needs the explicit allow-git entry for the fork under `unknown-git = "deny"`.

kayg commented

2026-11-02 15:30:20 +00:00

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J88 progress: duplicate-route-trie cut R4b row

Fork commit 823133f828d8805f5ea17139f623395cc5cf7afa (perf: replace peer route trie with compact list) is pushed on j88-linux-offloads. Fork tests and release build are green; pin-ready on fork tests. The route cut removes the peer-local trie while retaining the shared device routing trie.

The same R4b harness ran through perf-run --root on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), CPUs 1–3, 6 GiB. Exit 0 in 180 s; machine diff empty. One sample per engine/step. RSS and throughput include both endpoint processes; 1,000-peer case configures 1,000 peers per endpoint. Incremental RSS is the slope across 1 to 1,000 peers (1,998 added peers). Route-cut processes both reported THP_enabled: 0.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 flow (ms)	Loaded RTT64 p50/p99, 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS / peer	Kernel peer state / peer	cgroup anon_thp at 1 / 1,000 peers
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763	3.112 / 3.888	20.1 / 20.1	0	1.65 KiB	n/a
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631	7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a	n/a
GotaTun 0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733	4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a	n/a
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460	5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a	n/a
GotaTun offloads, paired THP-on control	3.15 / 2.80	0.79 / 0.98	1.878 / 6.861	6.577 / 12.159	9.6 / 109.7	51.3 KiB	n/a	0 / 62 MiB
GotaTun offloads + THP disabled	2.99 / 2.44	0.82 / 1.00	2.177 / 5.580	6.324 / 14.234	9.5 / 68.4	30.2 KiB	n/a	0 / 0
GotaTun + lazy session ring	3.04 / 2.54	0.81 / 1.00	2.050 / 5.124	6.564 / 13.579	9.6 / 52.3	21.9 KiB	n/a	0 / 0
GotaTun + compact peer routes (`823133f`)	3.011 / 2.513	0.810 / 0.997	1.916 / 4.516	6.173 / 12.379	9.3 / 37.1	14.2 KiB	1.65 KiB	not captured

The route cut lowered the 1,000-peer RSS by about 15.2 MiB and the incremental slope by 7.7 KiB/peer versus the lazy-ring row. The current slope is 2.84× the ≤5 KiB/peer target and 8.6× measured kernel peer state. Throughput remains about 54% / 50% of wireguard-go. Latency is one sample per variant; small changes are not causal evidence. The next step is profiling the loaded 1-flow path for queue residence/batching and making one evidence-backed latency cut. Estimate remains 2–4 engineering days for matched profiling, one or two bounded latency hypotheses, fork verification, and paired R4b rows.

Raw logs and JSON, cgroup snapshots, process THP status, machine diff, and perf-run receipts are attached: j88-routecut-823133f-r4b-20261102.tar.gz, SHA-256 f99bd493e77d8134903c198d9218d66fabb89b7dbd5a0d0bdcc61d68f4452b9a.

## J88 progress: duplicate-route-trie cut R4b row Fork commit `823133f828d8805f5ea17139f623395cc5cf7afa` (`perf: replace peer route trie with compact list`) is pushed on `j88-linux-offloads`. Fork tests and release build are green; **pin-ready on fork tests**. The route cut removes the peer-local trie while retaining the shared device routing trie. The same R4b harness ran through `perf-run --root` on `infraternal-perf-01-backup01` (Debian 13, kernel 6.12.113, Ryzen 7 3700X), CPUs 1–3, 6 GiB. Exit 0 in 180 s; machine diff empty. One sample per engine/step. RSS and throughput include both endpoint processes; 1,000-peer case configures 1,000 peers per endpoint. Incremental RSS is the slope across 1 to 1,000 peers (1,998 added peers). Route-cut processes both reported `THP_enabled: 0`. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 flow (ms) | Loaded RTT64 p50/p99, 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS / peer | Kernel peer state / peer | cgroup anon_thp at 1 / 1,000 peers | |---|---:|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763 | 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | n/a | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631 | 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | n/a | | GotaTun 0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733 | 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | n/a | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460 | 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | n/a | | GotaTun offloads, paired THP-on control | 3.15 / 2.80 | 0.79 / 0.98 | 1.878 / 6.861 | 6.577 / 12.159 | 9.6 / 109.7 | 51.3 KiB | n/a | 0 / 62 MiB | | GotaTun offloads + THP disabled | 2.99 / 2.44 | 0.82 / 1.00 | 2.177 / 5.580 | 6.324 / 14.234 | 9.5 / 68.4 | 30.2 KiB | n/a | 0 / 0 | | GotaTun + lazy session ring | 3.04 / 2.54 | 0.81 / 1.00 | 2.050 / 5.124 | 6.564 / 13.579 | 9.6 / 52.3 | 21.9 KiB | n/a | 0 / 0 | | GotaTun + compact peer routes (`823133f`) | 3.011 / 2.513 | 0.810 / 0.997 | 1.916 / 4.516 | 6.173 / 12.379 | 9.3 / 37.1 | 14.2 KiB | 1.65 KiB | not captured | The route cut lowered the 1,000-peer RSS by about 15.2 MiB and the incremental slope by 7.7 KiB/peer versus the lazy-ring row. The current slope is 2.84× the ≤5 KiB/peer target and 8.6× measured kernel peer state. Throughput remains about 54% / 50% of wireguard-go. Latency is one sample per variant; small changes are not causal evidence. The next step is profiling the loaded 1-flow path for queue residence/batching and making one evidence-backed latency cut. Estimate remains 2–4 engineering days for matched profiling, one or two bounded latency hypotheses, fork verification, and paired R4b rows. Raw logs and JSON, cgroup snapshots, process THP status, machine diff, and perf-run receipts are attached: `j88-routecut-823133f-r4b-20261102.tar.gz`, SHA-256 `f99bd493e77d8134903c198d9218d66fabb89b7dbd5a0d0bdcc61d68f4452b9a`.

j88-routecut-823133f-r4b-20261102.tar.gz

227 KiB

kayg commented

2026-11-02 15:52:25 +00:00

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J103 dependency finding with source evidence: crates/plugins/mesh/Cargo.toml currently enables GotaTun's tun feature. At the selected 823133f828d8805f5ea17139f623395cc5cf7afa fork revision, that feature activates registry crate tun 0.8.14; its normalized manifest at /home/claude/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tun-0.8.14/Cargo.toml declares license = "WTFPL". D169 excludes the bundled TUN dependency, so adding WTFPL to deny.toml is not acceptable. I will remove that feature and implement the Linux TUN adapter over GotaTun's existing IpSend/IpRecv boundary, preserving the GotaTun offload behavior without that crate; the MPL-2.0 fork remains allowed by the current deny.toml policy.

J103 dependency finding with source evidence: `crates/plugins/mesh/Cargo.toml` currently enables GotaTun's `tun` feature. At the selected `823133f828d8805f5ea17139f623395cc5cf7afa` fork revision, that feature activates registry crate `tun 0.8.14`; its normalized manifest at `/home/claude/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tun-0.8.14/Cargo.toml` declares `license = "WTFPL"`. D169 excludes the bundled TUN dependency, so adding WTFPL to `deny.toml` is not acceptable. I will remove that feature and implement the Linux TUN adapter over GotaTun's existing `IpSend`/`IpRecv` boundary, preserving the GotaTun offload behavior without that crate; the MPL-2.0 fork remains allowed by the current `deny.toml` policy.

kayg commented

2026-11-02 15:52:51 +00:00

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J88 progress: route-cut latency profile

Profiled the route-cut candidate (823133f828d8805f5ea17139f623395cc5cf7afa, raw binary SHA-256 6bf8fc35a4ae52f41a6c63b9104037e0a15788e8d43c46c664089755442fccc6) with the disposable J88 R4b mesh profile harness on infraternal-perf-01-backup01. The mesh-gotatun case ran via perf-run --root, CPUs 1–3, 6 GiB, and exited 0 in 184 s with an empty machine diff. Profiler overhead was enabled, so this profile run is not used as an R4b performance comparison row.

The existing route-cut R4b row and same-session comparison remain:

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 flow (ms)	Loaded RTT64 p50/p99, 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS / peer	Kernel peer state / peer	cgroup anon_thp at 1 / 1,000 peers
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763	3.112 / 3.888	20.1 / 20.1	0	1.65 KiB	n/a
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631	7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a	n/a
GotaTun 0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733	4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a	n/a
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460	5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a	n/a
GotaTun offloads, paired THP-on control	3.15 / 2.80	0.79 / 0.98	1.878 / 6.861	6.577 / 12.159	9.6 / 109.7	51.3 KiB	n/a	0 / 62 MiB
GotaTun offloads + THP disabled	2.99 / 2.44	0.82 / 1.00	2.177 / 5.580	6.324 / 14.234	9.5 / 68.4	30.2 KiB	n/a	0 / 0
GotaTun + lazy session ring	3.04 / 2.54	0.81 / 1.00	2.050 / 5.124	6.564 / 13.579	9.6 / 52.3	21.9 KiB	n/a	0 / 0
GotaTun + compact peer routes (`823133f`)	3.011 / 2.513	0.810 / 0.997	1.916 / 4.516	6.173 / 12.379	9.3 / 37.1	14.2 KiB	1.65 KiB	not captured

Profile sample	Task clock	Context switches	Raw syscalls	CPU migrations	Sampled stack overhead
1 flow	24.54 s	124,013 (5.053 K/s)	2,615,857 (106.583 K/s)	9,632 (392.455/s)	`finish_task_switch` 36.03%; `_raw_spin_unlock_irqrestore` 12.00%
8 flows	25.56 s	134,752 (5.272 K/s)	2,604,439 (101.893 K/s)	7,338 (287.083/s)	`finish_task_switch` 38.65%; `_raw_spin_unlock_irqrestore` 11.50%

Source trace shows four buffered workers, each with a 4,000-packet channel bound (UDP send has separate IPv4 and IPv6 queues). UDP sendmmsg/recvmmsg calls cap batches at 100; UDP GSO groups cap at 64 datagrams. The recv_many loops wait for the first item and drain what is already available; socket receive uses nonblocking recvmmsg after readiness. I found no timer-based GRO/GSO coalescing delay. The sampled profile has high scheduler cost, but does not reveal channel occupancy, so I have not yet attributed the extra loaded RTT to a particular queue.

Next I’m adding temporary, fork-local queue-depth and batch-size sampling to the same 1/8-flow loaded case. I’ll remove the diagnostic instrumentation before the latency change. No product or upstream changes are included here.

Raw profile logs, reports, perf.data, task-local wrapper, run receipts, and cleanup evidence are attached as j88-profile-routecut-823133f-20261102.tar.gz (SHA-256 3751950bc8578eb6441f3cdef03ae6d2043962fe8e15de2fe37dafdb709db61d).

## J88 progress: route-cut latency profile Profiled the route-cut candidate (`823133f828d8805f5ea17139f623395cc5cf7afa`, raw binary SHA-256 `6bf8fc35a4ae52f41a6c63b9104037e0a15788e8d43c46c664089755442fccc6`) with the disposable J88 R4b mesh profile harness on infraternal-perf-01-backup01. The `mesh-gotatun` case ran via `perf-run --root`, CPUs 1–3, 6 GiB, and exited 0 in 184 s with an empty machine diff. Profiler overhead was enabled, so this profile run is not used as an R4b performance comparison row. The existing route-cut R4b row and same-session comparison remain: | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 flow (ms) | Loaded RTT64 p50/p99, 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS / peer | Kernel peer state / peer | cgroup anon_thp at 1 / 1,000 peers | |---|---:|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763 | 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | n/a | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631 | 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | n/a | | GotaTun 0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733 | 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | n/a | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460 | 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | n/a | | GotaTun offloads, paired THP-on control | 3.15 / 2.80 | 0.79 / 0.98 | 1.878 / 6.861 | 6.577 / 12.159 | 9.6 / 109.7 | 51.3 KiB | n/a | 0 / 62 MiB | | GotaTun offloads + THP disabled | 2.99 / 2.44 | 0.82 / 1.00 | 2.177 / 5.580 | 6.324 / 14.234 | 9.5 / 68.4 | 30.2 KiB | n/a | 0 / 0 | | GotaTun + lazy session ring | 3.04 / 2.54 | 0.81 / 1.00 | 2.050 / 5.124 | 6.564 / 13.579 | 9.6 / 52.3 | 21.9 KiB | n/a | 0 / 0 | | GotaTun + compact peer routes (`823133f`) | 3.011 / 2.513 | 0.810 / 0.997 | 1.916 / 4.516 | 6.173 / 12.379 | 9.3 / 37.1 | 14.2 KiB | 1.65 KiB | not captured | | Profile sample | Task clock | Context switches | Raw syscalls | CPU migrations | Sampled stack overhead | |---|---:|---:|---:|---:|---| | 1 flow | 24.54 s | 124,013 (5.053 K/s) | 2,615,857 (106.583 K/s) | 9,632 (392.455/s) | `finish_task_switch` 36.03%; `_raw_spin_unlock_irqrestore` 12.00% | | 8 flows | 25.56 s | 134,752 (5.272 K/s) | 2,604,439 (101.893 K/s) | 7,338 (287.083/s) | `finish_task_switch` 38.65%; `_raw_spin_unlock_irqrestore` 11.50% | Source trace shows four buffered workers, each with a 4,000-packet channel bound (UDP send has separate IPv4 and IPv6 queues). UDP sendmmsg/recvmmsg calls cap batches at 100; UDP GSO groups cap at 64 datagrams. The `recv_many` loops wait for the first item and drain what is already available; socket receive uses nonblocking `recvmmsg` after readiness. I found no timer-based GRO/GSO coalescing delay. The sampled profile has high scheduler cost, but does not reveal channel occupancy, so I have not yet attributed the extra loaded RTT to a particular queue. Next I’m adding temporary, fork-local queue-depth and batch-size sampling to the same 1/8-flow loaded case. I’ll remove the diagnostic instrumentation before the latency change. No product or upstream changes are included here. Raw profile logs, reports, `perf.data`, task-local wrapper, run receipts, and cleanup evidence are attached as `j88-profile-routecut-823133f-20261102.tar.gz` (SHA-256 `3751950bc8578eb6441f3cdef03ae6d2043962fe8e15de2fe37dafdb709db61d`).

j88-profile-routecut-823133f-20261102.tar.gz

12 MiB

kayg commented

2026-11-02 16:14:56 +00:00

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J103 progress (2026-11-02): the Linux mesh adapter now consumes the infraternal-linux-tun::Device syscall boundary instead of issuing ioctl calls in the plugin crate. The existing /home/claude/J103-red5.log is stale, not current build evidence: compute01 worktree at 294042b56 has no gotatun_tun.rs and its gotatun_node.rs differs from the current worktree. I will sync and rerun once a VM slot frees. Queue check: compute01 4/4 slots busy; dev-02 has 2 occupied and 2 queued; neither queue has immediate capacity.

J103 progress (2026-11-02): the Linux mesh adapter now consumes the `infraternal-linux-tun::Device` syscall boundary instead of issuing ioctl calls in the plugin crate. The existing `/home/claude/J103-red5.log` is stale, not current build evidence: compute01 worktree at `294042b56` has no `gotatun_tun.rs` and its `gotatun_node.rs` differs from the current worktree. I will sync and rerun once a VM slot frees. Queue check: compute01 4/4 slots busy; dev-02 has 2 occupied and 2 queued; neither queue has immediate capacity.

kayg commented

2026-11-02 16:22:42 +00:00

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J103 compile finding (compute01, /home/claude/J103-focused.log): the first focused build on the synced source reached the new engine and stopped before tests on three compile errors: GotaTun Packet<Ip> has no AsRef in the TSO test, the IPv4 test helper borrowed its frame both mutably and immutably in one expression, and Engine::start moved the coordinator config into the async initializer before retaining it in worker state. I fixed the packet test to consume Packet::into_bytes, separated the frame length calculation, and cloned the public coordinator config for engine initialization. Verification is pending.

J103 compile finding (compute01, `/home/claude/J103-focused.log`): the first focused build on the synced source reached the new engine and stopped before tests on three compile errors: GotaTun `Packet<Ip>` has no `AsRef` in the TSO test, the IPv4 test helper borrowed its frame both mutably and immutably in one expression, and `Engine::start` moved the coordinator config into the async initializer before retaining it in worker state. I fixed the packet test to consume `Packet::into_bytes`, separated the frame length calculation, and cloned the public coordinator config for engine initialization. Verification is pending.

kayg commented

2026-11-02 16:24:44 +00:00

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J103 focused-test finding (compute01, /home/claude/J103-focused-r3.log): compilation now succeeds and the mesh plugin unit suite reached 81 passed / 1 failed / 14 ignored. The failure is in the new selected_engine_is_durable_outside_the_legacy_public_snapshot test: Store::open does not create the legacy snapshot until its first save, but the test tried to read it after only recording the separate engine file. I will initialize the legacy snapshot in the test, then rerun.

J103 focused-test finding (compute01, `/home/claude/J103-focused-r3.log`): compilation now succeeds and the mesh plugin unit suite reached 81 passed / 1 failed / 14 ignored. The failure is in the new `selected_engine_is_durable_outside_the_legacy_public_snapshot` test: `Store::open` does not create the legacy snapshot until its first save, but the test tried to read it after only recording the separate engine file. I will initialize the legacy snapshot in the test, then rerun.

kayg commented

2026-11-02 16:27:25 +00:00

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J88 latency profiling: queue and batch findings

The diagnostic R4b case on 823133f828d8805f5ea17139f623395cc5cf7afa exited 0 in 180 seconds through perf-run --root on the perf VM; its machine diff was empty. This is instrumentation data, not a comparable performance row.

The source has four buffered packet handoff paths, all bounded at 4,000 packets. Across the full run, sampled maximum depth was 2,048 / 512 for TUN→device, 1,106 / 512 for device→UDP, 512 / 2,307 for device→TUN, and 753 / 1,622 for UDP→device (endpoints A / B). The largest sampled send wait was 2.106 ms on endpoint B's device→UDP channel; this is a selected maximum, not a percentile. These queue maxima span the complete case and do not isolate one-flow latency.

Batching evidence shows no timer-based coalescing: recvmmsg delivered a median of 1 and p95 of 6 messages; UDP GRO output reached 333 packets per receive call, UDP send batches reached 100 packets, GSO planning reached 100 input segments in 9 groups, and TUN recv_many reached 1,047 packets. The earlier CPU profile sampled 5.1k–5.3k context switches/s and 102k–107k syscalls/s, with 36%–39% of sampled stacks in task-switch scheduling. I will test the bounded hypothesis that 4,000-packet worker queues retain avoidable backlog: lower only the queue capacity to 256 (over two 100-packet send batches) while preserving the 4,000-buffer reuse pool, then run fork tests and the identical R4b case. If throughput regresses, the change is rejected.

R4b comparison so far

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 / 8 flows (ms)	RSS 1 / 1,000 peers (MiB)	Incremental RSS/peer	Kernel peer state/peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
Offloads, paired THP-on control	3.15 / 2.80	0.79 / 0.98	1.878 / 6.861; 6.577 / 12.159	9.6 / 109.7	51.3 KiB	n/a
Offloads + THP disabled	2.99 / 2.44	0.82 / 1.00	2.177 / 5.580; 6.324 / 14.234	9.5 / 68.4	30.2 KiB	n/a
Offloads + THP disabled + lazy session ring	3.04 / 2.54	0.81 / 1.00	2.050 / 5.124; 6.564 / 13.579	9.6 / 52.3	21.9 KiB	n/a
Route-trie cut (`823133f`)	3.011 / 2.513	0.810 / 0.997	1.916 / 4.516; 6.173 / 12.379	9.3 / 37.1	14.2 KiB	n/a

Raw profile archive: j88-profile-routecut-823133f-20261102.tar.gz, SHA-256 3447302f9975c814090274357601921528d68ce3cf4eed36e43d6c6ebdf19c8f.

## J88 latency profiling: queue and batch findings The diagnostic R4b case on `823133f828d8805f5ea17139f623395cc5cf7afa` exited 0 in 180 seconds through `perf-run --root` on the perf VM; its machine diff was empty. This is instrumentation data, not a comparable performance row. The source has four buffered packet handoff paths, all bounded at 4,000 packets. Across the full run, sampled maximum depth was 2,048 / 512 for TUN→device, 1,106 / 512 for device→UDP, 512 / 2,307 for device→TUN, and 753 / 1,622 for UDP→device (endpoints A / B). The largest sampled send wait was 2.106 ms on endpoint B's device→UDP channel; this is a selected maximum, not a percentile. These queue maxima span the complete case and do not isolate one-flow latency. Batching evidence shows no timer-based coalescing: `recvmmsg` delivered a median of 1 and p95 of 6 messages; UDP GRO output reached 333 packets per receive call, UDP send batches reached 100 packets, GSO planning reached 100 input segments in 9 groups, and TUN `recv_many` reached 1,047 packets. The earlier CPU profile sampled 5.1k–5.3k context switches/s and 102k–107k syscalls/s, with 36%–39% of sampled stacks in task-switch scheduling. I will test the bounded hypothesis that 4,000-packet worker queues retain avoidable backlog: lower only the queue capacity to 256 (over two 100-packet send batches) while preserving the 4,000-buffer reuse pool, then run fork tests and the identical R4b case. If throughput regresses, the change is rejected. ### R4b comparison so far | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 / 8 flows (ms) | RSS 1 / 1,000 peers (MiB) | Incremental RSS/peer | Kernel peer state/peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | Offloads, paired THP-on control | 3.15 / 2.80 | 0.79 / 0.98 | 1.878 / 6.861; 6.577 / 12.159 | 9.6 / 109.7 | 51.3 KiB | n/a | | Offloads + THP disabled | 2.99 / 2.44 | 0.82 / 1.00 | 2.177 / 5.580; 6.324 / 14.234 | 9.5 / 68.4 | 30.2 KiB | n/a | | Offloads + THP disabled + lazy session ring | 3.04 / 2.54 | 0.81 / 1.00 | 2.050 / 5.124; 6.564 / 13.579 | 9.6 / 52.3 | 21.9 KiB | n/a | | Route-trie cut (`823133f`) | 3.011 / 2.513 | 0.810 / 0.997 | 1.916 / 4.516; 6.173 / 12.379 | 9.3 / 37.1 | 14.2 KiB | n/a | Raw profile archive: `j88-profile-routecut-823133f-20261102.tar.gz`, SHA-256 `3447302f9975c814090274357601921528d68ce3cf4eed36e43d6c6ebdf19c8f`.

j88-profile-routecut-823133f-20261102.tar.gz

14 MiB

kayg commented

2026-11-02 16:48:20 +00:00

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J88 latency-cut verification is queued, not started: compute01 had all 4 build slots busy and this job at queue position 2; dev-02 had both slots busy with 5 jobs queued. I checked both VMs and kept the job on compute01, which has the shorter queue. The locked build will run formatting, the GotaTun library suite, and the release CLI build. No build has started outside build-slot. I will continue with the R4b measurement after it completes.

kayg commented

2026-11-02 16:49:09 +00:00

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J103 finding with source evidence: the Linux TUN adapter attaches a non-persistent queue with IFF_TUN | IFF_NO_PI and does not set TUNSETPERSIST (crates/infraternal-linux-tun/src/lib.rs). Engine::stop stops GotaTun and drops its retained TUN handle (crates/plugins/mesh/src/gotatun_node.rs), so the last descriptor closing removes the interface. The restore test incorrectly expected that link to survive an engine drop. I changed it to assert the interface is absent after the drop, then that Node::restore recreates it with the persisted public identity; the privileged namespace test is pending on a VM slot.

J103 finding with source evidence: the Linux TUN adapter attaches a non-persistent queue with `IFF_TUN | IFF_NO_PI` and does not set `TUNSETPERSIST` (`crates/infraternal-linux-tun/src/lib.rs`). `Engine::stop` stops GotaTun and drops its retained TUN handle (`crates/plugins/mesh/src/gotatun_node.rs`), so the last descriptor closing removes the interface. The restore test incorrectly expected that link to survive an engine drop. I changed it to assert the interface is absent after the drop, then that `Node::restore` recreates it with the persisted public identity; the privileged namespace test is pending on a VM slot.

kayg commented

2026-11-02 16:55:43 +00:00

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J103 resume: mesh-gotatun-linux is based on origin/dev at 99668d8abc8dd55bba038c2c48a04e444c33e324, which already contains today’s D163 amendment. I synced the task worktree to compute01 at the same base; its stale duplicate DECISIONS edit was discarded. I corrected the restore test for the non-persistent TUN lifecycle. Current queue check: compute01 has 4/4 slots busy and 2 queued; dev-02 has 2 slots busy and 4 queued, with disk above the floor. No J103 build is queued yet; I am finishing source review before taking the shorter queue.

J103 resume: `mesh-gotatun-linux` is based on `origin/dev` at `99668d8abc8dd55bba038c2c48a04e444c33e324`, which already contains today’s D163 amendment. I synced the task worktree to compute01 at the same base; its stale duplicate DECISIONS edit was discarded. I corrected the restore test for the non-persistent TUN lifecycle. Current queue check: compute01 has 4/4 slots busy and 2 queued; dev-02 has 2 slots busy and 4 queued, with disk above the floor. No J103 build is queued yet; I am finishing source review before taking the shorter queue.

kayg commented

2026-11-02 16:57:40 +00:00

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J103 offload parser finding: ip_details currently treats the IPv6 base header next-header byte as the transport protocol and fixes its header length at 40 bytes (gotatun_tun.rs); segment_tcp then rejects anything whose protocol is not TCP. A valid TCPv6 TSO frame with a Hop-by-Hop extension therefore fails before segmentation. I added a focused literal-frame regression test for the extension, sequence/length repair, and checksum; it is pending its first VM run before any parser change.

J103 offload parser finding: `ip_details` currently treats the IPv6 base header next-header byte as the transport protocol and fixes its header length at 40 bytes (`gotatun_tun.rs`); `segment_tcp` then rejects anything whose protocol is not TCP. A valid TCPv6 TSO frame with a Hop-by-Hop extension therefore fails before segmentation. I added a focused literal-frame regression test for the extension, sequence/length repair, and checksum; it is pending its first VM run before any parser change.

kayg commented

2026-11-02 17:08:31 +00:00

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J103 verification: compute01 ran the new regression after waiting at queue position 4. It failed at segment_tcp with InvalidData: TCP GSO metadata does not match the IP packet, confirming that the Hop-by-Hop header leaves the decoder with protocol 0 and offset 40. The compile also emitted two private_interfaces warnings because public Store::record_engine/recorded_engine expose crate-private EngineKind; I will make those internal hooks crate-visible and extend the IPv6 header walk.

J103 verification: compute01 ran the new regression after waiting at queue position 4. It failed at `segment_tcp` with `InvalidData: TCP GSO metadata does not match the IP packet`, confirming that the Hop-by-Hop header leaves the decoder with protocol 0 and offset 40. The compile also emitted two `private_interfaces` warnings because public `Store::record_engine`/`recorded_engine` expose crate-private `EngineKind`; I will make those internal hooks crate-visible and extend the IPv6 header walk.

kayg commented

2026-11-02 17:36:56 +00:00

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J88 latency step: fork verification

On compute01, the queue-cap source diff passed cargo fmt --all -- --check, cargo test --locked -p gotatun --all-features --lib (131 passed, 7 ignored), and cargo build --release -p gotatun-cli (exit 0). The Cargo runner was set to /usr/bin/env for library tests because .cargo/config.toml otherwise invokes sudo -E, which is not passwordless on this VM. These tests ran unprivileged; the 7 Docker/TUN integration tests remain ignored by the upstream suite.

The broader cargo test --locked --workspace --all-features attempt stopped in the unchanged tikv-jemalloc-sys build script before tests ran: configure: error: cannot determine return type of strerror_r. The queue-cap diff changes no allocator or workspace feature configuration. I am now measuring the tested GotaTun candidate through the same R4b mesh-gotatun case, with 4,000 buffer-pool slots preserved and worker queues bounded at 256.

## J88 latency step: fork verification On compute01, the queue-cap source diff passed `cargo fmt --all -- --check`, `cargo test --locked -p gotatun --all-features --lib` (131 passed, 7 ignored), and `cargo build --release -p gotatun-cli` (exit 0). The Cargo runner was set to `/usr/bin/env` for library tests because `.cargo/config.toml` otherwise invokes `sudo -E`, which is not passwordless on this VM. These tests ran unprivileged; the 7 Docker/TUN integration tests remain ignored by the upstream suite. The broader `cargo test --locked --workspace --all-features` attempt stopped in the unchanged `tikv-jemalloc-sys` build script before tests ran: `configure: error: cannot determine return type of strerror_r`. The queue-cap diff changes no allocator or workspace feature configuration. I am now measuring the tested GotaTun candidate through the same R4b `mesh-gotatun` case, with 4,000 buffer-pool slots preserved and worker queues bounded at 256.

kayg commented

2026-11-02 17:37:19 +00:00

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J103 build finding: the corrected wrapper reached cargo fmt and stopped at the first --locked Cargo command with “cannot update the lock file” before clippy/tests ran. The current Cargo.lock has no infraternal-linux-tun package entry or dependency under infraternal-plugin-mesh, while the manifest now adds that path dependency. I will regenerate the lockfile on a build VM from the existing cache, then rerun the locked validation.

J103 build finding: the corrected wrapper reached `cargo fmt` and stopped at the first `--locked` Cargo command with “cannot update the lock file” before clippy/tests ran. The current `Cargo.lock` has no `infraternal-linux-tun` package entry or dependency under `infraternal-plugin-mesh`, while the manifest now adds that path dependency. I will regenerate the lockfile on a build VM from the existing cache, then rerun the locked validation.

kayg commented

2026-11-02 17:47:56 +00:00

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J88 latency step: packet channel capacity 256

Candidate bfcab98c5d67bd263ad62a2f29a48e28a64b3731 passed the matched R4b mesh-gotatun case through perf-run --root on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X, perf.slice CPUs 1–3, 6 GiB). The run exited 0 in 181 seconds with an empty machine diff. Both endpoints report source bfcab98; the buffer pool remains 4,000 entries and each packet handoff queue is 256.

The first harness attempt exited before traffic because the copied kit lacked its shared helper binaries; it also had an empty machine diff and produced no measurement. The corrected kit now contains the same 16 helper binaries as the reference and a verified manifest. The attached archive is the successful run only.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 / 8 flows (ms)	RSS 1 / 1,000 peers (MiB)	Incremental RSS/peer	Kernel peer state/peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
Offloads, paired THP-on control	3.15 / 2.80	0.79 / 0.98	1.878 / 6.861; 6.577 / 12.159	9.6 / 109.7	51.3 KiB	n/a
Offloads + THP disabled	2.99 / 2.44	0.82 / 1.00	2.177 / 5.580; 6.324 / 14.234	9.5 / 68.4	30.2 KiB	n/a
Offloads + THP disabled + lazy session ring	3.04 / 2.54	0.81 / 1.00	2.050 / 5.124; 6.564 / 13.579	9.6 / 52.3	21.9 KiB	n/a
Route-trie cut (`823133f`)	3.011 / 2.513	0.810 / 0.997	1.916 / 4.516; 6.173 / 12.379	9.3 / 37.1	14.2 KiB	n/a
Packet queue capacity 256 (`bfcab98`)	3.076 / 2.581	0.801 / 1.030	2.016 / 4.838; 4.991 / 10.802	9.6 / 29.2	10.1 KiB	n/a

The cap held throughput, improved 8-flow p99 by 12.7% against the route-trie row, and reduced 1,000-peer RSS by 7.9 MiB in this sample. At 1 flow, p99 increased 7.1% (4.516→4.838 ms), so I am repeating a matched route-cut control and candidate pair before calling this latency step pin-ready. The per-peer RSS slope remains about 2× the ≤5 KiB goal.

Raw successful R4b logs, machine-state receipts, harness, and candidate binary are attached as j88-bfcab98-queuecap256-20261102.tar.gz (SHA-256 c8e0de91af3456212130d1cebd465a86cf8fe0188e54073e5ada95afe0ef4fd8).

## J88 latency step: packet channel capacity 256 Candidate `bfcab98c5d67bd263ad62a2f29a48e28a64b3731` passed the matched R4b `mesh-gotatun` case through `perf-run --root` on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X, perf.slice CPUs 1–3, 6 GiB). The run exited 0 in 181 seconds with an empty machine diff. Both endpoints report source `bfcab98`; the buffer pool remains 4,000 entries and each packet handoff queue is 256. The first harness attempt exited before traffic because the copied kit lacked its shared helper binaries; it also had an empty machine diff and produced no measurement. The corrected kit now contains the same 16 helper binaries as the reference and a verified manifest. The attached archive is the successful run only. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 / 8 flows (ms) | RSS 1 / 1,000 peers (MiB) | Incremental RSS/peer | Kernel peer state/peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | Offloads, paired THP-on control | 3.15 / 2.80 | 0.79 / 0.98 | 1.878 / 6.861; 6.577 / 12.159 | 9.6 / 109.7 | 51.3 KiB | n/a | | Offloads + THP disabled | 2.99 / 2.44 | 0.82 / 1.00 | 2.177 / 5.580; 6.324 / 14.234 | 9.5 / 68.4 | 30.2 KiB | n/a | | Offloads + THP disabled + lazy session ring | 3.04 / 2.54 | 0.81 / 1.00 | 2.050 / 5.124; 6.564 / 13.579 | 9.6 / 52.3 | 21.9 KiB | n/a | | Route-trie cut (`823133f`) | 3.011 / 2.513 | 0.810 / 0.997 | 1.916 / 4.516; 6.173 / 12.379 | 9.3 / 37.1 | 14.2 KiB | n/a | | Packet queue capacity 256 (`bfcab98`) | 3.076 / 2.581 | 0.801 / 1.030 | 2.016 / 4.838; 4.991 / 10.802 | 9.6 / 29.2 | 10.1 KiB | n/a | The cap held throughput, improved 8-flow p99 by 12.7% against the route-trie row, and reduced 1,000-peer RSS by 7.9 MiB in this sample. At 1 flow, p99 increased 7.1% (4.516→4.838 ms), so I am repeating a matched route-cut control and candidate pair before calling this latency step pin-ready. The per-peer RSS slope remains about 2× the ≤5 KiB goal. Raw successful R4b logs, machine-state receipts, harness, and candidate binary are attached as `j88-bfcab98-queuecap256-20261102.tar.gz` (SHA-256 `c8e0de91af3456212130d1cebd465a86cf8fe0188e54073e5ada95afe0ef4fd8`).

j88-bfcab98-queuecap256-20261102.tar.gz

117 MiB

kayg commented

2026-11-02 18:13:14 +00:00

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J103 validation finding: the first locked clippy run on compute01 stopped with 26 errors and 1 warning. The diagnostics point to the new Linux adapter: missing code formatting in docs, an early-return loop, unchecked packet-index casts, a trait-required async method, and the restore function length. I have fixed those causes locally and moved the worktree to current origin/dev 1f005f2; I am rerunning validation before reporting this resolved.

J103 validation finding: the first locked clippy run on compute01 stopped with 26 errors and 1 warning. The diagnostics point to the new Linux adapter: missing code formatting in docs, an early-return loop, unchecked packet-index casts, a trait-required async method, and the restore function length. I have fixed those causes locally and moved the worktree to current origin/dev 1f005f2; I am rerunning validation before reporting this resolved.

kayg commented

2026-11-02 18:19:51 +00:00

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J88 latency step: queue capacity 256, two matched pairs

Measured the route-cut control (823133f828d8805f5ea17139f623395cc5cf7afa, queues 4,000) and the queue-cap candidate (bfcab98c5d67bd263ad62a2f29a48e28a64b3731, queues 256, buffer pool still 4,000) on the perf VM through perf-run --root. Both cases used the current R4b mesh-gotatun harness, H2H_PROFILE=0, CPUs 1–3 and the 6 GiB perf slice. Order was control→candidate, then candidate→control. All four runs exited 0 in 179–180 s and each machine diff was empty.

The GotaTun rows below are means of two independent samples per variant. The p50/p99 entries are means of each run's reported percentile, not a pooled percentile.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS / peer	Kernel peer state / peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun route cut, queues 4,000	3.033 / 2.659	0.803 / 0.995	2.078 / 5.198; 6.229 / 13.146	9.36 / 38.18	14.8 KiB	n/a
GotaTun queue cap 256 (`bfcab98`)	2.999 / 2.518	0.808 / 1.033	2.043 / 5.288; 4.776 / 10.676	9.46 / 29.09	10.1 KiB	n/a

Queue cap 256 improves 8-flow loaded p99 by about 18.8% and reduces the measured incremental RSS/peer by about 32%. It also lowers 8-flow throughput by about 5.3%; 1-flow p99 is about 1.7% worse on the two-run mean. The result misses the no-throughput-loss requirement, so bfcab98 is not pin-ready despite the library tests and release CLI build passing (131 passed, 7 ignored).

The previous queue profile found no timer-based coalescing delay. It recorded recvmmsg median/p95 batch sizes of 1/6, UDP GRO output up to 333 packets per receive, send batches up to 100, GSO planning up to 100 input segments in 9 groups, TUN recv_many up to 1,047 packets, and a maximum sampled channel-send wait of 2.106 ms. Four worker channels had 4,000-packet bounds; sampled queue maxima reached 2,307. The 256 bound constrains throughput too much.

Next: inspect the existing queue trace around the 1-flow loaded-latency window, then test a single 1,024-packet bound (near the observed 1,047-packet TUN receive burst), keeping the 4,000 buffer pool. Run the fork library suite and release build, then two reversed-order R4b pairs. Mark the commit pin-ready only if throughput holds and the 1-flow latency result improves. Estimate: 0.5–1 engineering day; stop before broader redesign if this bounded tuning misses either condition.

Raw successful-run logs, JSON, machine snapshots/diffs, receipts and the control harness are attached as j88-queuecap256-paired-r4b-20261102.tar.gz (SHA-256 7c0d3fe781c254d30fcaa42308f92671415611d862e1ecefade119624ddb8c0).

## J88 latency step: queue capacity 256, two matched pairs Measured the route-cut control (`823133f828d8805f5ea17139f623395cc5cf7afa`, queues 4,000) and the queue-cap candidate (`bfcab98c5d67bd263ad62a2f29a48e28a64b3731`, queues 256, buffer pool still 4,000) on the perf VM through `perf-run --root`. Both cases used the current R4b `mesh-gotatun` harness, `H2H_PROFILE=0`, CPUs 1–3 and the 6 GiB perf slice. Order was control→candidate, then candidate→control. All four runs exited 0 in 179–180 s and each machine diff was empty. The GotaTun rows below are means of two independent samples per variant. The p50/p99 entries are means of each run's reported percentile, not a pooled percentile. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS / peer | Kernel peer state / peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun route cut, queues 4,000 | 3.033 / 2.659 | 0.803 / 0.995 | 2.078 / 5.198; 6.229 / 13.146 | 9.36 / 38.18 | 14.8 KiB | n/a | | GotaTun queue cap 256 (`bfcab98`) | 2.999 / 2.518 | 0.808 / 1.033 | 2.043 / 5.288; 4.776 / 10.676 | 9.46 / 29.09 | 10.1 KiB | n/a | Queue cap 256 improves 8-flow loaded p99 by about 18.8% and reduces the measured incremental RSS/peer by about 32%. It also lowers 8-flow throughput by about 5.3%; 1-flow p99 is about 1.7% worse on the two-run mean. The result misses the no-throughput-loss requirement, so `bfcab98` is **not pin-ready** despite the library tests and release CLI build passing (131 passed, 7 ignored). The previous queue profile found no timer-based coalescing delay. It recorded `recvmmsg` median/p95 batch sizes of 1/6, UDP GRO output up to 333 packets per receive, send batches up to 100, GSO planning up to 100 input segments in 9 groups, TUN `recv_many` up to 1,047 packets, and a maximum sampled channel-send wait of 2.106 ms. Four worker channels had 4,000-packet bounds; sampled queue maxima reached 2,307. The 256 bound constrains throughput too much. Next: inspect the existing queue trace around the 1-flow loaded-latency window, then test a single 1,024-packet bound (near the observed 1,047-packet TUN receive burst), keeping the 4,000 buffer pool. Run the fork library suite and release build, then two reversed-order R4b pairs. Mark the commit pin-ready only if throughput holds and the 1-flow latency result improves. Estimate: 0.5–1 engineering day; stop before broader redesign if this bounded tuning misses either condition. Raw successful-run logs, JSON, machine snapshots/diffs, receipts and the control harness are attached as `j88-queuecap256-paired-r4b-20261102.tar.gz` (SHA-256 `7c0d3fe781c254d30fcaa42308f92671415611d862e1ecefade119624ddb8c0`).

j88-queuecap256-paired-r4b-20261102.tar.gz

968 KiB

kayg commented

2026-11-02 18:22:47 +00:00

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J103 validation runner finding: dev02 acquired slot 2/2, then exited before compilation because nix develop was launched from /home/claude and could not find the repo flake (log: “path "/home/claude" does not contain a flake.nix file”). I am changing the wrapper to cd into ~/worktrees/j103 before nix develop and retrying; no code validation completed in that attempt.

kayg commented

2026-11-02 18:45:13 +00:00

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J103 implementation start/resume: branch mesh-gotatun-linux from origin/dev at 1f005f2bc3. Selected GotaTun pin is 823133f828d8805f5ea17139f623395cc5cf7afa. The earlier compute01 clippy run reported 26 errors and 1 warning; fixes are in the worktree and I am rerunning the corrected locked validation. I checked both build-slot queues: compute01 had four busy slots and three queued; dev02 had two busy slots and three queued, with 114 GB free, so validation is going to dev02. The plan and estimate are in the earlier J103 comment. Next: locked validation, direct and relay namespace proofs including byte-exact failover/rebound, rotation overlap, scripts/verify fast, then the paired R4b run and final evidence.

J103 implementation start/resume: branch mesh-gotatun-linux from origin/dev at 1f005f2bc30b2e0c70afd3c4c97496cec4eb3deb. Selected GotaTun pin is 823133f828d8805f5ea17139f623395cc5cf7afa. The earlier compute01 clippy run reported 26 errors and 1 warning; fixes are in the worktree and I am rerunning the corrected locked validation. I checked both build-slot queues: compute01 had four busy slots and three queued; dev02 had two busy slots and three queued, with 114 GB free, so validation is going to dev02. The plan and estimate are in the earlier J103 comment. Next: locked validation, direct and relay namespace proofs including byte-exact failover/rebound, rotation overlap, scripts/verify fast, then the paired R4b run and final evidence.

kayg commented

2026-11-02 18:54:00 +00:00

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J88 latency work resumed on the existing fork branch j88-linux-offloads, based on GotaTun v0.10.2 (1d46b779f5e0743f30a13cc2c325b8114b901fb). Plan: verify the 1,024-packet queue-cap candidate with the 4,000-buffer pool unchanged; reproduce the ARM all-features library timeout failures serially; inspect queue/batch/handoff evidence; then run two reversed-order route-cut versus 1,024-cap R4b pairs through perf-run --root. I will keep the R4b table fields (1/8-flow throughput and CPU/Gbit, loaded RTT p50/p99, RSS at 1/1,000 peers, incremental RSS/peer, kernel peer memory), and mark a commit pin-ready only when fork tests pass and throughput holds. Estimate: 0.5–1 engineering day, including the two paired runs.

J88 latency work resumed on the existing fork branch `j88-linux-offloads`, based on GotaTun v0.10.2 (`1d46b779f5e0743f30a13cc2c325b8114b901fb`). Plan: verify the 1,024-packet queue-cap candidate with the 4,000-buffer pool unchanged; reproduce the ARM all-features library timeout failures serially; inspect queue/batch/handoff evidence; then run two reversed-order route-cut versus 1,024-cap R4b pairs through `perf-run --root`. I will keep the R4b table fields (1/8-flow throughput and CPU/Gbit, loaded RTT p50/p99, RSS at 1/1,000 peers, incremental RSS/peer, kernel peer memory), and mark a commit pin-ready only when fork tests pass and throughput holds. Estimate: 0.5–1 engineering day, including the two paired runs.

kayg commented

2026-11-02 19:07:48 +00:00

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J103 validation finding, with dev02 evidence: the corrected runner entered build-slot at 18:45:29, waited at queue position 4, and acquired a slot at 19:07:15. It then exited 1 at cargo fmt --all --check on one line-wrap in crates/plugins/mesh/src/gotatun_tun.rs (reported sequence_offset assignment); clippy, cargo tests, cargo-deny and example builds did not start. I corrected only that formatting issue locally.

kayg commented

2026-11-02 19:08:23 +00:00

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J103 queue selection update: the retry check shows compute01 with two queued ahead but only 28 GB free (25 GB build-slot floor; one Rust target can consume 25–40 GB). dev02 has four queued ahead and 112 GB free. I am choosing dev02 to avoid risking the compute01 filesystem during the full compile; both queue snapshots were checked before resubmission.

kayg commented

2026-11-02 19:29:15 +00:00

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J103 clippy finding, with dev02 evidence: the locked validation entered its slot at 19:07 and exited 101 with two clippy errors. The GotaTun source at pinned revision 823133f declares UdpTransportFactory::bind as a method returning impl Future, so the async implementation was unnecessary; I changed it to return ready(). Clippy also found segment_tcp at 108 lines; I extracted segment emission into a helper without changing the tested packet fields/checksum flow. Tests, cargo-deny and example builds did not run because clippy stopped the script.

kayg commented

2026-11-02 19:49:22 +00:00

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J103 clippy finding #2: the retry acquired dev02 slot 2/2 at 19:48:54 and exited 101 on crates/plugins/mesh/tests/gotatun_restore.rs:1 because the doc comment did not mark GotaTun as code. The factory and segmentation errors from the prior run no longer appear. No test, deny or example-build phase ran. I added the required backticks and am rechecking both queues before another run.

kayg commented

2026-11-02 19:49:53 +00:00

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J103 retry queue check: dev02 reports slot 2 free and 117 GB available; its status shows four queued requests. compute01 is fully occupied, one request is queued, and it has 68 GB free. I am selecting dev02 because it reports a free slot; the prior J103 runs are terminal.

kayg commented

2026-11-02 19:57:16 +00:00

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J88 latency step: queue capacity 1,024 (`ccbc4f0b42f0f0a38a73a24dd72f647e9312f2d0`)

The candidate keeps the 4,000-buffer reuse pool and sets each handoff queue to 1,024. The paired route-cut control used 4,000-packet queue bounds. Both variants used the same R4b mesh-gotatun harness, H2H_PROFILE=0, perf.slice CPUs 1–3 / 6 GiB, and two reversed-order pairs (control→candidate, then candidate→control). Each of the four perf-run --root cases exited 0 in 180–182 s with an empty machine diff. Values below are two-run means; p50/p99 are means of each run's reported percentiles.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB, both endpoints)	Incremental RSS / peer	Kernel peer state / peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun route cut, queue 4,000 (matched control)	2.904 / 2.515	0.819 / 1.000	2.011 / 5.443; 6.253 / 12.945	9.51 / 38.07	14.64 KiB	n/a
GotaTun queue cap 256 (`bfcab98`)	2.999 / 2.518	0.808 / 1.033	2.043 / 5.288; 4.776 / 10.676	9.46 / 29.09	10.1 KiB	n/a
GotaTun queue cap 1,024 (`ccbc4f0`)	2.970 / 2.591	0.805 / 0.992	2.074 / 5.555; 6.270 / 12.748	9.29 / 36.21	13.79 KiB	n/a

The 1,024 cap preserved throughput (+2.3% / +3.0% vs the matched control) and reduced 1,000-peer RSS by 1.87 MiB across both endpoints. It did not improve the latency-first 1-flow result: p99 averaged 5.555 ms vs 5.443 ms for control (+2.1%), with overlapping run ranges. The 8-flow p99 mean improved only 1.5%. This does not establish a latency win, so ccbc4f0 is not pin-ready; bfcab98 remains not pin-ready because its paired 8-flow throughput fell 5.3%.

Fork verification on x86_64 and AArch64 serially passed: formatting check; cargo test --locked -p gotatun --all-features --lib (131 passed, 7 ignored); x86_64 cargo build --locked --release -p gotatun-cli passed. An earlier parallel AArch64 run had five timeout failures among UDP/handshake tests; serial reruns passed on both architectures, so I have not treated that one run as a code regression.

The 1,024-cap paired raw JSON, daemon logs, machine snapshots/diffs, perf-run receipts and harness source-label overlay are attached as j88-queue1024-paired-r4b.tar.gz (SHA-256 25beb26bf64c6fda1a30164c7157c122caafa6a1c1a4fb2bec6912e068744539).

Next I’m tracing the existing 1-flow queue/profile samples around the loaded probe window. The present queue cap experiment does not justify a pin bump.

## J88 latency step: queue capacity 1,024 (`ccbc4f0b42f0f0a38a73a24dd72f647e9312f2d0`) The candidate keeps the 4,000-buffer reuse pool and sets each handoff queue to 1,024. The paired route-cut control used 4,000-packet queue bounds. Both variants used the same R4b `mesh-gotatun` harness, `H2H_PROFILE=0`, perf.slice CPUs 1–3 / 6 GiB, and two reversed-order pairs (control→candidate, then candidate→control). Each of the four `perf-run --root` cases exited 0 in 180–182 s with an empty machine diff. Values below are two-run means; p50/p99 are means of each run's reported percentiles. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB, both endpoints) | Incremental RSS / peer | Kernel peer state / peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun route cut, queue 4,000 (matched control) | 2.904 / 2.515 | 0.819 / 1.000 | 2.011 / 5.443; 6.253 / 12.945 | 9.51 / 38.07 | 14.64 KiB | n/a | | GotaTun queue cap 256 (`bfcab98`) | 2.999 / 2.518 | 0.808 / 1.033 | 2.043 / 5.288; 4.776 / 10.676 | 9.46 / 29.09 | 10.1 KiB | n/a | | GotaTun queue cap 1,024 (`ccbc4f0`) | 2.970 / 2.591 | 0.805 / 0.992 | 2.074 / 5.555; 6.270 / 12.748 | 9.29 / 36.21 | 13.79 KiB | n/a | The 1,024 cap preserved throughput (+2.3% / +3.0% vs the matched control) and reduced 1,000-peer RSS by 1.87 MiB across both endpoints. It did not improve the latency-first 1-flow result: p99 averaged 5.555 ms vs 5.443 ms for control (+2.1%), with overlapping run ranges. The 8-flow p99 mean improved only 1.5%. This does not establish a latency win, so `ccbc4f0` is **not pin-ready**; `bfcab98` remains not pin-ready because its paired 8-flow throughput fell 5.3%. Fork verification on x86_64 and AArch64 serially passed: formatting check; `cargo test --locked -p gotatun --all-features --lib` (131 passed, 7 ignored); x86_64 `cargo build --locked --release -p gotatun-cli` passed. An earlier parallel AArch64 run had five timeout failures among UDP/handshake tests; serial reruns passed on both architectures, so I have not treated that one run as a code regression. The 1,024-cap paired raw JSON, daemon logs, machine snapshots/diffs, `perf-run` receipts and harness source-label overlay are attached as `j88-queue1024-paired-r4b.tar.gz` (SHA-256 `25beb26bf64c6fda1a30164c7157c122caafa6a1c1a4fb2bec6912e068744539`). Next I’m tracing the existing 1-flow queue/profile samples around the loaded probe window. The present queue cap experiment does not justify a pin bump.

j88-queue1024-paired-r4b.tar.gz

939 KiB

kayg commented

2026-11-02 20:02:47 +00:00

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Latency follow-up (2026-11-02): inspected the existing route-cut queue-depth run and source paths. It confirms four buffered worker channels at capacity 4,000, no timed GRO/GSO coalescing, and a task-switch-heavy profile (~5.1k context switches/s). However, the queue high-water marks and send waits are aggregated across the whole harness, so they cannot be attributed to the loaded 1-flow RTT probe. The 256-cap candidate regressed 1-flow p99 / 8-flow throughput, and the 1,024-cap candidate did not improve 1-flow p99; neither is pin-ready.

Next I am correlating queue waits and batch sizes specifically with the loaded 1-flow probe, then I will change one evidenced path and repeat the paired R4b comparison. Estimate: 1–2 hours for targeted profiling, one scoped change, and a paired run; more only if the first hypothesis is not attributable.

Latency follow-up (2026-11-02): inspected the existing route-cut queue-depth run and source paths. It confirms four buffered worker channels at capacity 4,000, no timed GRO/GSO coalescing, and a task-switch-heavy profile (~5.1k context switches/s). However, the queue high-water marks and send waits are aggregated across the whole harness, so they cannot be attributed to the loaded 1-flow RTT probe. The 256-cap candidate regressed 1-flow p99 / 8-flow throughput, and the 1,024-cap candidate did not improve 1-flow p99; neither is pin-ready. Next I am correlating queue waits and batch sizes specifically with the loaded 1-flow probe, then I will change one evidenced path and repeat the paired R4b comparison. Estimate: 1–2 hours for targeted profiling, one scoped change, and a paired run; more only if the first hypothesis is not attributable.

kayg commented

2026-11-02 20:21:53 +00:00

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J103 sync correction: my prior scp destination ended at the worktree root, so the three changed files were copied there instead of into their source subdirectories. The next build therefore still saw the old GotaTun doc comment and exited at the same clippy error; no tests or later checks ran. I am removing only those misplaced copies, syncing to exact paths, verifying hashes, and rechecking both queues.

kayg commented

2026-11-02 20:23:15 +00:00

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J103 runner finding: compute01 admitted the run, but it exited 127 immediately with bash: cargo: command not found. The validation script used nix develop -c bash -lc; the login shell reset the Nix development PATH on compute01 before the first command, so formatting, clippy, tests, deny and example build did not run. I am switching to a non-login bash -c shell and checking the Nix environment before retrying.

J103 runner finding: compute01 admitted the run, but it exited 127 immediately with `bash: cargo: command not found`. The validation script used `nix develop -c bash -lc`; the login shell reset the Nix development PATH on compute01 before the first command, so formatting, clippy, tests, deny and example build did not run. I am switching to a non-login `bash -c` shell and checking the Nix environment before retrying.

kayg commented

2026-11-02 20:23:43 +00:00

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J103 runner check: on compute01, nix develop -c bash -c 'command -v cargo && cargo --version' returned /nix/store/02w3d1mmma133dcsl6pbxs7hbfdg2zv6-rust-minimal-1.99.0/bin/cargo and cargo 1.99.0. The queue snapshot shows compute01 slots 3 and 4 free, 63 GB free; dev02 has both slots busy and three queued. I am retrying the validation on compute01 with bash -c.

kayg commented

2026-11-02 20:24:51 +00:00

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J103 clippy finding #3: compute01 reached all-target clippy and reported four example issues. I verified relay_fixture's NodeConfig.port was never read; the Python fixture passed port 0, while the node reports and uses the actual ephemeral UDP port returned by Node::up. I removed that unused request field and its fixture argument, added GotaTun code formatting in both module docs, and made the peer map default explicit as BTreeMap::default().

kayg commented

2026-11-02 20:27:49 +00:00

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J103 test failure root cause: ip_details correctly advances IPv6 transport_offset from 40 to 48 for the 8-byte hop-by-hop header. The test's TCP data-offset and flags belong at 48+12=60 and 48+13=61, but ipv6_hop_by_hop_tcp_frame wrote them at 64/65, causing the expected "invalid TCP data offset". I corrected only the test frame offsets; the production parser remains unchanged.

kayg commented

2026-11-02 20:30:05 +00:00

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J103 validation finding: with the IPv6 fixture offsets corrected, cargo fmt and all-target clippy passed, and the full mesh test suite completed without failures. The runner then exited 2 at cargo deny check --locked because cargo-deny reports unexpected argument '--locked'; it did not run the deny check or example build. I will use cargo deny check (cargo-deny reads the checked-in Cargo.lock) and rerun the sequence.

J103 validation finding: with the IPv6 fixture offsets corrected, cargo fmt and all-target clippy passed, and the full mesh test suite completed without failures. The runner then exited 2 at `cargo deny check --locked` because cargo-deny reports `unexpected argument '--locked'`; it did not run the deny check or example build. I will use `cargo deny check` (cargo-deny reads the checked-in Cargo.lock) and rerun the sequence.

kayg commented

2026-11-02 20:30:29 +00:00

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J103 validation update: cargo fmt and all-target clippy passed; mesh tests passed 83, failed 0, with 14 ignored. Since the only issue was the unsupported cargo-deny --locked option and no source changed afterward, I am running just cargo deny check plus the GotaTun examples build to finish the locked validation.

kayg commented

2026-11-02 20:32:28 +00:00

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J103 cargo-deny finding: MPL-2.0 is already in deny.toml. The two rejected packages are ip_network 0.4.1 and ip_network_table 0.2.0, both BSD-2-Clause, used by the pinned GotaTun fork. I added BSD-2-Clause to the compatible-license allowlist and added the fork package version 0.10.2 beside the exact commit rev so cargo-deny no longer sees a wildcard Git dependency. The rev remains 823133f828d8805f5ea17139f623395cc5cf7afa.

kayg commented

2026-11-02 20:33:36 +00:00

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J103 locked validation update: cargo fmt passed; all-target clippy passed; the mesh suite passed 83 tests with 0 failures and 14 ignored; cargo-deny now reports advisories/bans/licenses/sources all ok; both mesh examples built successfully. The deny fixes retain the exact GotaTun revision and allow only the compatible BSD-2-Clause dependency license identified by cargo-deny.

kayg commented

2026-11-02 20:41:04 +00:00

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J88 latency follow-up plan (base: j88-linux-offloads at ccbc4f0, building on the route-trie cut and bounded handoff queues)

Revert the uncommitted 256-packet TUN batch experiment because its paired R4b result did not improve 1-flow p99 and regressed throughput. Read the complete #260 history, especially R4b comment 73644 and the offload status, and verify the existing baseline rows.
Profile the loaded 1-flow and 8-flow RTT phases on the perf VM. Correlate packet queue residence with batch depth, GRO/GSO coalescing, worker/task handoffs, channel bounds, and scheduling; use disposable diagnostics first and make no scheduling change until the dominant wait is identified.
Try one bounded change at a time at the measured bottleneck. For each, run fork tests and the edge matrix: loss/reordering, MTU and fragmentation boundaries, mixed offload/non-offload peers, kernel without TUN offload, IPv6, and per-peer memory. Keep only changes that lower loaded latency without reducing throughput.
Re-run the same R4b comparison for kernel WireGuard, wireguard-go, GotaTun control, and each candidate: throughput at 1/8 flows, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, plus kernel WireGuard's measured incremental peer-memory figure. Attach raw logs.
Commit and push each verified slice on the public fork branch, marking pin-ready only when its fork tests and paired R4b comparison are green. No upstream activity. Also record the exact GotaTun LICENSE declarations versus flake.nix for the outstanding licence note.

Estimate: 4–6 hours elapsed, including profiling, up to two focused tuning/test cycles, and paired perf runs (roughly 45–75 minutes of locked perf time). If profiling shows a required design change outside the existing queue/batching approach, stop and report the evidence first; stop for owner review if the task reaches 2× this estimate.

J88 latency follow-up plan (base: `j88-linux-offloads` at `ccbc4f0`, building on the route-trie cut and bounded handoff queues) 1. Revert the uncommitted 256-packet TUN batch experiment because its paired R4b result did not improve 1-flow p99 and regressed throughput. Read the complete #260 history, especially R4b comment 73644 and the offload status, and verify the existing baseline rows. 2. Profile the loaded 1-flow and 8-flow RTT phases on the perf VM. Correlate packet queue residence with batch depth, GRO/GSO coalescing, worker/task handoffs, channel bounds, and scheduling; use disposable diagnostics first and make no scheduling change until the dominant wait is identified. 3. Try one bounded change at a time at the measured bottleneck. For each, run fork tests and the edge matrix: loss/reordering, MTU and fragmentation boundaries, mixed offload/non-offload peers, kernel without TUN offload, IPv6, and per-peer memory. Keep only changes that lower loaded latency without reducing throughput. 4. Re-run the same R4b comparison for kernel WireGuard, wireguard-go, GotaTun control, and each candidate: throughput at 1/8 flows, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, plus kernel WireGuard's measured incremental peer-memory figure. Attach raw logs. 5. Commit and push each verified slice on the public fork branch, marking pin-ready only when its fork tests and paired R4b comparison are green. No upstream activity. Also record the exact GotaTun LICENSE declarations versus `flake.nix` for the outstanding licence note. Estimate: 4–6 hours elapsed, including profiling, up to two focused tuning/test cycles, and paired perf runs (roughly 45–75 minutes of locked perf time). If profiling shows a required design change outside the existing queue/batching approach, stop and report the evidence first; stop for owner review if the task reaches 2× this estimate.

kayg commented

2026-11-02 20:48:24 +00:00

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J103 integration finding, evidence from compute01 /home/claude/worktrees/J103/J103-integration.log (branch mesh-gotatun-linux, synchronized source):

Direct namespace fixture startup and config apply complete, then ping -c 1 10.254.0.2 exits 1.
Relay fixture reaches relay setup, but the proof reports AssertionError: no relayed handshake after its 20 s handshake window.
The ignored namespace restore test was invoked with CARGO_TARGET_DIR unset and panicked at gotatun_restore.rs:11 before engine startup. I will make its state directory independent of that variable.
Rotation overlap passed: 1 passed, 0 failed.
Both namespace proofs cleaned up: still_loaded: [], empty link/netns/module/sysctl diff, unchanged: true.

I have not changed the engine in response to these failures yet. Next: expose peer counters and route/interface state in the existing failing proofs, trace the first missing packet boundary, then make one test-led fix. Remaining estimate: 3–5 hours including integration reruns, final gate, issue evidence, and branch push; the existing J103 plan/initial estimate remain above.

J103 integration finding, evidence from compute01 `/home/claude/worktrees/J103/J103-integration.log` (branch `mesh-gotatun-linux`, synchronized source): - Direct namespace fixture startup and config apply complete, then `ping -c 1 10.254.0.2` exits 1. - Relay fixture reaches relay setup, but the proof reports `AssertionError: no relayed handshake` after its 20 s handshake window. - The ignored namespace restore test was invoked with `CARGO_TARGET_DIR` unset and panicked at `gotatun_restore.rs:11` before engine startup. I will make its state directory independent of that variable. - Rotation overlap passed: 1 passed, 0 failed. - Both namespace proofs cleaned up: `still_loaded: []`, empty link/netns/module/sysctl diff, `unchanged: true`. I have not changed the engine in response to these failures yet. Next: expose peer counters and route/interface state in the existing failing proofs, trace the first missing packet boundary, then make one test-led fix. Remaining estimate: 3–5 hours including integration reruns, final gate, issue evidence, and branch push; the existing J103 plan/initial estimate remain above.

kayg commented

2026-11-02 20:57:22 +00:00

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J103 packet-path diagnostic finding, compute01, source-synchronized branch mesh-gotatun-linux:

Direct proof creates both GotaTun engines and applies config; the routes and both TUN addresses are present. The failed ping leaves both peer counters at sent_bytes=0, received_bytes=0, and both TUN RX/TX counters at zero.
Relay proof sees the relay path and shim activity, but the GotaTun peers also report zero bytes and no handshake.
Both proofs completed cleanup: no loaded modules remain and the host link/netns/module/sysctl diff is empty.
The restore test source compiled, but this runner omitted --features agent; it ran 0 tests, so restore behavior remains unverified.

This places the first direct-path failure before encrypted UDP emission. I am tracing the TUN receive adapter and peer endpoint wiring before making a test-led change.

J103 packet-path diagnostic finding, compute01, source-synchronized branch `mesh-gotatun-linux`: - Direct proof creates both GotaTun engines and applies config; the routes and both TUN addresses are present. The failed ping leaves both peer counters at `sent_bytes=0, received_bytes=0`, and both TUN RX/TX counters at zero. - Relay proof sees the relay path and shim activity, but the GotaTun peers also report zero bytes and no handshake. - Both proofs completed cleanup: no loaded modules remain and the host link/netns/module/sysctl diff is empty. - The restore test source compiled, but this runner omitted `--features agent`; it ran 0 tests, so restore behavior remains unverified. This places the first direct-path failure before encrypted UDP emission. I am tracing the TUN receive adapter and peer endpoint wiring before making a test-led change.

kayg commented

2026-11-02 21:03:13 +00:00

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J88 phase-correlated queue trace finding (diagnostic only; no production change)

The disposable GotaTun trace build ran the R4b mesh-gotatun case through perf-run --root on the perf VM (exit 0, 180 s, machine diff empty). Its per-packet eprintln! instrumentation was too intrusive to use as a performance row: it generated 752,259,506 bytes / 7,001,770 lines across the two daemon logs, and observed throughput fell to 0.987 / 0.701 Gbit/s at 1 / 8 flows. Loaded RTT64 p99 rose to 19.11 / 33.35 ms. These numbers are instrumentation overhead, not a candidate result.

The trace identifies the probe frame sizes for a narrower retry: 92-byte inner IP packets on the TUN queues and 128-byte encrypted WireGuard payloads on the UDP queues. During the instrumented 1-flow window, those packets showed p99 residence of 5.307 ms in tun_to_device (queue depth p99/max 375/587; consumer batch p99/max 555/599) and 6.279 ms in udp_to_device (depth p99/max 409/603; GRO producer batch p99/max 306/406). Since the logger itself saturated this run, those residence figures are leads only and do not identify a production bottleneck. The source still has no timed GRO/GSO coalescing wait.

Next: keep the same harness and phase markers, filter to the 92/128-byte probes, sample 1 in 8 events, and verify that profile throughput remains close to the uninstrumented row. Then use only the filtered 1-flow/8-flow queue distributions to select one bounded scheduling change. No queue-cap or scheduling commit is being marked pin-ready.

J88 phase-correlated queue trace finding (diagnostic only; no production change) The disposable GotaTun trace build ran the R4b `mesh-gotatun` case through `perf-run --root` on the perf VM (exit 0, 180 s, machine diff empty). Its per-packet `eprintln!` instrumentation was too intrusive to use as a performance row: it generated 752,259,506 bytes / 7,001,770 lines across the two daemon logs, and observed throughput fell to 0.987 / 0.701 Gbit/s at 1 / 8 flows. Loaded RTT64 p99 rose to 19.11 / 33.35 ms. These numbers are instrumentation overhead, not a candidate result. The trace identifies the probe frame sizes for a narrower retry: 92-byte inner IP packets on the TUN queues and 128-byte encrypted WireGuard payloads on the UDP queues. During the instrumented 1-flow window, those packets showed p99 residence of 5.307 ms in `tun_to_device` (queue depth p99/max 375/587; consumer batch p99/max 555/599) and 6.279 ms in `udp_to_device` (depth p99/max 409/603; GRO producer batch p99/max 306/406). Since the logger itself saturated this run, those residence figures are leads only and do not identify a production bottleneck. The source still has no timed GRO/GSO coalescing wait. Next: keep the same harness and phase markers, filter to the 92/128-byte probes, sample 1 in 8 events, and verify that profile throughput remains close to the uninstrumented row. Then use only the filtered 1-flow/8-flow queue distributions to select one bounded scheduling change. No queue-cap or scheduling commit is being marked pin-ready.

kayg commented

2026-11-02 21:03:23 +00:00

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J103 root cause found by tracing the pinned GotaTun source and the coordinator path:

Node::up calls Engine::start(..., None), so DeviceBuilder::build receives no peers.
At pin 823133f, DeviceBuilder::build calls Connection::set_up only when its initial peer list is nonempty.
The first coordinator snapshot later calls add_or_update_peers; that API does not mark the device for reconfiguration, so no packet workers start.
This matches the reproduction: route and address setup succeeded while TUN and peer byte counters remained zero.

The implementation now defers GotaTun device construction until it has the first nonempty coordinator peer snapshot, retaining the prebound UDP sockets and key in the worker. I am validating direct and relay traffic before treating the diagnosis as confirmed.

J103 root cause found by tracing the pinned GotaTun source and the coordinator path: - Node::up calls Engine::start(..., None), so DeviceBuilder::build receives no peers. - At pin 823133f, DeviceBuilder::build calls Connection::set_up only when its initial peer list is nonempty. - The first coordinator snapshot later calls add_or_update_peers; that API does not mark the device for reconfiguration, so no packet workers start. - This matches the reproduction: route and address setup succeeded while TUN and peer byte counters remained zero. The implementation now defers GotaTun device construction until it has the first nonempty coordinator peer snapshot, retaining the prebound UDP sockets and key in the worker. I am validating direct and relay traffic before treating the diagnosis as confirmed.

kayg commented

2026-11-02 21:18:30 +00:00

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J103 integration rerun finding (compute01, source-synchronized mesh-gotatun-linux): direct namespace proof passed on GotaTun (mesh 47.1 Mbps; join-to-first-packet 383,520 us; IPv4 p99 6.01 ms, IPv6 p99 4.5 ms); restore passed 1/1 and rotation overlap passed 1/1. Relay proof failed before failover/rebound checks: initial relay ping loss was 100%. Cleanup receipts show still_loaded=[], links/netns/modules/sysctl diff empty, unchanged=true; no modules were loaded. I am tracing the first missing packet at the relay handoff.

kayg commented

2026-11-02 21:23:21 +00:00

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J103 relay-path diagnostic finding (compute01): both peers report endpoint=127.0.0.1:, active_relay=0, but GotaTun sent/received bytes stay 0 on both sides; shim sent/received/unlinked=0; relay links=1 but forwarded=0. The failure is before relay ciphertext handoff, after the peers are marked active. Cleanup again reports no modules, links, namespaces or sysctl changes. Next I am checking TUN route selection and interface counters before changing data-plane code.

J103 relay-path diagnostic finding (compute01): both peers report endpoint=127.0.0.1:<shim>, active_relay=0, but GotaTun sent/received bytes stay 0 on both sides; shim sent/received/unlinked=0; relay links=1 but forwarded=0. The failure is before relay ciphertext handoff, after the peers are marked active. Cleanup again reports no modules, links, namespaces or sysctl changes. Next I am checking TUN route selection and interface counters before changing data-plane code.

kayg commented

2026-11-02 21:28:55 +00:00

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J103 relay diagnostic continuation (compute01): ip route get 10.254.0.2 selects infraternal0; both TUN addresses are present and links are UP; nft sets include the destination in outgoing4_all; yet TUN RX/TX, both peer byte counters, shim counters and relay forwarded remain 0. A raw diagnostic ping reports 1 packet transmitted, 0 received, without a socket error. This confirms the packet is not reaching the TUN, but does not yet identify whether nft or route delivery drops it; I am adding a scoped nft trace to the failing namespace proof.

J103 relay diagnostic continuation (compute01): `ip route get 10.254.0.2` selects infraternal0; both TUN addresses are present and links are UP; nft sets include the destination in outgoing4_all; yet TUN RX/TX, both peer byte counters, shim counters and relay forwarded remain 0. A raw diagnostic ping reports 1 packet transmitted, 0 received, without a socket error. This confirms the packet is not reaching the TUN, but does not yet identify whether nft or route delivery drops it; I am adding a scoped nft trace to the failing namespace proof.

kayg commented

2026-11-02 21:30:21 +00:00

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J103 nft-trace finding (compute01): the failed ICMP echo request has oif infraternal0, and inet infraternal_mesh output jumps to outgoing, whose ip daddr @outgoing4_all rule accepts 10.254.0.2. The subsequent TUN link RX/TX counters remain zero and no GotaTun peer bytes increment. Thus the packet passes the mesh firewall but does not reach the TUN netdevice; I am tracing the engine/TUN attachment and endpoint update next. Cleanup receipts remain unchanged/empty.

J103 nft-trace finding (compute01): the failed ICMP echo request has `oif infraternal0`, and `inet infraternal_mesh output` jumps to `outgoing`, whose `ip daddr @outgoing4_all` rule accepts 10.254.0.2. The subsequent TUN link RX/TX counters remain zero and no GotaTun peer bytes increment. Thus the packet passes the mesh firewall but does not reach the TUN netdevice; I am tracing the engine/TUN attachment and endpoint update next. Cleanup receipts remain unchanged/empty.

kayg commented

2026-11-02 21:47:00 +00:00

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J88 latency profiling: low-overhead queue sample and next hypothesis

The disposable queue trace on 823133f828d8805f5ea17139f623395cc5cf7afa ran the R4b mesh-gotatun case through perf-run --root on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X, perf.slice CPUs 1–3 / 6 GiB). It exited 0 in 181 s with an empty machine diff. This diagnostic row is not a clean comparison.

The sampled loaded 1-flow windows show queue residence, not a configured coalescing timer: endpoint A TUN→device p50/p99 0.55/1.575 ms, depth p99 256–511, consumer batch p99 512–1,023; endpoint B UDP→device p50/p99 0.675/2.000 ms, depth p99 512–1,023, GRO producer batch p99 256–511. Cross-worker samples were 58% and 52%, and no sample was near the 4,000-packet queue bound. At 8 flows, the longest samples were endpoint A TUN→device 1.425/5.025 ms and endpoint B device→TUN 1.475/6.625 ms; endpoint B UDP→device p99 reached 4.750 ms. No timed GRO/GSO wait exists in the source. The measured batches and queue residence are the strongest actionable signal so far; queue-cap 256 and 1,024 did not improve the latency-first 1-flow p99 in their paired runs.

Next experiment: after UDP GRO segments are expanded, yield the receive producer after each 64 enqueued packets. This leaves the 4,000 queue bound and offload settings unchanged, and should let the consumer run during large GRO-expanded bursts. I will add a focused regression for loss/duplication across multiple yield intervals, then test the candidate with the same R4b case. This is a hypothesis, not a pin-ready change. Estimate for this candidate and its paired run: 1–2 hours.

R4b comparison so far

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 flow (ms)	Loaded RTT64 p50/p99, 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS / peer	Kernel peer state / peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763	3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631	7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733	4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460	5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
Offloads, paired THP-on control	3.15 / 2.80	0.79 / 0.98	1.878 / 6.861	6.577 / 12.159	9.6 / 109.7	51.3 KiB	n/a
Offloads + THP disabled	2.99 / 2.44	0.82 / 1.00	2.177 / 5.580	6.324 / 14.234	9.5 / 68.4	30.2 KiB	n/a
Offloads + lazy session ring	3.04 / 2.54	0.81 / 1.00	2.050 / 5.124	6.564 / 13.579	9.6 / 52.3	21.9 KiB	n/a
Compact peer routes (`823133f`)	3.011 / 2.513	0.810 / 0.997	1.916 / 4.516	6.173 / 12.379	9.3 / 37.1	14.2 KiB	n/a
Queue capacity 256 (`bfcab98`)	3.076 / 2.581	0.801 / 1.030	2.016 / 4.838	4.991 / 10.802	9.6 / 29.2	10.1 KiB	n/a
Queue capacity 1,024 (`ccbc4f0`)	2.970 / 2.591	0.805 / 0.992	2.074 / 5.555	6.270 / 12.748	9.29 / 36.21	13.79 KiB	n/a
Low-overhead queue profile (diagnostic only)	3.013 / 2.791	0.823 / 0.981	2.045 / 5.086	6.470 / 12.243	9.7 / 37.1	14.0 KiB	n/a

Raw logs and results: /home/claude/j20/r4b/j88-latency-queueprofile-lowoverhead-20261102/ on the perf VM. The diagnostic row is not pin-ready.

## J88 latency profiling: low-overhead queue sample and next hypothesis The disposable queue trace on `823133f828d8805f5ea17139f623395cc5cf7afa` ran the R4b `mesh-gotatun` case through `perf-run --root` on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X, perf.slice CPUs 1–3 / 6 GiB). It exited 0 in 181 s with an empty machine diff. This diagnostic row is not a clean comparison. The sampled loaded 1-flow windows show queue residence, not a configured coalescing timer: endpoint A TUN→device p50/p99 0.55/1.575 ms, depth p99 256–511, consumer batch p99 512–1,023; endpoint B UDP→device p50/p99 0.675/2.000 ms, depth p99 512–1,023, GRO producer batch p99 256–511. Cross-worker samples were 58% and 52%, and no sample was near the 4,000-packet queue bound. At 8 flows, the longest samples were endpoint A TUN→device 1.425/5.025 ms and endpoint B device→TUN 1.475/6.625 ms; endpoint B UDP→device p99 reached 4.750 ms. No timed GRO/GSO wait exists in the source. The measured batches and queue residence are the strongest actionable signal so far; queue-cap 256 and 1,024 did not improve the latency-first 1-flow p99 in their paired runs. Next experiment: after UDP GRO segments are expanded, yield the receive producer after each 64 enqueued packets. This leaves the 4,000 queue bound and offload settings unchanged, and should let the consumer run during large GRO-expanded bursts. I will add a focused regression for loss/duplication across multiple yield intervals, then test the candidate with the same R4b case. This is a hypothesis, not a pin-ready change. Estimate for this candidate and its paired run: 1–2 hours. ### R4b comparison so far | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 flow (ms) | Loaded RTT64 p50/p99, 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS / peer | Kernel peer state / peer | |---|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763 | 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631 | 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733 | 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460 | 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | Offloads, paired THP-on control | 3.15 / 2.80 | 0.79 / 0.98 | 1.878 / 6.861 | 6.577 / 12.159 | 9.6 / 109.7 | 51.3 KiB | n/a | | Offloads + THP disabled | 2.99 / 2.44 | 0.82 / 1.00 | 2.177 / 5.580 | 6.324 / 14.234 | 9.5 / 68.4 | 30.2 KiB | n/a | | Offloads + lazy session ring | 3.04 / 2.54 | 0.81 / 1.00 | 2.050 / 5.124 | 6.564 / 13.579 | 9.6 / 52.3 | 21.9 KiB | n/a | | Compact peer routes (`823133f`) | 3.011 / 2.513 | 0.810 / 0.997 | 1.916 / 4.516 | 6.173 / 12.379 | 9.3 / 37.1 | 14.2 KiB | n/a | | Queue capacity 256 (`bfcab98`) | 3.076 / 2.581 | 0.801 / 1.030 | 2.016 / 4.838 | 4.991 / 10.802 | 9.6 / 29.2 | 10.1 KiB | n/a | | Queue capacity 1,024 (`ccbc4f0`) | 2.970 / 2.591 | 0.805 / 0.992 | 2.074 / 5.555 | 6.270 / 12.748 | 9.29 / 36.21 | 13.79 KiB | n/a | | Low-overhead queue profile (diagnostic only) | 3.013 / 2.791 | 0.823 / 0.981 | 2.045 / 5.086 | 6.470 / 12.243 | 9.7 / 37.1 | 14.0 KiB | n/a | Raw logs and results: `/home/claude/j20/r4b/j88-latency-queueprofile-lowoverhead-20261102/` on the perf VM. The diagnostic row is not pin-ready.

kayg commented

2026-11-02 21:57:57 +00:00

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J103 relay proof finding (2026-11-02; compute01; branch mesh-gotatun-linux rebased to origin/dev): I added a direct peer C control around peer B's endpoint hand-off. The proof passes direct peer traffic before and after B is redirected to its local relay shim; both the 32 MiB relayed stream and 32 MiB direct stream complete with matching SHA-256. The required 384 MiB stream then stalls after relay 1 is killed and exits at the stream timeout. Cleanup reports no loaded modules and an empty host link/netns/module/sysctl diff. I am tracing whether link selection reaches relay 2 and collecting peer/shim counters during the stall before changing production code.

kayg commented

2026-11-02 22:10:38 +00:00

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J88 latency implementation progress (branch j88-linux-offloads, base 823133f828d8805f5ea17139f623395cc5cf7afa)

The only production diff is now the UDP receive producer yielding after each 64 packets in one recv_many_from batch. Temporary queue tracing has been removed. The three focused tests pass, formatting and targeted clippy pass, and the release CLI build passed (38.72 s).

The default full library test command invokes the repository's sudo -E Cargo runner and stopped because both dev VMs require a password. I reran the full library suite with CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER=env; result: 134 passed, 0 failed, 7 ignored. The candidate release binary is SHA-256 7c1de3f7dea06f3202d5e2cc8773e6ac7214ce30a36ed70e9c63a9e818094044.

The queue profile remains diagnostic: the 1-flow trace showed 256–511-packet producer batches and 512–1,023-packet queue depth at p99, with no timed GRO/GSO coalescing and no queue near its 4,000-packet cap. I am now running a paired route-cut control vs yield-64 comparison through the R4b mesh-gotatun harness, including its loss profile and the optional reorder profile. No commit is marked pin-ready until the paired latency and throughput result qualifies.

J88 latency implementation progress (branch `j88-linux-offloads`, base `823133f828d8805f5ea17139f623395cc5cf7afa`) The only production diff is now the UDP receive producer yielding after each 64 packets in one `recv_many_from` batch. Temporary queue tracing has been removed. The three focused tests pass, formatting and targeted clippy pass, and the release CLI build passed (38.72 s). The default full library test command invokes the repository's `sudo -E` Cargo runner and stopped because both dev VMs require a password. I reran the full library suite with `CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUNNER=env`; result: 134 passed, 0 failed, 7 ignored. The candidate release binary is SHA-256 `7c1de3f7dea06f3202d5e2cc8773e6ac7214ce30a36ed70e9c63a9e818094044`. The queue profile remains diagnostic: the 1-flow trace showed 256–511-packet producer batches and 512–1,023-packet queue depth at p99, with no timed GRO/GSO coalescing and no queue near its 4,000-packet cap. I am now running a paired route-cut control vs yield-64 comparison through the R4b `mesh-gotatun` harness, including its loss profile and the optional reorder profile. No commit is marked pin-ready until the paired latency and throughput result qualifies.

kayg commented

2026-11-02 22:21:15 +00:00

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J103 relay restart finding (compute01, rebased source): direct and relayed traffic reached the relay restart scenario, and the recovery ping passed. Relay 1 had been down for 90.9 s; after it restarted, it was ready in 17 ms and both clients relinked 4.40 s later. The proof then failed its <1500 ms assertion, although the measured total was 4.88 s. relay_path.rs intentionally permits exponential reconnect backoff up to 5 s after a relay has been unhealthy for over 60 s, so this observation is within the configured behavior. I will remove the functional test's arbitrary recovery-speed gate while retaining its recovered-traffic and byte-exact failover/rebound checks; latency remains measured in R4b.

J103 relay restart finding (compute01, rebased source): direct and relayed traffic reached the relay restart scenario, and the recovery ping passed. Relay 1 had been down for 90.9 s; after it restarted, it was ready in 17 ms and both clients relinked 4.40 s later. The proof then failed its `<1500 ms` assertion, although the measured total was 4.88 s. `relay_path.rs` intentionally permits exponential reconnect backoff up to 5 s after a relay has been unhealthy for over 60 s, so this observation is within the configured behavior. I will remove the functional test's arbitrary recovery-speed gate while retaining its recovered-traffic and byte-exact failover/rebound checks; latency remains measured in R4b.

kayg commented

2026-11-02 22:23:18 +00:00

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J88 latency step: yield-64 result

The low-overhead trace locates the queueing in packet handoffs: loaded 1-flow p99 residence was 1.575 ms on TUN→device and 2.000 ms on UDP→device; producer batches were 256–511 packets and queue depth was 256–1,023 at p99. Worker-crossing samples were 52–58%. There is no timed GRO/GSO coalescing wait, and the 4,000-packet channel bound was not approached. This supports yielding between large producer batches, but does not support shrinking the channel cap.

The yield-after-64 candidate passed the 134 active library tests (7 ignored), formatting, targeted clippy, and release build. The paired perf-run --root control and candidate both exited 0 with empty machine diffs. The reorder profile returned all 300 probes at each size in both runs. Under 2% loss per direction, the 64-byte probe count was 290/300 for control and 280/300 for candidate; the other sizes were 286/300 and 289/300 for candidate. The intentional-loss counts are retained in the raw logs.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50/p99, 1 flow (ms)	Loaded RTT64 p50/p99, 8 flows (ms)	RSS at 1 / 1,000 peers (MiB)	Incremental RSS / peer	Kernel peer state / peer
Kernel WireGuard	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763	3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631	7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733	4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460	5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
Offloads, paired THP-on control	3.15 / 2.80	0.79 / 0.98	1.878 / 6.861	6.577 / 12.159	9.6 / 109.7	51.3 KiB	n/a
Offloads + THP disabled	2.99 / 2.44	0.82 / 1.00	2.177 / 5.580	6.324 / 14.234	9.5 / 68.4	30.2 KiB	n/a
Offloads + lazy session ring	3.04 / 2.54	0.81 / 1.00	2.050 / 5.124	6.564 / 13.579	9.6 / 52.3	21.9 KiB	n/a
Compact peer routes (823133f)	3.011 / 2.513	0.810 / 0.997	1.916 / 4.516	6.173 / 12.379	9.3 / 37.1	14.2 KiB	n/a
Queue capacity 256 (bfcab98)	3.076 / 2.581	0.801 / 1.030	2.016 / 4.838	4.991 / 10.802	9.6 / 29.2	10.1 KiB	n/a
Queue capacity 1,024 (ccbc4f0)	2.970 / 2.591	0.805 / 0.992	2.074 / 5.555	6.270 / 12.748	9.29 / 36.21	13.79 KiB	n/a
Low-overhead queue profile (diagnostic)	3.013 / 2.791	0.823 / 0.981	2.045 / 5.086	6.470 / 12.243	9.7 / 37.1	14.0 KiB	n/a
Paired route-cut control	3.12 / 2.75	0.79 / 0.99	1.893 / 4.778	6.500 / 12.434	9.4 / 37.7	14.5 KiB	n/a
Yield after 64 UDP receive packets (not pin-ready)	3.03 / 2.50	0.81 / 1.03	1.838 / 4.689	5.486 / 11.363	9.4 / 35.1	13.2 KiB	n/a

Yield-64 improved loaded p99 by 0.089 ms at 1 flow and 1.071 ms at 8 flows against the paired control, while throughput fell 2.9% and 9.1%, respectively, and CPU/Gbit rose. It is not pin-ready. No commit has been created.

Raw logs, result JSON, R4b harness files, binaries, candidate source patch, and perf receipts are attached as j88-yield64-paired-raw.tar.gz (SHA-256 d3e5d768c57b87615335953573902c9086d3411a208d9c946598af6ef200f7cd).

Next I will test the same bounded yield at 128 packets per chunk. Estimate: about 1 hour for the focused checks and paired R4b run.

### J88 latency step: yield-64 result The low-overhead trace locates the queueing in packet handoffs: loaded 1-flow p99 residence was 1.575 ms on TUN→device and 2.000 ms on UDP→device; producer batches were 256–511 packets and queue depth was 256–1,023 at p99. Worker-crossing samples were 52–58%. There is no timed GRO/GSO coalescing wait, and the 4,000-packet channel bound was not approached. This supports yielding between large producer batches, but does not support shrinking the channel cap. The yield-after-64 candidate passed the 134 active library tests (7 ignored), formatting, targeted clippy, and release build. The paired `perf-run --root` control and candidate both exited 0 with empty machine diffs. The reorder profile returned all 300 probes at each size in both runs. Under 2% loss per direction, the 64-byte probe count was 290/300 for control and 280/300 for candidate; the other sizes were 286/300 and 289/300 for candidate. The intentional-loss counts are retained in the raw logs. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50/p99, 1 flow (ms) | Loaded RTT64 p50/p99, 8 flows (ms) | RSS at 1 / 1,000 peers (MiB) | Incremental RSS / peer | Kernel peer state / peer | |---|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763 | 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631 | 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733 | 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460 | 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | Offloads, paired THP-on control | 3.15 / 2.80 | 0.79 / 0.98 | 1.878 / 6.861 | 6.577 / 12.159 | 9.6 / 109.7 | 51.3 KiB | n/a | | Offloads + THP disabled | 2.99 / 2.44 | 0.82 / 1.00 | 2.177 / 5.580 | 6.324 / 14.234 | 9.5 / 68.4 | 30.2 KiB | n/a | | Offloads + lazy session ring | 3.04 / 2.54 | 0.81 / 1.00 | 2.050 / 5.124 | 6.564 / 13.579 | 9.6 / 52.3 | 21.9 KiB | n/a | | Compact peer routes (823133f) | 3.011 / 2.513 | 0.810 / 0.997 | 1.916 / 4.516 | 6.173 / 12.379 | 9.3 / 37.1 | 14.2 KiB | n/a | | Queue capacity 256 (bfcab98) | 3.076 / 2.581 | 0.801 / 1.030 | 2.016 / 4.838 | 4.991 / 10.802 | 9.6 / 29.2 | 10.1 KiB | n/a | | Queue capacity 1,024 (ccbc4f0) | 2.970 / 2.591 | 0.805 / 0.992 | 2.074 / 5.555 | 6.270 / 12.748 | 9.29 / 36.21 | 13.79 KiB | n/a | | Low-overhead queue profile (diagnostic) | 3.013 / 2.791 | 0.823 / 0.981 | 2.045 / 5.086 | 6.470 / 12.243 | 9.7 / 37.1 | 14.0 KiB | n/a | | Paired route-cut control | 3.12 / 2.75 | 0.79 / 0.99 | 1.893 / 4.778 | 6.500 / 12.434 | 9.4 / 37.7 | 14.5 KiB | n/a | | Yield after 64 UDP receive packets (not pin-ready) | 3.03 / 2.50 | 0.81 / 1.03 | 1.838 / 4.689 | 5.486 / 11.363 | 9.4 / 35.1 | 13.2 KiB | n/a | Yield-64 improved loaded p99 by 0.089 ms at 1 flow and 1.071 ms at 8 flows against the paired control, while throughput fell 2.9% and 9.1%, respectively, and CPU/Gbit rose. It is not pin-ready. No commit has been created. Raw logs, result JSON, R4b harness files, binaries, candidate source patch, and perf receipts are attached as `j88-yield64-paired-raw.tar.gz` (SHA-256 `d3e5d768c57b87615335953573902c9086d3411a208d9c946598af6ef200f7cd`). Next I will test the same bounded yield at 128 packets per chunk. Estimate: about 1 hour for the focused checks and paired R4b run.

j88-yield64-paired-raw.tar.gz

2.7 MiB

kayg commented

2026-11-02 22:40:06 +00:00

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J103 independent-review findings (source evidence, before the fix pass):

mesh.peers reads counters with wireguard::Device::counters() in node_actions.rs, although Node::counters() already dispatches to the selected engine. The action therefore cannot report GotaTun counters.
GotaTun retirement checks that the installation's recorded key equals its private key, while Device::active_engine() only identifies a static GotaTun alias and link kind. It does not bind the live TUN to that installation. Node::down() likewise checks only engine kind before Device::delete(), so stale ownership can remove a replacement TUN.
GotaTun Node::up() persists save(None, true) before Node::restore() replays its saved coordinator config. A replay error leaves the public state without the accepted config.
LinuxTun::send_packet() returns InvalidData for a decrypted packet above MTU. At the selected GotaTun pin, an adapter send error stops the packet workers; an oversized packet must be dropped without stopping later traffic.
The relay proof runs the sender concurrently but its callback kills relay 1 after a fixed delay, with no receiver gate. The 64 MiB transfer can finish before the kill, so the current byte/hash assertion does not prove a single stream crossed failover.

I will add focused regressions for these behaviors and make the relay proof hold a TCP stream after its first acknowledged MiB until relay 2 is active. The 2026-11-02 D163 GotaTun amendment is already present in the branch base from origin/dev. The J103 plan and estimate remain in the earlier issue comment.

J103 independent-review findings (source evidence, before the fix pass): - `mesh.peers` reads counters with `wireguard::Device::counters()` in `node_actions.rs`, although `Node::counters()` already dispatches to the selected engine. The action therefore cannot report GotaTun counters. - GotaTun retirement checks that the installation's recorded key equals its private key, while `Device::active_engine()` only identifies a static GotaTun alias and link kind. It does not bind the live TUN to that installation. `Node::down()` likewise checks only engine kind before `Device::delete()`, so stale ownership can remove a replacement TUN. - GotaTun `Node::up()` persists `save(None, true)` before `Node::restore()` replays its saved coordinator config. A replay error leaves the public state without the accepted config. - `LinuxTun::send_packet()` returns `InvalidData` for a decrypted packet above MTU. At the selected GotaTun pin, an adapter send error stops the packet workers; an oversized packet must be dropped without stopping later traffic. - The relay proof runs the sender concurrently but its callback kills relay 1 after a fixed delay, with no receiver gate. The 64 MiB transfer can finish before the kill, so the current byte/hash assertion does not prove a single stream crossed failover. I will add focused regressions for these behaviors and make the relay proof hold a TCP stream after its first acknowledged MiB until relay 2 is active. The 2026-11-02 D163 GotaTun amendment is already present in the branch base from origin/dev. The J103 plan and estimate remain in the earlier issue comment.

kayg commented

2026-11-02 22:54:15 +00:00

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J103 dependency finding (branch mesh-gotatun-linux, base 816f9ab3e8dc708d88a5f774d605cced22d82d22): at the selected fork pin 823133f828d8805f5ea17139f623395cc5cf7afa, LICENSE and Cargo.toml declare MPL-2.0, while the fork's flake.nix declares lib.licenses.bsd3. deny.toml already allows MPL-2.0 and this fork URL, so cargo-deny needs no license-policy change. I am recording the fork metadata mismatch here; license metadata remains an owner decision.

J103 dependency finding (branch `mesh-gotatun-linux`, base `816f9ab3e8dc708d88a5f774d605cced22d82d22`): at the selected fork pin `823133f828d8805f5ea17139f623395cc5cf7afa`, `LICENSE` and `Cargo.toml` declare MPL-2.0, while the fork's `flake.nix` declares `lib.licenses.bsd3`. `deny.toml` already allows MPL-2.0 and this fork URL, so cargo-deny needs no license-policy change. I am recording the fork metadata mismatch here; license metadata remains an owner decision.

kayg commented

2026-11-02 22:54:35 +00:00

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J88 yield-128 verification finding:

The synthetic 257-packet receive test passed across two yield points.
The real loopback burst timed out after 222 of 257 datagrams. The test sent the entire burst immediately, exceeding reliable local UDP receive buffering; I have reduced only that loopback fixture to 129 packets so it still crosses one yield. The synthetic batch remains 257 packets.
device::tests::one_keepalive and device::tests::test_indices failed only in the parallel full-suite run; both passed when run individually.
The 128-packet candidate has not been measured. Next I will run the full library suite serially, the release build, then the paired R4b comparison.

J88 yield-128 verification finding: - The synthetic 257-packet receive test passed across two yield points. - The real loopback burst timed out after 222 of 257 datagrams. The test sent the entire burst immediately, exceeding reliable local UDP receive buffering; I have reduced only that loopback fixture to 129 packets so it still crosses one yield. The synthetic batch remains 257 packets. - `device::tests::one_keepalive` and `device::tests::test_indices` failed only in the parallel full-suite run; both passed when run individually. - The 128-packet candidate has not been measured. Next I will run the full library suite serially, the release build, then the paired R4b comparison.

kayg commented

2026-11-02 23:02:14 +00:00

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J103 RED evidence (compute01, base 816f9ab3): the focused oversized_decrypted_packet_does_not_stop_the_next_valid_send test compiled and failed at its expected assertion because LinuxTun::send_packet returns an error for a packet above MTU. The next valid send was not attempted. No production code was changed in this check.

J103 RED evidence (compute01, base `816f9ab3`): the focused `oversized_decrypted_packet_does_not_stop_the_next_valid_send` test compiled and failed at its expected assertion because `LinuxTun::send_packet` returns an error for a packet above MTU. The next valid send was not attempted. No production code was changed in this check.

kayg commented

2026-11-02 23:03:09 +00:00

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J88 test_indices triage finding:

The failing test uses GotaTun's mock UdpChannelRx, which only implements recv_from; UdpRecv's default recv_many_from returns one packet per call. BufferedUdpReceive resets the yield counter for each received batch, so the 128-packet yield is unreachable on this test path and cannot directly explain its eavesdrop timeout.

Build-host load is a possible confounder to isolate: compute01 reported load average 21.59 while dev02 reported 0.54 at inspection. I am comparing the route-cut baseline and candidate under the same test conditions before attributing the timeout. The yield-128 candidate remains unmeasured and not pin-ready.

J88 test_indices triage finding: The failing test uses GotaTun's mock UdpChannelRx, which only implements recv_from; UdpRecv's default recv_many_from returns one packet per call. BufferedUdpReceive resets the yield counter for each received batch, so the 128-packet yield is unreachable on this test path and cannot directly explain its eavesdrop timeout. Build-host load is a possible confounder to isolate: compute01 reported load average 21.59 while dev02 reported 0.54 at inspection. I am comparing the route-cut baseline and candidate under the same test conditions before attributing the timeout. The yield-128 candidate remains unmeasured and not pin-ready.

kayg commented

2026-11-02 23:05:11 +00:00

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J103 RED evidence (compute01, unshare -Urn, base 816f9ab3): failed_gotatun_replay_keeps_the_accepted_coordinator_config failed because Node::restore overwrote the saved accepted config during GotaTun startup. The selected-engine mesh.peers proof also reached the action and failed with PluginError::Rejected, confirming it still queries the kernel counters instead of the GotaTun engine. I am tracing the ownership fixtures separately; they currently return NotFound before reaching their survival assertions.

J103 RED evidence (compute01, unshare `-Urn`, base `816f9ab3`): `failed_gotatun_replay_keeps_the_accepted_coordinator_config` failed because `Node::restore` overwrote the saved accepted config during GotaTun startup. The selected-engine `mesh.peers` proof also reached the action and failed with `PluginError::Rejected`, confirming it still queries the kernel counters instead of the GotaTun engine. I am tracing the ownership fixtures separately; they currently return `NotFound` before reaching their survival assertions.

kayg commented

2026-11-02 23:08:25 +00:00

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J103 RED evidence (compute01, unshare -Urn, base 816f9ab3): after correcting duplicate state-directory cleanup in the test fixture, both ownership regressions reach their intended assertions. retire_does_not_remove_another_installations_live_gotatun_tun fails because retirement does not report the replacement infraternal0 as left behind; down_does_not_remove_another_installations_replacement_gotatun_tun fails because stale down() removed the replacement TUN. No production code changed in these checks.

J103 RED evidence (compute01, unshare `-Urn`, base `816f9ab3`): after correcting duplicate state-directory cleanup in the test fixture, both ownership regressions reach their intended assertions. `retire_does_not_remove_another_installations_live_gotatun_tun` fails because retirement does not report the replacement `infraternal0` as left behind; `down_does_not_remove_another_installations_replacement_gotatun_tun` fails because stale `down()` removed the replacement TUN. No production code changed in these checks.

kayg commented

2026-11-02 23:10:51 +00:00

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J88 test_indices A/B result:

The corrected test_indices run selected exactly one test on each source. The route-cut HEAD passed in 0.55 s and the yield-128 working tree passed in 0.70 s on compute01 (load average at start: 20.25). The same mock-channel trace applies to both; it receives one packet per recv_many_from call, so neither run reaches the new yield gate.

This supports the existing one-second eavesdrop deadline being sensitive to build-host load, but does not prove that as the sole cause of the earlier timeout. I will run the full fork library suite serially before resuming perf. The candidate remains unmeasured and not pin-ready.

J88 test_indices A/B result: The corrected test_indices run selected exactly one test on each source. The route-cut HEAD passed in 0.55 s and the yield-128 working tree passed in 0.70 s on compute01 (load average at start: 20.25). The same mock-channel trace applies to both; it receives one packet per recv_many_from call, so neither run reaches the new yield gate. This supports the existing one-second eavesdrop deadline being sensitive to build-host load, but does not prove that as the sole cause of the earlier timeout. I will run the full fork library suite serially before resuming perf. The candidate remains unmeasured and not pin-ready.

kayg commented

2026-11-02 23:12:37 +00:00

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J88 yield-128 verification update:

The isolated test_indices A/B passed on both route-cut HEAD and the yield-128 working tree (one selected test each; 0.55 s / 0.70 s) on compute01. Source tracing confirms this mock-channel test receives one packet per batch, so the GRO-batch yield is not reached there; the earlier timeout is not attributable to that code path. The one-second fixture deadline remains load-sensitive under the build host's high shared load.

The complete GotaTun library suite passed with all features enabled and one test thread:

test result: ok. 134 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 7.88s

The yield-128 candidate is test-green but still not pin-ready. Next: optimized CLI build and paired R4b route-cut control vs candidate on the perf VM, including throughput, loaded latency, loss/reorder, and memory columns.

J88 yield-128 verification update: The isolated test_indices A/B passed on both route-cut HEAD and the yield-128 working tree (one selected test each; 0.55 s / 0.70 s) on compute01. Source tracing confirms this mock-channel test receives one packet per batch, so the GRO-batch yield is not reached there; the earlier timeout is not attributable to that code path. The one-second fixture deadline remains load-sensitive under the build host's high shared load. The complete GotaTun library suite passed with all features enabled and one test thread: test result: ok. 134 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 7.88s The yield-128 candidate is test-green but still not pin-ready. Next: optimized CLI build and paired R4b route-cut control vs candidate on the perf VM, including throughput, loaded latency, loss/reorder, and memory columns.

kayg commented

2026-11-02 23:26:20 +00:00

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J88 latency follow-up plan (2026-11-02), branch j88-linux-offloads, base 823133f (duplicate-trie cut).

Reuse the R4b perf VM/session and harness, confirm the paired route-cut control and candidate hashes, and preserve the existing queue/batch profile evidence. The only candidate variable is yielding after 128 packets from a large UDP receive result; no timed coalescing or channel-cap redesign without profile evidence.
Run route-cut control and candidate paired through perf-run --root in one blocked perf invocation, with the same R4b 1/8-flow throughput, CPU/Gbit, loaded p50/p99, and 1/1,000-peer memory cases. Include loss/reordering correctness and capture queue/batch diagnostics. Keep raw logs and empty machine diffs.
Keep the change only if it lowers loaded p99 without throughput loss and all correctness cases pass. Then run fork tests, commit atomically, push only origin, and mark the commit pin-ready; otherwise discard it and report the measured bottleneck and next bounded experiment.

Estimate: 45 minutes excluding perf-lock wait. Scope is this one latency experiment and its evidence; no product integration or upstream activity.

J88 latency follow-up plan (2026-11-02), branch `j88-linux-offloads`, base `823133f` (duplicate-trie cut). 1. Reuse the R4b perf VM/session and harness, confirm the paired route-cut control and candidate hashes, and preserve the existing queue/batch profile evidence. The only candidate variable is yielding after 128 packets from a large UDP receive result; no timed coalescing or channel-cap redesign without profile evidence. 2. Run route-cut control and candidate paired through `perf-run --root` in one blocked perf invocation, with the same R4b 1/8-flow throughput, CPU/Gbit, loaded p50/p99, and 1/1,000-peer memory cases. Include loss/reordering correctness and capture queue/batch diagnostics. Keep raw logs and empty machine diffs. 3. Keep the change only if it lowers loaded p99 without throughput loss and all correctness cases pass. Then run fork tests, commit atomically, push only `origin`, and mark the commit pin-ready; otherwise discard it and report the measured bottleneck and next bounded experiment. Estimate: 45 minutes excluding perf-lock wait. Scope is this one latency experiment and its evidence; no product integration or upstream activity.

kayg commented

2026-11-02 23:50:49 +00:00

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J88 latency step: yield-after-128 result (not pin-ready)

The R4b low-overhead queue trace places tail latency in packet queue residence and worker hand-offs: p99 residence was 1.575 ms on TUN→device and 2.000 ms on UDP→device; producer batches were 256–511 packets, p99 queue depth was 256–1,023, and 52–58% of samples crossed workers. There is no timed GRO/GSO coalescing wait, and the 4,000-packet channel bound was not approached. Yielding after each 128 queued receive packets did not reduce the loaded tail.

Same R4b harness, infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), perf.slice CPUs 1–3 / 6 GiB. Route-cut controls and GotaTun control ran in results set 20261102T233037Z; yield-128 ran in 20261102T234308Z. Every case used perf-run --root; machine diffs were empty.

Engine / step	Throughput, 1 / 8 flows (Gbit/s)	CPU, 1 / 8 flows (s/Gbit)	Loaded RTT64 p50 / p99, 1 flow (ms)	Loaded RTT64 p50 / p99, 8 flows (ms)	RSS at 1 / 1,000 peers (MiB, both endpoints)	Incremental RSS / peer	Kernel peer state / peer
Kernel WireGuard control	3.33 / 2.87	1.00 / 1.12	0.929 / 2.293	2.937 / 4.359	18.1 / 18.1	0	1.65 KiB
wireguard-go control	5.33 / 4.91	0.48 / 0.53	2.311 / 7.834	9.063 / 18.208	27.4 / 1,001.2	498.5 KiB	n/a
GotaTun route-cut control (`823133f`)	2.88 / 2.50	0.83 / 1.00	2.006 / 5.510	6.130 / 13.066	9.0 / 39.3	15.5 KiB	n/a
GotaTun yield-128 candidate	2.88 / 2.56	0.85 / 1.03	2.246 / 7.697	6.420 / 13.728	9.3 / 38.2	14.8 KiB	n/a

Yield-128 raised loaded p99 by 2.187 ms at 1 flow and 0.662 ms at 8 flows. Throughput was flat at 1 flow and +2.4% at 8 flows, while CPU/Gbit was slightly higher. RSS differences are small and do not change the memory conclusion. Under 25% reordering, all 300 probes arrived at each payload size for both GotaTun variants. Under intentional 2% loss per direction, received probes were 291/281/293 for control and 290/291/291 for yield-128 (64/512/1400 B); both cases completed with empty machine diffs.

The candidate full library suite passed (134 passed, 7 ignored), but the latency result fails the tuning goal. It remains uncommitted, unpushed, and not pin-ready. Raw logs, result JSON, machine snapshots/diffs, perf-run receipts, binaries, source patch, and test log are attached as j88-yield128-evidence.tar.gz (SHA-256 e1be24ec681bbfd3ea40eec169cbe89f57fd5d742dac36824714b90988fd077a).

Next: inspect the measured TUN/UDP hand-off sites and the earlier queue-cap result to identify one variable that can reduce the 1-flow tail without reducing throughput. Estimate: 30 minutes for source tracing and a bounded experiment plan before another code change.

## J88 latency step: yield-after-128 result (not pin-ready) The R4b low-overhead queue trace places tail latency in packet queue residence and worker hand-offs: p99 residence was 1.575 ms on TUN→device and 2.000 ms on UDP→device; producer batches were 256–511 packets, p99 queue depth was 256–1,023, and 52–58% of samples crossed workers. There is no timed GRO/GSO coalescing wait, and the 4,000-packet channel bound was not approached. Yielding after each 128 queued receive packets did not reduce the loaded tail. Same R4b harness, `infraternal-perf-01-backup01` (Debian 13, kernel 6.12.113, Ryzen 7 3700X), `perf.slice` CPUs 1–3 / 6 GiB. Route-cut controls and GotaTun control ran in results set `20261102T233037Z`; yield-128 ran in `20261102T234308Z`. Every case used `perf-run --root`; machine diffs were empty. | Engine / step | Throughput, 1 / 8 flows (Gbit/s) | CPU, 1 / 8 flows (s/Gbit) | Loaded RTT64 p50 / p99, 1 flow (ms) | Loaded RTT64 p50 / p99, 8 flows (ms) | RSS at 1 / 1,000 peers (MiB, both endpoints) | Incremental RSS / peer | Kernel peer state / peer | |---|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard control | 3.33 / 2.87 | 1.00 / 1.12 | 0.929 / 2.293 | 2.937 / 4.359 | 18.1 / 18.1 | 0 | 1.65 KiB | | wireguard-go control | 5.33 / 4.91 | 0.48 / 0.53 | 2.311 / 7.834 | 9.063 / 18.208 | 27.4 / 1,001.2 | 498.5 KiB | n/a | | GotaTun route-cut control (`823133f`) | 2.88 / 2.50 | 0.83 / 1.00 | 2.006 / 5.510 | 6.130 / 13.066 | 9.0 / 39.3 | 15.5 KiB | n/a | | GotaTun yield-128 candidate | 2.88 / 2.56 | 0.85 / 1.03 | 2.246 / 7.697 | 6.420 / 13.728 | 9.3 / 38.2 | 14.8 KiB | n/a | Yield-128 raised loaded p99 by 2.187 ms at 1 flow and 0.662 ms at 8 flows. Throughput was flat at 1 flow and +2.4% at 8 flows, while CPU/Gbit was slightly higher. RSS differences are small and do not change the memory conclusion. Under 25% reordering, all 300 probes arrived at each payload size for both GotaTun variants. Under intentional 2% loss per direction, received probes were 291/281/293 for control and 290/291/291 for yield-128 (64/512/1400 B); both cases completed with empty machine diffs. The candidate full library suite passed (134 passed, 7 ignored), but the latency result fails the tuning goal. It remains uncommitted, unpushed, and not pin-ready. Raw logs, result JSON, machine snapshots/diffs, `perf-run` receipts, binaries, source patch, and test log are attached as `j88-yield128-evidence.tar.gz` (SHA-256 `e1be24ec681bbfd3ea40eec169cbe89f57fd5d742dac36824714b90988fd077a`). Next: inspect the measured TUN/UDP hand-off sites and the earlier queue-cap result to identify one variable that can reduce the 1-flow tail without reducing throughput. Estimate: 30 minutes for source tracing and a bounded experiment plan before another code change.

j88-yield128-evidence.tar.gz

3.1 MiB

kayg commented

2026-11-02 23:53:51 +00:00

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J88 next latency experiment plan (2026-11-02), fork branch j88-linux-offloads, base 823133f828d8805f5ea17139f623395cc5cf7afa.

Finding: the low-overhead trace attributed 1.575 ms p99 residence to TUN→device and 2.000 ms to UDP→device, with 52–58% of samples crossing workers. UdpSocket already receives with recv_many_from, but Device::handle_incoming calls recv_from per datagram and BufferedUdpReceive inherits the trait's one-packet default. The 256 and 1,024 queue-cap trials did not improve 1-flow p99; the 256 cap improved 8-flow p99 while costing about 6% throughput. Yield-128 worsened loaded p99, so it is rejected.

Restore the clean route-cut source and add tests first for bounded ordered multi-packet dequeue and error preservation.
Prototype a bounded recv_many_from dequeue quantum (64 datagrams) in the buffered UDP receive path and have handle_incoming consume batches through the existing trait API. Keep channel capacity, GRO/GSO batching, TUN path, and endpoint semantics unchanged.
Run the full library suite and optimized CLI build on compute01. Run route-cut control and candidate through the same R4b kit on the perf VM, every case via perf-run --root, with loss/reordering, throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, and empty machine diffs.
Keep and commit only if loaded p99 improves and throughput is not reduced; otherwise discard and report the measured result.

Estimate: 60 minutes excluding perf-lock wait. This is one focused UDP consumer-batching experiment; no TUN redesign or channel-cap changes are in scope.

J88 next latency experiment plan (2026-11-02), fork branch `j88-linux-offloads`, base `823133f828d8805f5ea17139f623395cc5cf7afa`. Finding: the low-overhead trace attributed 1.575 ms p99 residence to TUN→device and 2.000 ms to UDP→device, with 52–58% of samples crossing workers. `UdpSocket` already receives with `recv_many_from`, but `Device::handle_incoming` calls `recv_from` per datagram and `BufferedUdpReceive` inherits the trait's one-packet default. The 256 and 1,024 queue-cap trials did not improve 1-flow p99; the 256 cap improved 8-flow p99 while costing about 6% throughput. Yield-128 worsened loaded p99, so it is rejected. 1. Restore the clean route-cut source and add tests first for bounded ordered multi-packet dequeue and error preservation. 2. Prototype a bounded `recv_many_from` dequeue quantum (64 datagrams) in the buffered UDP receive path and have `handle_incoming` consume batches through the existing trait API. Keep channel capacity, GRO/GSO batching, TUN path, and endpoint semantics unchanged. 3. Run the full library suite and optimized CLI build on compute01. Run route-cut control and candidate through the same R4b kit on the perf VM, every case via `perf-run --root`, with loss/reordering, throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, and empty machine diffs. 4. Keep and commit only if loaded p99 improves and throughput is not reduced; otherwise discard and report the measured result. Estimate: 60 minutes excluding perf-lock wait. This is one focused UDP consumer-batching experiment; no TUN redesign or channel-cap changes are in scope.

kayg commented

2026-11-03 00:02:43 +00:00

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J88 batch-dequeue TDD finding: the new test was added before production changes and compiled on compute01. With 130 queued datagrams, the current BufferedUdpReceive trait default returns one packet per call; the expected bounded batch assertion failed (queued datagrams should be drained together), exit 101. This confirms the specific dequeue gap from the queue profile. The implementation now overrides recv_many_from with a 64-packet cap and switches handle_incoming to that existing API; next is the focused green test and full library suite.

J88 batch-dequeue TDD finding: the new test was added before production changes and compiled on compute01. With 130 queued datagrams, the current `BufferedUdpReceive` trait default returns one packet per call; the expected bounded batch assertion failed (`queued datagrams should be drained together`), exit 101. This confirms the specific dequeue gap from the queue profile. The implementation now overrides `recv_many_from` with a 64-packet cap and switches `handle_incoming` to that existing API; next is the focused green test and full library suite.

kayg commented

2026-11-03 00:37:31 +00:00

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J88 resume (2026-11-03): continuing the latency plan already posted above. Fork branch j88-linux-offloads, route-cut base 823133f828d8805f5ea17139f623395cc5cf7afa; current uncommitted candidate batches BufferedUdpReceive dequeue to at most 64 queued packets and processes that batch through handle_incoming. The failing TDD assertion was recorded above. Next: inspect error/order semantics, run focused and full fork tests plus an optimized CLI build on a dev VM, then run the paired candidate/control matrix in one perf-run-backed R4b session. Existing estimate is 60 minutes excluding perf-lock wait. No upstream activity.

kayg commented

2026-11-03 00:43:28 +00:00

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J103 verify finding (compute01, /home/claude/.cache/codex-scratch/J103/evidence/verify-fast-after-ioctl.log): scripts/verify fast exited 1. After the ioctl fix, clippy identified six issues in the new mesh code: two missing GotaTun code marks, a fixed-size chunks_exact loop, Node::restore and Engine::start over the line limit, and a clone assignment. I extracted the restore and runtime setup steps, switched the fixed pair parser to as_chunks, and applied the suggested docs/clone changes.

The same gate's test phase had one failure in the existing real_binary_rootless_person_revocation_stops_existing_shells test: the fixture socket read exceeded its 1-second timeout while waiting for review-shell-started. The suite reported 10 passed / 1 failed in 34.29 seconds; the full test phase took 273 seconds. I have not attributed this timeout to a code regression or to host load yet and will rerun it. Static builds and cargo-deny passed in that gate.

J103 verify finding (compute01, `/home/claude/.cache/codex-scratch/J103/evidence/verify-fast-after-ioctl.log`): `scripts/verify fast` exited 1. After the ioctl fix, clippy identified six issues in the new mesh code: two missing `GotaTun` code marks, a fixed-size `chunks_exact` loop, `Node::restore` and `Engine::start` over the line limit, and a clone assignment. I extracted the restore and runtime setup steps, switched the fixed pair parser to `as_chunks`, and applied the suggested docs/clone changes. The same gate's test phase had one failure in the existing `real_binary_rootless_person_revocation_stops_existing_shells` test: the fixture socket read exceeded its 1-second timeout while waiting for `review-shell-started`. The suite reported 10 passed / 1 failed in 34.29 seconds; the full test phase took 273 seconds. I have not attributed this timeout to a code regression or to host load yet and will rerun it. Static builds and cargo-deny passed in that gate.

kayg commented

2026-11-03 01:09:14 +00:00

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J103 gate rerun update (compute01, through build-slot; log: /home/claude/.cache/codex-scratch/J103/evidence/verify-fast-final.log): fmt and clippy passed. The earlier rootless live-shell revocation test now passes. A different existing test, agent_sessions::latency_fixture_accepts_the_unsolicited_startup_inventory, failed in the full run: its fixture socket read timed out while waiting for CENSUS_FIXTURE_OK; that test binary reported 3 passed / 1 failed in 21.68 seconds. I have not attributed this to the mesh changes or shared host load. The gate is continuing its remaining checks; I will rerun or compare this test after it reaches a terminal result.

J103 gate rerun update (compute01, through build-slot; log: `/home/claude/.cache/codex-scratch/J103/evidence/verify-fast-final.log`): fmt and clippy passed. The earlier rootless live-shell revocation test now passes. A different existing test, `agent_sessions::latency_fixture_accepts_the_unsolicited_startup_inventory`, failed in the full run: its fixture socket read timed out while waiting for `CENSUS_FIXTURE_OK`; that test binary reported 3 passed / 1 failed in 21.68 seconds. I have not attributed this to the mesh changes or shared host load. The gate is continuing its remaining checks; I will rerun or compare this test after it reaches a terminal result.

kayg commented

2026-11-03 01:10:16 +00:00

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J88 verification finding (dev02, candidate still uncommitted): cargo fmt --all -- --check completed, then all-features/all-targets clippy stopped before tests/build. It flagged the new BufferedUdpReceive::recv_many_from as manual_async_fn and the already-present TUN offload constructor at gotatun/src/tun/tun_async_device.rs:116 as needless_return. The command's tee pipeline masked clippy's nonzero status as outer exit 0; no test/build result is claimed. I will express the new method as async fn and rerun with only the baseline TUN lint allowed, with pipefail enabled.

kayg commented

2026-11-03 01:17:26 +00:00

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J103 gate diagnostic follow-up: after the runtime/helper clippy fixes, the remaining clippy error was only a missing code mark on GotaTun in crates/plugins/mesh/tests/review_retire_ownership.rs:182 (full gate log, compute01). I added the backticks; the focused retest and final gate are pending.

J103 gate diagnostic follow-up: after the runtime/helper clippy fixes, the remaining clippy error was only a missing code mark on `GotaTun` in `crates/plugins/mesh/tests/review_retire_ownership.rs:182` (full gate log, compute01). I added the backticks; the focused retest and final gate are pending.

kayg commented

2026-11-03 01:19:25 +00:00

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J88 batch-dequeue verification (compute01, source base 823133f828d8805f5ea17139f623395cc5cf7afa): cargo fmt --all -- --check passed; all-features/all-targets clippy passed with (that single allowance covers the pre-existing TUN offload lint at tun_async_device.rs:116); the focused batch/order/error regression passed (1/1); full library suite passed: ; optimized x86_64 CLI build passed. Candidate binary SHA-256: 95d9d0e73af8956010a6407aa76f4e9aa3c1df22698b1525d72bfb53e4da40d0. This is the bounded dequeue candidate, distinct from the rejected yield-64 experiment. It is still unmeasured and not pin-ready. Next: paired route-cut control/candidate through one R4b hold with loss and reorder, then publish the table.

kayg commented

2026-11-03 01:20:16 +00:00

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Correction to the previous verification comment: shell quoting stripped its inline command/output fields. The actual compute01 result is: cargo fmt --all -- --check passed; all-features/all-targets clippy passed with only clippy::needless_return allowed for the existing TUN-offload source line; the focused batch/order/error regression passed (1 passed); full library suite passed with 132 passed, 0 failed, 7 ignored; optimized x86_64 CLI build passed. Candidate SHA-256 remains 95d9d0e73af8956010a6407aa76f4e9aa3c1df22698b1525d72bfb53e4da40d0. The candidate remains unmeasured and not pin-ready.

kayg commented

2026-11-03 01:21:22 +00:00

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J88 batch-dequeue R4b run queued (2026-11-03): the x86_64 candidate binary hash is 95d9d0e73af8956010a6407aa76f4e9aa3c1df22698b1525d72bfb53e4da40d0; route-cut control binary hash is recorded from the R4b kit at /home/claude/j20/r4b/h2h-kit-j88-routecut-823133f/bin/gotatun.raw. One perf-run --root hold will run control then candidate using mesh-gotatun, H2H_PROFILE=0, and the R4b reorder check. This records the same throughput, CPU, loaded RTT and peer-scale RSS rows plus the intentional-loss/reorder probes and per-case empty machine diffs. The perf VM currently has another perf-run active; this run will wait behind the shared lock. Results root: /home/claude/j20/r4b/j88-latency-batch64-20261103. The candidate is not pin-ready pending this result.

kayg commented

2026-11-03 01:31:29 +00:00

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J103 rebase update (2026-11-03): mesh-gotatun-linux is now based on current origin/dev at 299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f (the task-time base was 816f9ab3). The working changes reapplied cleanly in the control and compute01 worktrees; the synchronized tracked diff hashes match. No build or test from the stale base will count as final evidence. Next: rerun the isolated startup-inventory test and scripts/verify fast on the rebased tree.

J103 rebase update (2026-11-03): `mesh-gotatun-linux` is now based on current `origin/dev` at `299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f` (the task-time base was `816f9ab3`). The working changes reapplied cleanly in the control and compute01 worktrees; the synchronized tracked diff hashes match. No build or test from the stale base will count as final evidence. Next: rerun the isolated startup-inventory test and `scripts/verify fast` on the rebased tree.

kayg commented

2026-11-03 01:39:02 +00:00

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J88 batch-dequeue quantum 64: paired R4b result (not pin-ready)

The low-overhead profile showed 1.575 ms p99 residence on TUN→device and 2.000 ms on UDP→device, 256–511 packet producer batches, 512–1,023 queue depth at p99, and 52–58% worker crossings. There is no timed GRO/GSO coalescing wait, and the 4,000-packet channel bound was not approached. The candidate only changes BufferedUdpReceive to dequeue up to 64 queued datagrams per call; GSO/GRO and channel capacity are unchanged.

The paired run used the R4b mesh-gotatun harness on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), perf.slice CPUs 1–3 / 6 GiB, H2H_PROFILE=0, and one perf-run --root hold. Both cases exited 0 and had empty machine diffs. Reordering delivered all 300 probes at each size for both variants. Under independent 2% loss per direction, missing probes (64/512/1400 B) were 8/12/18 for control and 13/10/12 for the candidate. Control and candidate load at start were 0.73 and 0.20, respectively, so the single sequential pair does not isolate the apparent latency gain from run-order variation.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50 / p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB, both endpoints)	Incremental RSS / peer	Kernel peer state / peer
Kernel WireGuard reference	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go reference	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2 reference	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun route-cut control, same perf hold	2.85 / 2.61	0.83 / 1.01	2.176 / 6.090; 6.283 / 12.732	9.2 / 35.6	13.5 KiB	n/a
GotaTun buffered dequeue quantum 64	2.88 / 2.51	0.82 / 0.99	1.933 / 5.297; 6.230 / 13.335	9.4 / 37.5	14.4 KiB	n/a

Against the paired control, loaded 1-flow p99 fell by 0.793 ms (13.0%), but 8-flow p99 rose by 0.603 ms (4.7%) and 8-flow throughput fell by 3.8%. The candidate still measured 5.297 ms p99 at 1 flow, about 3× kernel WireGuard's 1.763 ms, and memory remains above the 5 KiB/peer target. Because throughput regressed and the 1-flow result is order-confounded, quantum 64 is not pin-ready and will not be committed.

Next bounded experiment: change only the dequeue quantum from 64 to 128, add a focused test that the queued 130-packet fixture yields one ordered batch of 128 followed by the remainder and error, then run fork tests and an optimized x86_64 build. Measure route-cut control and candidate in counterbalanced order (control, candidate, candidate, control) in one perf-run hold. Keep only if the averaged loaded p99 improves without throughput loss at either flow count. Estimate: 45 minutes excluding perf-lock wait. Raw logs, JSON, receipts, result summaries, binaries, and source patch are attached.

## J88 batch-dequeue quantum 64: paired R4b result (not pin-ready) The low-overhead profile showed 1.575 ms p99 residence on TUN→device and 2.000 ms on UDP→device, 256–511 packet producer batches, 512–1,023 queue depth at p99, and 52–58% worker crossings. There is no timed GRO/GSO coalescing wait, and the 4,000-packet channel bound was not approached. The candidate only changes BufferedUdpReceive to dequeue up to 64 queued datagrams per call; GSO/GRO and channel capacity are unchanged. The paired run used the R4b mesh-gotatun harness on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X), perf.slice CPUs 1–3 / 6 GiB, H2H_PROFILE=0, and one perf-run --root hold. Both cases exited 0 and had empty machine diffs. Reordering delivered all 300 probes at each size for both variants. Under independent 2% loss per direction, missing probes (64/512/1400 B) were 8/12/18 for control and 13/10/12 for the candidate. Control and candidate load at start were 0.73 and 0.20, respectively, so the single sequential pair does not isolate the apparent latency gain from run-order variation. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50 / p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB, both endpoints) | Incremental RSS / peer | Kernel peer state / peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard reference | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go reference | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 reference | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun route-cut control, same perf hold | 2.85 / 2.61 | 0.83 / 1.01 | 2.176 / 6.090; 6.283 / 12.732 | 9.2 / 35.6 | 13.5 KiB | n/a | | GotaTun buffered dequeue quantum 64 | 2.88 / 2.51 | 0.82 / 0.99 | 1.933 / 5.297; 6.230 / 13.335 | 9.4 / 37.5 | 14.4 KiB | n/a | Against the paired control, loaded 1-flow p99 fell by 0.793 ms (13.0%), but 8-flow p99 rose by 0.603 ms (4.7%) and 8-flow throughput fell by 3.8%. The candidate still measured 5.297 ms p99 at 1 flow, about 3× kernel WireGuard's 1.763 ms, and memory remains above the 5 KiB/peer target. Because throughput regressed and the 1-flow result is order-confounded, quantum 64 is not pin-ready and will not be committed. Next bounded experiment: change only the dequeue quantum from 64 to 128, add a focused test that the queued 130-packet fixture yields one ordered batch of 128 followed by the remainder and error, then run fork tests and an optimized x86_64 build. Measure route-cut control and candidate in counterbalanced order (control, candidate, candidate, control) in one perf-run hold. Keep only if the averaged loaded p99 improves without throughput loss at either flow count. Estimate: 45 minutes excluding perf-lock wait. Raw logs, JSON, receipts, result summaries, binaries, and source patch are attached.

j88-batch64-evidence.tar.gz

2.7 MiB

kayg commented

2026-11-03 01:40:37 +00:00

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J88 quantum-128 RED evidence (compute01): the focused buffered UDP receive regression compiled and failed as intended before production changes. With 130 queued packets, the current quantum returned 64, while the test requires a full 128-packet batch; exit 101. The fixture also checks total packet order and forwarding the terminal receive error. I will now change only the dequeue bound to 128.

kayg commented

2026-11-03 01:46:43 +00:00

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J88 quantum-128 verification (compute01, fork branch j88-linux-offloads, base 823133f828d8805f5ea17139f623395cc5cf7afa): the focused quantum/order/error regression passed (1/1), formatting passed, all-features/all-targets clippy passed with only the existing TUN-offload needless_return lint allowed, and the full library suite passed: 132 passed, 0 failed, 7 ignored. The optimized x86_64 CLI build passed. Candidate binary SHA-256: 60d91cc3211afaf423d14c2285ea48bee1689a141c03589b1bd58153dc95dff9. Next: route-cut control, quantum-128, quantum-128, route-cut control in that counterbalanced order inside one R4b perf-run hold. No candidate commit is pin-ready until that result qualifies.

kayg commented

2026-11-03 01:57:03 +00:00

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J103 gate attempt on the rebased mesh-gotatun-linux worktree did not reach its summary. The test phase stopped while linking infraternal-plugin-ssh and infraternal-server with rustc-LLVM ERROR: IO failure on output stream: No space left on device (log: /home/claude/.cache/codex-scratch/J103/evidence/verify-fast-rebased.log). The J103 process is terminal; no gate result is claimed. A later snapshot showed 52 GiB available and 8% inode use, so the transient ENOSPC cause is not yet identified. At that snapshot compute01 was 4/4 slots busy with one queued; dev-02 had two occupied slots, four queued, and 51 GiB available. The synchronized dev-02 J103 worktree is at 299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f with the same source diff and an existing 1.8 GiB target. Retrying there after freeing this job's failed compute01 target.

J103 gate attempt on the rebased `mesh-gotatun-linux` worktree did not reach its summary. The test phase stopped while linking `infraternal-plugin-ssh` and `infraternal-server` with `rustc-LLVM ERROR: IO failure on output stream: No space left on device` (log: `/home/claude/.cache/codex-scratch/J103/evidence/verify-fast-rebased.log`). The J103 process is terminal; no gate result is claimed. A later snapshot showed 52 GiB available and 8% inode use, so the transient ENOSPC cause is not yet identified. At that snapshot compute01 was 4/4 slots busy with one queued; dev-02 had two occupied slots, four queued, and 51 GiB available. The synchronized dev-02 J103 worktree is at `299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f` with the same source diff and an existing 1.8 GiB target. Retrying there after freeing this job's failed compute01 target.

kayg commented

2026-11-03 02:10:38 +00:00

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J88 UDP dequeue quantum 128: counterbalanced R4b result (not pin-ready)

The earlier low-overhead trace located queue residence at 1.575 ms p99 on TUN→device and 2.000 ms on UDP→device, with 52–58% of samples crossing workers. Queue depth was 512–1,023 at p99, below the 4,000-packet channel bound; there was no timed GRO/GSO coalescing wait. This candidate changed only the buffered UDP consumer dequeue bound from 64 to 128.

The same R4b mesh-gotatun harness ran route-cut control, candidate, candidate, control under one perf-run --root lock on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X; 4 CPUs, 6 GiB perf slice). All four cases exited 0 with empty machine diffs. The outer perf-run exited 0 in 969.6 seconds. Loaded RTT figures below are means of the two counterbalanced samples per variant.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50 / p99, 1 / 8 flows (ms)	RSS at 1 / 1,000 peers (MiB, both endpoints)	Incremental RSS / peer	Kernel peer state / peer
Kernel WireGuard reference	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763; 3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go reference	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631; 7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2 reference	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733; 4.654 / 11.876	9.6 / 104.6	48.7 KiB	n/a
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460; 5.846 / 12.502	10.0 / 108.6	50.5 KiB	n/a
GotaTun route-cut control, this hold (mean of 2)	2.93 / 2.57	0.82 / 1.01	1.947 / 4.932; 6.128 / 12.259	9.3 / 36.6	14.0 KiB	1.65 KiB
GotaTun buffered UDP dequeue quantum 128 (mean of 2)	3.00 / 2.57	0.81 / 0.99	1.936 / 5.036; 6.090 / 13.600	9.4 / 37.1	14.2 KiB	1.65 KiB

Quantum 128 raised loaded p99 by 0.104 ms (2.1%) at 1 flow and 1.341 ms (10.9%) at 8 flows. Throughput averaged +2.4% at 1 flow and −0.2% at 8 flows, so the latency result does not qualify. RSS at 1,000 peers was 0.5 MiB higher. This candidate remains uncommitted and is not pin-ready.

The reorder profile delivered all 300 probes at all three payload sizes in all four runs. Under independent 2% loss per direction, missing probes (64/512/1400 B) were 10/13/10 and 9/10/12 for the controls; 16/11/11 and 10/14/13 for quantum 128. These are the raw intentional-loss counts. Machine diffs were empty for all four cases.

Raw logs, JSON, machine snapshots/diffs, perf receipts, hashes, runner and source patch are attached as j88-batch128-evidence.tar.gz (SHA-256 7255bc3996644e3659f6cfe1aae6d30760929e08610c2d729c3ff48405c431d5). It is stored under /home/claude/j20/r4b/j88-latency-batch128-counterbalanced-20261103/ on the perf VM.

Next bounded experiment

I will discard the rejected dequeue candidate and prototype one receive-path change: pass the existing UDP UdpRecv directly to handle_incoming, bypassing only BufferedUdpReceive's producer task and 4,000-entry channel. Keep socket recvmmsg/GRO, the TUN path, send buffering, and offload settings unchanged. This targets the measured UDP→device residence and 52–58% cross-worker handoffs. Validate with the fork library tests, IPv4/IPv6 receive coverage, loss/reorder checks in the R4b harness, an optimized x86_64 build, then one control/candidate/candidate/control perf hold. Estimate: 60 minutes excluding the perf lock.

## J88 UDP dequeue quantum 128: counterbalanced R4b result (not pin-ready) The earlier low-overhead trace located queue residence at 1.575 ms p99 on TUN→device and 2.000 ms on UDP→device, with 52–58% of samples crossing workers. Queue depth was 512–1,023 at p99, below the 4,000-packet channel bound; there was no timed GRO/GSO coalescing wait. This candidate changed only the buffered UDP consumer dequeue bound from 64 to 128. The same R4b `mesh-gotatun` harness ran route-cut control, candidate, candidate, control under one `perf-run --root` lock on infraternal-perf-01-backup01 (Debian 13, kernel 6.12.113, Ryzen 7 3700X; 4 CPUs, 6 GiB perf slice). All four cases exited 0 with empty machine diffs. The outer perf-run exited 0 in 969.6 seconds. Loaded RTT figures below are means of the two counterbalanced samples per variant. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50 / p99, 1 / 8 flows (ms) | RSS at 1 / 1,000 peers (MiB, both endpoints) | Incremental RSS / peer | Kernel peer state / peer | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard reference | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763; 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go reference | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631; 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 reference | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733; 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | n/a | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460; 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | n/a | | GotaTun route-cut control, this hold (mean of 2) | 2.93 / 2.57 | 0.82 / 1.01 | 1.947 / 4.932; 6.128 / 12.259 | 9.3 / 36.6 | 14.0 KiB | 1.65 KiB | | GotaTun buffered UDP dequeue quantum 128 (mean of 2) | 3.00 / 2.57 | 0.81 / 0.99 | 1.936 / 5.036; 6.090 / 13.600 | 9.4 / 37.1 | 14.2 KiB | 1.65 KiB | Quantum 128 raised loaded p99 by 0.104 ms (2.1%) at 1 flow and 1.341 ms (10.9%) at 8 flows. Throughput averaged +2.4% at 1 flow and −0.2% at 8 flows, so the latency result does not qualify. RSS at 1,000 peers was 0.5 MiB higher. This candidate remains uncommitted and is not pin-ready. The reorder profile delivered all 300 probes at all three payload sizes in all four runs. Under independent 2% loss per direction, missing probes (64/512/1400 B) were 10/13/10 and 9/10/12 for the controls; 16/11/11 and 10/14/13 for quantum 128. These are the raw intentional-loss counts. Machine diffs were empty for all four cases. Raw logs, JSON, machine snapshots/diffs, perf receipts, hashes, runner and source patch are attached as `j88-batch128-evidence.tar.gz` (SHA-256 `7255bc3996644e3659f6cfe1aae6d30760929e08610c2d729c3ff48405c431d5`). It is stored under `/home/claude/j20/r4b/j88-latency-batch128-counterbalanced-20261103/` on the perf VM. ### Next bounded experiment I will discard the rejected dequeue candidate and prototype one receive-path change: pass the existing UDP `UdpRecv` directly to `handle_incoming`, bypassing only `BufferedUdpReceive`'s producer task and 4,000-entry channel. Keep socket `recvmmsg`/GRO, the TUN path, send buffering, and offload settings unchanged. This targets the measured UDP→device residence and 52–58% cross-worker handoffs. Validate with the fork library tests, IPv4/IPv6 receive coverage, loss/reorder checks in the R4b harness, an optimized x86_64 build, then one control/candidate/candidate/control perf hold. Estimate: 60 minutes excluding the perf lock.

j88-batch128-evidence.tar.gz

1.1 MiB

kayg commented

2026-11-03 02:49:38 +00:00

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J103 resumed 2026-11-03. Branch mesh-gotatun-linux, based on origin/dev at 299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f.

Plan: (1) confirm the latest J88 commit that passed its fork tests with UDP/TUN offloads and THP off, then pin that exact commit; (2) fix the relay-handshake blocker while keeping the #220 hand-off and #285 rotation hooks unchanged; (3) prove direct and relayed namespace paths, byte-exact failover/rebound, restore and rotation overlap; (4) keep GotaTun as Linux default with the kernel engine selectable per node, document rootless as own-traffic only, and leave a clean future interception hook without implementing #221 S4/#281; (5) run cargo-deny, the R4b comparison against kernel WireGuard, scripts/verify fast, and push this branch.

Estimate: 3–5 hours of work, excluding VM-slot and perf-lock wait. The fork license/flake metadata mismatch is already recorded in comment 76001; MPL-2.0 is already allowed. I will stop if the work reaches twice this estimate.

J103 resumed 2026-11-03. Branch `mesh-gotatun-linux`, based on `origin/dev` at `299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f`. Plan: (1) confirm the latest J88 commit that passed its fork tests with UDP/TUN offloads and THP off, then pin that exact commit; (2) fix the relay-handshake blocker while keeping the #220 hand-off and #285 rotation hooks unchanged; (3) prove direct and relayed namespace paths, byte-exact failover/rebound, restore and rotation overlap; (4) keep GotaTun as Linux default with the kernel engine selectable per node, document rootless as own-traffic only, and leave a clean future interception hook without implementing #221 S4/#281; (5) run cargo-deny, the R4b comparison against kernel WireGuard, `scripts/verify fast`, and push this branch. Estimate: 3–5 hours of work, excluding VM-slot and perf-lock wait. The fork license/flake metadata mismatch is already recorded in comment 76001; MPL-2.0 is already allowed. I will stop if the work reaches twice this estimate.

kayg commented

2026-11-03 02:49:39 +00:00

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J103 P1 finding (compute01, corrected namespace proof, /home/claude/worktrees/J103/J103-fix-rerun.log): the direct GotaTun proof passes at 43.75 Mbps, but the relay proof fails before the failover/rebound assertions with no relayed handshake. Both GotaTun peers show handshake_secs=0, sent_bytes=0, and received_bytes=0; the shim tap saw two packets. Cleanup reports no loaded modules and an unchanged host-state diff. The observed failure is at the existing #220 relay-to-engine hand-off; its cause is still under investigation.

Next: trace the GotaTun receive/relay injection boundary without changing the relay protocol or rotation hooks, add a regression that requires a relayed handshake and delivered stream, then rerun the 32 MiB and failover/rebound byte-hash checks. Direct-path success does not qualify the relay path. The rebased scripts/verify fast attempt stopped during linking on an LLVM output error reporting no space, so it has no gate result; no final gate or R4b comparison is claimed.

J103 P1 finding (compute01, corrected namespace proof, `/home/claude/worktrees/J103/J103-fix-rerun.log`): the direct GotaTun proof passes at 43.75 Mbps, but the relay proof fails before the failover/rebound assertions with `no relayed handshake`. Both GotaTun peers show `handshake_secs=0`, `sent_bytes=0`, and `received_bytes=0`; the shim tap saw two packets. Cleanup reports no loaded modules and an unchanged host-state diff. The observed failure is at the existing #220 relay-to-engine hand-off; its cause is still under investigation. Next: trace the GotaTun receive/relay injection boundary without changing the relay protocol or rotation hooks, add a regression that requires a relayed handshake and delivered stream, then rerun the 32 MiB and failover/rebound byte-hash checks. Direct-path success does not qualify the relay path. The rebased `scripts/verify fast` attempt stopped during linking on an LLVM output error reporting no space, so it has no gate result; no final gate or R4b comparison is claimed.

kayg commented

2026-11-03 02:50:54 +00:00

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J103 checkpoint: blocked on the relay-handshake P1 recorded above. The corrected namespace run is terminal (J103_FIX_RERUN_EXIT=1); its direct, restore, and rotation cases passed, but relay failed before failover/rebound. Final queue check: compute01 has one free build slot and dev-02 has two occupied slots with four queued jobs; neither queue contains J103 work. I stopped only the orphaned J103 gate watcher that was waiting on a missing VERIFY_EXIT marker and confirmed both watcher PIDs are gone. No other queue work was changed.

The rebased scripts/verify fast attempt has no result: the link phase emitted rustc-LLVM ERROR: IO failure on output stream: No space left on device. Current branch head remains 299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f; the implementation worktree is still uncommitted and has not been pushed. Resume by tracing the relay-to-GotaTun receive boundary, then rerun the relay proof and byte-exact failover/rebound checks before the final gate and R4b comparison.

J103 checkpoint: blocked on the relay-handshake P1 recorded above. The corrected namespace run is terminal (`J103_FIX_RERUN_EXIT=1`); its direct, restore, and rotation cases passed, but relay failed before failover/rebound. Final queue check: compute01 has one free build slot and dev-02 has two occupied slots with four queued jobs; neither queue contains J103 work. I stopped only the orphaned J103 gate watcher that was waiting on a missing `VERIFY_EXIT` marker and confirmed both watcher PIDs are gone. No other queue work was changed. The rebased `scripts/verify fast` attempt has no result: the link phase emitted `rustc-LLVM ERROR: IO failure on output stream: No space left on device`. Current branch head remains `299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f`; the implementation worktree is still uncommitted and has not been pushed. Resume by tracing the relay-to-GotaTun receive boundary, then rerun the relay proof and byte-exact failover/rebound checks before the final gate and R4b comparison.

kayg commented

2026-11-03 02:51:16 +00:00

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J88 direct-receive validation finding (compute01): the first all-features clippy attempt exited 101 before the test or release-build steps. It found that BufferedUdpReceive and its constructor are now unused in Linux non-test builds; I have gated that adapter to non-Linux builds and tests. The parallel tikv-jemalloc-sys build also failed its configure probe: Cargo selected OPT_LEVEL=0, while the Nix GCC wrapper defines _FORTIFY_SOURCE=3 and treats the resulting optimization warning as an error (cannot determine return type of strerror_r). Full log: /home/claude/worktrees/gotatun-j88-latency/j88-direct-rx-validation.log. I will rerun the same fork checks with the build-dependency override at optimization level 2; no test, clippy, or build success is claimed from the failed run.

J88 direct-receive validation finding (compute01): the first all-features clippy attempt exited 101 before the test or release-build steps. It found that `BufferedUdpReceive` and its constructor are now unused in Linux non-test builds; I have gated that adapter to non-Linux builds and tests. The parallel `tikv-jemalloc-sys` build also failed its configure probe: Cargo selected `OPT_LEVEL=0`, while the Nix GCC wrapper defines `_FORTIFY_SOURCE=3` and treats the resulting optimization warning as an error (`cannot determine return type of strerror_r`). Full log: `/home/claude/worktrees/gotatun-j88-latency/j88-direct-rx-validation.log`. I will rerun the same fork checks with the build-dependency override at optimization level 2; no test, clippy, or build success is claimed from the failed run.

kayg commented

2026-11-03 02:58:14 +00:00

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Correction to the direct-receive validation note: the first retry set CARGO_PROFILE_DEV_BUILD_OVERRIDE_OPT_LEVEL=2 outside nix develop, which stripped it before Cargo ran; the retry log still shows OPT_LEVEL = Some(0). The non-Linux/test cfg fix removed the BufferedUdpReceive dead-code clippy errors. I confirmed that an optimization override must be exported inside the Nix shell and will rerun with both dev/test build overrides set there. The failed retry log is /home/claude/worktrees/gotatun-j88-latency/j88-direct-rx-validation-retry.log; it exited 101 before tests and release build.

Correction to the direct-receive validation note: the first retry set `CARGO_PROFILE_DEV_BUILD_OVERRIDE_OPT_LEVEL=2` outside `nix develop`, which stripped it before Cargo ran; the retry log still shows `OPT_LEVEL = Some(0)`. The non-Linux/test cfg fix removed the `BufferedUdpReceive` dead-code clippy errors. I confirmed that an optimization override must be exported inside the Nix shell and will rerun with both dev/test build overrides set there. The failed retry log is `/home/claude/worktrees/gotatun-j88-latency/j88-direct-rx-validation-retry.log`; it exited 101 before tests and release build.

kayg commented

2026-11-03 03:04:49 +00:00

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J103 relay trace finding (branch mesh-gotatun-linux, base 299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f): relay_with_endpoint updates the selected node engine, but after links settle settle() calls start_handshake(&peer.kernel). That helper reads wireguard::Device::counters() and removes/re-adds the peer with a kernel netlink client. It therefore bypasses GotaTun's selected-engine counters and command path. This is a concrete engine-dispatch defect at relay activation; I am adding relay-path counters to the failing proof output to verify whether it fully explains the missing handshake or whether the inbound UDP injection boundary also drops the ciphertext.

J103 relay trace finding (branch `mesh-gotatun-linux`, base `299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f`): `relay_with_endpoint` updates the selected node engine, but after links settle `settle()` calls `start_handshake(&peer.kernel)`. That helper reads `wireguard::Device::counters()` and removes/re-adds the peer with a kernel netlink client. It therefore bypasses GotaTun's selected-engine counters and command path. This is a concrete engine-dispatch defect at relay activation; I am adding relay-path counters to the failing proof output to verify whether it fully explains the missing handshake or whether the inbound UDP injection boundary also drops the ciphertext.

kayg commented

2026-11-03 03:18:53 +00:00

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J88 build-environment diagnosis: exporting both Cargo build-override values inside the Nix shell still leaves tikv-jemalloc-sys at OPT_LEVEL=0, so that override does not control this package's configure flags. The configure error is reproducible: the Nix GCC wrapper defines _FORTIFY_SOURCE=3, and jemalloc's debug configure passes -O0 -Werror, turning glibc's Fortify warning into a hard failure. A standalone compile probe passed after setting NIX_CFLAGS_COMPILE=-U_FORTIFY_SOURCE inside the Nix shell. I will apply that workaround only for clippy/tests and unset it before the release build, leaving the measured binary on the normal release toolchain.

J88 build-environment diagnosis: exporting both Cargo build-override values inside the Nix shell still leaves `tikv-jemalloc-sys` at `OPT_LEVEL=0`, so that override does not control this package's configure flags. The configure error is reproducible: the Nix GCC wrapper defines `_FORTIFY_SOURCE=3`, and jemalloc's debug configure passes `-O0 -Werror`, turning glibc's Fortify warning into a hard failure. A standalone compile probe passed after setting `NIX_CFLAGS_COMPILE=-U_FORTIFY_SOURCE` inside the Nix shell. I will apply that workaround only for clippy/tests and unset it before the release build, leaving the measured binary on the normal release toolchain.

kayg commented

2026-11-03 03:43:27 +00:00

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J88 direct UDP receive validation

The direct-receive candidate passes the focused handshake test and the serialized all-features GotaTun library suite. The fresh Cargo run exited 0: 131 passed, 0 failed, 7 ignored, finished in 8.52 s. The earlier parallel run did time out device::tests::test_indices; this result does not establish why that scheduling-sensitive timeout occurred.

The candidate is still unmeasured and not pin-ready. Next: build the optimized x86_64 CLI, then run route-cut control / direct-receive candidate / candidate / control in one R4b perf hold, with throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, loss/reordering, queue diagnostics and empty machine diffs. Remaining estimate: about 45 minutes excluding perf-lock wait.

## J88 direct UDP receive validation The direct-receive candidate passes the focused handshake test and the serialized all-features GotaTun library suite. The fresh Cargo run exited 0: 131 passed, 0 failed, 7 ignored, finished in 8.52 s. The earlier parallel run did time out `device::tests::test_indices`; this result does not establish why that scheduling-sensitive timeout occurred. The candidate is still unmeasured and not pin-ready. Next: build the optimized x86_64 CLI, then run route-cut control / direct-receive candidate / candidate / control in one R4b perf hold, with throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, loss/reordering, queue diagnostics and empty machine diffs. Remaining estimate: about 45 minutes excluding perf-lock wait.

kayg commented

2026-11-03 03:51:06 +00:00

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J88 direct receive: build and perf setup

The all-features library suite passed serially (131 passed, 0 failed, 7 ignored). The optimized x86_64 CLI build completed through compute01 build-slot in 2m11s. Candidate binary SHA-256: 7517890c2498f92712098a9a63b727db2d7f52b3dda6601a8ac49b559b574a98; the copy on the perf VM has the same hash and its glibc 2.40 loader is present there.

I confirmed the R4b route-cut control is the 823133f828d8805f5ea17139f623395cc5cf7afa build (SHA-256 6bf8fc35a4ae52f41a6c63b9104037e0a15788e8d43c46c664089755442fccc6). The next single perf-run --root hold will run the kernel WireGuard and wireguard-go references plus route-cut control / direct-receive / direct-receive / control on the same R4b mesh case. It captures 1/8-flow throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, intentional loss, reordering, and machine diffs.

The direct-receive change remains uncommitted and not pin-ready pending the perf result. Estimate: about 25 minutes for the six cases, excluding perf-lock wait.

## J88 direct receive: build and perf setup The all-features library suite passed serially (131 passed, 0 failed, 7 ignored). The optimized x86_64 CLI build completed through compute01 build-slot in 2m11s. Candidate binary SHA-256: `7517890c2498f92712098a9a63b727db2d7f52b3dda6601a8ac49b559b574a98`; the copy on the perf VM has the same hash and its glibc 2.40 loader is present there. I confirmed the R4b route-cut control is the `823133f828d8805f5ea17139f623395cc5cf7afa` build (SHA-256 `6bf8fc35a4ae52f41a6c63b9104037e0a15788e8d43c46c664089755442fccc6`). The next single `perf-run --root` hold will run the kernel WireGuard and wireguard-go references plus route-cut control / direct-receive / direct-receive / control on the same R4b mesh case. It captures 1/8-flow throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, intentional loss, reordering, and machine diffs. The direct-receive change remains uncommitted and not pin-ready pending the perf result. Estimate: about 25 minutes for the six cases, excluding perf-lock wait.

kayg commented

2026-11-03 03:54:57 +00:00

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J103 relay receive-boundary finding (2026-11-03): RelayPaths::inbound removes the existing datagram header and sends the ciphertext through its connected loopback socket to the node port. At the pinned GotaTun source, UdpSocketFactory::bind returns a clone and the original of one Arc-backed UDP socket, so that port is also the engine receive port; the receive boundary is not dropping this handshake. The original failure is before that boundary: the legacy endpoint update writes through kernel WireGuard, leaving the default GotaTun peer on its coordinator endpoint. The #220 settle hook also used kernel counters/netlink for its kick. I am routing that kick through the selected engine force_handshake API after the relay link settles, with the relay framing and #285 key-rotation state untouched. The regression and release reruns are next.

J103 relay receive-boundary finding (2026-11-03): `RelayPaths::inbound` removes the existing datagram header and sends the ciphertext through its connected loopback socket to the node port. At the pinned GotaTun source, `UdpSocketFactory::bind` returns a clone and the original of one Arc-backed UDP socket, so that port is also the engine receive port; the receive boundary is not dropping this handshake. The original failure is before that boundary: the legacy endpoint update writes through kernel WireGuard, leaving the default GotaTun peer on its coordinator endpoint. The #220 settle hook also used kernel counters/netlink for its kick. I am routing that kick through the selected engine `force_handshake` API after the relay link settles, with the relay framing and #285 key-rotation state untouched. The regression and release reruns are next.

kayg commented

2026-11-03 04:12:47 +00:00

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J103 verification update: the first run from the rebased tree exited 127 before compilation because bash -lc reset Cargo's PATH after entering nix develop. Evidence: cargo: command not found at the first cargo command; direct nix develop -c cargo --version and nix develop -c bash -c 'command -v cargo && cargo --version' both pass, while the login-shell probe does not find Cargo. No product test ran in that attempt. I am rerunning through a non-login shell on the current origin/dev base (c135935fa). The implementation checkpoint is pushed at d09c47f32380b34c80d7ef1c23173e5ce1fd2401.

J103 verification update: the first run from the rebased tree exited 127 before compilation because `bash -lc` reset Cargo's PATH after entering `nix develop`. Evidence: `cargo: command not found` at the first cargo command; direct `nix develop -c cargo --version` and `nix develop -c bash -c 'command -v cargo && cargo --version'` both pass, while the login-shell probe does not find Cargo. No product test ran in that attempt. I am rerunning through a non-login shell on the current `origin/dev` base (`c135935fa`). The implementation checkpoint is pushed at `d09c47f32380b34c80d7ef1c23173e5ce1fd2401`.

kayg commented

2026-11-03 04:20:49 +00:00

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J103 relay follow-up on the rebased branch (d09c47f3, base c135935fa): the direct GotaTun namespace proof passes. The relay proof still misses its 5 s observation window, but its final stats show A's relayed peer has a completed handshake timestamp while B's corresponding row is still zero; the relay forwarded 3 datagrams and the host-state diff is empty. The direct run is a dev build and not performance evidence (mesh_mbps=102.22, underlay 9225.04 Mbps, load 6.88).

The pinned GotaTun source explains the delay: Device::force_handshake calls PeerState::force_handshake, which uses format_handshake_initiation(false). If the initial direct-path initiation is still in progress, it waits for that attempt instead of sending a fresh initiation to the newly installed relay endpoint. The tunnel timer then retries after its normal interval. The kernel helper resets a peer that has no completed handshake by removing and re-adding it. I will apply the equivalent selected-engine behavior for GotaTun only when no session exists, preserving established sessions, relay framing, and #285 rotation state, then rerun the 5 s regression and byte-exact failover/rebound.

J103 relay follow-up on the rebased branch (`d09c47f3`, base `c135935fa`): the direct GotaTun namespace proof passes. The relay proof still misses its 5 s observation window, but its final stats show A's relayed peer has a completed handshake timestamp while B's corresponding row is still zero; the relay forwarded 3 datagrams and the host-state diff is empty. The direct run is a dev build and not performance evidence (`mesh_mbps=102.22`, underlay `9225.04 Mbps`, load `6.88`). The pinned GotaTun source explains the delay: `Device::force_handshake` calls `PeerState::force_handshake`, which uses `format_handshake_initiation(false)`. If the initial direct-path initiation is still in progress, it waits for that attempt instead of sending a fresh initiation to the newly installed relay endpoint. The tunnel timer then retries after its normal interval. The kernel helper resets a peer that has no completed handshake by removing and re-adding it. I will apply the equivalent selected-engine behavior for GotaTun only when no session exists, preserving established sessions, relay framing, and #285 rotation state, then rerun the 5 s regression and byte-exact failover/rebound.

kayg commented

2026-11-03 04:21:51 +00:00

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J88 latency follow-up plan (2026-11-03)

Branch: j88-linux-offloads, control head 823133f828d8805f5ea17139f623395cc5cf7afa; direct UDP receive is still uncommitted.

Evidence so far: the queue trace showed p99 residence of 2.000 ms on UDP→device and 1.575 ms on TUN→device, 52–58% cross-worker samples, p99 depth 512–1,023 / 4,000, and no timed GRO/GSO wait. Dequeue quantum 128 did not improve loaded p99. Direct UDP receive reduced p99 in the first paired hold, but its 8-flow throughput was lower and noisy.

Plan:

Run a short control/candidate/candidate/control R4b repeat under one perf-run lock. Include 1/8-flow throughput, CPU/Gbit, loaded p50/p99, 1/1,000-peer RSS, queue diagnostics, 64/512/1400-byte intentional loss and reordering, and empty machine diffs.
Aggregate the existing direct-receive hold’s loss/reordering results. Keep the candidate only if the repeat confirms the tail-latency gain without a throughput regression and the correctness matrix stays clean; otherwise discard it.
If rejected, use the same queue trace to isolate the remaining TUN→device / worker-handoff residence, then propose one bounded candidate before changing code.

Estimate: 20–35 minutes for the confirmation and report, excluding perf-lock wait; one further candidate adds about 30 minutes excluding lock/build-slot waits. Current candidate is not pin-ready.

## J88 latency follow-up plan (2026-11-03) Branch: `j88-linux-offloads`, control head `823133f828d8805f5ea17139f623395cc5cf7afa`; direct UDP receive is still uncommitted. Evidence so far: the queue trace showed p99 residence of 2.000 ms on UDP→device and 1.575 ms on TUN→device, 52–58% cross-worker samples, p99 depth 512–1,023 / 4,000, and no timed GRO/GSO wait. Dequeue quantum 128 did not improve loaded p99. Direct UDP receive reduced p99 in the first paired hold, but its 8-flow throughput was lower and noisy. Plan: 1. Run a short control/candidate/candidate/control R4b repeat under one perf-run lock. Include 1/8-flow throughput, CPU/Gbit, loaded p50/p99, 1/1,000-peer RSS, queue diagnostics, 64/512/1400-byte intentional loss and reordering, and empty machine diffs. 2. Aggregate the existing direct-receive hold’s loss/reordering results. Keep the candidate only if the repeat confirms the tail-latency gain without a throughput regression and the correctness matrix stays clean; otherwise discard it. 3. If rejected, use the same queue trace to isolate the remaining TUN→device / worker-handoff residence, then propose one bounded candidate before changing code. Estimate: 20–35 minutes for the confirmation and report, excluding perf-lock wait; one further candidate adds about 30 minutes excluding lock/build-slot waits. Current candidate is not pin-ready.

kayg commented

2026-11-03 04:40:53 +00:00

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J88 latency confirmation: first hold had an external state diff

The counterbalanced control/direct-receive/direct-receive/control hold completed in 982 s, but returned exit 1 because the final control’s host snapshot found one unrelated file added during that case: /tmp/j118-perf-incident.sh. Its machine diff contains only that path; I did not touch or remove it. The first three cases exited 0 with empty diffs, so these numbers are provisional pending a clean repeat.

Variant	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 (s/Gbit)	Loaded RTT64 p50 / p99, 1 flow (ms)	Loaded RTT64 p50 / p99, 8 flows (ms)	RSS 1 / 1,000 peers (MiB)
Route-cut control, first case	2.89 / 2.46	0.82 / 0.98	1.990 / 5.198	6.372 / 13.994	9.3 / 39.5
Direct UDP receive, first	2.96 / 2.44	0.81 / 1.02	1.803 / 5.089	4.298 / 10.617	9.4 / 34.4
Direct UDP receive, second	3.05 / 2.62	0.80 / 1.00	1.891 / 4.770	4.910 / 10.627	9.4 / 35.3
Route-cut control, last (diff; excluded)	2.89 / 2.45	0.84 / 0.99	2.067 / 5.311	6.602 / 13.390	8.9 / 36.9

The two candidate rows show better loaded tails and no observed throughput loss, but I am not treating the experiment as complete with the nonempty host diff. I’ll rerun the same four-case order with the unrelated file present in the starting snapshot, then aggregate the 64/512/1400-byte loss/reorder checks. Estimate: about 17 minutes excluding perf-lock wait. Direct receive remains uncommitted and not pin-ready.

## J88 latency confirmation: first hold had an external state diff The counterbalanced control/direct-receive/direct-receive/control hold completed in 982 s, but returned exit 1 because the final control’s host snapshot found one unrelated file added during that case: `/tmp/j118-perf-incident.sh`. Its machine diff contains only that path; I did not touch or remove it. The first three cases exited 0 with empty diffs, so these numbers are provisional pending a clean repeat. | Variant | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 (s/Gbit) | Loaded RTT64 p50 / p99, 1 flow (ms) | Loaded RTT64 p50 / p99, 8 flows (ms) | RSS 1 / 1,000 peers (MiB) | |---|---:|---:|---:|---:|---:| | Route-cut control, first case | 2.89 / 2.46 | 0.82 / 0.98 | 1.990 / 5.198 | 6.372 / 13.994 | 9.3 / 39.5 | | Direct UDP receive, first | 2.96 / 2.44 | 0.81 / 1.02 | 1.803 / 5.089 | 4.298 / 10.617 | 9.4 / 34.4 | | Direct UDP receive, second | 3.05 / 2.62 | 0.80 / 1.00 | 1.891 / 4.770 | 4.910 / 10.627 | 9.4 / 35.3 | | Route-cut control, last (diff; excluded) | 2.89 / 2.45 | 0.84 / 0.99 | 2.067 / 5.311 | 6.602 / 13.390 | 8.9 / 36.9 | The two candidate rows show better loaded tails and no observed throughput loss, but I am not treating the experiment as complete with the nonempty host diff. I’ll rerun the same four-case order with the unrelated file present in the starting snapshot, then aggregate the 64/512/1400-byte loss/reorder checks. Estimate: about 17 minutes excluding perf-lock wait. Direct receive remains uncommitted and not pin-ready.

kayg commented

2026-11-03 04:51:30 +00:00

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J103 relay finding (2026-11-03, branch mesh-gotatun-linux, head d09c47f3): the test-only endpoint diagnostics confirm both nodes took the no-session reset path (has_session=false, reset_removed=true). The proof still misses its 5 s relayed-handshake window. At failure A reports 148 peer bytes received while B reports 0; relay state is asymmetric (relay 1 has a link, relay 0 has none), and the host-state diff is empty. This updates the earlier diagnosis: endpoint reset is occurring, so the remaining failure is in relay path/session establishment; the GotaTun UDP socket boundary is receiving at least one peer packet. Next I am adding event history to the failing proof to locate when the relay states diverge, without changing the relay protocol or #285 hooks. Remaining estimate: 2–4 hours, excluding build-slot and perf-lock waits.

J103 relay finding (2026-11-03, branch `mesh-gotatun-linux`, head `d09c47f3`): the test-only endpoint diagnostics confirm both nodes took the no-session reset path (`has_session=false`, `reset_removed=true`). The proof still misses its 5 s relayed-handshake window. At failure A reports 148 peer bytes received while B reports 0; relay state is asymmetric (relay 1 has a link, relay 0 has none), and the host-state diff is empty. This updates the earlier diagnosis: endpoint reset is occurring, so the remaining failure is in relay path/session establishment; the GotaTun UDP socket boundary is receiving at least one peer packet. Next I am adding event history to the failing proof to locate when the relay states diverge, without changing the relay protocol or #285 hooks. Remaining estimate: 2–4 hours, excluding build-slot and perf-lock waits.

kayg commented

2026-11-03 04:53:16 +00:00

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J88 latency step: direct Linux UDP receive

Branch j88-linux-offloads, pushed head 47175889642b35b6832227c450725c1bd79ff11c. Pin-ready for review: yes; fork tests and optimized CLI build are green. The all-features library suite passed 131 tests, 0 failed, 7 ignored. Candidate binary SHA-256: 7517890c2498f92712098a9a63b727db2d7f52b3dda6601a8ac49b559b574a98.

The profile found queue residence at p99 of 2.000 ms on UDP→device and 1.575 ms on TUN→device; 52–58% of samples crossed workers, depth p99 was 512–1,023 of 4,000, and no timed GRO/GSO coalescing wait was found. This commit bypasses the extra UDP receive worker/channel on Linux; non-Linux keeps the buffered adapter.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 (s/Gbit)	Loaded RTT64 p50 / p99, 1 flow (ms)	Loaded RTT64 p50 / p99, 8 flows (ms)	RSS 1 / 1,000 peers (MiB)	Incremental RSS / peer	Kernel peer reference
Kernel WireGuard reference	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763	3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go reference	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631	7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2 reference	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733	4.654 / 11.876	9.6 / 104.6	48.7 KiB	1.65 KiB
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460	5.846 / 12.502	10.0 / 108.6	50.5 KiB	1.65 KiB
GotaTun route-cut control (n=2, clean hold)	2.77 / 2.47	0.85 / 1.00	2.144 / 5.753	6.022 / 13.357	9.3 / 37.3	14.3 KiB	1.65 KiB
GotaTun direct UDP receive (n=2, clean hold)	2.95 / 2.25	0.82 / 0.99	1.743 / 4.478	4.624 / 9.926	9.4 / 33.7	12.4 KiB	1.65 KiB

The primary control/candidate/candidate/control hold exited 0, and all six case diffs were empty. Loaded p99 fell 22% at 1 flow and 26% at 8 flows. The primary 8-flow mean fell 8.6%, driven by one 1.916 Gbit/s candidate sample. In the subsequent confirmation, control-first and both candidate cases exited 0 with empty case diffs: the two candidates averaged 2.528 Gbit/s at 8 flows versus 2.458 for control, with loaded p99 10.622 ms versus 13.994 ms. The final control was rejected because another job added /tmp/j118-perf-incident.sh; a later retry stopped after its first control when root/.cache/nix/sentry rotated. Those external snapshot changes are retained in the raw evidence. So the p99 gain repeats, while the 8-flow throughput effect remains noisy.

The direct receive row is still about 12.4 KiB/peer against the 5 KiB target, and throughput remains below wireguard-go. Full raw logs, case JSON, diffs, receipts, scripts, binaries, and patch are attached. Archive SHA-256: 36948ca388df1b3b4aa06d16505fbbfe42a211dec6cfbe14c69feddac7b937eb. MPL-2.0 license note remains recorded in comment 76001.

## J88 latency step: direct Linux UDP receive Branch `j88-linux-offloads`, pushed head `47175889642b35b6832227c450725c1bd79ff11c`. **Pin-ready for review: yes; fork tests and optimized CLI build are green.** The all-features library suite passed 131 tests, 0 failed, 7 ignored. Candidate binary SHA-256: `7517890c2498f92712098a9a63b727db2d7f52b3dda6601a8ac49b559b574a98`. The profile found queue residence at p99 of 2.000 ms on UDP→device and 1.575 ms on TUN→device; 52–58% of samples crossed workers, depth p99 was 512–1,023 of 4,000, and no timed GRO/GSO coalescing wait was found. This commit bypasses the extra UDP receive worker/channel on Linux; non-Linux keeps the buffered adapter. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 (s/Gbit) | Loaded RTT64 p50 / p99, 1 flow (ms) | Loaded RTT64 p50 / p99, 8 flows (ms) | RSS 1 / 1,000 peers (MiB) | Incremental RSS / peer | Kernel peer reference | |---|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard reference | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763 | 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go reference | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631 | 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 reference | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733 | 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | 1.65 KiB | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460 | 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | 1.65 KiB | | GotaTun route-cut control (n=2, clean hold) | 2.77 / 2.47 | 0.85 / 1.00 | 2.144 / 5.753 | 6.022 / 13.357 | 9.3 / 37.3 | 14.3 KiB | 1.65 KiB | | GotaTun direct UDP receive (n=2, clean hold) | 2.95 / 2.25 | 0.82 / 0.99 | 1.743 / 4.478 | 4.624 / 9.926 | 9.4 / 33.7 | 12.4 KiB | 1.65 KiB | The primary control/candidate/candidate/control hold exited 0, and all six case diffs were empty. Loaded p99 fell 22% at 1 flow and 26% at 8 flows. The primary 8-flow mean fell 8.6%, driven by one 1.916 Gbit/s candidate sample. In the subsequent confirmation, control-first and both candidate cases exited 0 with empty case diffs: the two candidates averaged 2.528 Gbit/s at 8 flows versus 2.458 for control, with loaded p99 10.622 ms versus 13.994 ms. The final control was rejected because another job added `/tmp/j118-perf-incident.sh`; a later retry stopped after its first control when `root/.cache/nix/sentry` rotated. Those external snapshot changes are retained in the raw evidence. So the p99 gain repeats, while the 8-flow throughput effect remains noisy. The direct receive row is still about 12.4 KiB/peer against the 5 KiB target, and throughput remains below wireguard-go. Full raw logs, case JSON, diffs, receipts, scripts, binaries, and patch are attached. Archive SHA-256: `36948ca388df1b3b4aa06d16505fbbfe42a211dec6cfbe14c69feddac7b937eb`. MPL-2.0 license note remains recorded in comment 76001.

evidence.tar.gz

3.6 MiB

test-final.log

10 KiB

kayg commented

2026-11-03 04:55:18 +00:00

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J103 relay trace update (#260, 2026-11-03): the active-link snapshot shows the shim's cumulative unlinked=1 while GotaTun had emitted a 148-byte handshake initiation and the relay sent 0 datagrams. The endpoint reset at set_endpoint was too early: re-adding the peer allowed an initiation to hit the shim before a relay link was active; the later #220 force_handshake then waited on that dropped in-flight attempt. I am moving the no-session reset into the existing settle-triggered handshake callback, after the relay becomes active. Established sessions remain endpoint-only updates; relay framing and #285 rotation are unchanged. Next: rerun the relay handshake plus delivered-stream regression and byte-exact failover/rebound.

J103 relay trace update (#260, 2026-11-03): the active-link snapshot shows the shim's cumulative `unlinked=1` while GotaTun had emitted a 148-byte handshake initiation and the relay sent 0 datagrams. The endpoint reset at `set_endpoint` was too early: re-adding the peer allowed an initiation to hit the shim before a relay link was active; the later #220 `force_handshake` then waited on that dropped in-flight attempt. I am moving the no-session reset into the existing settle-triggered handshake callback, after the relay becomes active. Established sessions remain endpoint-only updates; relay framing and #285 rotation are unchanged. Next: rerun the relay handshake plus delivered-stream regression and byte-exact failover/rebound.

kayg commented

2026-11-03 04:57:43 +00:00

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J88 direct-receive final verification for head 47175889642b35b6832227c450725c1bd79ff11c:

Fresh serial all-features library suite on compute01 through build-slot: test result: ok. 131 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 8.88s.
Optimized x86_64 CLI build passed on the same candidate source; binary SHA-256 is recorded in the evidence archive.
Independent review of the commit found no findings.
origin/j88-linux-offloads resolves to this head. No upstream activity and no product integration were performed.
Pin-ready: yes for fork tests/review. The 8-flow throughput result remains noisy as described in the R4b table above.

The fresh test log is attached to the R4b result comment; SHA-256 241d8d5d9e2acc6e872ce472c5b133e9252850acf69f614ff525c5748b2c5461.

J88 direct-receive final verification for head `47175889642b35b6832227c450725c1bd79ff11c`: - Fresh serial all-features library suite on compute01 through build-slot: `test result: ok. 131 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 8.88s`. - Optimized x86_64 CLI build passed on the same candidate source; binary SHA-256 is recorded in the evidence archive. - Independent review of the commit found no findings. - `origin/j88-linux-offloads` resolves to this head. No upstream activity and no product integration were performed. - Pin-ready: yes for fork tests/review. The 8-flow throughput result remains noisy as described in the R4b table above. The fresh test log is attached to the R4b result comment; SHA-256 `241d8d5d9e2acc6e872ce472c5b133e9252850acf69f614ff525c5748b2c5461`.

kayg commented

2026-11-03 04:59:21 +00:00

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J88 next latency step: TUN→device receive

Base: j88-linux-offloads at 47175889642b35b6832227c450725c1bd79ff11c (fresh fork tests pass; direct UDP step is pin-ready for review).

The low-overhead profile measured TUN→device queue residence at 1.575 ms p99 at 1 flow, and up to 5.025 ms at 8 flows. The TUN producer batch p99 was 256–511, queue depth p99 256–511 at 1 flow, and no timed GRO/GSO wait was found. The direct UDP change removes the other receive-side worker handoff.

Plan:

Prototype a Linux-only direct TUN receive mode in the existing buffer adapter, retaining buffered TUN sends and all non-Linux behavior. Reuse the existing receive scratch vector; preserve packet order, vnet-header TSO expansion, transient/fatal error behavior, cancellation, and connection restart semantics.
Add focused tests for ordered multi-packet batches, transient receive recovery, and fatal receive termination; run the full fork suite and optimized x86_64 CLI build on a dev VM.
Compare the committed direct-UDP binary and candidate in one R4b perf-run hold, control/candidate/candidate/control. Record the standard throughput, CPU/Gbit, loaded p50/p99, RSS, 64/512/1400-byte loss/reorder checks, queue diagnostics, and machine diffs.
Keep and push the change only if loaded p99 falls without a throughput regression and all cases pass; otherwise discard it and report the measurement.

Estimate: about 45 minutes excluding build-slot and perf-lock waits. No upstream activity.

## J88 next latency step: TUN→device receive Base: `j88-linux-offloads` at `47175889642b35b6832227c450725c1bd79ff11c` (fresh fork tests pass; direct UDP step is pin-ready for review). The low-overhead profile measured TUN→device queue residence at 1.575 ms p99 at 1 flow, and up to 5.025 ms at 8 flows. The TUN producer batch p99 was 256–511, queue depth p99 256–511 at 1 flow, and no timed GRO/GSO wait was found. The direct UDP change removes the other receive-side worker handoff. Plan: 1. Prototype a Linux-only direct TUN receive mode in the existing buffer adapter, retaining buffered TUN sends and all non-Linux behavior. Reuse the existing receive scratch vector; preserve packet order, vnet-header TSO expansion, transient/fatal error behavior, cancellation, and connection restart semantics. 2. Add focused tests for ordered multi-packet batches, transient receive recovery, and fatal receive termination; run the full fork suite and optimized x86_64 CLI build on a dev VM. 3. Compare the committed direct-UDP binary and candidate in one R4b perf-run hold, control/candidate/candidate/control. Record the standard throughput, CPU/Gbit, loaded p50/p99, RSS, 64/512/1400-byte loss/reorder checks, queue diagnostics, and machine diffs. 4. Keep and push the change only if loaded p99 falls without a throughput regression and all cases pass; otherwise discard it and report the measurement. Estimate: about 45 minutes excluding build-slot and perf-lock waits. No upstream activity.

kayg commented

2026-11-03 04:59:51 +00:00

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J103 relay follow-up (#260, current proof log /home/claude/worktrees/J103-gotatun-namespace-regressions.log): moving reset out of endpoint installation removed the shim drop (unlinked=0), but the 5 s handshake still fails. The settle callback is intentionally run only by the lower host id, so only A reset its unestablished peer; B retained its pending direct-path initiation and did not respond to A through the relay. I will prepare/reset an unestablished peer on both endpoints after the link becomes active, while preserving the existing single-initiator rule. The direct GotaTun namespace proof passed in the same debug run; its 48.68 Mbps number is functional evidence only, not a perf result.

J103 relay follow-up (#260, current proof log `/home/claude/worktrees/J103-gotatun-namespace-regressions.log`): moving reset out of endpoint installation removed the shim drop (`unlinked=0`), but the 5 s handshake still fails. The settle callback is intentionally run only by the lower host id, so only A reset its unestablished peer; B retained its pending direct-path initiation and did not respond to A through the relay. I will prepare/reset an unestablished peer on both endpoints after the link becomes active, while preserving the existing single-initiator rule. The direct GotaTun namespace proof passed in the same debug run; its 48.68 Mbps number is functional evidence only, not a perf result.

kayg commented

2026-11-03 05:04:20 +00:00

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J103 resumed 2026-11-03 after the disk and queue changes. Branch mesh-gotatun-linux, base origin/dev at 299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f, current pushed head d09c47f32380b34c80d7ef1c23173e5ce1fd2401.

Plan:

Trace the active relay receive path and prepare unestablished peers on both ends after link activation, while retaining the existing lower-host-id initiator. Keep relay framing and #285 rotation hooks unchanged.
Strengthen the namespace regression to require a relayed handshake at both peers and a byte-exact delivered stream, then rerun failover/rebound byte hashes.
Explain the 43.75 Mbps direct result from its build metadata, then compare the integrated GotaTun engine with kernel WireGuard in the R4b harness on the perf VM.
Run cargo-deny and the full fast gate; commit and push each verified slice.

Evidence: the latest debug namespace run reports both peers active on relay 0, relay 0 forwarded 3 datagrams, A received 148 peer bytes, and B received 0 before the 5 s handshake deadline. This proves ciphertext reached one GotaTun receive path; the reverse handshake leg is still unresolved. The 43.75 Mbps direct result is functional-only until its build profile is confirmed and the integrated R4b measurement is run.

Remaining estimate: 2–4 hours, excluding build-slot and perf-lock waits.

J103 resumed 2026-11-03 after the disk and queue changes. Branch `mesh-gotatun-linux`, base `origin/dev` at `299b7ad30bdbf3c45b3436f7ba63d05b3599aa9f`, current pushed head `d09c47f32380b34c80d7ef1c23173e5ce1fd2401`. Plan: 1. Trace the active relay receive path and prepare unestablished peers on both ends after link activation, while retaining the existing lower-host-id initiator. Keep relay framing and #285 rotation hooks unchanged. 2. Strengthen the namespace regression to require a relayed handshake at both peers and a byte-exact delivered stream, then rerun failover/rebound byte hashes. 3. Explain the 43.75 Mbps direct result from its build metadata, then compare the integrated GotaTun engine with kernel WireGuard in the R4b harness on the perf VM. 4. Run cargo-deny and the full fast gate; commit and push each verified slice. Evidence: the latest debug namespace run reports both peers active on relay 0, relay 0 forwarded 3 datagrams, A received 148 peer bytes, and B received 0 before the 5 s handshake deadline. This proves ciphertext reached one GotaTun receive path; the reverse handshake leg is still unresolved. The 43.75 Mbps direct result is functional-only until its build profile is confirmed and the integrated R4b measurement is run. Remaining estimate: 2–4 hours, excluding build-slot and perf-lock waits.

kayg commented

2026-11-03 05:12:12 +00:00

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J88 latency finding: TUN receive queue (2026-11-03)

Branch j88-linux-offloads, base 47175889642b35b6832227c450725c1bd79ff11c; no TUN receive code change yet. The posted plan in comment 76443 remains the scope and estimate (about 45 minutes, excluding build-slot and perf-lock waits).

The existing queue trace measured TUN→device residence p99 of 1.575 ms at one flow and 5.025 ms at eight flows, with a producer batch p99 of 256–511 and no timed GRO/GSO wait. The direct UDP step already removes the UDP-side receive handoff. I added focused Linux receive tests and ran the compiled test binary as the build user because .cargo/config.toml sets a sudo -E test runner, which is unavailable on the dev VM. On the unchanged buffered path, the demand-driven test observed 3 reads before the consumer requested one (expected 0); the fatal-error test observed UnexpectedEof instead of the original BrokenPipe. Both are the intended red results.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 flows (s/Gbit)	Loaded RTT64 p50 / p99, 1 flow (ms)	Loaded RTT64 p50 / p99, 8 flows (ms)	RSS 1 / 1,000 peers (MiB)	Incremental RSS / peer	Kernel peer reference
Kernel WireGuard reference	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763	3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go reference	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631	7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2 reference	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733	4.654 / 11.876	9.6 / 104.6	48.7 KiB	1.65 KiB
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460	5.846 / 12.502	10.0 / 108.6	50.5 KiB	1.65 KiB
GotaTun route-cut control (n=2, clean hold)	2.77 / 2.47	0.85 / 1.00	2.144 / 5.753	6.022 / 13.357	9.3 / 37.3	14.3 KiB	1.65 KiB
GotaTun direct UDP receive control (n=2, clean hold)	2.95 / 2.25	0.82 / 0.99	1.743 / 4.478	4.624 / 9.926	9.4 / 33.7	12.4 KiB	1.65 KiB
GotaTun direct TUN receive prototype	not measured	not measured	not measured	not measured	not measured	not measured	1.65 KiB

Next: make Linux receive calls demand-driven in the existing adapter, retaining the buffered send and non-Linux receive path; preserve ordered batches, transient retry, fatal termination, cancellation, TSO expansion and restart ownership. Then run the full fork suite and optimized build, followed by one control/candidate/candidate/control R4b hold with loss/reordering checks and empty machine diffs. No upstream activity or product integration.

## J88 latency finding: TUN receive queue (2026-11-03) Branch `j88-linux-offloads`, base `47175889642b35b6832227c450725c1bd79ff11c`; no TUN receive code change yet. The posted plan in comment 76443 remains the scope and estimate (about 45 minutes, excluding build-slot and perf-lock waits). The existing queue trace measured TUN→device residence p99 of 1.575 ms at one flow and 5.025 ms at eight flows, with a producer batch p99 of 256–511 and no timed GRO/GSO wait. The direct UDP step already removes the UDP-side receive handoff. I added focused Linux receive tests and ran the compiled test binary as the build user because `.cargo/config.toml` sets a `sudo -E` test runner, which is unavailable on the dev VM. On the unchanged buffered path, the demand-driven test observed 3 reads before the consumer requested one (expected 0); the fatal-error test observed `UnexpectedEof` instead of the original `BrokenPipe`. Both are the intended red results. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 flows (s/Gbit) | Loaded RTT64 p50 / p99, 1 flow (ms) | Loaded RTT64 p50 / p99, 8 flows (ms) | RSS 1 / 1,000 peers (MiB) | Incremental RSS / peer | Kernel peer reference | |---|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard reference | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763 | 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go reference | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631 | 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 reference | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733 | 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | 1.65 KiB | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460 | 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | 1.65 KiB | | GotaTun route-cut control (n=2, clean hold) | 2.77 / 2.47 | 0.85 / 1.00 | 2.144 / 5.753 | 6.022 / 13.357 | 9.3 / 37.3 | 14.3 KiB | 1.65 KiB | | GotaTun direct UDP receive control (n=2, clean hold) | 2.95 / 2.25 | 0.82 / 0.99 | 1.743 / 4.478 | 4.624 / 9.926 | 9.4 / 33.7 | 12.4 KiB | 1.65 KiB | | GotaTun direct TUN receive prototype | not measured | not measured | not measured | not measured | not measured | not measured | 1.65 KiB | Next: make Linux receive calls demand-driven in the existing adapter, retaining the buffered send and non-Linux receive path; preserve ordered batches, transient retry, fatal termination, cancellation, TSO expansion and restart ownership. Then run the full fork suite and optimized build, followed by one control/candidate/candidate/control R4b hold with loss/reordering checks and empty machine diffs. No upstream activity or product integration.

kayg commented

2026-11-03 05:12:22 +00:00

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J103 relay finding: the two-sided no-session reset compiles, but the strengthened namespace regression still fails. At the 5 s deadline A has sent 148 peer bytes and received 0; B has received the 148-byte initiation and sent a 92-byte response. Relay stats report 2 forwarded datagrams; B's shim delivered one inbound datagram while A's delivered none. This narrows the remaining break to delivery of the response on A's inbound relay path, before its GotaTun peer counter changes. I am adding test-fixture-only drop counters to separate QUIC link lookup, peer lookup, shim UDP injection, and GotaTun receive.

kayg commented

2026-11-03 05:17:00 +00:00

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J103 throughput clarification: the 43.75 Mbps direct result in J103-fix-rerun.log used Finished dev profile [unoptimized + debuginfo]. The namespace proof sends a fixed 128 MiB TCP stream with no rate cap; its underlay control measured 21,029.23 Mbps. This rules out a 43.75 Mbps veth ceiling or an explicit test throttle. The direct number is debug-build functional evidence and cannot establish the optimized integrated engine's performance; I will use the R4b release comparison for that decision.

J103 throughput clarification: the 43.75 Mbps direct result in `J103-fix-rerun.log` used `Finished `dev` profile [unoptimized + debuginfo]`. The namespace proof sends a fixed 128 MiB TCP stream with no rate cap; its underlay control measured 21,029.23 Mbps. This rules out a 43.75 Mbps veth ceiling or an explicit test throttle. The direct number is debug-build functional evidence and cannot establish the optimized integrated engine's performance; I will use the R4b release comparison for that decision.

kayg commented

2026-11-03 05:23:05 +00:00

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Review finding: disabled restore currently adopts the shared firewall table before checking whether another GotaTun TUN is live, then removes that table in the unowned/disabled cleanup path. Reproduction sequence is old node up/down, second installation up and apply deny policy, then restore the old disabled state. I am adding a disposable-namespace regression proving the second node policy and TUN survive, then will gate the smallest ownership fence.

kayg commented

2026-11-03 05:25:36 +00:00

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Pin update pushed on mesh-gotatun-linux at a790fe11e: GotaTun now resolves to latest J88 head 47175889642b35b6832227c450725c1bd79ff11c. J88 records 131 library tests passed, 7 ignored, and an optimized CLI build for that exact commit; it retains GSO/TSO-GRO and THP-off. MPL-2.0 is already allowed and the fork remains explicitly allow-listed by git URL. I will compare this integrated pin against kernel WireGuard in R4b after the relay regression passes.

Pin update pushed on mesh-gotatun-linux at a790fe11e: GotaTun now resolves to latest J88 head 47175889642b35b6832227c450725c1bd79ff11c. J88 records 131 library tests passed, 7 ignored, and an optimized CLI build for that exact commit; it retains GSO/TSO-GRO and THP-off. MPL-2.0 is already allowed and the fork remains explicitly allow-listed by git URL. I will compare this integrated pin against kernel WireGuard in R4b after the relay regression passes.

kayg commented

2026-11-03 05:29:45 +00:00

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J103 branch rebased onto current origin/dev a6812c3cf and pushed at 3336a9f8d. The five upstream commits since the prior base were independent D159 and #315 test-isolation changes; the in-progress relay edits remain local pending the queued boundary run.

J103 branch rebased onto current origin/dev a6812c3cf and pushed at 3336a9f8d. The five upstream commits since the prior base were independent D159 and #315 test-isolation changes; the in-progress relay edits remain local pending the queued boundary run.

kayg commented

2026-11-03 05:34:05 +00:00

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J88 latency step: remove the TUN receive handoff

Branch j88-linux-offloads, base 47175889642b35b6832227c450725c1bd79ff11c. The existing profile reports TUN→device queue residence p99 of 1.575 ms at 1 flow and 5.025 ms at 8 flows; producer batch p99 and queue depth are 256–511 at 1 flow, with no timed GRO/GSO coalescing wait. The direct UDP receive worker cut is already committed; the working tree contains focused tests and a Linux direct TUN receive prototype.

Plan:

Confirm the profile’s batch, queue, GRO/GSO-wait, and worker-handoff counters against its raw artifacts; inspect cancellation and reconnection ownership in the receive adapter.
Finish the Linux-only demand-driven TUN receive path, retaining buffered send and non-Linux behavior. Keep packet order, TSO expansion, transient retry, fatal-error propagation, cancellation, and reader release on restart. Run focused tests for ordered batches, transient/fatal errors, cancellation/restart, then the full fork library suite and optimized CLI build on a dev VM.
If tests pass, commit this as one latency slice and run a single R4b perf-run --root hold on the perf VM with control/candidate/candidate/control. Report 1/8-flow throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, loss/reordering checks, queue diagnostics, and machine diffs in the existing table. Keep the slice only if p99 improves without a throughput regression; mark it pin-ready only with green fork tests.

Estimate: 45 minutes of engineering, excluding build-slot and perf-lock waits. No upstream or infraternal product changes.

## J88 latency step: remove the TUN receive handoff Branch `j88-linux-offloads`, base `47175889642b35b6832227c450725c1bd79ff11c`. The existing profile reports TUN→device queue residence p99 of 1.575 ms at 1 flow and 5.025 ms at 8 flows; producer batch p99 and queue depth are 256–511 at 1 flow, with no timed GRO/GSO coalescing wait. The direct UDP receive worker cut is already committed; the working tree contains focused tests and a Linux direct TUN receive prototype. Plan: 1. Confirm the profile’s batch, queue, GRO/GSO-wait, and worker-handoff counters against its raw artifacts; inspect cancellation and reconnection ownership in the receive adapter. 2. Finish the Linux-only demand-driven TUN receive path, retaining buffered send and non-Linux behavior. Keep packet order, TSO expansion, transient retry, fatal-error propagation, cancellation, and reader release on restart. Run focused tests for ordered batches, transient/fatal errors, cancellation/restart, then the full fork library suite and optimized CLI build on a dev VM. 3. If tests pass, commit this as one latency slice and run a single R4b `perf-run --root` hold on the perf VM with control/candidate/candidate/control. Report 1/8-flow throughput, CPU/Gbit, loaded p50/p99, RSS at 1/1,000 peers, loss/reordering checks, queue diagnostics, and machine diffs in the existing table. Keep the slice only if p99 improves without a throughput regression; mark it pin-ready only with green fork tests. Estimate: 45 minutes of engineering, excluding build-slot and perf-lock waits. No upstream or infraternal product changes.

kayg commented

2026-11-03 05:44:00 +00:00

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J103 resumed 2026-11-03. Branch mesh-gotatun-linux, base origin/dev at a6812c3cf528; checkpoint pushed at 20629f429084.

The active-link relay proof still fails its 5 s fresh-handshake assertion. On the latest run A reports 148 peer bytes received and 240 sent; B reports 0 received and 296 sent, despite both peers reporting the relay path active. Source tracing shows relay_with_endpoint still installs each loopback shim endpoint before the relay link is active, allowing GotaTun to start crossed handshakes before the settle callback resets the peers.

Next: defer peer endpoint updates until the relay link is active, preserve established sessions with endpoint-only updates, clear only unestablished handshakes on both ends, and retain the lower-host-id initiator. The namespace proof will require the relayed handshake and byte-exact delivered stream, followed by byte-exact failover/rebound. The 43.75 Mbps namespace result was a dev/debug build with an uncapped 128 MiB stream; its underlay measured 21.0 Gbit/s, so it is functional evidence only. I will compare the integrated engine with kernel WireGuard in the R4b perf harness, then run cargo-deny and scripts/verify fast.

Estimate: 2–4 hours excluding build-slot and perf-lock waits. No relay framing change or #285 rotation-hook change.

J103 resumed 2026-11-03. Branch `mesh-gotatun-linux`, base `origin/dev` at `a6812c3cf528`; checkpoint pushed at `20629f429084`. The active-link relay proof still fails its 5 s fresh-handshake assertion. On the latest run A reports 148 peer bytes received and 240 sent; B reports 0 received and 296 sent, despite both peers reporting the relay path active. Source tracing shows `relay_with_endpoint` still installs each loopback shim endpoint before the relay link is active, allowing GotaTun to start crossed handshakes before the settle callback resets the peers. Next: defer peer endpoint updates until the relay link is active, preserve established sessions with endpoint-only updates, clear only unestablished handshakes on both ends, and retain the lower-host-id initiator. The namespace proof will require the relayed handshake and byte-exact delivered stream, followed by byte-exact failover/rebound. The 43.75 Mbps namespace result was a dev/debug build with an uncapped 128 MiB stream; its underlay measured 21.0 Gbit/s, so it is functional evidence only. I will compare the integrated engine with kernel WireGuard in the R4b perf harness, then run cargo-deny and `scripts/verify fast`. Estimate: 2–4 hours excluding build-slot and perf-lock waits. No relay framing change or #285 rotation-hook change.

kayg commented

2026-11-03 05:46:46 +00:00

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J88 TUN receive checkpoint (2026-11-03): formatted the in-progress src/tun/buffer.rs candidate; the compute01 worktree contains the exact source hash e2c48f5d81d0ece2ed8fb7acffadae75d023011d3c392503a01e1b01f9577a10 on base 47175889642b35b6832227c450725c1bd79ff11c. The first verification attempt stopped at rustfmt before tests and has no test result. The corrected sequence (fmt, focused Linux receive tests, full all-features library suite, optimized CLI build) is queued through compute01 build-slot as PID 1513272, currently position 1; log: /home/claude/worktrees/j88-latency-tun/J88-tun-focused.log. No code commit or pin-ready claim yet.

J88 TUN receive checkpoint (2026-11-03): formatted the in-progress `src/tun/buffer.rs` candidate; the compute01 worktree contains the exact source hash `e2c48f5d81d0ece2ed8fb7acffadae75d023011d3c392503a01e1b01f9577a10` on base `47175889642b35b6832227c450725c1bd79ff11c`. The first verification attempt stopped at rustfmt before tests and has no test result. The corrected sequence (fmt, focused Linux receive tests, full all-features library suite, optimized CLI build) is queued through compute01 build-slot as PID `1513272`, currently position 1; log: `/home/claude/worktrees/j88-latency-tun/J88-tun-focused.log`. No code commit or pin-ready claim yet.

kayg commented

2026-11-03 05:56:48 +00:00

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J88 TUN receive verification update (2026-11-03): the first x86 VM run completed the focused Linux receive tests (3 passed), full all-features library suite (134 passed, 0 failed, 7 ignored), and optimized CLI build, but emitted three Linux-only warnings (cfg-unused PhantomData and two irrefutable direct-mode patterns). I fixed those locally and synced the change; exact src/tun/buffer.rs SHA-256 is ec244600664a0bd28bbd5f7941a757e7a089278fa571ea6f3469d419134ab57d.

The clean rerun adds all-features/all-targets clippy with only the existing TUN-offload clippy::needless_return allowance, then repeats the focused/full tests and release CLI build. It is queued via compute01 build-slot at position 5 as PID 1672738; log: /home/claude/worktrees/j88-latency-tun/J88-tun-final-check.log. No commit or pin-ready claim yet; the R4b comparison follows only after this run completes.

J88 TUN receive verification update (2026-11-03): the first x86 VM run completed the focused Linux receive tests (3 passed), full all-features library suite (134 passed, 0 failed, 7 ignored), and optimized CLI build, but emitted three Linux-only warnings (cfg-unused `PhantomData` and two irrefutable direct-mode patterns). I fixed those locally and synced the change; exact `src/tun/buffer.rs` SHA-256 is `ec244600664a0bd28bbd5f7941a757e7a089278fa571ea6f3469d419134ab57d`. The clean rerun adds all-features/all-targets clippy with only the existing TUN-offload `clippy::needless_return` allowance, then repeats the focused/full tests and release CLI build. It is queued via compute01 build-slot at position 5 as PID `1672738`; log: `/home/claude/worktrees/j88-latency-tun/J88-tun-final-check.log`. No commit or pin-ready claim yet; the R4b comparison follows only after this run completes.

kayg commented

2026-11-03 06:15:04 +00:00

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J88 latency step: direct Linux TUN receive

Commit 7264486b69f71cf8e075131f77cf127a0bf89146 is pushed on j88-linux-offloads. Pin-ready on fork tests: yes. The TUN receive R4b comparison is next; its throughput qualification is pending.

Verification on compute01, exact commit source: cargo fmt --all -- --check passed; all-features/all-targets clippy passed with only the existing clippy::needless_return allowance; focused receive tests passed (3 passed); full all-features library suite: test result: ok. 134 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 1.52s; optimized x86_64 CLI build passed. Candidate binary SHA-256: 590ac52cfbb394cd5d8dee2542e0a72f950bafc556e7093d36ae53f716b2bb57. Full log: /home/claude/worktrees/j88-latency-tun/J88-tun-final-check.log.

The profile found no timed GRO/GSO coalescing wait; the Linux change removes the TUN receive worker and 4,000-packet handoff channel, while preserving buffered sends, non-Linux buffering, ordered batches, transient retry, fatal errors, cancellation, and reader release.

Engine / step	Throughput 1 / 8 flows (Gbit/s)	CPU 1 / 8 (s/Gbit)	Loaded RTT64 p50 / p99, 1 flow (ms)	Loaded RTT64 p50 / p99, 8 flows (ms)	RSS 1 / 1,000 peers (MiB)	Incremental RSS / peer	Kernel peer reference
Kernel WireGuard reference	2.98 / 2.69	1.08 / 1.19	0.927 / 1.763	3.112 / 3.888	20.1 / 20.1	0	1.65 KiB
wireguard-go reference	5.58 / 5.01	0.48 / 0.54	2.483 / 6.631	7.839 / 15.205	25.4 / 1,070.1	535.5 KiB	n/a
GotaTun 0.10.2 reference	1.71 / 1.79	1.30 / 1.34	2.523 / 7.733	4.654 / 11.876	9.6 / 104.6	48.7 KiB	1.65 KiB
GotaTun UDP GSO + TUN TSO/GRO	3.05 / 2.64	0.79 / 0.98	1.974 / 5.460	5.846 / 12.502	10.0 / 108.6	50.5 KiB	1.65 KiB
GotaTun route-cut control (n=2)	2.77 / 2.47	0.85 / 1.00	2.144 / 5.753	6.022 / 13.357	9.3 / 37.3	14.3 KiB	1.65 KiB
GotaTun direct UDP receive (n=2)	2.95 / 2.25	0.82 / 0.99	1.743 / 4.478	4.624 / 9.926	9.4 / 33.7	12.4 KiB	1.65 KiB
GotaTun direct TUN receive (`7264486`)	pending	pending	pending	pending	pending	pending	1.65 KiB

No upstream PR, issue, or comment was made. The prior license note remains: LICENSE and Cargo metadata say MPL-2.0; flake.nix says BSD-3-Clause (recorded in comment 76001).

## J88 latency step: direct Linux TUN receive Commit `7264486b69f71cf8e075131f77cf127a0bf89146` is pushed on [`j88-linux-offloads`](https://github.com/kaygdotorg/gotatun/tree/j88-linux-offloads). **Pin-ready on fork tests: yes.** The TUN receive R4b comparison is next; its throughput qualification is pending. Verification on compute01, exact commit source: `cargo fmt --all -- --check` passed; all-features/all-targets clippy passed with only the existing `clippy::needless_return` allowance; focused receive tests passed (**3 passed**); full all-features library suite: `test result: ok. 134 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 1.52s`; optimized x86_64 CLI build passed. Candidate binary SHA-256: `590ac52cfbb394cd5d8dee2542e0a72f950bafc556e7093d36ae53f716b2bb57`. Full log: `/home/claude/worktrees/j88-latency-tun/J88-tun-final-check.log`. The profile found no timed GRO/GSO coalescing wait; the Linux change removes the TUN receive worker and 4,000-packet handoff channel, while preserving buffered sends, non-Linux buffering, ordered batches, transient retry, fatal errors, cancellation, and reader release. | Engine / step | Throughput 1 / 8 flows (Gbit/s) | CPU 1 / 8 (s/Gbit) | Loaded RTT64 p50 / p99, 1 flow (ms) | Loaded RTT64 p50 / p99, 8 flows (ms) | RSS 1 / 1,000 peers (MiB) | Incremental RSS / peer | Kernel peer reference | |---|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard reference | 2.98 / 2.69 | 1.08 / 1.19 | 0.927 / 1.763 | 3.112 / 3.888 | 20.1 / 20.1 | 0 | 1.65 KiB | | wireguard-go reference | 5.58 / 5.01 | 0.48 / 0.54 | 2.483 / 6.631 | 7.839 / 15.205 | 25.4 / 1,070.1 | 535.5 KiB | n/a | | GotaTun 0.10.2 reference | 1.71 / 1.79 | 1.30 / 1.34 | 2.523 / 7.733 | 4.654 / 11.876 | 9.6 / 104.6 | 48.7 KiB | 1.65 KiB | | GotaTun UDP GSO + TUN TSO/GRO | 3.05 / 2.64 | 0.79 / 0.98 | 1.974 / 5.460 | 5.846 / 12.502 | 10.0 / 108.6 | 50.5 KiB | 1.65 KiB | | GotaTun route-cut control (n=2) | 2.77 / 2.47 | 0.85 / 1.00 | 2.144 / 5.753 | 6.022 / 13.357 | 9.3 / 37.3 | 14.3 KiB | 1.65 KiB | | GotaTun direct UDP receive (n=2) | 2.95 / 2.25 | 0.82 / 0.99 | 1.743 / 4.478 | 4.624 / 9.926 | 9.4 / 33.7 | 12.4 KiB | 1.65 KiB | | GotaTun direct TUN receive (`7264486`) | pending | pending | pending | pending | pending | pending | 1.65 KiB | No upstream PR, issue, or comment was made. The prior license note remains: `LICENSE` and Cargo metadata say MPL-2.0; `flake.nix` says BSD-3-Clause (recorded in comment 76001).

kayg commented

2026-11-03 06:21:56 +00:00

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J88 latency follow-up plan (2026-11-03)

Branch j88-linux-offloads, current pushed head 7264486b69f71cf8e075131f77cf127a0bf89146. The prior R4b profile attributes queue residence to worker hand-offs (TUN→device p99 1.575 ms at 1 flow / 5.025 ms at 8; UDP→device p99 2.000 ms), with 256–511 packet batches, 256–1,023 p99 queue depth, 52–58% crossing workers, no timed GRO/GSO wait, and no approach to the 4,000-packet channel bound. The direct Linux TUN receive commit removes that worker/channel; its R4b row is still pending.

Reuse the existing R4b session and prepared harness. Confirm the raw queue/batch counters and exact binary/source hashes; do not add instrumentation that changes the packet path.
Run the paired direct-UDP control and direct-TUN candidate with the existing kernel WireGuard and wireguard-go references in one perf-run --root hold. Record the same table: 1/8-flow throughput, CPU/Gbit, loaded RTT64 p50/p99, RSS at 1/1,000 peers, plus loss/reordering checks, queue/batch/handoff diagnostics, and empty machine diffs.
Keep the hand-off cut only if loaded tails improve without a throughput regression and fork tests stay green. If a queueing source remains, use that profile to select one bounded cut, verify it on the fork, and compare it under the same R4b harness before marking its commit pin-ready.

Estimate: 45 minutes for the paired hold and table update, plus up to 45 minutes for one profile-driven code slice and fork verification, excluding perf-lock waits. No product integration or upstream activity.

## J88 latency follow-up plan (2026-11-03) Branch `j88-linux-offloads`, current pushed head `7264486b69f71cf8e075131f77cf127a0bf89146`. The prior R4b profile attributes queue residence to worker hand-offs (TUN→device p99 1.575 ms at 1 flow / 5.025 ms at 8; UDP→device p99 2.000 ms), with 256–511 packet batches, 256–1,023 p99 queue depth, 52–58% crossing workers, no timed GRO/GSO wait, and no approach to the 4,000-packet channel bound. The direct Linux TUN receive commit removes that worker/channel; its R4b row is still pending. 1. Reuse the existing R4b session and prepared harness. Confirm the raw queue/batch counters and exact binary/source hashes; do not add instrumentation that changes the packet path. 2. Run the paired direct-UDP control and direct-TUN candidate with the existing kernel WireGuard and wireguard-go references in one `perf-run --root` hold. Record the same table: 1/8-flow throughput, CPU/Gbit, loaded RTT64 p50/p99, RSS at 1/1,000 peers, plus loss/reordering checks, queue/batch/handoff diagnostics, and empty machine diffs. 3. Keep the hand-off cut only if loaded tails improve without a throughput regression and fork tests stay green. If a queueing source remains, use that profile to select one bounded cut, verify it on the fork, and compare it under the same R4b harness before marking its commit pin-ready. Estimate: 45 minutes for the paired hold and table update, plus up to 45 minutes for one profile-driven code slice and fork verification, excluding perf-lock waits. No product integration or upstream activity.

kayg commented

2026-11-03 06:25:40 +00:00

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J88 latency R4b setup finding (2026-11-03)

The first perf-run --root returned exit 1 after 0.786 s, before any mesh case or measurement ran. The prepared runner's source-metadata overlay expected a start_gotatun switch/mkdir anchor that is absent in the current R4b kit. The actual cases/mesh.sh records a fixed source at the GotaTun version note; this is a stale harness edit, not a fork or engine failure.

Receipt: /home/claude/j20/r4b/j88-latency-tun-rx-20261103/receipts/perf-run-20261103T072420-350901.{before,after}.txt. Runner log: /home/claude/j20/r4b/j88-latency-tun-rx-20261103/run-direct-tun-rx.log. No performance row is produced. I will preserve this failed setup, adjust only the metadata overlay to use the per-case source hash, then retry the counterbalanced comparison in one perf-run --root hold.

## J88 latency R4b setup finding (2026-11-03) The first `perf-run --root` returned exit 1 after 0.786 s, before any mesh case or measurement ran. The prepared runner's source-metadata overlay expected a `start_gotatun` switch/`mkdir` anchor that is absent in the current R4b kit. The actual `cases/mesh.sh` records a fixed source at the GotaTun version note; this is a stale harness edit, not a fork or engine failure. Receipt: `/home/claude/j20/r4b/j88-latency-tun-rx-20261103/receipts/perf-run-20261103T072420-350901.{before,after}.txt`. Runner log: `/home/claude/j20/r4b/j88-latency-tun-rx-20261103/run-direct-tun-rx.log`. No performance row is produced. I will preserve this failed setup, adjust only the metadata overlay to use the per-case source hash, then retry the counterbalanced comparison in one `perf-run --root` hold.

kayg commented

2026-11-03 06:43:50 +00:00

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J103 review finding (2026-11-03, branch mesh-gotatun-linux, current head 20629f429): P1 ownership gap in disabled restore. Node::restore unconditionally adopts the shared firewall before proving the active link belongs to this state; a disabled stale state then removes that table. Reproduction in the working tree: start/stop installation A, start GotaTun installation B and install policy, restore A; the active TUN remains B’s while A removes B’s firewall. I will add the owner fence and commit this separately from the relay repair. Estimate: 20–30 minutes excluding VM queue time.

J103 review finding (2026-11-03, branch `mesh-gotatun-linux`, current head `20629f429`): P1 ownership gap in disabled restore. `Node::restore` unconditionally adopts the shared firewall before proving the active link belongs to this state; a disabled stale state then removes that table. Reproduction in the working tree: start/stop installation A, start GotaTun installation B and install policy, restore A; the active TUN remains B’s while A removes B’s firewall. I will add the owner fence and commit this separately from the relay repair. Estimate: 20–30 minutes excluding VM queue time.

kayg commented

2026-11-03 06:49:14 +00:00

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J88 direct-TUN R4b partial table (not a performance qualification)

The counterbalanced run reached kernel WireGuard, wireguard-go, direct-UDP control, and both direct-TUN samples. It stopped after candidate-second because that case's machine diff found only rotating /root/.cache/nix/sentry entries; its harness exit was 3, so control-last did not run. The 1,098.172 s outer perf-run --root exited 1. Candidate-first had an empty diff. These rows are provisional and do not qualify the commit for performance.

Engine / step	Throughput 1 / 8 (Gbit/s)	CPU 1 / 8 (s/Gbit)	Loaded RTT64 p50 / p99, 1 flow (ms)	Loaded RTT64 p50 / p99, 8 flows (ms)	RSS 1 / 1,000 peers (MiB, both endpoints)	Incremental RSS / peer	Kernel peer state / peer	Case status
Kernel WireGuard reference	3.21 / 2.76	1.04 / 1.17	0.989 / 1.922	3.098 / 4.590	20.1 / 20.1	0	1.65 KiB	exit 0, empty diff
wireguard-go reference	5.13 / 4.99	0.49 / 0.55	2.450 / 8.003	8.534 / 16.775	25.7 / 1,007.4	502.9 KiB	n/a	exit 0, empty diff
GotaTun direct UDP control (n=1)	2.82 / 2.30	0.84 / 1.02	1.957 / 6.244	5.034 / 12.183	9.4 / 35.1	13.2 KiB	1.65 KiB	exit 0, empty diff
GotaTun direct TUN receive (`7264486`), candidate-first	2.69 / 2.42	0.86 / 1.02	2.087 / 5.894	4.387 / 11.805	9.4 / 33.1	12.1 KiB	1.65 KiB	exit 0, empty diff
GotaTun direct TUN receive (`7264486`), candidate-second	2.69 / 2.22	0.82 / 1.02	1.936 / 5.079	4.486 / 11.900	9.4 / 35.3	13.3 KiB	1.65 KiB	exit 3, Nix cache diff

The loss/reordering probes completed in both candidate cases: all 300 probes arrived for each payload size under 25% reordering; with independent 2% loss each way, whole-probe losses were 11/12/11 and 8/16/18 (64/512/1400 B). I am preserving these raw results, then rerunning the full counterbalanced matrix in a fresh result directory. The direct-TUN commit remains fork-test-green; performance qualification is pending.

## J88 direct-TUN R4b partial table (not a performance qualification) The counterbalanced run reached kernel WireGuard, wireguard-go, direct-UDP control, and both direct-TUN samples. It stopped after candidate-second because that case's machine diff found only rotating `/root/.cache/nix/sentry` entries; its harness exit was 3, so control-last did not run. The 1,098.172 s outer `perf-run --root` exited 1. Candidate-first had an empty diff. These rows are provisional and do not qualify the commit for performance. | Engine / step | Throughput 1 / 8 (Gbit/s) | CPU 1 / 8 (s/Gbit) | Loaded RTT64 p50 / p99, 1 flow (ms) | Loaded RTT64 p50 / p99, 8 flows (ms) | RSS 1 / 1,000 peers (MiB, both endpoints) | Incremental RSS / peer | Kernel peer state / peer | Case status | |---|---:|---:|---:|---:|---:|---:|---:|---| | Kernel WireGuard reference | 3.21 / 2.76 | 1.04 / 1.17 | 0.989 / 1.922 | 3.098 / 4.590 | 20.1 / 20.1 | 0 | 1.65 KiB | exit 0, empty diff | | wireguard-go reference | 5.13 / 4.99 | 0.49 / 0.55 | 2.450 / 8.003 | 8.534 / 16.775 | 25.7 / 1,007.4 | 502.9 KiB | n/a | exit 0, empty diff | | GotaTun direct UDP control (n=1) | 2.82 / 2.30 | 0.84 / 1.02 | 1.957 / 6.244 | 5.034 / 12.183 | 9.4 / 35.1 | 13.2 KiB | 1.65 KiB | exit 0, empty diff | | GotaTun direct TUN receive (`7264486`), candidate-first | 2.69 / 2.42 | 0.86 / 1.02 | 2.087 / 5.894 | 4.387 / 11.805 | 9.4 / 33.1 | 12.1 KiB | 1.65 KiB | exit 0, empty diff | | GotaTun direct TUN receive (`7264486`), candidate-second | 2.69 / 2.22 | 0.82 / 1.02 | 1.936 / 5.079 | 4.486 / 11.900 | 9.4 / 35.3 | 13.3 KiB | 1.65 KiB | exit 3, Nix cache diff | The loss/reordering probes completed in both candidate cases: all 300 probes arrived for each payload size under 25% reordering; with independent 2% loss each way, whole-probe losses were 11/12/11 and 8/16/18 (64/512/1400 B). I am preserving these raw results, then rerunning the full counterbalanced matrix in a fresh result directory. The direct-TUN commit remains fork-test-green; performance qualification is pending.

kayg commented

2026-11-03 10:09:44 +00:00

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J88c takeover (2026-11-03, 15:40 IST)

J88c takes over J88 after a provider rate limit stopped it. Same fork, branch and rules. No upstream PRs, issues or comments.

State found

Fork kaygdotorg/gotatun branch j88-linux-offloads, head 7264486b69f71cf8e075131f77cf127a0bf89146 (direct Linux TUN receive). The compute01 worktree ~/worktrees/j88-latency-tun had an uncommitted gotatun/src/tun/buffer.rs. It is byte-identical to 7264486's file (SHA-256 ec244600…), so no work was lost.
No J88 processes are running on compute01, dev-02 or the perf VM. No perf-run is held.
The full counterbalanced rerun had already finished, but was never posted. It is /home/claude/j20/r4b/j88-latency-tun-rx-20261103-rerun/ on the perf VM: one perf-run --root hold, 07:50–08:12 UTC, 1,332.9 s, outer exit 0. Six cases ran: kernel WG, wireguard-go, direct-UDP control, candidate, candidate, control. Every case exited 0 with an empty machine diff. The /root/.cache/nix/sentry entries did not rotate during this hold, so no path was excluded from the diff. Binaries: control 7517890c… (4717588), candidate 590ac52c… (7264486).

Full matrix: direct-TUN receive vs direct-UDP control (same hold)

LAN, perf.slice CPUs 1–3 / 6 GiB. Loaded RTT is 64 B probes at 1 ms during the TCP transfer, 2,000 probes per phase. Probe loss is probes sent minus probes received; p50/p99 cover received probes only. The loss and reorder columns are the R4b 198 ms RTT profiles at 64/512/1400 B, 300 probes each: lost probes under 2% independent loss per direction, and lost probes under 25%/50% netem reordering.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	Loaded RTT p50/p99, 1 flow (ms)	Loaded RTT p50/p99, 8 flows (ms)	Loaded probe loss 1 / 8 flows	RSS 1 / 1,000 peers (MiB)	Incr. RSS/peer	2% loss: lost 64/512/1400	Reorder: lost
Kernel WireGuard	3.23 / 2.78	1.03 / 1.15	1.033 / 2.403	3.065 / 4.728	0 / 0	20.1 / 20.1	0 (kernel state 1.65 KiB)	14/5/19	n/a
wireguard-go	4.94 / 4.88	0.49 / 0.56	3.068 / 54.606	8.731 / 15.502	0 / 0	23.5 / 1,087.6	545.4 KiB	9/5/23	n/a
direct-UDP control, first	2.93 / 2.59	0.83 / 0.99	1.956 / 5.092	4.825 / 10.895	125 / 318	9.5 / 36.4	13.8 KiB	8/14/13	0/0/0
direct-TUN candidate, first	2.95 / 2.42	0.83 / 1.00	2.059 / 5.309	4.335 / 10.980	138 / 292	9.3 / 36.0	13.7 KiB	4/15/13	0/0/0
direct-TUN candidate, second	2.99 / 2.49	0.81 / 1.00	1.802 / 5.480	5.432 / 12.834	127 / 271	9.4 / 35.9	13.6 KiB	9/14/12	0/0/0
direct-UDP control, last	2.85 / 2.53	0.84 / 0.99	1.737 / 4.501	4.627 / 11.443	97 / 303	9.5 / 35.0	13.1 KiB	12/12/13	0/0/0
control mean	2.89 / 2.56	0.84 / 0.99	1.847 / 4.797	4.726 / 11.169	5.6% / 15.5%	9.5 / 35.7	13.4 KiB
candidate mean	2.97 / 2.46	0.82 / 1.00	1.931 / 5.395	4.884 / 11.907	6.6% / 14.1%	9.4 / 36.0	13.6 KiB

Decision: drop the direct-TUN hand-off cut. Against the control mean, it is 12.5% worse on 1-flow p99, 6.6% worse on 8-flow p99, and 4.0% lower on 8-flow throughput. Adding the earlier partial hold changes nothing: the four candidate samples average 5.44 ms 1-flow p99, against 5.28 ms for the three control samples. I will revert 7264486 on the fork with a revert commit, not a force-push. The fork's last pin-ready head returns to 4717588, which J103 already pins.

New finding: GotaTun drops loaded probes; kernel and wireguard-go do not

Under load GotaTun loses 5–16% of the 64 B probes. Kernel WireGuard and wireguard-go lose 0/2,000 in the same hold. This was not reported before, but it is in every GotaTun row since R4b. The unpatched 0.10.2 baseline lost 171–276 per phase, and the route-cut run lost 50 / 222. Because p99 counts only received probes, every GotaTun loaded p99 so far understates the real tail. One lead in the source: gotatun-cli requests 7 MiB UDP buffers through SO_RCVBUF/SO_SNDBUF (gotatun-cli/src/unix/mod.rs:219). The kernel silently caps those at net.core.rmem_max, which is 212,992 B on the perf VM. wireguard-go uses the *FORCE variants, which the daemon may use because it holds CAP_NET_ADMIN. This is not yet proven to cause the drops.

Remaining plan and estimate

Revert 7264486 and push the fork branch (10 min).
Run one diagnostic mesh-gotatun case under perf-run --root that snapshots the netns /proc/net/snmp + /proc/net/netstat (UdpRcvbufErrors), ip -s -s link on the TUN, and tc -s qdisc before and after the LAN profile. This finds where the probes drop: socket receive buffer, TUN ring, or qdisc (20 min).
Take one bounded cut at the measured drop site. If it is the receive buffer: on Linux, try SO_RCVBUFFORCE/SO_SNDBUFFORCE first and fall back to the current call. Verify on the fork (fmt, clippy, full library suite, release build), then measure kernel / wg-go / control / cand / cand / control in one fresh perf-run --root hold. Keep rule, set before measuring: loaded probe loss falls, mean loaded p99 does not rise, and throughput does not fall at either flow count (about 1.5 h, excluding queue waits).
Memory toward ≤5 KiB/peer. The two named leads are already done: the lazy session ring (77109e5, 30.2 → 21.9 KiB) and dropping the per-peer trie (823133f, 21.9 → 14.2 KiB). About 13.4 KiB/peer remains. Next comes an allocation attribution at 1 vs 1,000 peers on a dev VM, then one test-first cut, measured in R4b (about 2–3 h).

Total about 4–5 h, excluding build-slot and perf-lock waits. I will stop and report at 2× that. License note, unchanged: LICENSE and Cargo say MPL-2.0, while flake.nix says BSD-3-Clause. I am not changing either.

## J88c takeover (2026-11-03, 15:40 IST) J88c takes over J88 after a provider rate limit stopped it. Same fork, branch and rules. No upstream PRs, issues or comments. ### State found - Fork `kaygdotorg/gotatun` branch `j88-linux-offloads`, head `7264486b69f71cf8e075131f77cf127a0bf89146` (direct Linux TUN receive). The compute01 worktree `~/worktrees/j88-latency-tun` had an uncommitted `gotatun/src/tun/buffer.rs`. It is byte-identical to `7264486`'s file (SHA-256 `ec244600…`), so no work was lost. - No J88 processes are running on compute01, dev-02 or the perf VM. No perf-run is held. - **The full counterbalanced rerun had already finished, but was never posted.** It is `/home/claude/j20/r4b/j88-latency-tun-rx-20261103-rerun/` on the perf VM: one `perf-run --root` hold, 07:50–08:12 UTC, 1,332.9 s, outer exit 0. Six cases ran: kernel WG, wireguard-go, direct-UDP control, candidate, candidate, control. **Every case exited 0 with an empty machine diff.** The `/root/.cache/nix/sentry` entries did not rotate during this hold, so no path was excluded from the diff. Binaries: control `7517890c…` (`4717588`), candidate `590ac52c…` (`7264486`). ### Full matrix: direct-TUN receive vs direct-UDP control (same hold) LAN, perf.slice CPUs 1–3 / 6 GiB. Loaded RTT is 64 B probes at 1 ms during the TCP transfer, 2,000 probes per phase. **Probe loss** is probes sent minus probes received; p50/p99 cover received probes only. The loss and reorder columns are the R4b 198 ms RTT profiles at 64/512/1400 B, 300 probes each: lost probes under 2% independent loss per direction, and lost probes under 25%/50% netem reordering. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | Loaded RTT p50/p99, 1 flow (ms) | Loaded RTT p50/p99, 8 flows (ms) | Loaded probe loss 1 / 8 flows | RSS 1 / 1,000 peers (MiB) | Incr. RSS/peer | 2% loss: lost 64/512/1400 | Reorder: lost | |---|---:|---:|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 3.23 / 2.78 | 1.03 / 1.15 | 1.033 / 2.403 | 3.065 / 4.728 | 0 / 0 | 20.1 / 20.1 | 0 (kernel state 1.65 KiB) | 14/5/19 | n/a | | wireguard-go | 4.94 / 4.88 | 0.49 / 0.56 | 3.068 / 54.606 | 8.731 / 15.502 | 0 / 0 | 23.5 / 1,087.6 | 545.4 KiB | 9/5/23 | n/a | | direct-UDP control, first | 2.93 / 2.59 | 0.83 / 0.99 | 1.956 / 5.092 | 4.825 / 10.895 | 125 / 318 | 9.5 / 36.4 | 13.8 KiB | 8/14/13 | 0/0/0 | | direct-TUN candidate, first | 2.95 / 2.42 | 0.83 / 1.00 | 2.059 / 5.309 | 4.335 / 10.980 | 138 / 292 | 9.3 / 36.0 | 13.7 KiB | 4/15/13 | 0/0/0 | | direct-TUN candidate, second | 2.99 / 2.49 | 0.81 / 1.00 | 1.802 / 5.480 | 5.432 / 12.834 | 127 / 271 | 9.4 / 35.9 | 13.6 KiB | 9/14/12 | 0/0/0 | | direct-UDP control, last | 2.85 / 2.53 | 0.84 / 0.99 | 1.737 / 4.501 | 4.627 / 11.443 | 97 / 303 | 9.5 / 35.0 | 13.1 KiB | 12/12/13 | 0/0/0 | | **control mean** | 2.89 / 2.56 | 0.84 / 0.99 | 1.847 / 4.797 | 4.726 / 11.169 | 5.6% / 15.5% | 9.5 / 35.7 | 13.4 KiB | | | | **candidate mean** | 2.97 / 2.46 | 0.82 / 1.00 | 1.931 / 5.395 | 4.884 / 11.907 | 6.6% / 14.1% | 9.4 / 36.0 | 13.6 KiB | | | **Decision: drop the direct-TUN hand-off cut.** Against the control mean, it is 12.5% worse on 1-flow p99, 6.6% worse on 8-flow p99, and 4.0% lower on 8-flow throughput. Adding the earlier partial hold changes nothing: the four candidate samples average 5.44 ms 1-flow p99, against 5.28 ms for the three control samples. I will revert `7264486` on the fork with a revert commit, not a force-push. The fork's last pin-ready head returns to `4717588`, which J103 already pins. ### New finding: GotaTun drops loaded probes; kernel and wireguard-go do not Under load GotaTun loses 5–16% of the 64 B probes. Kernel WireGuard and wireguard-go lose 0/2,000 in the same hold. This was not reported before, but it is in every GotaTun row since R4b. The unpatched 0.10.2 baseline lost 171–276 per phase, and the route-cut run lost 50 / 222. Because p99 counts only received probes, **every GotaTun loaded p99 so far understates the real tail.** One lead in the source: `gotatun-cli` requests 7 MiB UDP buffers through `SO_RCVBUF`/`SO_SNDBUF` (`gotatun-cli/src/unix/mod.rs:219`). The kernel silently caps those at `net.core.rmem_max`, which is 212,992 B on the perf VM. wireguard-go uses the `*FORCE` variants, which the daemon may use because it holds `CAP_NET_ADMIN`. This is not yet proven to cause the drops. ### Remaining plan and estimate 1. Revert `7264486` and push the fork branch (10 min). 2. Run one diagnostic `mesh-gotatun` case under `perf-run --root` that snapshots the netns `/proc/net/snmp` + `/proc/net/netstat` (`UdpRcvbufErrors`), `ip -s -s link` on the TUN, and `tc -s qdisc` before and after the LAN profile. This finds where the probes drop: socket receive buffer, TUN ring, or qdisc (20 min). 3. Take one bounded cut at the measured drop site. If it is the receive buffer: on Linux, try `SO_RCVBUFFORCE`/`SO_SNDBUFFORCE` first and fall back to the current call. Verify on the fork (fmt, clippy, full library suite, release build), then measure kernel / wg-go / control / cand / cand / control in one fresh `perf-run --root` hold. **Keep rule, set before measuring:** loaded probe loss falls, mean loaded p99 does not rise, and throughput does not fall at either flow count (about 1.5 h, excluding queue waits). 4. Memory toward ≤5 KiB/peer. The two named leads are **already done**: the lazy session ring (`77109e5`, 30.2 → 21.9 KiB) and dropping the per-peer trie (`823133f`, 21.9 → 14.2 KiB). About 13.4 KiB/peer remains. Next comes an allocation attribution at 1 vs 1,000 peers on a dev VM, then one test-first cut, measured in R4b (about 2–3 h). Total about 4–5 h, excluding build-slot and perf-lock waits. I will stop and report at 2× that. License note, unchanged: `LICENSE` and Cargo say MPL-2.0, while `flake.nix` says BSD-3-Clause. I am not changing either.

kayg commented

2026-11-03 10:21:57 +00:00

Author

Owner

J103c takeover (2026-11-03, 15:55 IST)

J103c (Claude Opus 5.5) takes over J103 after a provider rate limit stopped it at about 07:00 UTC. Same branch and rules: no merge, no deploy, no fork change.

State found

Branch mesh-gotatun-linux, pushed head 20629f429 on base origin/dev a6812c3cf. Since then, origin/dev has 31 more commits (UI, tracer and decisions only). Only one line in scripts/verify.d/ts.sh overlaps the gate, so the rebase is trivial. I will do it before the final gate.
Uncommitted J103 work in compute01 ~/worktrees/J103-gotatun-run, byte-identical to the control-host worktree (diff SHA-256 5fe26510…). I committed it as 26c66f0c4 "WIP from the previous job" and pushed it. Contents:
- relay endpoints deferred until the link is active;
- force_handshake moved out of the worker command loop;
- the test disabled_restore_leaves_another_gotatun_nodes_installed_policy. Its production fence was not written yet.
Not taken: the uncommitted GotaTun pin bump to 7264486b. J88c rejected that fork commit on a full R4b hold (comment 76745) and reverted it (07fc7bd, tree equal to 4717588). The branch keeps 47175889, the last fork head with green tests and a qualifying R4b row. The brief says the pin is 823133f8, but that is out of date: the branch moved to 47175889 in 3336a9f8d.
No J103 processes are running on compute01, dev-02 or the perf VM.
Stale J103 targets: compute01 ~/worktrees/J103/target (17 GB, old base 1f005f2) and ~/.cache/codex-scratch/J103/target. I am deleting both. My one VM worktree and target is compute01 ~/worktrees/J103-gotatun-run.

Relay handshake: root cause from J103's last log

Log: ~/.cache/codex-scratch/J103/evidence/relay-boundary-run.log, compute01, 05:33 UTC.

What it shows:
- A (initiator) sent its 148 B initiation (sent=1).
- The relay forwarded both datagrams (forwarded=2).
- B answered with 92 B.
- A's relay reader saw inbound_datagrams=0.
- B's link dropped about 3 s after activation.
Why:
- The GotaTun worker awaited force_handshake for up to 5 s inside its serialized command loop.
- The node's counters() call blocks until the worker replies. The proof polls stats every 5 ms, and that call runs on the node's single runtime thread, the same thread that runs the relay shim and its QUIC driver.
- So the initiator's shim stayed frozen until the wait timed out, and the response could not reach its engine. "Crossed handshakes" were not the cause. GotaTun keeps a pending InitSent in previous and still accepts its response (noise/handshake.rs).
The WIP's extra async RwLock around the device does not fully fix this. The spawned wait holds a read guard for up to 5 s, so any coordinator update, rotation or peer reset queued as a writer stalls the loop again. GotaTun's own Device::write(&self, …) already gives exclusive access, so the extra lock is not needed.

Plan (estimate about 5–6 h of work, excluding build-slot and perf-lock waits; I stop and report at 2×)

P1 owner fence, in its own commit, with disabled_restore_leaves_another_gotatun_nodes_installed_policy: RED, then GREEN, as root in a disposable namespace on compute01.
- Restore and down may adopt or remove the shared mesh filter only while no mesh link is live, or while the live link is this node's own.
- A GotaTun TUN exists only while its engine process holds it. So at restore, a live TUN always belongs to another running node.
- About 1 h.
Relay handshake.
- Hold the device as a plain shared handle, with no outer lock.
- Run the forced handshake as a bounded task.
- Defer endpoint updates until the relay link is active.
- At activation, keep an established session with an endpoint-only update. Leave alone a peer whose endpoint is already the shim: it can only get there from an authenticated relayed packet, so it is mid-handshake. Reset any other unestablished peer to an endpoint-less responder.
- Keep the lower-host-id initiator.
- No change to relay framing or the #285 rotation hook.
- About 1.5 h.
Namespace proofs.
- Relay: fresh handshake on both peers within 5 s of activation, then a byte-exact relayed stream, byte-exact failover to relay 2, no-relay and restart, and a byte-exact rebind.
- Plus the direct proof, restore and rotation-overlap tests.
- About 45 min.
R4b benchmark: the integrated engine as a release build against kernel WireGuard in one perf-run --root hold, queued behind J88c. The 43.75 Mbps figure came from a debug build and is not used. About 1.5 h.
cargo-deny and scripts/verify fast on the rebased head. Restructure the WIP commits into atomic commits, push, and post the final comment. About 1 h.

## J103c takeover (2026-11-03, 15:55 IST) J103c (Claude Opus 5.5) takes over J103 after a provider rate limit stopped it at about 07:00 UTC. Same branch and rules: no merge, no deploy, no fork change. ### State found - Branch `mesh-gotatun-linux`, pushed head `20629f429` on base `origin/dev` `a6812c3cf`. Since then, `origin/dev` has 31 more commits (UI, tracer and decisions only). Only one line in `scripts/verify.d/ts.sh` overlaps the gate, so the rebase is trivial. I will do it before the final gate. - Uncommitted J103 work in compute01 `~/worktrees/J103-gotatun-run`, byte-identical to the control-host worktree (diff SHA-256 `5fe26510…`). I committed it as `26c66f0c4` "WIP from the previous job" and pushed it. Contents: - relay endpoints deferred until the link is active; - `force_handshake` moved out of the worker command loop; - the test `disabled_restore_leaves_another_gotatun_nodes_installed_policy`. Its production fence was not written yet. - **Not taken:** the uncommitted GotaTun pin bump to `7264486b`. J88c rejected that fork commit on a full R4b hold (comment 76745) and reverted it (`07fc7bd`, tree equal to `4717588`). The branch keeps `47175889`, the last fork head with green tests and a qualifying R4b row. The brief says the pin is `823133f8`, but that is out of date: the branch moved to `47175889` in `3336a9f8d`. - No J103 processes are running on compute01, dev-02 or the perf VM. - Stale J103 targets: compute01 `~/worktrees/J103/target` (17 GB, old base `1f005f2`) and `~/.cache/codex-scratch/J103/target`. I am deleting both. My one VM worktree and target is compute01 `~/worktrees/J103-gotatun-run`. ### Relay handshake: root cause from J103's last log Log: `~/.cache/codex-scratch/J103/evidence/relay-boundary-run.log`, compute01, 05:33 UTC. - What it shows: - A (initiator) sent its 148 B initiation (`sent=1`). - The relay forwarded both datagrams (`forwarded=2`). - B answered with 92 B. - A's relay reader saw `inbound_datagrams=0`. - B's link dropped about 3 s after activation. - Why: - The GotaTun worker awaited `force_handshake` for up to 5 s inside its serialized command loop. - The node's `counters()` call blocks until the worker replies. The proof polls `stats` every 5 ms, and that call runs on the node's single runtime thread, the same thread that runs the relay shim and its QUIC driver. - So the initiator's shim stayed frozen until the wait timed out, and the response could not reach its engine. "Crossed handshakes" were not the cause. GotaTun keeps a pending `InitSent` in `previous` and still accepts its response (`noise/handshake.rs`). - The WIP's extra async `RwLock` around the device does not fully fix this. The spawned wait holds a read guard for up to 5 s, so any coordinator update, rotation or peer reset queued as a writer stalls the loop again. GotaTun's own `Device::write(&self, …)` already gives exclusive access, so the extra lock is not needed. ### Plan (estimate about 5–6 h of work, excluding build-slot and perf-lock waits; I stop and report at 2×) 1. **P1 owner fence**, in its own commit, with `disabled_restore_leaves_another_gotatun_nodes_installed_policy`: RED, then GREEN, as root in a disposable namespace on compute01. - Restore and down may adopt or remove the shared mesh filter only while no mesh link is live, or while the live link is this node's own. - A GotaTun TUN exists only while its engine process holds it. So at restore, a live TUN always belongs to another running node. - About 1 h. 2. **Relay handshake.** - Hold the device as a plain shared handle, with no outer lock. - Run the forced handshake as a bounded task. - Defer endpoint updates until the relay link is active. - At activation, keep an established session with an endpoint-only update. Leave alone a peer whose endpoint is already the shim: it can only get there from an authenticated relayed packet, so it is mid-handshake. Reset any other unestablished peer to an endpoint-less responder. - Keep the lower-host-id initiator. - No change to relay framing or the #285 rotation hook. - About 1.5 h. 3. **Namespace proofs.** - Relay: fresh handshake on both peers within 5 s of activation, then a byte-exact relayed stream, byte-exact failover to relay 2, no-relay and restart, and a byte-exact rebind. - Plus the direct proof, restore and rotation-overlap tests. - About 45 min. 4. **R4b benchmark:** the integrated engine as a release build against kernel WireGuard in one `perf-run --root` hold, queued behind J88c. The 43.75 Mbps figure came from a debug build and is not used. About 1.5 h. 5. cargo-deny and `scripts/verify fast` on the rebased head. Restructure the WIP commits into atomic commits, push, and post the final comment. About 1 h.

kayg commented

2026-11-03 10:45:29 +00:00

Author

Owner

J103c progress (2026-11-03, 16:25 IST): relay handshake fixed, namespace proofs pass

Branch mesh-gotatun-linux, head 5a0446a81. Since the takeover comment I pushed:

8ac8aa69a mesh: never adopt or remove another live node's filter. This is the P1 owner fence.
- Restore adopts the shared filter only when no GotaTun link is live.
- A node that holds no live link of its own removes the filter only while no mesh link is live at all. That covers restore's disabled cleanup and down after a failed up that had adopted the table.
- An unmarked interface with the shared name counts as live.
- Kernel links keep dev's adoption: their key can change under rotation.
57a344905 mesh: keep the GotaTun worker free while a relay handshake waits.
- The device is now a plain Arc with no extra lock, and force_handshake runs as a task bounded to 5 s.
- Endpoints stay deferred until a relay link is active. An established session gets an endpoint-only update; an unestablished peer becomes an endpoint-less responder; the lower host id initiates.
- The unused Node::set_endpoint and its worker command are gone.
5a0446a81 fixes three inherited clippy findings (let-else, two doc code marks) and one in the test helper.

Namespace proofs (compute01, debug build, label "build host, x86_64, not perf evidence")

Run at 57a344905; evidence is in ~/.cache/codex-scratch/J103/evidence/j103c-ns-2.log. The proof JSON is j103c-relay-proof-57a344905.json, SHA-256 eb94ef2b….

Relay proof: exit 0.
- A fresh relayed handshake on both peers came 59.7 ms after the second end relayed, and 9.0 ms after its link activated. Before this fix it never completed inside 5 s.
- A 32 MiB relayed stream arrived byte-exact (unlinked=0, too_large=0), and so did a 32 MiB direct stream to C. C stayed direct before and after B moved to its shim.
- Relay 1 was killed while a 64 MiB stream was held at 1 MiB. Both ends moved to relay 2 3.0 s after the kill, and the stream arrived byte-exact; its largest gap was 3.65 s.
- With no relay, ping loss was 100%. After relay 1 restarted, links returned in 425 ms and ping loss went to 0%.
- Rebind to the second uplink: a 16 MiB stream arrived byte-exact, and the old mapping was retired.
- Host state diff: empty.
Direct namespace proof: exit 0.
GotaTun restore suite: 2/2 passed.
Mesh unit tests: 85 passed, 0 failed.
The debug-build throughputs (13.1 Mbit/s relayed, 85.7 Mbit/s direct) are not performance evidence.

Findings and corrections

My first P1 RED/GREEN run did not reach the assertion. The namespace tests spawn nft by name, but the Nix dev shell's PATH lacks /usr/sbin, where nft lives on compute01. Their cleanup also failed, which left tables behind and polluted the rest of that file's run. Production code uses /usr/sbin/nft, so this affects only the test environment.
Next run, queued on compute01:
- P1 RED at 26c66f0c4 and GREEN at 8ac8aa69a, with /usr/sbin on PATH.
- Every ignored namespace test that exercises restore, down, retire or the filter (15 test files), at RED and at HEAD, with both the default GotaTun engine and INFRATERNAL_MESH_ENGINE=kernel.
- Clippy at HEAD.
- A failure at HEAD that passes at RED with the same engine is a regression. Some #235 retire tests were written for kernel interfaces that persist after the process exits, and the GotaTun default may break them. This run separates that from my change.
Release static infraternal and coordinator_fixture builds of 57a344905 are compiling now for the R4b run. The hold will compare kernel, integrated, fork CLI (4717588), integrated and kernel, in that order. The integrated and kernel cases use the same binary; only INFRATERNAL_MESH_ENGINE differs. After those come 1,000-peer idle RSS cases for both engines, compiled by the production coordinator with 999 inert members. It will queue behind J88c's perf lock.

## J103c progress (2026-11-03, 16:25 IST): relay handshake fixed, namespace proofs pass Branch `mesh-gotatun-linux`, head `5a0446a81`. Since the takeover comment I pushed: - `8ac8aa69a` **mesh: never adopt or remove another live node's filter.** This is the P1 owner fence. - Restore adopts the shared filter only when no GotaTun link is live. - A node that holds no live link of its own removes the filter only while no mesh link is live at all. That covers restore's disabled cleanup and `down` after a failed `up` that had adopted the table. - An unmarked interface with the shared name counts as live. - Kernel links keep dev's adoption: their key can change under rotation. - `57a344905` **mesh: keep the GotaTun worker free while a relay handshake waits.** - The device is now a plain `Arc` with no extra lock, and `force_handshake` runs as a task bounded to 5 s. - Endpoints stay deferred until a relay link is active. An established session gets an endpoint-only update; an unestablished peer becomes an endpoint-less responder; the lower host id initiates. - The unused `Node::set_endpoint` and its worker command are gone. - `5a0446a81` fixes three inherited clippy findings (let-else, two doc code marks) and one in the test helper. ### Namespace proofs (compute01, debug build, label "build host, x86_64, not perf evidence") Run at `57a344905`; evidence is in `~/.cache/codex-scratch/J103/evidence/j103c-ns-2.log`. The proof JSON is `j103c-relay-proof-57a344905.json`, SHA-256 `eb94ef2b…`. - **Relay proof: exit 0.** - A fresh relayed handshake on *both* peers came 59.7 ms after the second end relayed, and 9.0 ms after its link activated. Before this fix it never completed inside 5 s. - A 32 MiB relayed stream arrived byte-exact (`unlinked=0`, `too_large=0`), and so did a 32 MiB direct stream to C. C stayed direct before and after B moved to its shim. - Relay 1 was killed while a 64 MiB stream was held at 1 MiB. Both ends moved to relay 2 3.0 s after the kill, and the stream arrived byte-exact; its largest gap was 3.65 s. - With no relay, ping loss was 100%. After relay 1 restarted, links returned in 425 ms and ping loss went to 0%. - Rebind to the second uplink: a 16 MiB stream arrived byte-exact, and the old mapping was retired. - Host state diff: empty. - **Direct namespace proof:** exit 0. - **GotaTun restore suite:** 2/2 passed. - **Mesh unit tests:** 85 passed, 0 failed. - The debug-build throughputs (13.1 Mbit/s relayed, 85.7 Mbit/s direct) are not performance evidence. ### Findings and corrections - My first P1 RED/GREEN run did not reach the assertion. The namespace tests spawn `nft` by name, but the Nix dev shell's PATH lacks `/usr/sbin`, where `nft` lives on compute01. Their cleanup also failed, which left tables behind and polluted the rest of that file's run. Production code uses `/usr/sbin/nft`, so this affects only the test environment. - Next run, queued on compute01: - P1 RED at `26c66f0c4` and GREEN at `8ac8aa69a`, with `/usr/sbin` on PATH. - Every ignored namespace test that exercises restore, down, retire or the filter (15 test files), at RED and at HEAD, with both the default GotaTun engine and `INFRATERNAL_MESH_ENGINE=kernel`. - Clippy at HEAD. - A failure at HEAD that passes at RED with the same engine is a regression. Some #235 retire tests were written for kernel interfaces that persist after the process exits, and the GotaTun default may break them. This run separates that from my change. - Release static `infraternal` and `coordinator_fixture` builds of `57a344905` are compiling now for the R4b run. The hold will compare kernel, integrated, fork CLI (`4717588`), integrated and kernel, in that order. The integrated and kernel cases use the same binary; only `INFRATERNAL_MESH_ENGINE` differs. After those come 1,000-peer idle RSS cases for both engines, compiled by the production coordinator with 999 inert members. It will queue behind J88c's perf lock.

kayg commented

2026-11-03 10:48:37 +00:00

Author

Owner

J88c progress: drop site found, forced-buffer candidate, sentry path excluded

Fork: j88-linux-offloads now ends 07fc7bd (revert of direct-TUN receive; tree identical to 4717588) → 73eb9f1 (perf: force UDP socket buffers past rmem_max on Linux, not pin-ready).

Where GotaTun loses loaded probes (diagnostic case, not a perf row)

I ran one mesh-gotatun case on the direct-UDP control binary (7517890c…) under perf-run --root. It took netns counter snapshots before and after each loaded LAN phase. Evidence is in /home/claude/j20/r4b/j88c-drop-diag-20261103/ on the perf VM.

Site	1 flow	8 flows
Receiver (h2h-b) GotaTun UDP socket, `Udp: RcvbufErrors`	+11,770	+31,963
Receiver socket `skmem`	`rb425984`, `d11770`	`rb425984`, `d43733` (cumulative)
Sender (h2h-a) `wgA` `fq` qdisc drops	+1,780	0
Receiver `wgB` TUN tx dropped	0	+343
Sender TCP `TCPSackRecovery`	+1,044	+4,382

gotatun-cli asks for 7 MiB, but SO_RCVBUF is clamped to rmem_max (212,992 B, which the kernel doubles to 425,984), so the receiving socket overflows. The run itself was clean for the LAN phases and the machine diff was empty. My wrapper then stopped the case at the WAN profile ([[ … ]] && … returned 1 under set -e). That is a harness slip, not an engine failure; the full matrix below uses a fixed overlay.

Bounded cut: `73eb9f1`

On Linux, try SO_RCVBUFFORCE/SO_SNDBUFFORCE first, which the TUN owner's CAP_NET_ADMIN permits, and fall back to the clamped call otherwise. Tests were written first. RED: they did not compile without the helper. GREEN on compute01 through build-slot: fmt ok, all-features/all-targets clippy ok (only the existing needless_return allowed), focused tests 3 passed, full library suite 135 passed, 0 failed, 7 ignored, release CLI built (SHA-256 a1bc7eb7…, from a tree verified identical to 73eb9f1).

Machine-diff exclusion: `/root/.cache/nix/sentry` (proved unrelated)

The first counterbalanced hold for 73eb9f1 stopped at candidate-second (exit 3) on the same rotation J88 hit. I am excluding that one path, for these reasons:

The same 8-line change (one <uuid>.run dir and its 3 files removed, a new one added) has now stopped holds on four different binaries: route-cut 823133f (control2-first, 2026-11-03), direct-TUN 7264486, forced buffers 73eb9f1, and the mixed case on 2026-11-02. Each of those diffs contains nothing else.
The path is session state of root's Nix crash reporter. crashpad_handler (PID 944) has run since boot on 2026-10-31 05:42, started with determinate-nixd (PID 733) and nix-daemon (PID 841). It rotates on the daemon's own schedule.
The harness, its cases and the measured binaries never invoke nix (grep of run.sh, cases/, lib/, perf-run). The binaries only use a /nix/store glibc loader, which needs no daemon.

The overlay adds -o -path '/root/.cache/nix/sentry' to lib/snapshot.sh's prune list in the disposable kit copy only. Its diff is stored as runner-overlays/lib-snapshot.sh.diff. Every other path is still compared.

Partial hold (provisional: control-last and the peer-scale cases did not run)

Case	Gbit/s 1 / 8	Loaded RTT p50/p99, 1 flow	Loaded RTT p50/p99, 8 flows	Lost probes 1 / 8 (of 2,000)	Receiver `RcvbufErrors` 1 / 8	RSS idle / after load / 1,000 peers (MiB)
Kernel WireGuard	3.08 / 2.83	0.997 / 3.285	2.985 / 4.331	0 / 0	0 / 0	20.1 / 20.1 / 20.1
wireguard-go	4.26 / 3.64	3.704 / 130.179	12.870 / 50.434	0 / 0	0 / 0	29.2 / 964.3 / 1,144.3
control (`4717588`), first	2.62 / 2.36	2.107 / 6.670	4.261 / 11.045	176 / 333	14,270 / 33,651	9.4 / 32.3 / 36.0
forced buffers (`73eb9f1`), first	2.85 / 2.58	3.667 / 10.040	10.421 / 18.608	1 / 39	0 / 0	9.4 / 39.7 / 42.2
forced buffers (`73eb9f1`), second	2.60 / 2.25	3.290 / 8.716	10.293 / 19.228	1 / 2	0 / 0	9.4 / 38.8 / 39.7

Forcing the buffer removes the socket drops and nearly all probe loss. It also turns the drops into a standing queue: received-probe p50 and p99 rise sharply. By the keep rule I set before measuring (loss falls, mean p99 does not rise, no throughput loss), this candidate fails. The complete matrix is now running as one perf-run --root hold in the fresh directory /home/claude/j20/r4b/j88c-bufforce-full-20261103/: kernel, wireguard-go, control/candidate/candidate/control, then no-traffic peer-scale cases (control, candidate, wireguard-go).

Memory metric finding

After the LAN load phase, GotaTun's RSS at one peer is already 32–34 MiB across both endpoints (9.5 MiB when idle before traffic): the packet pool and channel buffers stay allocated. The harness slope is (RSS at 1,000 peers after all traffic − idle RSS at 1 peer before traffic) / 1,998. That charges about 11–12 KiB of retained traffic buffers to each peer. In the rerun, the step from post-load RSS to RSS at 1,000 peers is only 1.3–2.0 KiB/peer, and that is an upper bound because the WAN phases run in between. The no-traffic peer-scale cases in the running hold measure peer state alone.

## J88c progress: drop site found, forced-buffer candidate, sentry path excluded **Fork:** `j88-linux-offloads` now ends `07fc7bd` (revert of direct-TUN receive; tree identical to `4717588`) → `73eb9f1` (`perf: force UDP socket buffers past rmem_max on Linux`, **not pin-ready**). ### Where GotaTun loses loaded probes (diagnostic case, not a perf row) I ran one `mesh-gotatun` case on the direct-UDP control binary (`7517890c…`) under `perf-run --root`. It took netns counter snapshots before and after each loaded LAN phase. Evidence is in `/home/claude/j20/r4b/j88c-drop-diag-20261103/` on the perf VM. | Site | 1 flow | 8 flows | |---|---:|---:| | Receiver (h2h-b) GotaTun UDP socket, `Udp: RcvbufErrors` | **+11,770** | **+31,963** | | Receiver socket `skmem` | `rb425984`, `d11770` | `rb425984`, `d43733` (cumulative) | | Sender (h2h-a) `wgA` `fq` qdisc drops | +1,780 | 0 | | Receiver `wgB` TUN tx dropped | 0 | +343 | | Sender TCP `TCPSackRecovery` | +1,044 | +4,382 | `gotatun-cli` asks for 7 MiB, but `SO_RCVBUF` is clamped to `rmem_max` (212,992 B, which the kernel doubles to 425,984), so the receiving socket overflows. The run itself was clean for the LAN phases and the machine diff was empty. My wrapper then stopped the case at the WAN profile (`[[ … ]] && …` returned 1 under `set -e`). That is a harness slip, not an engine failure; the full matrix below uses a fixed overlay. ### Bounded cut: `73eb9f1` On Linux, try `SO_RCVBUFFORCE`/`SO_SNDBUFFORCE` first, which the TUN owner's `CAP_NET_ADMIN` permits, and fall back to the clamped call otherwise. Tests were written first. RED: they did not compile without the helper. GREEN on compute01 through build-slot: fmt ok, all-features/all-targets clippy ok (only the existing `needless_return` allowed), focused tests 3 passed, full library suite **135 passed, 0 failed, 7 ignored**, release CLI built (SHA-256 `a1bc7eb7…`, from a tree verified identical to `73eb9f1`). ### Machine-diff exclusion: `/root/.cache/nix/sentry` (proved unrelated) The first counterbalanced hold for `73eb9f1` stopped at candidate-second (exit 3) on the same rotation J88 hit. I am excluding that one path, for these reasons: - The same 8-line change (one `<uuid>.run` dir and its 3 files removed, a new one added) has now stopped holds on **four different binaries**: route-cut `823133f` (control2-first, 2026-11-03), direct-TUN `7264486`, forced buffers `73eb9f1`, and the mixed case on 2026-11-02. Each of those diffs contains **nothing else**. - The path is session state of root's Nix crash reporter. `crashpad_handler` (PID 944) has run since boot on 2026-10-31 05:42, started with `determinate-nixd` (PID 733) and `nix-daemon` (PID 841). It rotates on the daemon's own schedule. - The harness, its cases and the measured binaries never invoke nix (grep of `run.sh`, `cases/`, `lib/`, `perf-run`). The binaries only use a `/nix/store` glibc loader, which needs no daemon. The overlay adds `-o -path '/root/.cache/nix/sentry'` to `lib/snapshot.sh`'s prune list in the disposable kit copy only. Its diff is stored as `runner-overlays/lib-snapshot.sh.diff`. Every other path is still compared. ### Partial hold (provisional: control-last and the peer-scale cases did not run) | Case | Gbit/s 1 / 8 | Loaded RTT p50/p99, 1 flow | Loaded RTT p50/p99, 8 flows | Lost probes 1 / 8 (of 2,000) | Receiver `RcvbufErrors` 1 / 8 | RSS idle / after load / 1,000 peers (MiB) | |---|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 3.08 / 2.83 | 0.997 / 3.285 | 2.985 / 4.331 | 0 / 0 | 0 / 0 | 20.1 / 20.1 / 20.1 | | wireguard-go | 4.26 / 3.64 | 3.704 / 130.179 | 12.870 / 50.434 | 0 / 0 | 0 / 0 | 29.2 / 964.3 / 1,144.3 | | control (`4717588`), first | 2.62 / 2.36 | 2.107 / 6.670 | 4.261 / 11.045 | 176 / 333 | 14,270 / 33,651 | 9.4 / 32.3 / 36.0 | | forced buffers (`73eb9f1`), first | 2.85 / 2.58 | 3.667 / 10.040 | 10.421 / 18.608 | 1 / 39 | 0 / 0 | 9.4 / 39.7 / 42.2 | | forced buffers (`73eb9f1`), second | 2.60 / 2.25 | 3.290 / 8.716 | 10.293 / 19.228 | 1 / 2 | 0 / 0 | 9.4 / 38.8 / 39.7 | Forcing the buffer removes the socket drops and nearly all probe loss. It also turns the drops into a standing queue: received-probe p50 and p99 rise sharply. By the keep rule I set before measuring (loss falls, mean p99 does not rise, no throughput loss), this candidate fails. The complete matrix is now running as one `perf-run --root` hold in the fresh directory `/home/claude/j20/r4b/j88c-bufforce-full-20261103/`: kernel, wireguard-go, control/candidate/candidate/control, then **no-traffic** peer-scale cases (control, candidate, wireguard-go). ### Memory metric finding After the LAN load phase, GotaTun's RSS at **one** peer is already 32–34 MiB across both endpoints (9.5 MiB when idle before traffic): the packet pool and channel buffers stay allocated. The harness slope is (RSS at 1,000 peers after all traffic − idle RSS at 1 peer before traffic) / 1,998. That charges about 11–12 KiB of retained traffic buffers to each peer. In the rerun, the step from post-load RSS to RSS at 1,000 peers is only 1.3–2.0 KiB/peer, and that is an upper bound because the WAN phases run in between. The no-traffic peer-scale cases in the running hold measure peer state alone.

kayg commented

2026-11-03 11:24:53 +00:00

Author

Owner

J103c R4b: integrated GotaTun engine vs kernel WireGuard (release build). Finding: the integration halves throughput

One perf-run --root hold on infraternal-perf-01-backup01, 12:02–12:23 CET. Setup: perf.slice CPUs 1–3, 6 GiB, outer exit 0, wall 1,265.6 s, steal 2,657 of 507,887 jiffies. All seven cases exited 0 with an empty machine diff. Harness: the R4b kit h2h-kit-j88-routecut-823133f with J88c's drop-counter overlay. My overlay adds two things: engine labels, and a 1,000-peer step compiled by the production coordinator; the overlay diffs are in the archive.

Binaries:

infraternal, release, static, from 57a344905, SHA-256 be5725f6….
coordinator_fixture, static, SHA-256 9e32e7b2….

The integrated and kernel cases run the same binary; only INFRATERNAL_MESH_ENGINE differs. The fork CLI control is J88's 4717588 build, 7517890c….

The final head differs from 57a344905 only by relay-feature gates, which are not in the shipping build, and by lint fixes and history changes. The shipping data path is identical.

Case (order run)	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	Loaded RTT64 p50/p99, 1 flow (ms)	Loaded RTT64 p50/p99, 8 flows (ms)	Probe loss under load 1 / 8 (of 2,000)	RSS idle, 1 peer (MiB, both nodes)
1. Kernel WireGuard via the agent	3.20 / 2.75	1.04 / 1.18	1.032 / 3.855	3.108 / 55.659	0 / 0	21.5
2. Integrated GotaTun	1.52 / 1.47	1.41 / 1.57	2.069 / 5.591	5.687 / 10.165	119 / 152	23.3
3. Fork CLI `4717588` (standalone engine)	2.75 / 2.24	0.89 / 1.11	1.787 / 4.821	4.946 / 11.053	96 / 276	9.4
4. Integrated GotaTun	1.47 / 1.50	1.45 / 1.45	2.014 / 5.759	5.667 / 9.597	149 / 191	23.3
5. Kernel WireGuard via the agent	2.76 / 2.45	1.17 / 1.31	1.125 / 2.857	3.591 / 6.585	0 / 0	21.5
Kernel mean	2.98 / 2.60	1.11 / 1.25	1.079 / 3.356	3.350 / 6.585 *	0	21.5
Integrated mean	1.50 / 1.49	1.43 / 1.51	2.042 / 5.675	5.677 / 9.881	6.7% / 8.6%	23.3

* The 8-flow kernel p99 is the kernel-last value. Kernel-first's 55.659 ms is a single outlier, and the two runs do not agree.

The 2% loss and reordering probes behave the same on all engines:

2% loss each way (lost of 300, at 64/512/1400 B): kernel 14/11/21 and 16/14/21; integrated 7/13/17 and 14/11/6; fork CLI 10/9/14.
25%/50% reordering: 0 lost in every case.

First packet: about 204 ms for both engines.

Peer state at 1,000 peers. Each endpoint got 999 inert members with no endpoints, compiled by the production coordinator, with no traffic:

Integrated: 23.3 → 30.7 MiB across both agents, about 3.8 KiB per peer in the process. These peers never handshake, so GotaTun's lazy session ring is never allocated; peers with sessions cost more (J88).
Kernel engine: the agent stays at 21.4 MiB. Peer state lives in the kernel, 1.65 KiB per peer in J88's memcg measurement.

Diagnosis (measured, not yet tested by a fix)

The engine is the fork; the loss is in the integration. Engine-process CPU per Gbit is 1.21 s integrated versus 0.79 s for the fork CLI, about 53% more work per byte. The integrated engine also runs at about one core per node (watched_cpu_s 18.8 s over 10.2 s across two nodes), while the CLI uses about 1.1 cores.
Receive side. Our TUN adapter writes every decrypted packet with its own buffer copy, mutex and write() (gotatun_tun.rs send_packet). There is no GRO coalescing into virtio GSO frames. The fork CLI's TUN has GRO on this path (J88's TSO/GRO). J103 could not reuse it because GotaTun's tun feature pulls the WTFPL tun crate. The receiving namespace logged 2,970 UDP RcvbufErrors in the 1-flow loaded phase, and the sender logged none: the receiver's engine cannot drain its socket. This explains the throughput gap and the 7–9% probe loss.
The engine runtime is current_thread; the CLI uses tokio's multi-thread runtime.

Owner decision needed

As built, the Linux default delivers half of kernel throughput (1.5 vs 3.0/2.6 Gbit/s). The D163 amendment records the fork as matching kernel. Recommendation:

Merge with GotaTun as the default only after a follow-up job brings our adapter to parity with the fork CLI. The kernel fallback stays selectable meanwhile.
That job would (1) give TUN writes GRO, batching consecutive decrypted segments into virtio GSO frames, and (2) measure a multi-thread engine runtime. Each change gets its own R4b row against this table.
Alternatively, J88 could move the fork's TSO/GRO TUN code out from behind the WTFPL tun dependency, so our adapter can reuse it under MPL-2.0.

Evidence: j103c-r4b-evidence-20261103.tar.gz (attached; SHA-256 dd2be05b22f36857bb098497c3c7225debec8ac7b7686f380a4afe824f9be537). It holds results, overlays, receipts, run log and binary hashes. On the perf VM it is ~/j20/r4b/j103c-integrated-20261103/.

## J103c R4b: integrated GotaTun engine vs kernel WireGuard (release build). Finding: the integration halves throughput One `perf-run --root` hold on infraternal-perf-01-backup01, 12:02–12:23 CET. Setup: perf.slice CPUs 1–3, 6 GiB, outer exit 0, wall 1,265.6 s, steal 2,657 of 507,887 jiffies. All seven cases exited 0 with an empty machine diff. Harness: the R4b kit `h2h-kit-j88-routecut-823133f` with J88c's drop-counter overlay. My overlay adds two things: engine labels, and a 1,000-peer step compiled by the production coordinator; the overlay diffs are in the archive. Binaries: - `infraternal`, release, static, from `57a344905`, SHA-256 `be5725f6…`. - `coordinator_fixture`, static, SHA-256 `9e32e7b2…`. The integrated and kernel cases run **the same binary**; only `INFRATERNAL_MESH_ENGINE` differs. The fork CLI control is J88's `4717588` build, `7517890c…`. The final head differs from `57a344905` only by relay-feature gates, which are not in the shipping build, and by lint fixes and history changes. The shipping data path is identical. | Case (order run) | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | Loaded RTT64 p50/p99, 1 flow (ms) | Loaded RTT64 p50/p99, 8 flows (ms) | Probe loss under load 1 / 8 (of 2,000) | RSS idle, 1 peer (MiB, both nodes) | |---|---:|---:|---:|---:|---:|---:| | 1. Kernel WireGuard via the agent | 3.20 / 2.75 | 1.04 / 1.18 | 1.032 / 3.855 | 3.108 / 55.659 | 0 / 0 | 21.5 | | 2. **Integrated GotaTun** | **1.52 / 1.47** | 1.41 / 1.57 | 2.069 / 5.591 | 5.687 / 10.165 | 119 / 152 | 23.3 | | 3. Fork CLI `4717588` (standalone engine) | 2.75 / 2.24 | 0.89 / 1.11 | 1.787 / 4.821 | 4.946 / 11.053 | 96 / 276 | 9.4 | | 4. **Integrated GotaTun** | **1.47 / 1.50** | 1.45 / 1.45 | 2.014 / 5.759 | 5.667 / 9.597 | 149 / 191 | 23.3 | | 5. Kernel WireGuard via the agent | 2.76 / 2.45 | 1.17 / 1.31 | 1.125 / 2.857 | 3.591 / 6.585 | 0 / 0 | 21.5 | | **Kernel mean** | 2.98 / 2.60 | 1.11 / 1.25 | 1.079 / 3.356 | 3.350 / 6.585 * | 0 | 21.5 | | **Integrated mean** | **1.50 / 1.49** | 1.43 / 1.51 | 2.042 / 5.675 | 5.677 / 9.881 | 6.7% / 8.6% | 23.3 | \* The 8-flow kernel p99 is the kernel-last value. Kernel-first's 55.659 ms is a single outlier, and the two runs do not agree. The 2% loss and reordering probes behave the same on all engines: - 2% loss each way (lost of 300, at 64/512/1400 B): kernel 14/11/21 and 16/14/21; integrated 7/13/17 and 14/11/6; fork CLI 10/9/14. - 25%/50% reordering: 0 lost in every case. First packet: about 204 ms for both engines. **Peer state at 1,000 peers.** Each endpoint got 999 inert members with no endpoints, compiled by the production coordinator, with no traffic: - Integrated: 23.3 → 30.7 MiB across both agents, about **3.8 KiB per peer** in the process. These peers never handshake, so GotaTun's lazy session ring is never allocated; peers with sessions cost more (J88). - Kernel engine: the agent stays at 21.4 MiB. Peer state lives in the kernel, 1.65 KiB per peer in J88's memcg measurement. ### Diagnosis (measured, not yet tested by a fix) - **The engine is the fork; the loss is in the integration.** Engine-process CPU per Gbit is 1.21 s integrated versus 0.79 s for the fork CLI, about 53% more work per byte. The integrated engine also runs at about one core per node (`watched_cpu_s` 18.8 s over 10.2 s across two nodes), while the CLI uses about 1.1 cores. - **Receive side.** Our TUN adapter writes every decrypted packet with its own buffer copy, mutex and `write()` (`gotatun_tun.rs` `send_packet`). There is no GRO coalescing into virtio GSO frames. The fork CLI's TUN has GRO on this path (J88's TSO/GRO). J103 could not reuse it because GotaTun's `tun` feature pulls the WTFPL `tun` crate. The receiving namespace logged **2,970 UDP `RcvbufErrors`** in the 1-flow loaded phase, and the sender logged none: the receiver's engine cannot drain its socket. This explains the throughput gap and the 7–9% probe loss. - The engine runtime is `current_thread`; the CLI uses tokio's multi-thread runtime. ### Owner decision needed As built, the Linux default delivers half of kernel throughput (1.5 vs 3.0/2.6 Gbit/s). The D163 amendment records the fork as matching kernel. **Recommendation:** - Merge with GotaTun as the default only after a follow-up job brings our adapter to parity with the fork CLI. The kernel fallback stays selectable meanwhile. - That job would (1) give TUN writes GRO, batching consecutive decrypted segments into virtio GSO frames, and (2) measure a multi-thread engine runtime. Each change gets its own R4b row against this table. - Alternatively, J88 could move the fork's TSO/GRO TUN code out from behind the WTFPL `tun` dependency, so our adapter can reuse it under MPL-2.0. Evidence: `j103c-r4b-evidence-20261103.tar.gz` (attached; SHA-256 `dd2be05b22f36857bb098497c3c7225debec8ac7b7686f380a4afe824f9be537`). It holds results, overlays, receipts, run log and binary hashes. On the perf VM it is `~/j20/r4b/j103c-integrated-20261103/`.

j103c-r4b-evidence-20261103.tar.gz

1.7 MiB

kayg commented

2026-11-03 11:26:12 +00:00

Author

Owner

J103c: P1 RED/GREEN, and what the mesh namespace suites say under the GotaTun default

Run on compute01. Each test binary ran as root in its own unshare -Urn, with /usr/sbin on PATH; the Nix shell drops it, and the tests call nft by name. Logs: ~/.cache/codex-scratch/J103/evidence/ns2/; summary: j103c-ns2.log.

P1 owner fence. disabled_restore_leaves_another_gotatun_nodes_installed_policy:

RED at 26c66f0c4, without the fence: restoring the disabled old node removed the live node's policy table.
GREEN at 8ac8aa69a, with the fence: 1 passed. In the restructured history this is e7ac223d1, the identical patch.

No regressions from this job's changes. The comparison covers 15 namespace test files that exercise restore, down, retire or the filter. Each ran at RED (26c66f0c4) and at HEAD (5a0446a81, tree-equal to today's head apart from relay-feature gates), with the default engine and with INFRATERNAL_MESH_ENGINE=kernel:

Every failure is the same at RED and HEAD, except that the P1 test turns green.
With the kernel engine, all kernel-era files pass. The GotaTun-only tests fail there, which is expected.

Pre-existing finding (J103's default switch, not run by the gate because all are #[ignore]): under the default GotaTun engine, 15 tests fail. They fall into three groups.

Kernel-only tests that do not select the kernel engine: 11 tests in 6 files.
- Files: policy_snapshot_ordering (4), access_updates (2), restart_route_ownership, review_restart_routes, review_endpoint_transaction, review_route_inventory (2).
- They call kernel WireGuard netlink directly (Device::counters(), Device::peers(), raw genetlink). On a TUN those calls get EOPNOTSUPP (os error 95) during setup. One more failure is a leftover state directory from the test before it.
- All of them pass with INFRATERNAL_MESH_ENGINE=kernel. Their properties are snapshot identity fences, compact deltas, endpoint transactions and route ownership. That code is engine-independent, but nothing runs it against the GotaTun engine.
#235 retire tests that need an interface to outlive its node: 3 tests.
- retire_decides_every_object_and_leaves_a_foreign_table, retire_leaves_another_installations_interface_and_filter and retire_with_a_record_leaves_a_foreign_interface_and_names_it.
- Each brings a node up and drops it. A GotaTun TUN closes with its process, so the link is already gone before the step that checks or deletes it (planning changed the kernel, ip link delete infraternal0).
- The same ownership property for GotaTun passes in retire_does_not_remove_another_installations_live_gotatun_tun and the P1 test.
One real behaviour change: review_route_scope::restart_preserves_operator_gateway_host_route.
- The test drops the node and restores it. With GotaTun this closes the TUN, so the interface, its addresses and every route on it go. That includes an operator's static route via infraternal0, which this test checks survives a restart.
- The kernel interface outlived the process (D166 "kernel state and established flows survive control process loss"). The GotaTun TUN is non-persistent by design: J103 comment 75366.
- Owner question: accept that an agent restart drops the mesh interface, operator routes on it and in-flight flows? Or keep the TUN across restarts with TUNSETPERSIST, so routes and addresses survive and traffic pauses until the engine reattaches? The second has its own ownership and cleanup trade-offs.

Recommendation:

Select INFRATERNAL_MESH_ENGINE=kernel explicitly for the kernel-era tests in groups 1 and 2 (their ignore reasons should say so). Add GotaTun equivalents where the property matters.
Group 3 needs the owner's answer.
I have not changed these tests in this job (scope); it is about 1–2 h of follow-up.

## J103c: P1 RED/GREEN, and what the mesh namespace suites say under the GotaTun default Run on compute01. Each test binary ran as root in its own `unshare -Urn`, with `/usr/sbin` on PATH; the Nix shell drops it, and the tests call `nft` by name. Logs: `~/.cache/codex-scratch/J103/evidence/ns2/`; summary: `j103c-ns2.log`. **P1 owner fence.** `disabled_restore_leaves_another_gotatun_nodes_installed_policy`: - RED at `26c66f0c4`, without the fence: `restoring the disabled old node removed the live node's policy table`. - GREEN at `8ac8aa69a`, with the fence: 1 passed. In the restructured history this is `e7ac223d1`, the identical patch. **No regressions from this job's changes.** The comparison covers 15 namespace test files that exercise restore, down, retire or the filter. Each ran at RED (`26c66f0c4`) and at HEAD (`5a0446a81`, tree-equal to today's head apart from relay-feature gates), with the default engine and with `INFRATERNAL_MESH_ENGINE=kernel`: - Every failure is the same at RED and HEAD, except that the P1 test turns green. - With the kernel engine, all kernel-era files pass. The GotaTun-only tests fail there, which is expected. **Pre-existing finding (J103's default switch, not run by the gate because all are `#[ignore]`):** under the default GotaTun engine, 15 tests fail. They fall into three groups. 1. **Kernel-only tests that do not select the kernel engine: 11 tests in 6 files.** - Files: `policy_snapshot_ordering` (4), `access_updates` (2), `restart_route_ownership`, `review_restart_routes`, `review_endpoint_transaction`, `review_route_inventory` (2). - They call kernel WireGuard netlink directly (`Device::counters()`, `Device::peers()`, raw genetlink). On a TUN those calls get `EOPNOTSUPP` (os error 95) during setup. One more failure is a leftover state directory from the test before it. - All of them pass with `INFRATERNAL_MESH_ENGINE=kernel`. Their properties are snapshot identity fences, compact deltas, endpoint transactions and route ownership. That code is engine-independent, but nothing runs it against the GotaTun engine. 2. **#235 retire tests that need an interface to outlive its node: 3 tests.** - `retire_decides_every_object_and_leaves_a_foreign_table`, `retire_leaves_another_installations_interface_and_filter` and `retire_with_a_record_leaves_a_foreign_interface_and_names_it`. - Each brings a node up and drops it. A GotaTun TUN closes with its process, so the link is already gone before the step that checks or deletes it (`planning changed the kernel`, `ip link delete infraternal0`). - The same ownership property for GotaTun passes in `retire_does_not_remove_another_installations_live_gotatun_tun` and the P1 test. 3. **One real behaviour change: `review_route_scope::restart_preserves_operator_gateway_host_route`.** - The test drops the node and restores it. With GotaTun this closes the TUN, so the interface, its addresses and every route on it go. That includes an operator's static route via `infraternal0`, which this test checks survives a restart. - The kernel interface outlived the process (D166 "kernel state and established flows survive control process loss"). The GotaTun TUN is non-persistent by design: J103 comment 75366. - **Owner question:** accept that an agent restart drops the mesh interface, operator routes on it and in-flight flows? Or keep the TUN across restarts with `TUNSETPERSIST`, so routes and addresses survive and traffic pauses until the engine reattaches? The second has its own ownership and cleanup trade-offs. **Recommendation:** - Select `INFRATERNAL_MESH_ENGINE=kernel` explicitly for the kernel-era tests in groups 1 and 2 (their ignore reasons should say so). Add GotaTun equivalents where the property matters. - Group 3 needs the owner's answer. - I have not changed these tests in this job (scope); it is about 1–2 h of follow-up.

kayg commented

2026-11-03 11:49:50 +00:00

Author

Owner

J88c finish: clean full matrix, forced-buffer trade-off, memory target met on a fair metric

Fork kaygdotorg/gotatun j88-linux-offloads, head 73eb9f1ae185313609d031c644cb4a81f3c927dc:

07fc7bd revert: restore buffered Linux TUN receive. Tree identical to 4717588. Last pin-ready state; J103 already pins 4717588.
73eb9f1 perf: force UDP socket buffers past rmem_max on Linux. Fork tests green. Not pin-ready: fails the keep rule set before measuring. Owner decision below.

No upstream PR, issue or comment. No infraternal code changed, so scripts/verify fast does not apply.

Hold

/home/claude/j20/r4b/j88c-bufforce-full2-20261103/ on the perf VM: one perf-run --root hold (12:23–12:47 CET, 1,442 s, steal 1,018/576,665 jiffies), outer exit 0, all 9 cases exit 0, every machine diff 0 bytes. The diff pruned only /root/.cache/nix/sentry (proof in comment 76773); no rotation happened in this hold. Two earlier attempts are kept, not used: one stopped on the sentry rotation, and one stopped when another job (J103c) created /tmp/j103c-dry.AFdg mid-case. The runner now records a failed case and continues, so the order is never lost. Binaries: control 7517890c… (4717588), candidate a1bc7eb7… (73eb9f1).

LAN loaded RTT uses 64 B probes at 1 ms during the TCP transfer, 2,000 per phase. p50/p99 cover received probes only. Receiver drops come from netns counter snapshots around each loaded phase.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	Loaded RTT p50/p99, 1 flow (ms)	Loaded RTT p50/p99, 8 flows (ms)	Lost probes 1 / 8	Receiver `RcvbufErrors` 1 / 8	Socket `rb`
Kernel WireGuard	2.84 / 2.64	1.16 / 1.24	1.084 / 2.563	3.119 / 4.288	0 / 0	0 / 0	n/a
wireguard-go	4.93 / 4.92	0.50 / 0.56	2.577 / 38.897	8.354 / 16.004	0 / 0	0 / 0	14,680,064
control, first	2.79 / 2.43	0.85 / 1.02	1.955 / 5.658	4.752 / 11.912	140 / 317	13,398 / 34,371	425,984
forced buffers, first	2.93 / 2.70	0.82 / 0.95	2.443 / 5.866	9.547 / 16.108	0 / 9	0 / 0	14,680,064
forced buffers, second	3.09 / 2.70	0.79 / 0.95	2.293 / 5.815	9.231 / 15.025	0 / 12	0 / 0	14,680,064
control, last	2.90 / 2.62	0.84 / 1.00	1.931 / 4.698	5.769 / 10.936	93 / 266	12,157 / 32,821	425,984
control mean	2.84 / 2.53	0.85 / 1.01	1.943 / 5.178	5.261 / 11.424	5.8% / 14.6%
forced mean	3.01 / 2.70	0.80 / 0.95	2.368 / 5.841	9.389 / 15.567	0% / 0.5%

Correctness at 198 ms RTT, 300 probes per size (lost at 64/512/1400 B). Under 2% independent loss per direction: kernel 15/14/22, wireguard-go 19/6/20, control 11/9/12 and 22/7/11, forced 10/12/9 and 13/14/13. Under 25%/50% reordering, every GotaTun case lost 0/0/0. The sender TUN fq qdisc drops (control 1,860 and 1,689 at 1 flow) are also 0 for the candidate.

Forced buffers against the control mean: throughput +5.9% / +6.8%, CPU/Gbit −5% / −6%, probe loss 5.8% → 0% at 1 flow and 14.6% → 0.5% at 8 flows. But received-probe p99 is +12.8% (1 flow) and +36.3% (8 flows), and 8-flow p50 nearly doubles. The bigger socket buffer turns drops into a standing queue. The keep rule I set before measuring (comment 76745: loss falls, mean p99 does not rise, no throughput loss) rejects it, so it is not pin-ready.

Memory: ≤5 KB/peer is met on a fair metric

The no-traffic peer-scale cases measure idle RSS at 1 peer, then add 999 peers per endpoint (one /32 each, no endpoint, the same shape as the kernel reference). There is no traffic in between.

Engine	RSS 1 → 1,000 peers, both endpoints (MiB)	Per added peer
Kernel WireGuard (in-kernel `wg_peer` + allowedips slab, J88 2026-11-02)	n/a	1.65 KiB
GotaTun control (`4717588`)	9.5 → 13.7	2.17 KiB
GotaTun forced buffers (`73eb9f1`)	9.25 → 13.4	2.15 KiB
wireguard-go	27.2 → 95.9	35.2 KiB

The ~13 KiB/peer reported before came from the harness slope: RSS at 1,000 peers after all traffic, minus idle RSS at 1 peer before traffic. In this hold, GotaTun's 1-peer RSS rises from 9.4 to 31.8–32.4 MiB over the LAN load alone, because the packet pool and channel buffers stay allocated. With forced buffers it reaches 36.2–37.5 MiB. That is a fixed cost of about 11–14 MiB per endpoint after load, and it is the real remaining memory gap to kernel WireGuard. The owner's two named leads, the lazy session ring (77109e5) and dropping the per-peer trie (823133f), were already done. No further per-peer cut is needed for the target.

Fork gate for `73eb9f1` (compute01, through build-slot, from a tree verified identical to the commit)

build-slot: [11:23:05] got slot 4/4
== HEAD 07fc7bd09ca2a229c26e0f62454e282da2233566 dirty=4
== fmt
== clippy
== focused
test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 139 filtered out; finished in 0.00s
== full lib suite
test result: ok. 135 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 9.12s
== release cli
a1bc7eb702989d3ec8b9e2a033f5e0a56863f36524ef33c1eb8fd754a93a297f  target/release/gotatun
J88C_CHECK_EXIT=0

Clippy ran with --all-features --all-targets -D warnings, allowing only the existing needless_return. RED evidence: the new tests failed to compile before the helper existed (j88c-red.log). 07fc7bd's tree equals 4717588, whose suite passed 131/0/7 (comment 76440).

Owner decisions needed

How should lost probes count in loaded tails? Today p99 ignores them, so the control's 5.8% / 14.6% loss looks better than the forced buffer's 0% / 0.5% at a higher p99. For interactive TCP (SSH), a lost segment costs a retransmit, which is far worse than a few ms of queueing. Recommendation: count lost probes as tail events (loss-aware p99), and pin 73eb9f1. On that metric it wins: the control's loss-aware p99 is unbounded in both phases, and the candidate is bounded while also gaining 6–7% throughput. If you keep the received-only rule, revert 73eb9f1 (one revert commit).
Next memory step, fixed post-load buffers (~11–14 MiB per endpoint): shrink or release the 4,000-buffer packet pool when idle. Not started; it is outside the per-peer target.

Still open from the original list: GotaTun loaded p99 is ~2× kernel's (5.2–5.8 vs 2.6 ms at 1 flow). In this hold forced-buffer GotaTun (3.01 / 2.70 Gbit/s) is at or above kernel (2.84 / 2.64), but kernel ranged 2.56–3.23 Gbit/s at 1 flow across today's holds, so meeting the "≥ kernel" target needs repeats. Both are well below wireguard-go (4.9). The remaining drop sites are the sender TUN fq qdisc and the receiver TUN tx ring. The deeper limit is single-task receive processing.

License note, unchanged: LICENSE and Cargo say MPL-2.0, flake.nix says BSD-3-Clause. Not changed.

Cleanup: J88 target dirs on compute01 and dev-02 removed. No J88 process is running on any VM; perf-VM temp scripts removed.

Evidence: j88c-evidence-20261103.tar.gz (attached), SHA-256 d6bee69b8e5b0b49091c4b7600072a4abba6d88c5e633b6a974af58de36d7507. It holds the drop diagnostic, all three forced-buffer holds (raw JSON, logs, netns counters, machine diffs, receipts, overlays), the direct-TUN rerun, the runner/analyzer scripts and summaries. The binaries are kept on the perf VM under /home/claude/j20/r4b/.

## J88c finish: clean full matrix, forced-buffer trade-off, memory target met on a fair metric **Fork** `kaygdotorg/gotatun` `j88-linux-offloads`, **head `73eb9f1ae185313609d031c644cb4a81f3c927dc`**: - `07fc7bd` revert: restore buffered Linux TUN receive. Tree identical to `4717588`. **Last pin-ready state; J103 already pins `4717588`.** - `73eb9f1` perf: force UDP socket buffers past rmem_max on Linux. Fork tests green. **Not pin-ready: fails the keep rule set before measuring. Owner decision below.** No upstream PR, issue or comment. No infraternal code changed, so `scripts/verify fast` does not apply. ### Hold `/home/claude/j20/r4b/j88c-bufforce-full2-20261103/` on the perf VM: one `perf-run --root` hold (12:23–12:47 CET, 1,442 s, steal 1,018/576,665 jiffies), **outer exit 0, all 9 cases exit 0, every machine diff 0 bytes**. The diff pruned only `/root/.cache/nix/sentry` (proof in comment 76773); no rotation happened in this hold. Two earlier attempts are kept, not used: one stopped on the sentry rotation, and one stopped when another job (J103c) created `/tmp/j103c-dry.AFdg` mid-case. The runner now records a failed case and continues, so the order is never lost. Binaries: control `7517890c…` (`4717588`), candidate `a1bc7eb7…` (`73eb9f1`). LAN loaded RTT uses 64 B probes at 1 ms during the TCP transfer, 2,000 per phase. **p50/p99 cover received probes only.** Receiver drops come from netns counter snapshots around each loaded phase. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | Loaded RTT p50/p99, 1 flow (ms) | Loaded RTT p50/p99, 8 flows (ms) | Lost probes 1 / 8 | Receiver `RcvbufErrors` 1 / 8 | Socket `rb` | |---|---:|---:|---:|---:|---:|---:|---:| | Kernel WireGuard | 2.84 / 2.64 | 1.16 / 1.24 | 1.084 / 2.563 | 3.119 / 4.288 | 0 / 0 | 0 / 0 | n/a | | wireguard-go | 4.93 / 4.92 | 0.50 / 0.56 | 2.577 / 38.897 | 8.354 / 16.004 | 0 / 0 | 0 / 0 | 14,680,064 | | control, first | 2.79 / 2.43 | 0.85 / 1.02 | 1.955 / 5.658 | 4.752 / 11.912 | 140 / 317 | 13,398 / 34,371 | 425,984 | | forced buffers, first | 2.93 / 2.70 | 0.82 / 0.95 | 2.443 / 5.866 | 9.547 / 16.108 | 0 / 9 | 0 / 0 | 14,680,064 | | forced buffers, second | 3.09 / 2.70 | 0.79 / 0.95 | 2.293 / 5.815 | 9.231 / 15.025 | 0 / 12 | 0 / 0 | 14,680,064 | | control, last | 2.90 / 2.62 | 0.84 / 1.00 | 1.931 / 4.698 | 5.769 / 10.936 | 93 / 266 | 12,157 / 32,821 | 425,984 | | **control mean** | **2.84 / 2.53** | 0.85 / 1.01 | 1.943 / **5.178** | 5.261 / **11.424** | **5.8% / 14.6%** | | | | **forced mean** | **3.01 / 2.70** | 0.80 / 0.95 | 2.368 / **5.841** | 9.389 / **15.567** | **0% / 0.5%** | | | Correctness at 198 ms RTT, 300 probes per size (lost at 64/512/1400 B). Under 2% independent loss per direction: kernel 15/14/22, wireguard-go 19/6/20, control 11/9/12 and 22/7/11, forced 10/12/9 and 13/14/13. Under 25%/50% reordering, every GotaTun case lost 0/0/0. The sender TUN `fq` qdisc drops (control 1,860 and 1,689 at 1 flow) are also 0 for the candidate. **Forced buffers against the control mean:** throughput +5.9% / +6.8%, CPU/Gbit −5% / −6%, probe loss 5.8% → 0% at 1 flow and 14.6% → 0.5% at 8 flows. **But received-probe p99 is +12.8% (1 flow) and +36.3% (8 flows), and 8-flow p50 nearly doubles.** The bigger socket buffer turns drops into a standing queue. The keep rule I set before measuring (comment 76745: loss falls, mean p99 does not rise, no throughput loss) **rejects it**, so it is not pin-ready. ### Memory: ≤5 KB/peer is met on a fair metric The no-traffic peer-scale cases measure idle RSS at 1 peer, then add 999 peers per endpoint (one `/32` each, no endpoint, the same shape as the kernel reference). There is no traffic in between. | Engine | RSS 1 → 1,000 peers, both endpoints (MiB) | Per added peer | |---|---:|---:| | Kernel WireGuard (in-kernel `wg_peer` + allowedips slab, J88 2026-11-02) | n/a | **1.65 KiB** | | GotaTun control (`4717588`) | 9.5 → 13.7 | **2.17 KiB** | | GotaTun forced buffers (`73eb9f1`) | 9.25 → 13.4 | 2.15 KiB | | wireguard-go | 27.2 → 95.9 | 35.2 KiB | The ~13 KiB/peer reported before came from the harness slope: RSS at 1,000 peers *after all traffic*, minus idle RSS at 1 peer *before* traffic. In this hold, GotaTun's 1-peer RSS rises from 9.4 to 31.8–32.4 MiB over the LAN load alone, because the packet pool and channel buffers stay allocated. With forced buffers it reaches 36.2–37.5 MiB. That is a **fixed** cost of about 11–14 MiB per endpoint after load, and it is the real remaining memory gap to kernel WireGuard. The owner's two named leads, the lazy session ring (`77109e5`) and dropping the per-peer trie (`823133f`), were already done. No further per-peer cut is needed for the target. ### Fork gate for `73eb9f1` (compute01, through build-slot, from a tree verified identical to the commit) ```text build-slot: [11:23:05] got slot 4/4 == HEAD 07fc7bd09ca2a229c26e0f62454e282da2233566 dirty=4 == fmt == clippy == focused test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 139 filtered out; finished in 0.00s == full lib suite test result: ok. 135 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 9.12s == release cli a1bc7eb702989d3ec8b9e2a033f5e0a56863f36524ef33c1eb8fd754a93a297f target/release/gotatun J88C_CHECK_EXIT=0 ``` Clippy ran with `--all-features --all-targets -D warnings`, allowing only the existing `needless_return`. RED evidence: the new tests failed to compile before the helper existed (`j88c-red.log`). `07fc7bd`'s tree equals `4717588`, whose suite passed 131/0/7 (comment 76440). ### Owner decisions needed 1. **How should lost probes count in loaded tails?** Today p99 ignores them, so the control's 5.8% / 14.6% loss looks better than the forced buffer's 0% / 0.5% at a higher p99. For interactive TCP (SSH), a lost segment costs a retransmit, which is far worse than a few ms of queueing. **Recommendation:** count lost probes as tail events (loss-aware p99), and pin `73eb9f1`. On that metric it wins: the control's loss-aware p99 is unbounded in both phases, and the candidate is bounded while also gaining 6–7% throughput. If you keep the received-only rule, revert `73eb9f1` (one revert commit). 2. **Next memory step, fixed post-load buffers (~11–14 MiB per endpoint):** shrink or release the 4,000-buffer packet pool when idle. Not started; it is outside the per-peer target. Still open from the original list: GotaTun loaded p99 is ~2× kernel's (5.2–5.8 vs 2.6 ms at 1 flow). In this hold forced-buffer GotaTun (3.01 / 2.70 Gbit/s) is at or above kernel (2.84 / 2.64), but kernel ranged 2.56–3.23 Gbit/s at 1 flow across today's holds, so meeting the "≥ kernel" target needs repeats. Both are well below wireguard-go (4.9). The remaining drop sites are the sender TUN `fq` qdisc and the receiver TUN tx ring. The deeper limit is single-task receive processing. License note, unchanged: `LICENSE` and Cargo say MPL-2.0, `flake.nix` says BSD-3-Clause. Not changed. Cleanup: J88 target dirs on compute01 and dev-02 removed. No J88 process is running on any VM; perf-VM temp scripts removed. Evidence: `j88c-evidence-20261103.tar.gz` (attached), SHA-256 `d6bee69b8e5b0b49091c4b7600072a4abba6d88c5e633b6a974af58de36d7507`. It holds the drop diagnostic, all three forced-buffer holds (raw JSON, logs, netns counters, machine diffs, receipts, overlays), the direct-TUN rerun, the runner/analyzer scripts and summaries. The binaries are kept on the perf VM under `/home/claude/j20/r4b/`.

j88c-evidence-20261103.tar.gz

9.5 MiB

kayg commented

2026-11-03 12:00:54 +00:00

Author

Owner

J88d start and plan (2026-11-03)

J88d continues J88/J88c. Fork kaygdotorg/gotatun, branch j88-linux-offloads, base 73eb9f1ae185313609d031c644cb4a81f3c927dc (the pin under D331). No upstream PRs, issues or comments. No infraternal code changes: J103c owns the integration and the pin. Read: J88/J88c comments through 76819, D163, D169, D331.

Per D331, loaded latency counts lost probes: every loaded row reports a loss-aware p99, where a lost probe counts as an infinite RTT, next to the received-only p99 and the loss count.

Steps and estimates (excluding build-slot and perf-lock waits)

Idle memory (about 3.5 h). Find what holds the 11–14 MiB per endpoint after load: the packet pool, channel buffers, socket-side queues and allocator retention. Write a test first, then release the pool and buffers after a bounded idle period and return the memory to the OS. Measure in one perf-run --root hold against 73eb9f1 (control/cand/cand/control, with kernel WireGuard as reference): RSS at idle, after load, and after load plus the idle period. Also measure first-RTT after idle, p50/p99 over repeated idle→probe cycles, against the control. Keep it only if after-idle RSS falls, first-RTT p99 shows no visible regression, and loaded throughput and p99 do not move.
Loaded p99 (about 2.5 h). Profile where queueing sits with the 14 MiB buffer (socket queue depth, TUN tx ring and channel occupancy over time). Pick ONE bounded cut, then measure it in the same hold against the control. Keep rule, set now: the loss-aware p99 at 1 flow improves, 8 flows does not get worse, and throughput does not fall.
Linux soak (about 2 h, including at least 1 h of run time). Perf VM, one perf-run --root hold: a TCP bulk flow, 64 B interactive probes, 1,000 peers, and a set of peers that flap through remove/re-add and handshake. Sample loss, reordering, RSS over time and handshake failures each minute.
macOS (about 2.5 h). lume@infraternal-macos-01-std, under the /tmp/mac-bench.lock flock, released after each run. Build the fork CLI and run correctness tests: a byte-exact transfer (SHA-256), handshake, and a rekey after forced session expiry. Then measure latency, throughput and RSS against wireguard-go on macOS. These are not perf-host numbers. I won't touch lume's keychain or TCC.

Total about 10.5 h. I stop and report if I reach 2× that. Each candidate keeps the fork gate green: fmt, clippy -D warnings, the full library suite and the release CLI. I'll post a table per step and a consolidated table at the end.

## J88d start and plan (2026-11-03) J88d continues J88/J88c. Fork `kaygdotorg/gotatun`, branch `j88-linux-offloads`, **base `73eb9f1ae185313609d031c644cb4a81f3c927dc`** (the pin under D331). No upstream PRs, issues or comments. No infraternal code changes: J103c owns the integration and the pin. Read: J88/J88c comments through 76819, D163, D169, D331. Per D331, **loaded latency counts lost probes**: every loaded row reports a loss-aware p99, where a lost probe counts as an infinite RTT, next to the received-only p99 and the loss count. ### Steps and estimates (excluding build-slot and perf-lock waits) 1. **Idle memory (about 3.5 h).** Find what holds the 11–14 MiB per endpoint after load: the packet pool, channel buffers, socket-side queues and allocator retention. Write a test first, then release the pool and buffers after a bounded idle period and return the memory to the OS. Measure in one `perf-run --root` hold against `73eb9f1` (control/cand/cand/control, with kernel WireGuard as reference): RSS at idle, after load, and after load plus the idle period. Also measure **first-RTT after idle**, p50/p99 over repeated idle→probe cycles, against the control. Keep it only if after-idle RSS falls, first-RTT p99 shows no visible regression, and loaded throughput and p99 do not move. 2. **Loaded p99 (about 2.5 h).** Profile where queueing sits with the 14 MiB buffer (socket queue depth, TUN tx ring and channel occupancy over time). Pick ONE bounded cut, then measure it in the same hold against the control. Keep rule, set now: the loss-aware p99 at 1 flow improves, 8 flows does not get worse, and throughput does not fall. 3. **Linux soak (about 2 h, including at least 1 h of run time).** Perf VM, one `perf-run --root` hold: a TCP bulk flow, 64 B interactive probes, 1,000 peers, and a set of peers that flap through remove/re-add and handshake. Sample loss, reordering, RSS over time and handshake failures each minute. 4. **macOS (about 2.5 h).** `lume@infraternal-macos-01-std`, under the `/tmp/mac-bench.lock` flock, released after each run. Build the fork CLI and run correctness tests: a byte-exact transfer (SHA-256), handshake, and a rekey after forced session expiry. Then measure latency, throughput and RSS against wireguard-go on macOS. These are **not perf-host numbers**. I won't touch lume's keychain or TCC. Total about 10.5 h. I stop and report if I reach 2× that. Each candidate keeps the fork gate green: fmt, clippy `-D warnings`, the full library suite and the release CLI. I'll post a table per step and a consolidated table at the end.

kayg commented

2026-11-03 12:15:27 +00:00

Author

Owner

J88d finding: where the post-load memory sits (diagnostic, not a perf row)

One mesh-gotatun case on the pin 73eb9f1 (binary a1bc7eb7…) under perf-run --root: exit 0, 164 s, empty machine diff. It took /proc/<pid>/smaps snapshots before load, right after the R4b LAN profile (1 and 8 flows), and after 30 s and 120 s idle. Evidence: /home/claude/j20/r4b/j88d-memdiag-73eb9f1-20261103/ on the perf VM.

Endpoint	Before load	After load	+30 s / +120 s idle	malloc arenas (anon)	UDP GRO receive buffer
sender (h2h-a)	4.7 MiB	11.6 MiB	11.6 / 11.6	6.1 MiB	0.7 MiB
receiver (h2h-b)	4.7 MiB	26.5 MiB	26.5 / 26.5	15.4 MiB	6.2 MiB

Nothing comes back while idle. 4.2 MiB of the 4.7 MiB idle RSS is the binary's own file-backed text.
The GRO receive buffer is reserved as 100 × 256 KiB = 25.6 MiB (RecvManyBuf, udp/socket/linux.rs). Only pages the kernel wrote into are resident, but they stay resident for good: up to 6.2 MiB.
The malloc arenas hold the packet pool's returned 4 KiB buffers (capacity 4,000) plus freed TSO/coalescing buffers. glibc keeps freed small chunks in its arenas and never returns them unless something trims.

Design of the cut (being verified now)

The pool tracks use under the lock it already takes on every get and return. release_if_idle() frees all retained buffers after one full check period without a get.
The receive task holds one timer for its whole life. It re-arms once per 5 s period and is polled only when the socket would block (biased select, receive first), so a busy link pays nothing per packet. On idle it releases the pool, drops the GRO buffer's pages in place with madvise(MADV_DONTNEED), and on glibc calls malloc_trim(0) once.
The GRO buffer is not freed and reallocated. That would raise glibc's dynamic mmap threshold to 25.6 MiB and move the next allocation into an arena, where calloc zero-fills, and so touches, all of it.
Memory returns 5–10 s after the last packet. Note for J103c: the infraternal binary uses musl's allocator, where malloc_trim does not exist. The pool and GRO parts are allocator-independent, but how much freed heap musl returns needs its own check in the integration.

Tests first: idle_release_waits_for_a_full_unused_period (pool) and release_pages_drops_touched_pages_and_keeps_buffers_usable (Linux GRO buffer). The RED and GREEN run is queued on compute01 (all 4 slots busy). The hold runner (kernel / control / cand / cand / control, with 30 warm and 30 after-idle single-probe RTTs) is staged at ~/j20/r4b/j88d-scripts/run-idle-hold.sh.

## J88d finding: where the post-load memory sits (diagnostic, not a perf row) One `mesh-gotatun` case on the pin `73eb9f1` (binary `a1bc7eb7…`) under `perf-run --root`: exit 0, 164 s, empty machine diff. It took `/proc/<pid>/smaps` snapshots before load, right after the R4b LAN profile (1 and 8 flows), and after 30 s and 120 s idle. Evidence: `/home/claude/j20/r4b/j88d-memdiag-73eb9f1-20261103/` on the perf VM. | Endpoint | Before load | After load | +30 s / +120 s idle | malloc arenas (anon) | UDP GRO receive buffer | |---|---:|---:|---:|---:|---:| | sender (h2h-a) | 4.7 MiB | 11.6 MiB | 11.6 / 11.6 | 6.1 MiB | 0.7 MiB | | receiver (h2h-b) | 4.7 MiB | 26.5 MiB | 26.5 / 26.5 | 15.4 MiB | 6.2 MiB | - Nothing comes back while idle. 4.2 MiB of the 4.7 MiB idle RSS is the binary's own file-backed text. - The **GRO receive buffer** is reserved as 100 × 256 KiB = 25.6 MiB (`RecvManyBuf`, `udp/socket/linux.rs`). Only pages the kernel wrote into are resident, but they stay resident for good: up to 6.2 MiB. - The **malloc arenas** hold the packet pool's returned 4 KiB buffers (capacity 4,000) plus freed TSO/coalescing buffers. glibc keeps freed small chunks in its arenas and never returns them unless something trims. ### Design of the cut (being verified now) - The pool tracks use under the lock it already takes on every `get` and return. `release_if_idle()` frees all retained buffers after one full check period without a `get`. - The receive task holds **one** timer for its whole life. It re-arms once per 5 s period and is polled only when the socket would block (`biased` select, receive first), so a busy link pays nothing per packet. On idle it releases the pool, drops the GRO buffer's pages in place with `madvise(MADV_DONTNEED)`, and on glibc calls `malloc_trim(0)` once. - The GRO buffer is **not** freed and reallocated. That would raise glibc's dynamic mmap threshold to 25.6 MiB and move the next allocation into an arena, where `calloc` zero-fills, and so touches, all of it. - Memory returns 5–10 s after the last packet. Note for J103c: the infraternal binary uses musl's allocator, where `malloc_trim` does not exist. The pool and GRO parts are allocator-independent, but how much freed heap musl returns needs its own check in the integration. Tests first: `idle_release_waits_for_a_full_unused_period` (pool) and `release_pages_drops_touched_pages_and_keeps_buffers_usable` (Linux GRO buffer). The RED and GREEN run is queued on compute01 (all 4 slots busy). The hold runner (`kernel / control / cand / cand / control`, with 30 warm and 30 after-idle single-probe RTTs) is staged at `~/j20/r4b/j88d-scripts/run-idle-hold.sh`.

kayg commented

2026-11-03 12:16:24 +00:00

Author

Owner

J103c: D331 pin, and the agent now asks for the buffers (2026-11-03, 18:50 IST)

Branch mesh-gotatun-linux, head 84381478f (pushed). Base is origin/dev 67556332b; the branch merges cleanly with today's 470c6610f. Two new commits:

29d76393a mesh: pin GotaTun at the uncapped UDP socket buffer step (#260, D331).
- The fork moves to 73eb9f1ae185313609d031c644cb4a81f3c927dc.
- Cargo.lock changes only gotatun's source revision; cargo metadata --locked passes.
- I rejected cargo update -p gotatun, which also moved windows-sys 0.52 → 0.59 under three unrelated Windows-only dependencies.
84381478f mesh: request the large GotaTun UDP buffers in the agent (#260, D331).
- Finding: the pin alone would not change the product. 73eb9f1 forces a buffer size only when the caller asks for one: UdpSocketFactory::recv_buffer_size / send_buffer_size, which the CLI sets to 7 MiB. The agent's bind_udp used UdpSocketFactory::default(), so its engine socket kept the kernel default.
- In my earlier R4b hold the receiver's engine socket had rb 212,992 and logged 2,970 / 2,905 and 2,443 / 3,209 RcvbufErrors per loaded 1 / 8-flow phase. Same columns as J88c's analyzer; the hold's evidence is attached to comment 76806.
- The agent now asks for the CLI's 7 MiB send and receive buffers. GotaTun binds one dual-stack socket, so this is at most about 28 MiB of kernel socket memory per node after the kernel's doubling, used only while packets queue.
- Test engine_udp_socket_requests_the_large_buffers compares the engine socket with an explicit request of the same size. The kernel doubles only an explicit request, so the test fails for an unrequested socket even where rmem_default equals rmem_max. RED/GREEN is queued.

In progress:

compute01 (queued for a build slot):
- checks at both new commits;
- the buffer test RED/GREEN;
- the 15 namespace test files under both engines, and the P1 test;
- relay and direct namespace proofs;
- release static binaries;
- then scripts/verify fast at the head.
perf VM: the R4b rerun with this pin starts as soon as the binaries exist. It reports in J88c's columns (comment 76819), with the fork CLI 73eb9f1 build a1bc7eb7… as the control.
Mac VM (under /tmp/mac-bench.lock): my branch adds the fork dependency and infraternal-linux-tun to the default feature graph on every platform, so I am checking that the mesh crate and the infraternal binary still build on macOS, and running the mesh crate's portable unit tests there. The GotaTun engine itself is Linux-only on this branch, and the D169 macOS adapter is not on dev.

Coordination finding for the orchestrator:

J80's macos-node-265-s1 declares gotatun = { version = "0.10.2", features = ["device"] } from crates.io under [target.'cfg(target_os = "macos")'.dependencies]. This branch takes gotatun from the fork by git.
Cargo requires one source per dependency name across targets, so whichever of the two branches merges second will fail to resolve until the macOS adapter moves to the same fork pin. D163's amendment already says every platform runs our fork.

My mistake: my overlay dry run created /tmp/j103c-dry.* on the perf VM during J88c's hold and spoiled one of their attempts (comment 76819). I now keep every perf-VM file under my evidence directory and check that no hold is running before touching that machine.

## J103c: D331 pin, and the agent now asks for the buffers (2026-11-03, 18:50 IST) Branch `mesh-gotatun-linux`, head `84381478f` (pushed). Base is `origin/dev` `67556332b`; the branch merges cleanly with today's `470c6610f`. Two new commits: - `29d76393a` **mesh: pin GotaTun at the uncapped UDP socket buffer step (#260, D331).** - The fork moves to `73eb9f1ae185313609d031c644cb4a81f3c927dc`. - `Cargo.lock` changes only gotatun's source revision; `cargo metadata --locked` passes. - I rejected `cargo update -p gotatun`, which also moved `windows-sys` 0.52 → 0.59 under three unrelated Windows-only dependencies. - `84381478f` **mesh: request the large GotaTun UDP buffers in the agent (#260, D331).** - **Finding:** the pin alone would not change the product. `73eb9f1` forces a buffer size only when the caller asks for one: `UdpSocketFactory::recv_buffer_size` / `send_buffer_size`, which the CLI sets to 7 MiB. The agent's `bind_udp` used `UdpSocketFactory::default()`, so its engine socket kept the kernel default. - In my earlier R4b hold the receiver's engine socket had `rb` 212,992 and logged 2,970 / 2,905 and 2,443 / 3,209 `RcvbufErrors` per loaded 1 / 8-flow phase. Same columns as J88c's analyzer; the hold's evidence is attached to comment 76806. - The agent now asks for the CLI's 7 MiB send and receive buffers. GotaTun binds one dual-stack socket, so this is at most about 28 MiB of kernel socket memory per node after the kernel's doubling, used only while packets queue. - Test `engine_udp_socket_requests_the_large_buffers` compares the engine socket with an explicit request of the same size. The kernel doubles only an explicit request, so the test fails for an unrequested socket even where `rmem_default` equals `rmem_max`. RED/GREEN is queued. **In progress:** - **compute01** (queued for a build slot): - checks at both new commits; - the buffer test RED/GREEN; - the 15 namespace test files under both engines, and the P1 test; - relay and direct namespace proofs; - release static binaries; - then `scripts/verify fast` at the head. - **perf VM:** the R4b rerun with this pin starts as soon as the binaries exist. It reports in J88c's columns (comment 76819), with the fork CLI `73eb9f1` build `a1bc7eb7…` as the control. - **Mac VM** (under `/tmp/mac-bench.lock`): my branch adds the fork dependency and `infraternal-linux-tun` to the default feature graph on every platform, so I am checking that the mesh crate and the `infraternal` binary still build on macOS, and running the mesh crate's portable unit tests there. The GotaTun engine itself is Linux-only on this branch, and the D169 macOS adapter is not on dev. **Coordination finding for the orchestrator:** - J80's `macos-node-265-s1` declares `gotatun = { version = "0.10.2", features = ["device"] }` from crates.io under `[target.'cfg(target_os = "macos")'.dependencies]`. This branch takes `gotatun` from the fork by git. - Cargo requires one source per dependency name across targets, so whichever of the two branches merges second will fail to resolve until the macOS adapter moves to the same fork pin. D163's amendment already says every platform runs our fork. **My mistake:** my overlay dry run created `/tmp/j103c-dry.*` on the perf VM during J88c's hold and spoiled one of their attempts (comment 76819). I now keep every perf-VM file under my evidence directory and check that no hold is running before touching that machine.

kayg commented

2026-11-03 12:49:23 +00:00

Author

Owner

J88d progress (WIP branch `j88d-wip` @ `6361a0d`; the pin branch is untouched at `73eb9f1`)

Step 1, idle release (commit 7a902bb on j88d-wip), refined after one finding. The R4b harness configures persistent_keepalive_interval=1, so "no packet in a period" never holds there, and real links with keepalives hit the same problem. A 5 s period now counts as quiet when fewer than 64 pool buffers were taken (about 13 packets/s), and memory is released once at the first quiet period after a busy one. RED is recorded on compute01: without the implementation the tests do not compile (E0432/E0599, idle-check-red.log).

Step 2, finding (diagnostic, not a perf row). On the pin, a 50 ms queue sample during the 1-flow loaded phase (/home/claude/j20/r4b/j88d-qdiag-73eb9f1-20261103/):

Where bytes sit (1 flow, 132 samples)	p50	max
inner TCP in flight (`unacked × mss`)	1,756 KB	2,917 KB
`wgA` fq qdisc (sender TUN)	67 KB	667 KB
receiver GotaTun UDP socket (`rmem`, 0 drops)	76 KB	1,225 KB
sender UDP socket / `wgB` qdisc	0 / 0	2 KB / 0
residue: GotaTun userspace handoffs	≈1,380 KB	≈2,580 KB

With the forced buffer the standing queue lives in GotaTun's FIFO handoffs: about 4.5 ms at 2.5 Gbit/s. J88's trace put the 1-flow wait mostly in TUN→device, whose recv drained up to 4,000 packets at once.

The one cut for step 2 (commit 6361a0d): BufferedIpRecv gets a small-packet lane (IP length ≤ 256 B: ACKs, keystrokes, probes; bound 1,024, falling back to bulk when full). Each recv takes up to 64 small packets, then up to 64 bulk packets. A probe waits for at most one 64-packet bulk chunk, and bulk cannot starve. Capacities are unchanged; J88 already showed caps cost throughput. Nonces are assigned after this queue. Keep rule (set before measuring): 1-flow loss-aware p99 improves, 8-flow does not get worse, throughput does not fall. RED: E0432/E0609 without the implementation.

Loss-aware p99 (D331): h2h stores only percentiles. So with 0 lost the loss-aware p99 is the received p99; with 0 < loss ≤ 1% it is shown as ≤max (bounded by the received max); above 1% it is ∞. First-RTT-after-idle uses single-probe cycles, so those numbers are raw samples.

Gate: the first combined fork check failed only cargo fmt in two test spots; fixed, and fmt --check passes on compute01. The full gate for both commits (clippy -D warnings, full library suite, release CLI) is queued on compute01, all 4 slots busy.

Step 3 soak harness: 2-minute smoke run passes (exit 0, empty machine diff). It covers 1,000 peers on each endpoint, 4 flapping peers in their own netns (flaps reconnect in 19–255 ms), 50 s bulk per minute with probes every 10 ms, quiet minutes, and per-minute RSS, TCP reorder/retransmit, UDP drop, link and softnet counters. Running now: the 62-minute soak on the pin 73eb9f1 (baseline, started 13:38 CET). The final head gets the same soak afterwards.

Smoke finding on the pin: 0.4% / 0.68% of probes lost under 1 / 4 flows with 0 UDP socket drops. That points at the TUN write / netdev backlog side (J88c saw wgB TX drops). The soak now logs ip -s link and softnet_stat per minute to attribute it.

Step 4 macOS: there are no netns on macOS, so both endpoints run on the Mac over loopback UDP. Every test socket is bound to its utun (IP_BOUND_IF), and a verify step checks the engines' own tx/rx byte counters, so traffic must cross both tunnels. Tests: handshake, byte-exact 256 MiB (SHA-256), idle/loaded latency, throughput, RSS idle/after load/+15 s, first RTT after idle, and a 150 s transfer across the 120 s rekey. Engines: the fork head, the pin, and wireguard-go b3bc704 (the Linux kit's pin). Building under /tmp/mac-bench.lock with Rust 1.99.0 and the CLT clang: the fork's flake has no Darwin shell, and nix gcc lacks the Apple SDK aws-lc needs. Not a perf host; numbers will be labelled.

## J88d progress (WIP branch `j88d-wip` @ `6361a0d`; the pin branch is untouched at `73eb9f1`) **Step 1, idle release (commit `7a902bb` on `j88d-wip`)**, refined after one finding. The R4b harness configures `persistent_keepalive_interval=1`, so "no packet in a period" never holds there, and real links with keepalives hit the same problem. A 5 s period now counts as quiet when fewer than 64 pool buffers were taken (about 13 packets/s), and memory is released once at the first quiet period after a busy one. RED is recorded on compute01: without the implementation the tests do not compile (`E0432`/`E0599`, `idle-check-red.log`). **Step 2, finding (diagnostic, not a perf row).** On the pin, a 50 ms queue sample during the 1-flow loaded phase (`/home/claude/j20/r4b/j88d-qdiag-73eb9f1-20261103/`): | Where bytes sit (1 flow, 132 samples) | p50 | max | |---|---:|---:| | inner TCP in flight (`unacked × mss`) | 1,756 KB | 2,917 KB | | `wgA` fq qdisc (sender TUN) | 67 KB | 667 KB | | receiver GotaTun UDP socket (`rmem`, 0 drops) | 76 KB | 1,225 KB | | sender UDP socket / `wgB` qdisc | 0 / 0 | 2 KB / 0 | | **residue: GotaTun userspace handoffs** | **≈1,380 KB** | **≈2,580 KB** | With the forced buffer the standing queue lives in GotaTun's FIFO handoffs: about 4.5 ms at 2.5 Gbit/s. J88's trace put the 1-flow wait mostly in TUN→device, whose `recv` drained up to 4,000 packets at once. **The one cut for step 2 (commit `6361a0d`):** `BufferedIpRecv` gets a small-packet lane (IP length ≤ 256 B: ACKs, keystrokes, probes; bound 1,024, falling back to bulk when full). Each `recv` takes up to 64 small packets, then up to 64 bulk packets. A probe waits for at most one 64-packet bulk chunk, and bulk cannot starve. Capacities are unchanged; J88 already showed caps cost throughput. Nonces are assigned after this queue. Keep rule (set before measuring): **1-flow loss-aware p99 improves, 8-flow does not get worse, throughput does not fall.** RED: `E0432`/`E0609` without the implementation. **Loss-aware p99 (D331):** h2h stores only percentiles. So with 0 lost the loss-aware p99 is the received p99; with 0 < loss ≤ 1% it is shown as `≤max` (bounded by the received max); above 1% it is ∞. First-RTT-after-idle uses single-probe cycles, so those numbers are raw samples. **Gate:** the first combined fork check failed only `cargo fmt` in two test spots; fixed, and `fmt --check` passes on compute01. The full gate for both commits (clippy `-D warnings`, full library suite, release CLI) is queued on compute01, all 4 slots busy. **Step 3 soak harness:** 2-minute smoke run passes (exit 0, empty machine diff). It covers 1,000 peers on each endpoint, 4 flapping peers in their own netns (flaps reconnect in 19–255 ms), 50 s bulk per minute with probes every 10 ms, quiet minutes, and per-minute RSS, TCP reorder/retransmit, UDP drop, link and softnet counters. **Running now: the 62-minute soak on the pin `73eb9f1`** (baseline, started 13:38 CET). The final head gets the same soak afterwards. - Smoke finding on the pin: **0.4% / 0.68% of probes lost under 1 / 4 flows with 0 UDP socket drops.** That points at the TUN write / netdev backlog side (J88c saw `wgB` TX drops). The soak now logs `ip -s link` and `softnet_stat` per minute to attribute it. **Step 4 macOS:** there are no netns on macOS, so both endpoints run on the Mac over loopback UDP. Every test socket is bound to its utun (`IP_BOUND_IF`), and a verify step checks the engines' own tx/rx byte counters, so traffic must cross both tunnels. Tests: handshake, byte-exact 256 MiB (SHA-256), idle/loaded latency, throughput, RSS idle/after load/+15 s, first RTT after idle, and a 150 s transfer across the 120 s rekey. Engines: the fork head, the pin, and wireguard-go `b3bc704` (the Linux kit's pin). Building under `/tmp/mac-bench.lock` with Rust 1.99.0 and the CLT clang: the fork's flake has no Darwin shell, and nix gcc lacks the Apple SDK aws-lc needs. Not a perf host; numbers will be labelled.

kayg commented

2026-11-03 13:00:28 +00:00

Author

Owner

J103c: parity steps after the orchestrator's decisions (2026-11-03, 19:55 IST)

Correction to comment 76806. I wrote that "the fork CLI's TUN has GRO on this path". That was wrong.

At 73eb9f1, gotatun/src/tun/tun_async_device.rs writes every packet with its own write() and an all-zero virtio header (VIRTIO_NET_HDR_GSO_NONE). The fork has TSO only on TUN reads (tso.rs) and no GRO on writes.
So the CLI's lead over our integration does not come from GRO. Both run the same device: Connection::set_up joins UDP receive and decryption, TUN reads, TUN writes, and encryption as separate tasks through GotaTun's buffered channels.
The CLI runs those tasks on tokio's multi-thread runtime. The agent ran them on a current_thread runtime, where the channels add hand-offs and nothing overlaps. That fits both symptoms: half the throughput, and 53% more engine CPU per byte.
There is no fork GRO code to reuse, so J88d has nothing to move for step (b).

Order. I am doing (c), the multi-thread runtime, before (b), GRO. (c) is the small change that likely closes most of the gap to the CLI. (b) is new work beyond the fork, so measuring it on top of (c) keeps each R4b row clean. Each step still gets its own row against the earlier table.

Commits on mesh-gotatun-linux, head fb11ada1e, all pushed:

f857027dd mesh: let engine-specific tests name their engine.
- Adds Node::with_engine and Node::restore_with_engine, the same pattern as Node::with_firewall.
- The 15 kernel-era namespace tests from comment 76807 now select kernel WireGuard explicitly. The GotaTun restore, ownership and owner-fence tests, and the relay fixture, select GotaTun.
cd8c426e1 mesh: keep kernel WireGuard the Linux default until GotaTun reaches parity.
- EngineKind's default is kernel. GotaTun stays selectable per node, and an installation that recorded GotaTun keeps it.
- D163's 2026-11-02 amendment still records GotaTun as the Linux engine. Recording this hold is for the owner.
cf720551b step (c) — mesh: run the GotaTun engine on worker threads.
- The engine runtime is multi-thread, with one worker per available core and at most four. THP stays disabled.
fb11ada1e step (b) — mesh: merge decrypted TCP segments into GSO frames on TUN writes.
- One writer task owns TUN writes and takes whatever is queued, so an idle link gets no timer and no added latency.
- Consecutive in-sequence ACK/PSH segments of one TCP flow become one virtio GSO frame (TCPv4/v6, partial checksum), at most 64 segments within one IP packet. Everything else is written as before.
- A merged frame the kernel refuses is written segment by segment. A gone device stops GotaTun as before.
- Unit tests check that a GSO frame re-segments to the original packets byte for byte (IPv4 and IPv6), that its partial checksum completes correctly, and that every merge boundary holds. The WTFPL tun crate is not used.

Measurement queue:

R4b row (a), the D331 pin with the requested buffers, 84381478f: queued on the perf VM behind J88d's soak hold.
Rows (c) and (b): the release static binaries for cf720551b and fb11ada1e build in the compute01 session that also runs:
- per-commit clippy (test and shipping features) and unit tests;
- the runtime test RED/GREEN;
- all namespace suites with explicit engines;
- the relay and direct GotaTun proofs at the GRO head, so their byte-exact TCP streams cross the new write path.

macOS (Mac VM, under the lock), same results on my branch and on unmodified dev d6c3b5b9b:

The mesh library compiles with the fork pin and the Linux TUN crate, and its 31 portable unit tests pass, with the system toolchain (unset SDKROOT DEVELOPER_DIR; CC=/usr/bin/clang, as dev needed before #265's wrapper).
tests/access_updates.rs is gated only on agent and fails to compile on macOS on both.
The infraternal-shim build reports "unsupported Zig build host" on both, for the plugin-agent,remote,plugin-mesh binary.

The J80 crates.io → fork-pin move is pending J80's merge.

## J103c: parity steps after the orchestrator's decisions (2026-11-03, 19:55 IST) **Correction to comment 76806.** I wrote that "the fork CLI's TUN has GRO on this path". That was wrong. - At `73eb9f1`, `gotatun/src/tun/tun_async_device.rs` writes every packet with its own `write()` and an all-zero virtio header (`VIRTIO_NET_HDR_GSO_NONE`). The fork has TSO only on TUN *reads* (`tso.rs`) and no GRO on writes. - So the CLI's lead over our integration does not come from GRO. Both run the same device: `Connection::set_up` joins UDP receive and decryption, TUN reads, TUN writes, and encryption as separate tasks through GotaTun's buffered channels. - The CLI runs those tasks on tokio's multi-thread runtime. The agent ran them on a `current_thread` runtime, where the channels add hand-offs and nothing overlaps. That fits both symptoms: half the throughput, and 53% more engine CPU per byte. - There is no fork GRO code to reuse, so J88d has nothing to move for step (b). **Order.** I am doing (c), the multi-thread runtime, before (b), GRO. (c) is the small change that likely closes most of the gap to the CLI. (b) is new work beyond the fork, so measuring it on top of (c) keeps each R4b row clean. Each step still gets its own row against the earlier table. **Commits on `mesh-gotatun-linux`, head `fb11ada1e`, all pushed:** - `f857027dd` **mesh: let engine-specific tests name their engine.** - Adds `Node::with_engine` and `Node::restore_with_engine`, the same pattern as `Node::with_firewall`. - The 15 kernel-era namespace tests from comment 76807 now select kernel WireGuard explicitly. The GotaTun restore, ownership and owner-fence tests, and the relay fixture, select GotaTun. - `cd8c426e1` **mesh: keep kernel WireGuard the Linux default until GotaTun reaches parity.** - `EngineKind`'s default is kernel. GotaTun stays selectable per node, and an installation that recorded GotaTun keeps it. - D163's 2026-11-02 amendment still records GotaTun as the Linux engine. Recording this hold is for the owner. - `cf720551b` **step (c) — mesh: run the GotaTun engine on worker threads.** - The engine runtime is multi-thread, with one worker per available core and at most four. THP stays disabled. - `fb11ada1e` **step (b) — mesh: merge decrypted TCP segments into GSO frames on TUN writes.** - One writer task owns TUN writes and takes whatever is queued, so an idle link gets no timer and no added latency. - Consecutive in-sequence ACK/PSH segments of one TCP flow become one virtio GSO frame (TCPv4/v6, partial checksum), at most 64 segments within one IP packet. Everything else is written as before. - A merged frame the kernel refuses is written segment by segment. A gone device stops GotaTun as before. - Unit tests check that a GSO frame re-segments to the original packets byte for byte (IPv4 and IPv6), that its partial checksum completes correctly, and that every merge boundary holds. The WTFPL `tun` crate is not used. **Measurement queue:** - R4b row (a), the D331 pin with the requested buffers, `84381478f`: queued on the perf VM behind J88d's soak hold. - Rows (c) and (b): the release static binaries for `cf720551b` and `fb11ada1e` build in the compute01 session that also runs: - per-commit clippy (test and shipping features) and unit tests; - the runtime test RED/GREEN; - all namespace suites with explicit engines; - the relay and direct GotaTun proofs at the GRO head, so their byte-exact TCP streams cross the new write path. **macOS (Mac VM, under the lock)**, same results on my branch and on unmodified dev `d6c3b5b9b`: - The mesh library compiles with the fork pin and the Linux TUN crate, and its 31 portable unit tests pass, with the system toolchain (`unset SDKROOT DEVELOPER_DIR; CC=/usr/bin/clang`, as dev needed before #265's wrapper). - `tests/access_updates.rs` is gated only on `agent` and fails to compile on macOS on both. - The `infraternal-shim` build reports "unsupported Zig build host" on both, for the `plugin-agent,remote,plugin-mesh` binary. The J80 crates.io → fork-pin move is pending J80's merge.

kayg commented

2026-11-03 14:19:28 +00:00

Author

Owner

J103c: history rebuilt, two findings, R4b row (a), macOS (2026-11-03, 19:50 IST)

Branch mesh-gotatun-linux, pushed head ee4bea9bb. Commits on base 67556332b:

29d76393a pins GotaTun at 73eb9f1 (D331).
84381478f requests the large UDP buffers.
a1cdaeb6c lets tests name their engine explicitly.
93d3d9671 keeps kernel WireGuard as the Linux default.
c64c1cc1b is step (c), the worker-thread runtime.
ee4bea9bb is step (b), GRO.

There is one more commit, 6bf9fa6f1, which is test-only (finding 2). I'll push it once its own head checks pass; then verify fast runs at it as the final head.

Correction to comment 76940

The head listed there, fb11ada1e, did not build. The GRO writer queued BytesMut, but Packet::into_bytes() returns Packet<[u8]> (E0308).
f857027dd, cd8c426e1 and cf720551b were not rustfmt-clean.
That comment's header says 19:55 IST. It was posted at 18:30 IST.

I rebuilt the four commits on 84381478f and ran cargo fmt --all on each. To prove the rebuild changed only formatting, I ran rustfmt over each old commit and diffed the result against the new commit:

Old	New	`git diff` between rustfmt(old) and new
`f857027dd`	`a1cdaeb6c`	empty
`cd8c426e1`	`93d3d9671`	empty
`cf720551b`	`c64c1cc1b`	empty
`fb11ada1e`	`ee4bea9bb`	`gotatun_tun.rs` only: the type fix, finding 1, and one clippy fix in a test (`slice::from_ref`; the interim `393f0dbfc` failed clippy, so I never pushed it)

Finding 1: two missing GRO merge rules (fixed in `ee4bea9bb`)

I reviewed the writer against how the kernel re-segments a virtio GSO frame (inet_gso_segment, tcp_gso_segment): it copies the first segment's headers, counts the IPv4 identification up by one per segment, and sets PSH only on the last segment. The kernel's own GRO (inet_gro_receive, tcp_gro_receive) checks two things our rules did not:

IPv4 identification. We ignored it. A run whose identifications do not count up, such as one from a sender that randomises them, would have been re-segmented with new identifications.
- An IPv4 run now needs consecutive identifications.
- Our read-side TSO segmenter already counts them up, and Linux's per-socket counter continues across TSO frames. Kernel WireGuard and GotaTun senders still merge.
- I rejected merging don't-fragment segments whatever their identification: virtio has no fixed-identification GSO type, and the kernel's GRO refuses that case too.
TCP window and urgent pointer. We did not compare them, so a window update in the middle of a run took the first segment's stale window. Every header byte that re-segmentation copies must now match.

With both rules, re-segmentation gives back every original segment byte for byte. build_gso_frame also takes its length from what it wrote, and refuses a segment shorter than the run's headers instead of underflowing.

Two limits of the evidence:

The namespace proofs cannot catch a wrong partial checksum: the kernel never verifies a locally delivered NEEDS_CSUM frame. The guard is the unit test that compares the partial checksum with a from-scratch one.
GotaTun at 73eb9f1 (device/mod.rs) truncates each decrypted packet to its IP length (try_into_ipvx) and checks the source against the peer's allowed IPs before our adapter sees it. GRO therefore sees exact IP packets and never merges across peers.

Finding 2: one library namespace test still assumed GotaTun was the default (fix `6bf9fa6f1`)

These ignored tests had not run in this job before; the session-3 build of them failed at fb11ada1e. Rootless, at ee4bea9bb: 12 pass and 3 fail.

node_actions::tests::mesh_peers_action_reads_counters_from_the_selected_gotatun_engine failed with assertion failed: Device::owned_tun().expect("selected GotaTun TUN").
- This is a regression from 93d3d9671: MeshNodePlugin restores its node with the default engine.
- a1cdaeb6c named the engine in tests/ and in the relay fixture, but missed this test inside the library.
- Fix: the test seeds the plugin's node with Node::restore_with_engine(.., EngineKind::GotaTun). It cannot set INFRATERNAL_MESH_ENGINE itself, because set_var is unsafe in edition 2024 and the workspace forbids unsafe code.
The other two failures do not depend on the engine and cannot pass in a rootless namespace on the build host:
- applied_server_route_and_observed_link_survive_only_explicit_component_up needs real root to read /proc/1/ns/net.
- public_state_restore_at_1000_peers runs only on the perf VM with INFRATERNAL_STATE_RESTORE_MODE set.

Evidence at `ee4bea9bb` (compute01, session 4)

Per-commit checks. fmt, clippy with test features, clippy with shipping features (agent), and the mesh unit tests:

Commit	fmt	clippy	clippy (shipping)	Unit tests
`a1cdaeb6c`	0	0	0	86 passed
`93d3d9671`	0	0	0	86 passed
`c64c1cc1b`	0	0	0	87 passed
`ee4bea9bb`	0	0	0	90 passed

RED/GREEN. Each change reverted in place, then restored:

Change	RED (reverted)	GREEN
Worker-thread runtime	`left: CurrentThread, right: MultiThread`	passes
GRO writer (runs forced to one packet)	the first frame comes out unmerged, with a zero virtio header	passes
Identification rule	`a different identification ends the frame`, left 2, right 1	passes
Window rule	`a different window ends the frame`, left 2, right 1	passes

Namespace suites. All 15 suites under tests/ pass with explicit engines:

review_retire_ownership: 10
kernel: 6
policy_snapshot_ordering: 6
access_updates: 3
gotatun_restore: 2
review_firewall_marker, review_ingress_translation, review_local_delivery, review_route_inventory, authorized_local_binding, review_authorized_reenrollment: 2 each
review_endpoint_transaction, review_restart_routes, review_route_scope, restart_route_ownership: 1 each

Relay proof. GotaTun debug build, built in this session, so its TCP streams cross the new write path. Build host, not perf evidence:

After the second end goes relayed, it links in 3.7 ms, and its first handshake completes at 119.2 ms.
A 32 MiB relayed stream and a 32 MiB direct stream are each sha256-equal.
The relay was killed mid-stream: a 64 MiB stream stays sha256-equal, both ends are on relay 2 after 3,016 ms, and the longest gap is 3.2 s.
Rebind to a new mapping: the old mapping is retired, and a 16 MiB stream stays sha256-equal, with a longest gap of 399 ms.
With no relay: recovery takes 5.9 s after the relay restarts.

Direct proof.

deny_new_ping, deny_new_tcp, retired_stream_refused and permitted_port_and_other_port_refusal all hold.

Release static binaries (x86_64 musl).

runtime c64c1cc1b: a4ca419b…
GRO ee4bea9bb: 667dc5ec…
coordinator: 9e32e7b2…, unchanged from row (a)

R4b row (a): `84381478f`, the D331 pin with the requested 7 MiB buffers

This binary still has the current_thread runtime and writes one packet per TUN write.

Hold: /home/claude/j20/r4b/j103c-d331-20261103/, one perf-run --root hold. Outer exit 0, all 7 cases exit 0, every machine diff empty. Wall time 1,272 s, steal 1,692 of 508,598 jiffies.
Binaries: 64e2fc4e… (agent), fork CLI 73eb9f1 (a1bc7eb7…).
Order: kernel, integrated, fork CLI, integrated, kernel, then 1,000 peers per engine.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	Loaded RTT p50/p99, 1 flow (ms)	Loaded RTT p50/p99, 8 flows (ms)	Lost probes 1 / 8	Receiver `RcvbufErrors` 1 / 8	Socket `rb`	Receiver TUN bytes/RX packet 1 / 8
kernel-first	3.15 / 2.77	1.05 / 1.15	1.064 / 4.761	3.106 / 5.409	0 / 0	0 / 0	212,992	1411 / 1411
integrated-first	1.20 / 1.19	1.71 / 1.76	2.723 / 9.088	8.172 / 14.594	0 / 0	0 / 0	14,680,064	1378 / 1378
fork-cli	3.16 / 2.69	0.77 / 0.94	2.294 / 6.538	8.855 / 14.551	0 / 0	0 / 0	14,680,064	–
integrated-second	1.38 / 1.34	1.43 / 1.51	2.082 / 5.830	6.811 / 12.275	0 / 0	0 / 0	14,680,064	1378 / 1378
kernel-last	3.39 / 2.78	1.00 / 1.19	0.953 / 2.093	3.054 / 4.893	0 / 0	0 / 0	212,992	1411 / 1411
kernel mean	3.27 / 2.78	1.02 / 1.17	1.008 / 3.427	3.080 / 5.151	0.0% / 0.0%
integrated mean	1.29 / 1.26	1.57 / 1.64	2.402 / 7.459	7.492 / 13.434	0.0% / 0.0%

Memory (RSS, both endpoints)	1 peer, idle	After load	1,000 peers, idle	Per added peer
integrated	24.2 MiB	37.1 MiB	31.6 MiB	3.82 KiB
kernel	22.3 MiB	22.3 MiB	24.2 MiB	0.96 KiB
fork CLI	9.5 MiB	37.8 MiB	see J88c	see J88c

The impairment checks match across cases. With 2% loss each way, lost probes at 64/512/1400 bytes (of 300) are 6–29 everywhere. With 25%/50% reordering, every case loses 0.

Reading.

D331's buffers fix the loss. The receiver's engine socket now has rb 14,680,064 (the kernel doubles the 7 MiB request). Every loaded phase logs 0 RcvbufErrors and 0 lost probes. The earlier hold had 2,443–3,209 errors per phase and 6.7% / 8.6% lost. With no loss, D331's loss-aware p99 equals the received p99 in every row.
Throughput does not improve. The integrated engine reaches 1.29 / 1.26 Gbit/s, which is 39% / 45% of kernel WireGuard. Its loaded p99 is 7.5 / 13.4 ms, against kernel's 3.4 / 5.2 ms. It uses 1.57 / 1.64 CPU s/Gbit, against the fork CLI's 0.77 / 0.94.
That pattern matches the current_thread finding (comment 76940). Rows (c) and (b) measure the fixes.
The receiver TUN averages 1,378 bytes per RX packet, so nothing merges before GRO. With GRO, this column should rise well above the 1,380-byte MTU.

macOS (Mac VM, `lockf -k /tmp/mac-bench.lock`, `393f0dbfc`)

macOS compiles the same tree for 393f0dbfc and ee4bea9bb. The GotaTun engine, its TUN adapter and the node are Linux-only. Since the first Mac check at 84381478f, the only change macOS compiles is the agent feature's tokio/rt-multi-thread.

Results match that first check and unmodified dev d6c3b5b9b:

The mesh library with agent compiles (exit 0).
The 31 portable unit tests pass.
tests/access_updates.rs fails to compile on macOS, as on dev; it is gated only on agent.
The plugin-agent,remote,plugin-mesh binary fails in the shim build script with "unsupported Zig build host", as on dev.

The J80 crates.io → fork-pin move is still pending J80's merge; origin/dev at bcca3054f has no macOS node yet.

Rows (c) and (b). One counterbalanced hold, /home/claude/j20/r4b/j103c-parity-20261103/, queued behind J88d's idle hold: kernel, runtime, GRO, fork CLI, GRO, runtime, kernel, then 1,000 peers.
Final checks at 6bf9fa6f1 (compute01, session 5, queued):
- head checks;
- the fixed test's RED (ee4bea9bb) and GREEN;
- the library's ignored suite;
- verify fast.

## J103c: history rebuilt, two findings, R4b row (a), macOS (2026-11-03, 19:50 IST) **Branch `mesh-gotatun-linux`, pushed head `ee4bea9bb`.** Commits on base `67556332b`: - `29d76393a` pins GotaTun at `73eb9f1` (D331). - `84381478f` requests the large UDP buffers. - `a1cdaeb6c` lets tests name their engine explicitly. - `93d3d9671` keeps kernel WireGuard as the Linux default. - `c64c1cc1b` is step (c), the worker-thread runtime. - `ee4bea9bb` is step (b), GRO. There is one more commit, `6bf9fa6f1`, which is test-only (finding 2). I'll push it once its own head checks pass; then `verify fast` runs at it as the final head. ### Correction to comment 76940 - The head listed there, `fb11ada1e`, did not build. The GRO writer queued `BytesMut`, but `Packet::into_bytes()` returns `Packet<[u8]>` (E0308). - `f857027dd`, `cd8c426e1` and `cf720551b` were not rustfmt-clean. - That comment's header says 19:55 IST. It was posted at 18:30 IST. I rebuilt the four commits on `84381478f` and ran `cargo fmt --all` on each. To prove the rebuild changed only formatting, I ran rustfmt over each old commit and diffed the result against the new commit: | Old | New | `git diff` between rustfmt(old) and new | |---|---|---| | `f857027dd` | `a1cdaeb6c` | empty | | `cd8c426e1` | `93d3d9671` | empty | | `cf720551b` | `c64c1cc1b` | empty | | `fb11ada1e` | `ee4bea9bb` | `gotatun_tun.rs` only: the type fix, finding 1, and one clippy fix in a test (`slice::from_ref`; the interim `393f0dbfc` failed clippy, so I never pushed it) | ### Finding 1: two missing GRO merge rules (fixed in `ee4bea9bb`) I reviewed the writer against how the kernel re-segments a virtio GSO frame (`inet_gso_segment`, `tcp_gso_segment`): it copies the first segment's headers, counts the IPv4 identification up by one per segment, and sets PSH only on the last segment. The kernel's own GRO (`inet_gro_receive`, `tcp_gro_receive`) checks two things our rules did not: - **IPv4 identification.** We ignored it. A run whose identifications do not count up, such as one from a sender that randomises them, would have been re-segmented with new identifications. - An IPv4 run now needs consecutive identifications. - Our read-side TSO segmenter already counts them up, and Linux's per-socket counter continues across TSO frames. Kernel WireGuard and GotaTun senders still merge. - I rejected merging don't-fragment segments whatever their identification: virtio has no fixed-identification GSO type, and the kernel's GRO refuses that case too. - **TCP window and urgent pointer.** We did not compare them, so a window update in the middle of a run took the first segment's stale window. Every header byte that re-segmentation copies must now match. With both rules, re-segmentation gives back every original segment byte for byte. `build_gso_frame` also takes its length from what it wrote, and refuses a segment shorter than the run's headers instead of underflowing. Two limits of the evidence: - The namespace proofs cannot catch a wrong partial checksum: the kernel never verifies a locally delivered `NEEDS_CSUM` frame. The guard is the unit test that compares the partial checksum with a from-scratch one. - GotaTun at `73eb9f1` (`device/mod.rs`) truncates each decrypted packet to its IP length (`try_into_ipvx`) and checks the source against the peer's allowed IPs before our adapter sees it. GRO therefore sees exact IP packets and never merges across peers. ### Finding 2: one library namespace test still assumed GotaTun was the default (fix `6bf9fa6f1`) These ignored tests had not run in this job before; the session-3 build of them failed at `fb11ada1e`. Rootless, at `ee4bea9bb`: 12 pass and 3 fail. - `node_actions::tests::mesh_peers_action_reads_counters_from_the_selected_gotatun_engine` failed with `assertion failed: Device::owned_tun().expect("selected GotaTun TUN")`. - This is a regression from `93d3d9671`: `MeshNodePlugin` restores its node with the default engine. - `a1cdaeb6c` named the engine in `tests/` and in the relay fixture, but missed this test inside the library. - Fix: the test seeds the plugin's node with `Node::restore_with_engine(.., EngineKind::GotaTun)`. It cannot set `INFRATERNAL_MESH_ENGINE` itself, because `set_var` is unsafe in edition 2024 and the workspace forbids unsafe code. - The other two failures do not depend on the engine and cannot pass in a rootless namespace on the build host: - `applied_server_route_and_observed_link_survive_only_explicit_component_up` needs real root to read `/proc/1/ns/net`. - `public_state_restore_at_1000_peers` runs only on the perf VM with `INFRATERNAL_STATE_RESTORE_MODE` set. ### Evidence at `ee4bea9bb` (compute01, session 4) **Per-commit checks.** fmt, clippy with test features, clippy with shipping features (`agent`), and the mesh unit tests: | Commit | fmt | clippy | clippy (shipping) | Unit tests | |---|---|---|---|---| | `a1cdaeb6c` | 0 | 0 | 0 | 86 passed | | `93d3d9671` | 0 | 0 | 0 | 86 passed | | `c64c1cc1b` | 0 | 0 | 0 | 87 passed | | `ee4bea9bb` | 0 | 0 | 0 | 90 passed | **RED/GREEN.** Each change reverted in place, then restored: | Change | RED (reverted) | GREEN | |---|---|---| | Worker-thread runtime | `left: CurrentThread, right: MultiThread` | passes | | GRO writer (runs forced to one packet) | the first frame comes out unmerged, with a zero virtio header | passes | | Identification rule | `a different identification ends the frame`, left 2, right 1 | passes | | Window rule | `a different window ends the frame`, left 2, right 1 | passes | **Namespace suites.** All 15 suites under `tests/` pass with explicit engines: - `review_retire_ownership`: 10 - `kernel`: 6 - `policy_snapshot_ordering`: 6 - `access_updates`: 3 - `gotatun_restore`: 2 - `review_firewall_marker`, `review_ingress_translation`, `review_local_delivery`, `review_route_inventory`, `authorized_local_binding`, `review_authorized_reenrollment`: 2 each - `review_endpoint_transaction`, `review_restart_routes`, `review_route_scope`, `restart_route_ownership`: 1 each **Relay proof.** GotaTun debug build, built in this session, so its TCP streams cross the new write path. Build host, not perf evidence: - After the second end goes relayed, it links in 3.7 ms, and its first handshake completes at 119.2 ms. - A 32 MiB relayed stream and a 32 MiB direct stream are each sha256-equal. - The relay was killed mid-stream: a 64 MiB stream stays sha256-equal, both ends are on relay 2 after 3,016 ms, and the longest gap is 3.2 s. - Rebind to a new mapping: the old mapping is retired, and a 16 MiB stream stays sha256-equal, with a longest gap of 399 ms. - With no relay: recovery takes 5.9 s after the relay restarts. **Direct proof.** - `deny_new_ping`, `deny_new_tcp`, `retired_stream_refused` and `permitted_port_and_other_port_refusal` all hold. **Release static binaries (x86_64 musl).** - runtime `c64c1cc1b`: `a4ca419b…` - GRO `ee4bea9bb`: `667dc5ec…` - coordinator: `9e32e7b2…`, unchanged from row (a) ### R4b row (a): `84381478f`, the D331 pin with the requested 7 MiB buffers This binary still has the `current_thread` runtime and writes one packet per TUN write. - Hold: `/home/claude/j20/r4b/j103c-d331-20261103/`, one `perf-run --root` hold. Outer exit 0, all 7 cases exit 0, every machine diff empty. Wall time 1,272 s, steal 1,692 of 508,598 jiffies. - Binaries: `64e2fc4e…` (agent), fork CLI `73eb9f1` (`a1bc7eb7…`). - Order: kernel, integrated, fork CLI, integrated, kernel, then 1,000 peers per engine. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | Loaded RTT p50/p99, 1 flow (ms) | Loaded RTT p50/p99, 8 flows (ms) | Lost probes 1 / 8 | Receiver `RcvbufErrors` 1 / 8 | Socket `rb` | Receiver TUN bytes/RX packet 1 / 8 | |---|---:|---:|---:|---:|---:|---:|---:|---:| | kernel-first | 3.15 / 2.77 | 1.05 / 1.15 | 1.064 / 4.761 | 3.106 / 5.409 | 0 / 0 | 0 / 0 | 212,992 | 1411 / 1411 | | integrated-first | 1.20 / 1.19 | 1.71 / 1.76 | 2.723 / 9.088 | 8.172 / 14.594 | 0 / 0 | 0 / 0 | 14,680,064 | 1378 / 1378 | | fork-cli | 3.16 / 2.69 | 0.77 / 0.94 | 2.294 / 6.538 | 8.855 / 14.551 | 0 / 0 | 0 / 0 | 14,680,064 | – | | integrated-second | 1.38 / 1.34 | 1.43 / 1.51 | 2.082 / 5.830 | 6.811 / 12.275 | 0 / 0 | 0 / 0 | 14,680,064 | 1378 / 1378 | | kernel-last | 3.39 / 2.78 | 1.00 / 1.19 | 0.953 / 2.093 | 3.054 / 4.893 | 0 / 0 | 0 / 0 | 212,992 | 1411 / 1411 | | **kernel mean** | **3.27 / 2.78** | 1.02 / 1.17 | 1.008 / **3.427** | 3.080 / **5.151** | **0.0% / 0.0%** | | | | | **integrated mean** | **1.29 / 1.26** | 1.57 / 1.64 | 2.402 / **7.459** | 7.492 / **13.434** | **0.0% / 0.0%** | | | | | Memory (RSS, both endpoints) | 1 peer, idle | After load | 1,000 peers, idle | Per added peer | |---|---:|---:|---:|---:| | integrated | 24.2 MiB | 37.1 MiB | 31.6 MiB | 3.82 KiB | | kernel | 22.3 MiB | 22.3 MiB | 24.2 MiB | 0.96 KiB | | fork CLI | 9.5 MiB | 37.8 MiB | see J88c | see J88c | The impairment checks match across cases. With 2% loss each way, lost probes at 64/512/1400 bytes (of 300) are 6–29 everywhere. With 25%/50% reordering, every case loses 0. **Reading.** - **D331's buffers fix the loss.** The receiver's engine socket now has `rb` 14,680,064 (the kernel doubles the 7 MiB request). Every loaded phase logs 0 `RcvbufErrors` and 0 lost probes. The earlier hold had 2,443–3,209 errors per phase and 6.7% / 8.6% lost. With no loss, D331's loss-aware p99 equals the received p99 in every row. - **Throughput does not improve.** The integrated engine reaches 1.29 / 1.26 Gbit/s, which is 39% / 45% of kernel WireGuard. Its loaded p99 is 7.5 / 13.4 ms, against kernel's 3.4 / 5.2 ms. It uses 1.57 / 1.64 CPU s/Gbit, against the fork CLI's 0.77 / 0.94. - That pattern matches the `current_thread` finding (comment 76940). Rows (c) and (b) measure the fixes. - The receiver TUN averages 1,378 bytes per RX packet, so nothing merges before GRO. With GRO, this column should rise well above the 1,380-byte MTU. ### macOS (Mac VM, `lockf -k /tmp/mac-bench.lock`, `393f0dbfc`) macOS compiles the same tree for `393f0dbfc` and `ee4bea9bb`. The GotaTun engine, its TUN adapter and the node are Linux-only. Since the first Mac check at `84381478f`, the only change macOS compiles is the `agent` feature's `tokio/rt-multi-thread`. Results match that first check and unmodified dev `d6c3b5b9b`: - The mesh library with `agent` compiles (exit 0). - The 31 portable unit tests pass. - `tests/access_updates.rs` fails to compile on macOS, as on dev; it is gated only on `agent`. - The `plugin-agent,remote,plugin-mesh` binary fails in the shim build script with "unsupported Zig build host", as on dev. The J80 crates.io → fork-pin move is still pending J80's merge; `origin/dev` at `bcca3054f` has no macOS node yet. ### Next - **Rows (c) and (b).** One counterbalanced hold, `/home/claude/j20/r4b/j103c-parity-20261103/`, queued behind J88d's idle hold: kernel, runtime, GRO, fork CLI, GRO, runtime, kernel, then 1,000 peers. - **Final checks at `6bf9fa6f1`** (compute01, session 5, queued): - head checks; - the fixed test's RED (`ee4bea9bb`) and GREEN; - the library's ignored suite; - `verify fast`.

kayg commented

2026-11-03 14:29:08 +00:00

Author

Owner

J88d step 1 result: idle release is kept (Linux R4b hold)

Hold /home/claude/j20/r4b/j88d-hold-idle-20261103/ on the perf VM: one perf-run --root hold, all 5 cases exit 0, every machine diff empty (only J88c's sentry prune applied). Order: kernel WireGuard, control 73eb9f1 (a1bc7eb7…), candidate 7a902bb (41112c0f…) twice, control again. Per case: the R4b LAN profile, RSS right after load, 30 warm single probes, RSS after 15 s idle, 30 single probes each after ≥11 s idle, then RSS again. RSS is for both endpoints together.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99	RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints)
kernel-reference	3.11 / 2.82	1.05 / 1.14	1.043 / 2.090 / 5.558	2.090
control-first	3.15 / 2.77	0.78 / 0.94	2.181 / 5.750 / 9.405	5.750
candidate-first	3.00 / 2.64	0.78 / 0.94	2.250 / 6.197 / 8.420	6.197
candidate-second	3.02 / 2.70	0.79 / 0.95	2.320 / 6.062 / 10.623	6.062
control-last	2.92 / 2.57	0.79 / 0.90	2.407 / 6.222 / 8.989	6.222

Case	warm single-probe RTT p50 / p90 / max (ms), lost	first RTT after >=11 s idle p50 / p90 / max (ms), lost
kernel-reference	0.191 / 0.209 / 0.222, 0/30	0.199 / 0.220 / 0.244, 0/30
control-first	0.239 / 0.302 / 0.520, 0/30	0.262 / 0.397 / 1.701, 0/30
candidate-first	0.228 / 0.275 / 0.294, 0/30	0.239 / 0.295 / 1.402, 0/30
candidate-second	0.228 / 0.266 / 0.279, 0/30	0.244 / 0.275 / 0.317, 0/30
control-last	0.223 / 0.287 / 0.306, 0/30	0.240 / 0.282 / 0.325, 0/30

Means against the control: throughput 3.01 / 2.67 vs 3.04 / 2.67 Gbit/s (−0.8% / 0%, within the spread of both controls, 2.92–3.15). 1-flow loss-aware p99 6.13 vs 5.99 ms (no loss in either); 8-flow ≤18.4 and ≤19.0 vs ≤18.5 and ∞ (control-last lost 46). RSS after 15 s idle: 11.9 vs 37.5 MiB. The candidate returns about 26 MiB, and its idle RSS sits 1.3–1.5 MiB per endpoint above the cold start (9.1–9.3 MiB). The control keeps all of it. First RTT after idle shows no cost: candidate p50 / p90 0.239–0.244 / 0.275–0.295 ms against control 0.240–0.262 / 0.282–0.397 ms, and kernel 0.199 / 0.220. A trickle of one probe every 11 s does not regrow it ("after cycles" stays at 11.6–12.2 MiB).

Keep rule (comment 76873): after-idle RSS falls, first-RTT p99 shows no visible regression, and loaded throughput and p99 do not move. Met. 7a902bb is kept.

macOS (the Mac VM, not a perf host): the release fires there too, proved by a debug log line on both endpoints about 7 s after load (commit 46e3588). But phys_footprint does not move: receiver MALLOC_SMALL is 2,960 KB after load and still 2,960 KB 20 s later. That is because on macOS the residue is small and shares pages with live allocations, most likely tokio channel blocks that tokio keeps for reuse. Adding malloc_zone_pressure_relief(NULL, 0) (b5c2a45) changed the footprint by 0 KB, so it is reverted (8ef6579). Absolute macOS numbers stay small: 8.9 MiB phys_footprint for both endpoints after load, against wireguard-go's 162 MiB.

Next on the perf VM: the step-2 hold (small-packet lane, full R4b profile).

## J88d step 1 result: idle release is kept (Linux R4b hold) Hold `/home/claude/j20/r4b/j88d-hold-idle-20261103/` on the perf VM: one `perf-run --root` hold, **all 5 cases exit 0, every machine diff empty** (only J88c's `sentry` prune applied). Order: kernel WireGuard, control `73eb9f1` (`a1bc7eb7…`), candidate `7a902bb` (`41112c0f…`) twice, control again. Per case: the R4b LAN profile, RSS right after load, 30 warm single probes, **RSS after 15 s idle**, 30 single probes each after ≥11 s idle, then RSS again. RSS is for both endpoints together. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | 1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99 | 8 flows p50 / p99 / max \| lost \| loss-aware p99 | RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints) | |---|---:|---:|---|---|---| | kernel-reference | 3.11 / 2.82 | 1.05 / 1.14 | 1.043 / 2.090 / 5.558 | 0 | 2.090 | 2.954 / 4.171 / 5.406 | 0 | 4.171 | 20.1 / 20.1 / 20.1 / 20.1 / - | | control-first | 3.15 / 2.77 | 0.78 / 0.94 | 2.181 / 5.750 / 9.405 | 0 | 5.750 | 8.416 / 15.749 / 18.460 | 2 | <=18.460 | 9.1 / 34.4 / 34.4 / 34.5 / - | | candidate-first | 3.00 / 2.64 | 0.78 / 0.94 | 2.250 / 6.197 / 8.420 | 0 | 6.197 | 9.350 / 16.292 / 18.403 | 20 | <=18.403 | 9.3 / 39.5 / 12.2 / 12.2 / - | | candidate-second | 3.02 / 2.70 | 0.79 / 0.95 | 2.320 / 6.062 / 10.623 | 0 | 6.062 | 9.089 / 15.019 / 19.000 | 7 | <=19.000 | 9.1 / 36.7 / 11.6 / 11.6 / - | | control-last | 2.92 / 2.57 | 0.79 / 0.90 | 2.407 / 6.222 / 8.989 | 0 | 6.222 | 10.442 / 18.952 / 23.426 | 46 | inf | 9.4 / 40.5 / 40.5 / 40.5 / - | | Case | warm single-probe RTT p50 / p90 / max (ms), lost | first RTT after >=11 s idle p50 / p90 / max (ms), lost | |---|---|---| | kernel-reference | 0.191 / 0.209 / 0.222, 0/30 | 0.199 / 0.220 / 0.244, 0/30 | | control-first | 0.239 / 0.302 / 0.520, 0/30 | 0.262 / 0.397 / 1.701, 0/30 | | candidate-first | 0.228 / 0.275 / 0.294, 0/30 | 0.239 / 0.295 / 1.402, 0/30 | | candidate-second | 0.228 / 0.266 / 0.279, 0/30 | 0.244 / 0.275 / 0.317, 0/30 | | control-last | 0.223 / 0.287 / 0.306, 0/30 | 0.240 / 0.282 / 0.325, 0/30 | **Means against the control:** throughput 3.01 / 2.67 vs 3.04 / 2.67 Gbit/s (−0.8% / 0%, within the spread of both controls, 2.92–3.15). 1-flow loss-aware p99 6.13 vs 5.99 ms (no loss in either); 8-flow ≤18.4 and ≤19.0 vs ≤18.5 and ∞ (control-last lost 46). **RSS after 15 s idle: 11.9 vs 37.5 MiB.** The candidate returns about 26 MiB, and its idle RSS sits 1.3–1.5 MiB per endpoint above the cold start (9.1–9.3 MiB). The control keeps all of it. **First RTT after idle shows no cost:** candidate p50 / p90 0.239–0.244 / 0.275–0.295 ms against control 0.240–0.262 / 0.282–0.397 ms, and kernel 0.199 / 0.220. A trickle of one probe every 11 s does not regrow it ("after cycles" stays at 11.6–12.2 MiB). Keep rule (comment 76873): after-idle RSS falls, first-RTT p99 shows no visible regression, and loaded throughput and p99 do not move. **Met. `7a902bb` is kept.** **macOS (the Mac VM, not a perf host):** the release **fires** there too, proved by a debug log line on both endpoints about 7 s after load (commit `46e3588`). But phys_footprint does not move: receiver `MALLOC_SMALL` is 2,960 KB after load and still 2,960 KB 20 s later. That is because on macOS the residue is small and shares pages with live allocations, most likely tokio channel blocks that tokio keeps for reuse. Adding `malloc_zone_pressure_relief(NULL, 0)` (`b5c2a45`) changed the footprint by 0 KB, so it is **reverted** (`8ef6579`). Absolute macOS numbers stay small: 8.9 MiB phys_footprint for both endpoints after load, against wireguard-go's 162 MiB. Next on the perf VM: the step-2 hold (small-packet lane, full R4b profile).

kayg commented

2026-11-03 15:05:40 +00:00

Author

Owner

J88d step 2 result: the small-packet lane is kept, and the fork branch now points at `8ef6579`

Linux R4b hold

Hold /home/claude/j20/r4b/j88d-hold-prio-20261103/: one perf-run --root hold, full R4b profile (LAN, DE↔IN, 2% loss, 25%/50% reorder, 1,000 peers), all 5 cases exit 0, every machine diff empty. Control is step 1 7a902bb (41112c0f…); candidate is 6361a0d (94550685…), run twice; order kernel, control, cand, cand, control.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99	8 flows p50 / p99 / max \| lost \| loss-aware p99	RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints)
kernel-reference	3.11 / 2.76	1.06 / 1.17	1.027 / 2.157 / 5.724	0	2.157
control-first	2.85 / 2.59	0.78 / 0.91	3.177 / 9.007 / 11.234	1	<=11.234
candidate-first	2.92 / 2.59	0.79 / 0.93	2.183 / 6.595 / 9.018	0	6.595
candidate-second	3.25 / 2.78	0.76 / 0.95	2.494 / 7.885 / 11.906	0	7.885
control-last	3.26 / 2.69	0.77 / 0.96	2.805 / 6.496 / 7.979	0	6.496

Case	2% loss: lost 64/512/1400 (of 300)	reorder 25%/50%: lost
kernel-reference	8/12/26	-/-/-
control-first	10/9/8	0/0/0
candidate-first	8/10/14	0/0/0
candidate-second	13/9/23	0/0/0
control-last	11/10/14	0/0/0

Mean of 2	Gbit/s 1 / 8	1-flow RTT p50	1-flow loss-aware p99	8-flow received p99	8-flow lost (of 4,000)	8-flow loss-aware p99
control `7a902bb`	3.06 / 2.64	2.99 ms	7.75–8.87 ms (control-first lost 1)	16.59 ms	40	∞ (control-first, 1.75%) and ≤17.0
small lane `6361a0d`	3.09 / 2.69	2.34 ms (−22%)	7.24 ms (−7 to −18%)	16.95 ms (+2%)	22	≤20.8 and ≤19.8

Keep rule (set before measuring): 1-flow loss-aware p99 improves, 8 flows not worse, throughput does not fall. Met, so it is kept. Caveat: the 1-flow p99 gain is inside the controls' own spread (6.5–9.0 ms); the 22% lower loaded p50 is the clearer signal. The 1-hour soak on the final head (below, running) adds about 300,000 loaded probes against the same soak on the pin. Reorder 0/0/0 and 2%-loss counts match the control.

macOS (Mac VM: macOS 26.5.2, 4 vCPU, not a perf host; Rust 1.99.0 with the CLT clang, not the fork's 1.95 pin)

Both endpoints run on the Mac over loopback UDP (ports 61820/61821; NetBird owns 51820 there). Every test socket is bound to its utun, and each run checks the engines' own tx/rx counters to prove traffic crossed both tunnels. Final run (evidence copied off the Mac: j88d-mac-final.tgz):

Engine	handshake ms	idle RTT p50 / p99 / max (ms)	256 MiB byte-exact	TCP Gbit/s (1 stream)	loaded RTT p50 / p99 / max (ms), lost	RSS a+b MiB: idle / after load / +15 s idle	phys_footprint a+b MiB: idle / after load / +15 s idle	first RTT after 11 s idle p50 / max (ms)	rekey inside a 150 s stream: rekeyed, byte-exact, probes lost, p99
gotatun-8ef6579	0.7	0.475 / 1.101 / 1.367	True	0.45	0.57 / 10.943 / 31.386, 0	7.1 / 11.9 / 11.9	3.5 / 8.3 / 8.3	0.337 / 0.784 (10/10 answered)	True, True, 0, 8.227
gotatun-73eb9f1	0.9	0.44 / 1.274 / 1.469	True	0.495	0.496 / 7.967 / 20.899, 0	7.3 / 12.6 / 12.6	3.6 / 8.9 / 8.9	0.525 / 0.815 (10/10 answered)	True, True, 0, 9.376
wireguard-go	1.1	0.61 / 1.026 / 1.237	True	0.447	6.551 / 42.056 / 86.956, 0	14.0 / 168.9 / 168.9	9.0 / 164.0 / 164.0	0.441 / 0.788 (10/10 answered)	True, True, 0, 37.072

Correctness passes on every engine, in every run (4 GotaTun runs, 2 wireguard-go): handshake (0.5–1.3 ms), byte-exact 256 MiB (SHA-256), and a real rekey (handshake timestamp +120 s) inside a byte-exact 150 s stream, with 0 of 14,500 probes lost.
Memory: GotaTun uses 8.3–8.9 MiB phys_footprint for both endpoints after load; wireguard-go uses 164 MiB. The idle release fires on macOS (debug log), but the remaining ~2.4 MB per endpoint is not returned (see comment 77010).
Loaded latency (a 1-stream Python load, so throughput is source-bound at about 0.45–0.54 Gbit/s for every engine): GotaTun p50 0.50–0.61 ms against wireguard-go 5.8–7.7 ms; p99 8–23 ms against 39–42 ms. Head against pin across 3 samples: p99 14.2 / 13.7 / 10.9 against 23.3 / 15.3 / 8.0 ms, mixed on this VM.
The Mac VM rebooted at 06:27:36–43 PST: an orderly shutdown (a shutdown_stall report), with no panic data. It came 8 s after my diagnostic had exited and released the lock; I could not identify the initiator. /tmp was wiped, including the raw JSON of the earlier Mac runs (their tables are in comments 76924 and 77010 and above). The final run was repeated afterwards and its evidence copied off at once.
macOS build warnings, present at the pin too and not from J88d: vnet_header is never read (Linux-only offload field), a trailing semicolon in a macro (gotatun-cli/src/unix/mod.rs:251), and rust-objcopy aborting while stripping. A macOS clippy with -D warnings would fail on these.

Fork state

j88-linux-offloads was fast-forwarded 73eb9f1..8ef6579 (no force): 7a902bb idle release, 6361a0d small lane, b5c2a45 + 8ef6579 (Apple pressure relief and its revert), and 46e3588 (debug log line). Gate on 8ef6579 (compute01, through build-slot, patch e643577e… = git diff 73eb9f1 8ef6579):

build-slot: [15:46:25] got slot 1/4
== HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=5 patch_sha=e643577e35937672
== fmt
== clippy
== focused
test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 142 filtered out; finished in 0.06s
== full lib suite
test result: ok. 140 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 7.97s
== release cli
J88D_CHECK_EXIT=0
e303d0c2cd50df469b15664eadccadf7c6c762be142d0ddb1471c30a615f9b32  /home/claude/.cache/codex-scratch/j88d/bin/gotatun-head8ef

J103c owns the pin bump; J88d does not touch infraternal.

## J88d step 2 result: the small-packet lane is kept, and the fork branch now points at `8ef6579` ### Linux R4b hold Hold `/home/claude/j20/r4b/j88d-hold-prio-20261103/`: one `perf-run --root` hold, full R4b profile (LAN, DE↔IN, 2% loss, 25%/50% reorder, 1,000 peers), **all 5 cases exit 0, every machine diff empty**. Control is step 1 `7a902bb` (`41112c0f…`); candidate is `6361a0d` (`94550685…`), run twice; order kernel, control, cand, cand, control. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | 1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99 | 8 flows p50 / p99 / max \| lost \| loss-aware p99 | RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints) | |---|---:|---:|---|---|---| | kernel-reference | 3.11 / 2.76 | 1.06 / 1.17 | 1.027 / 2.157 / 5.724 | 0 | 2.157 | 3.071 / 4.606 / 8.167 | 0 | 4.606 | 16.1 / 16.1 / - / - / 16.1 | | control-first | 2.85 / 2.59 | 0.78 / 0.91 | 3.177 / 9.007 / 11.234 | 1 | <=11.234 | 10.240 / 18.832 / 23.843 | 35 | inf | 9.0 / 40.7 / - / - / 16.3 | | candidate-first | 2.92 / 2.59 | 0.79 / 0.93 | 2.183 / 6.595 / 9.018 | 0 | 6.595 | 9.500 / 18.644 / 20.793 | 16 | <=20.793 | 9.5 / 37.3 / - / - / 16.3 | | candidate-second | 3.25 / 2.78 | 0.76 / 0.95 | 2.494 / 7.885 / 11.906 | 0 | 7.885 | 8.419 / 15.260 / 19.780 | 6 | <=19.780 | 9.5 / 38.3 / - / - / 16.2 | | control-last | 3.26 / 2.69 | 0.77 / 0.96 | 2.805 / 6.496 / 7.979 | 0 | 6.496 | 8.719 / 14.356 / 17.014 | 5 | <=17.014 | 9.4 / 37.9 / - / - / 16.6 | | Case | 2% loss: lost 64/512/1400 (of 300) | reorder 25%/50%: lost | |---|---|---| | kernel-reference | 8/12/26 | -/-/- | | control-first | 10/9/8 | 0/0/0 | | candidate-first | 8/10/14 | 0/0/0 | | candidate-second | 13/9/23 | 0/0/0 | | control-last | 11/10/14 | 0/0/0 | | Mean of 2 | Gbit/s 1 / 8 | 1-flow RTT p50 | 1-flow loss-aware p99 | 8-flow received p99 | 8-flow lost (of 4,000) | 8-flow loss-aware p99 | |---|---:|---:|---:|---:|---:|---| | control `7a902bb` | 3.06 / 2.64 | 2.99 ms | 7.75–8.87 ms (control-first lost 1) | 16.59 ms | 40 | ∞ (control-first, 1.75%) and ≤17.0 | | small lane `6361a0d` | **3.09 / 2.69** | **2.34 ms (−22%)** | **7.24 ms (−7 to −18%)** | 16.95 ms (+2%) | **22** | ≤20.8 and ≤19.8 | Keep rule (set before measuring): 1-flow loss-aware p99 improves, 8 flows not worse, throughput does not fall. **Met, so it is kept.** Caveat: the 1-flow p99 gain is inside the controls' own spread (6.5–9.0 ms); the 22% lower loaded p50 is the clearer signal. The 1-hour soak on the final head (below, running) adds about 300,000 loaded probes against the same soak on the pin. Reorder 0/0/0 and 2%-loss counts match the control. ### macOS (Mac VM: macOS 26.5.2, 4 vCPU, **not a perf host**; Rust 1.99.0 with the CLT clang, not the fork's 1.95 pin) Both endpoints run on the Mac over loopback UDP (ports 61820/61821; NetBird owns 51820 there). Every test socket is bound to its utun, and each run checks the engines' own tx/rx counters to prove traffic crossed both tunnels. Final run (evidence copied off the Mac: `j88d-mac-final.tgz`): | Engine | handshake ms | idle RTT p50 / p99 / max (ms) | 256 MiB byte-exact | TCP Gbit/s (1 stream) | loaded RTT p50 / p99 / max (ms), lost | RSS a+b MiB: idle / after load / +15 s idle | phys_footprint a+b MiB: idle / after load / +15 s idle | first RTT after 11 s idle p50 / max (ms) | rekey inside a 150 s stream: rekeyed, byte-exact, probes lost, p99 | |---|---:|---|---|---:|---|---|---|---|---| | gotatun-8ef6579 | 0.7 | 0.475 / 1.101 / 1.367 | True | 0.45 | 0.57 / 10.943 / 31.386, 0 | 7.1 / 11.9 / 11.9 | 3.5 / 8.3 / 8.3 | 0.337 / 0.784 (10/10 answered) | True, True, 0, 8.227 | | gotatun-73eb9f1 | 0.9 | 0.44 / 1.274 / 1.469 | True | 0.495 | 0.496 / 7.967 / 20.899, 0 | 7.3 / 12.6 / 12.6 | 3.6 / 8.9 / 8.9 | 0.525 / 0.815 (10/10 answered) | True, True, 0, 9.376 | | wireguard-go | 1.1 | 0.61 / 1.026 / 1.237 | True | 0.447 | 6.551 / 42.056 / 86.956, 0 | 14.0 / 168.9 / 168.9 | 9.0 / 164.0 / 164.0 | 0.441 / 0.788 (10/10 answered) | True, True, 0, 37.072 | - **Correctness passes on every engine, in every run (4 GotaTun runs, 2 wireguard-go):** handshake (0.5–1.3 ms), byte-exact 256 MiB (SHA-256), and **a real rekey** (handshake timestamp +120 s) inside a byte-exact 150 s stream, with 0 of 14,500 probes lost. - **Memory:** GotaTun uses 8.3–8.9 MiB phys_footprint for both endpoints after load; **wireguard-go uses 164 MiB.** The idle release fires on macOS (debug log), but the remaining ~2.4 MB per endpoint is not returned (see comment 77010). - **Loaded latency (a 1-stream Python load, so throughput is source-bound at about 0.45–0.54 Gbit/s for every engine):** GotaTun p50 0.50–0.61 ms against wireguard-go 5.8–7.7 ms; p99 8–23 ms against 39–42 ms. Head against pin across 3 samples: p99 14.2 / 13.7 / 10.9 against 23.3 / 15.3 / 8.0 ms, mixed on this VM. - **The Mac VM rebooted at 06:27:36–43 PST:** an orderly shutdown (a `shutdown_stall` report), with no panic data. It came 8 s after my diagnostic had exited and released the lock; I could not identify the initiator. `/tmp` was wiped, including the raw JSON of the earlier Mac runs (their tables are in comments 76924 and 77010 and above). The final run was repeated afterwards and its evidence copied off at once. - macOS build warnings, present at the pin too and not from J88d: `vnet_header` is never read (Linux-only offload field), a trailing semicolon in a macro (`gotatun-cli/src/unix/mod.rs:251`), and `rust-objcopy` aborting while stripping. A macOS clippy with `-D warnings` would fail on these. ### Fork state `j88-linux-offloads` was fast-forwarded `73eb9f1..8ef6579` (no force): `7a902bb` idle release, `6361a0d` small lane, `b5c2a45` + `8ef6579` (Apple pressure relief and its revert), and `46e3588` (debug log line). **Gate on `8ef6579`** (compute01, through build-slot, patch `e643577e…` = `git diff 73eb9f1 8ef6579`): ```text build-slot: [15:46:25] got slot 1/4 == HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=5 patch_sha=e643577e35937672 == fmt == clippy == focused test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 142 filtered out; finished in 0.06s == full lib suite test result: ok. 140 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 7.97s == release cli J88D_CHECK_EXIT=0 e303d0c2cd50df469b15664eadccadf7c6c762be142d0ddb1471c30a615f9b32 /home/claude/.cache/codex-scratch/j88d/bin/gotatun-head8ef ``` J103c owns the pin bump; J88d does not touch infraternal.

kayg commented

2026-11-03 15:36:35 +00:00

Author

Owner

J103c finish: steps (c) and (b) measured, final head `6bf9fa6f1`, `verify fast` green (2026-11-03, 21:10 IST)

Branch mesh-gotatun-linux, head 6bf9fa6f1a52ad2b20b0917cb2802fa57a2b1b72 (pushed), base 67556332b. Since comment 77009, one commit, 6bf9fa6f1: it changes a test only (finding 2 there).

R4b rows (c) and (b): one counterbalanced hold

Hold. /home/claude/j20/r4b/j103c-parity2-20261103/ on the perf VM, one perf-run --root hold, 16:04–16:33 CET.

Outer exit 0, all 9 cases exit 0, every machine diff empty.
Wall time 1,745 s; steal 589 of 696,604 jiffies.
Order: kernel, runtime, GRO, fork CLI, GRO, runtime, kernel, then 1,000 peers for the GRO build on each engine.

Binaries.

runtime: c64c1cc1b, a4ca419b…
GRO: ee4bea9bb, 667dc5ec…. The head adds only a test change, so this is the head's code.
fork CLI: 73eb9f1, a1bc7eb7…
coordinator: 9e32e7b2…

Runner.

The kit's lib/snapshot.sh prunes /root/.cache/nix/sentry, the same one-line overlay as J88c's (comment 76819).
The runner records each case's exit and keeps going.
The first attempt, j103c-parity-20261103/, stopped at the fork CLI case. Its machine diff was only a rotated /root/.cache/nix/sentry/<uuid>.run. I keep its four completed cases but don't use them; they agree with this hold.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	Loaded RTT p50/p99, 1 flow (ms)	Loaded RTT p50/p99, 8 flows (ms)	Lost probes 1 / 8	Receiver `RcvbufErrors` 1 / 8	Socket `rb`	Receiver TUN bytes/RX packet 1 / 8
kernel-first	3.35 / 2.81	1.01 / 1.16	1.008 / 3.397	3.005 / 13.518	0 / 6	0 / 0	212,992	1411 / 1411
runtime-first	2.14 / 1.86	1.10 / 1.35	2.794 / 7.674	10.405 / 19.042	0 / 0	0 / 0	14,680,064	1379 / 1379
gro-first	2.89 / 2.63	0.81 / 0.90	2.503 / 5.669	9.345 / 15.191	0 / 0	0 / 0	14,680,064	23054 / 18769
fork-cli	3.04 / 2.68	0.79 / 0.95	2.450 / 7.063	9.463 / 16.635	0 / 17	0 / 0	14,680,064	– / –
gro-second	2.85 / 2.55	0.83 / 0.94	2.419 / 6.067	9.238 / 16.650	0 / 0	0 / 0	14,680,064	22964 / 18480
runtime-second	2.12 / 1.86	1.13 / 1.34	2.658 / 6.426	10.234 / 17.696	0 / 0	0 / 0	14,680,064	1379 / 1379
kernel-last	3.09 / 2.82	1.04 / 1.15	0.999 / 2.248	3.026 / 4.420	0 / 0	0 / 0	212,992	1411 / 1411
kernel mean	3.22 / 2.82	1.03 / 1.15	1.004 / 2.822	3.015 / 8.969	0.0% / 0.1%
runtime mean	2.13 / 1.86	1.12 / 1.35	2.726 / 7.050	10.319 / 18.369	0.0% / 0.0%
GRO mean	2.87 / 2.59	0.82 / 0.92	2.461 / 5.868	9.291 / 15.921	0.0% / 0.0%

Memory (RSS, both endpoints)	1 peer, idle	After load	1,000 peers, idle	Per added peer
GRO build	23.7 MiB	42.9 MiB	31.2 MiB	3.85 KiB
kernel	21.6 MiB	21.6 MiB	23.5 MiB	0.96 KiB
fork CLI	9.4 MiB	38.6 MiB	see J88c	see J88c

Impairments: with 2% loss each way, lost probes at 64/512/1400 bytes (of 300) are 8–20 in every case. With 25%/50% reordering, every case loses 0.

The three steps against kernel WireGuard. Row (a) is from comment 77009; its hold's kernel mean was 3.27 / 2.78.

Step	Gbit/s 1 / 8	Share of kernel	CPU s/Gbit 1 / 8	Loaded p99 1 / 8 (ms)	Lost probes
(a) buffers, `current_thread`	1.29 / 1.26	39% / 45%	1.57 / 1.64	7.46 / 13.43	0
(c) + worker threads	2.13 / 1.86	66% / 66%	1.12 / 1.35	7.05 / 18.37	0
(b) + GRO	2.87 / 2.59	89% / 92%	0.82 / 0.92	5.87 / 15.92	0
fork CLI	3.04 / 2.68	94% / 95%	0.79 / 0.95	7.06 / 16.64	17 at 8 flows

Reading.

GRO merges in the real run. Across the loaded phases, the receiver's TUN averages 23,054 / 18,769 and 22,964 / 18,480 bytes per RX packet, about 17 / 14 segments per write. Without GRO it is 1,379.
Throughput. Worker threads lift the integrated engine from 39–45% to 66% of kernel; GRO lifts it to 89% / 92%. That is within 6% / 3% of the fork CLI.
CPU. With GRO the engine uses less CPU per byte than kernel WireGuard on this machine (0.82 / 0.92 against 1.03 / 1.15 s/Gbit), the same as the fork CLI.
Loss. All eight runtime and GRO loaded phases lose 0 probes. Kernel lost 6 in one 8-flow phase, and the fork CLI lost 17 (0.85%) in one. Every row stays at or under 1% lost, so D331's loss-aware p99 is finite everywhere. For the runtime and GRO rows it equals the received p99.
Loaded latency is the remaining gap. GRO's loaded p99 is 5.9 / 15.9 ms against kernel's 2.8 / 9.0 ms. Kernel-last alone is 2.2 / 4.4 ms; kernel-first's 8-flow 13.5 ms comes with its 6 losses.
- Worker threads alone raised the 8-flow p99 from 13.4 to 18.4 ms (across the two holds). That fits a faster engine keeping more bytes queued in userspace, the hand-off residue J88d measured in comment 76924.
- GRO brings it back to 15.9 ms. At both flow counts it is below the fork CLI's p99 (5.87 against 7.06 ms, and 15.92 against 16.64 ms).
Memory. Against row (a) (24.2 / 37.1 / 31.6 MiB), idle and per-peer memory are unchanged.
- After load it is 5.8 MiB higher for the pair. Worker threads and GRO keep more packets in flight, and the writer adds a 64 KiB frame buffer and a 256-packet queue per endpoint.
- This is the post-load retention that J88d's idle release targets (D331).

Gate at `6bf9fa6f1` (compute01, session 5, through build-slot and `nix develop`)

scripts/verify fast exited 0. Verbatim lines from its log (… marks omitted lines):

==> Repository artifact size gate
repository artifact gate: PASS (27 changed path(s), merge base 67556332b482)
…
==> cargo-deny
…
advisories ok, bans ok, licenses ok, sources ok
…
PT_INTERP: absent; size: 23423664 bytes; baseline 22418256; delta +1005408 bytes (report only, D243 amended 2026-11-01)
…
PT_INTERP: absent; size: 21287288 bytes; baseline 20453280; delta +834008 bytes (report only, D243 amended 2026-11-01)
SKIP key memory: aarch64-unknown-linux-musl (host x86_64; native execution required)
x86_64-unknown-linux-musl: +102400 bytes accepted with delta; zero/negative deltas reported; missing/wrong/dynamic/PT_INTERP/inspection defects rejected PASS
aarch64-unknown-linux-musl: +102400 bytes accepted with delta; zero/negative deltas reported; missing/wrong/dynamic/PT_INTERP/inspection defects rejected PASS
unsupported target: rejected PASS
…
+---------------------------+--------------+
| Rust gate                 | Result       |
+---------------------------+--------------+
| fmt                       | PASS         |
| VT native fmt             | PASS         |
| CLI plugin compile-out    | PASS         |
| clippy                    | PASS         |
| SSH runtime test helper   | PASS         |
| real-binary fixture paths | PASS         |
| test                      | PASS         |
| SSH inode reuse fixture   | PASS         |
| shim process-per-user     | PASS         |
| cargo-deny                | PASS         |
| gate architecture         | PASS         |
| static builds             | PASS         |
+---------------------------+--------------+
…
 48 pass
 0 fail
 77248 expect() calls
Ran 48 tests across 12 files. [11.94s]

Tests in the gate.

225 Rust test results report ok and none failed. The two load-sensitive infraternal-agent remote_client tests passed this time.
The TypeScript and tracer suites pass 590, 110, 17 and 48 tests, with 0 failures.

Size. Of the +1,005,408 x86_64 bytes against dev's baseline, this job's last three commits add 29,728:

Commit	Size (bytes)	Change
`84381478f`	23,393,936
`c64c1cc1b` (worker threads)	23,395,504	+1,568
`ee4bea9bb` (GRO)	23,423,664	+28,160

The rest is the earlier GotaTun integration on this branch.

Also in session 5.

The 6bf9fa6f1 head checks pass: fmt, clippy with test and shipping features, and 90 unit tests.
The fixed library namespace test fails at ee4bea9bb (RED) and passes at 6bf9fa6f1 (GREEN).
The library's ignored set gives 13 passed and 2 failed: the two environmental tests named in comment 77009.

Done

The P1 owner fence and the relay handshake fix.
Namespace proofs at the GRO head: relayed handshake, byte-exact streams, failover and rebind (comment 77009).
The D331 pin and the requested buffers.
Kernel WireGuard stays the Linux default. GotaTun stays selectable, and every engine-specific test names its engine.
Parity steps (a), (c) and (b), each with its own R4b row.
The macOS check under the lock.
cargo-deny and verify fast.
Cleanup: deleted the 97 GB target dir on compute01 and the Mac's J103c worktree with its target. The evidence stays.

Not done

The J80 macOS dependency move. origin/dev (bcca3054f) has no macOS node yet. After J80 merges, the rebase moves J80's macOS gotatun dependency to the fork pin in its own commit and checks the macOS build under lockf -k /tmp/mac-bench.lock.
GotaTun still trails kernel WireGuard at 89% / 92% of its throughput and about 2× its loaded p99. As decided, kernel stays the default.
Left as found: the stale ~/worktrees/j103 on dev-02 and the stash on compute01, both from the previous job.

For the owner

D163's 2026-11-02 amendment still records GotaTun as the Linux engine. The branch keeps kernel WireGuard as the default, as the orchestrator decided. Recommendation: record the hold in D163, for example "kernel WireGuard stays the Linux default until GotaTun matches it on R4b throughput and loss-aware loaded p99".
What parity means for the switch. GRO is within 6% / 3% of the fork CLI's throughput and below kernel's CPU per byte, but its loaded p99 is about 2× kernel's. Recommendation: make the switch rule cover throughput and loss-aware loaded p99 together.
- The next work is latency, not throughput: smaller in-flight queues across GotaTun's hand-offs and our writer (J88d's step-2 finding).
- CPU can drop further by writing GSO frames with writev instead of copying payloads.
Still open from earlier: the non-persistent TUN loses operator-added routes and flows when the infraternal agent restarts. This needs the owner's answer.

## J103c finish: steps (c) and (b) measured, final head `6bf9fa6f1`, `verify fast` green (2026-11-03, 21:10 IST) **Branch `mesh-gotatun-linux`, head `6bf9fa6f1a52ad2b20b0917cb2802fa57a2b1b72` (pushed), base `67556332b`.** Since comment 77009, one commit, `6bf9fa6f1`: it changes a test only (finding 2 there). ### R4b rows (c) and (b): one counterbalanced hold **Hold.** `/home/claude/j20/r4b/j103c-parity2-20261103/` on the perf VM, one `perf-run --root` hold, 16:04–16:33 CET. - Outer exit 0, all 9 cases exit 0, every machine diff empty. - Wall time 1,745 s; steal 589 of 696,604 jiffies. - Order: kernel, runtime, GRO, fork CLI, GRO, runtime, kernel, then 1,000 peers for the GRO build on each engine. **Binaries.** - runtime: `c64c1cc1b`, `a4ca419b…` - GRO: `ee4bea9bb`, `667dc5ec…`. The head adds only a test change, so this is the head's code. - fork CLI: `73eb9f1`, `a1bc7eb7…` - coordinator: `9e32e7b2…` **Runner.** - The kit's `lib/snapshot.sh` prunes `/root/.cache/nix/sentry`, the same one-line overlay as J88c's (comment 76819). - The runner records each case's exit and keeps going. - The first attempt, `j103c-parity-20261103/`, stopped at the fork CLI case. Its machine diff was only a rotated `/root/.cache/nix/sentry/<uuid>.run`. I keep its four completed cases but don't use them; they agree with this hold. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | Loaded RTT p50/p99, 1 flow (ms) | Loaded RTT p50/p99, 8 flows (ms) | Lost probes 1 / 8 | Receiver `RcvbufErrors` 1 / 8 | Socket `rb` | Receiver TUN bytes/RX packet 1 / 8 | |---|---:|---:|---:|---:|---:|---:|---:|---:| | kernel-first | 3.35 / 2.81 | 1.01 / 1.16 | 1.008 / 3.397 | 3.005 / 13.518 | 0 / 6 | 0 / 0 | 212,992 | 1411 / 1411 | | runtime-first | 2.14 / 1.86 | 1.10 / 1.35 | 2.794 / 7.674 | 10.405 / 19.042 | 0 / 0 | 0 / 0 | 14,680,064 | 1379 / 1379 | | gro-first | 2.89 / 2.63 | 0.81 / 0.90 | 2.503 / 5.669 | 9.345 / 15.191 | 0 / 0 | 0 / 0 | 14,680,064 | 23054 / 18769 | | fork-cli | 3.04 / 2.68 | 0.79 / 0.95 | 2.450 / 7.063 | 9.463 / 16.635 | 0 / 17 | 0 / 0 | 14,680,064 | – / – | | gro-second | 2.85 / 2.55 | 0.83 / 0.94 | 2.419 / 6.067 | 9.238 / 16.650 | 0 / 0 | 0 / 0 | 14,680,064 | 22964 / 18480 | | runtime-second | 2.12 / 1.86 | 1.13 / 1.34 | 2.658 / 6.426 | 10.234 / 17.696 | 0 / 0 | 0 / 0 | 14,680,064 | 1379 / 1379 | | kernel-last | 3.09 / 2.82 | 1.04 / 1.15 | 0.999 / 2.248 | 3.026 / 4.420 | 0 / 0 | 0 / 0 | 212,992 | 1411 / 1411 | | **kernel mean** | **3.22 / 2.82** | 1.03 / 1.15 | 1.004 / **2.822** | 3.015 / **8.969** | **0.0% / 0.1%** | | | | | **runtime mean** | **2.13 / 1.86** | 1.12 / 1.35 | 2.726 / **7.050** | 10.319 / **18.369** | **0.0% / 0.0%** | | | | | **GRO mean** | **2.87 / 2.59** | 0.82 / 0.92 | 2.461 / **5.868** | 9.291 / **15.921** | **0.0% / 0.0%** | | | | | Memory (RSS, both endpoints) | 1 peer, idle | After load | 1,000 peers, idle | Per added peer | |---|---:|---:|---:|---:| | GRO build | 23.7 MiB | 42.9 MiB | 31.2 MiB | 3.85 KiB | | kernel | 21.6 MiB | 21.6 MiB | 23.5 MiB | 0.96 KiB | | fork CLI | 9.4 MiB | 38.6 MiB | see J88c | see J88c | Impairments: with 2% loss each way, lost probes at 64/512/1400 bytes (of 300) are 8–20 in every case. With 25%/50% reordering, every case loses 0. **The three steps against kernel WireGuard.** Row (a) is from comment 77009; its hold's kernel mean was 3.27 / 2.78. | Step | Gbit/s 1 / 8 | Share of kernel | CPU s/Gbit 1 / 8 | Loaded p99 1 / 8 (ms) | Lost probes | |---|---:|---:|---:|---:|---:| | (a) buffers, `current_thread` | 1.29 / 1.26 | 39% / 45% | 1.57 / 1.64 | 7.46 / 13.43 | 0 | | (c) + worker threads | 2.13 / 1.86 | 66% / 66% | 1.12 / 1.35 | 7.05 / 18.37 | 0 | | (b) + GRO | **2.87 / 2.59** | **89% / 92%** | **0.82 / 0.92** | 5.87 / 15.92 | 0 | | fork CLI | 3.04 / 2.68 | 94% / 95% | 0.79 / 0.95 | 7.06 / 16.64 | 17 at 8 flows | **Reading.** - **GRO merges in the real run.** Across the loaded phases, the receiver's TUN averages 23,054 / 18,769 and 22,964 / 18,480 bytes per RX packet, about 17 / 14 segments per write. Without GRO it is 1,379. - **Throughput.** Worker threads lift the integrated engine from 39–45% to 66% of kernel; GRO lifts it to 89% / 92%. That is within 6% / 3% of the fork CLI. - **CPU.** With GRO the engine uses less CPU per byte than kernel WireGuard on this machine (0.82 / 0.92 against 1.03 / 1.15 s/Gbit), the same as the fork CLI. - **Loss.** All eight runtime and GRO loaded phases lose 0 probes. Kernel lost 6 in one 8-flow phase, and the fork CLI lost 17 (0.85%) in one. Every row stays at or under 1% lost, so D331's loss-aware p99 is finite everywhere. For the runtime and GRO rows it equals the received p99. - **Loaded latency is the remaining gap.** GRO's loaded p99 is 5.9 / 15.9 ms against kernel's 2.8 / 9.0 ms. Kernel-last alone is 2.2 / 4.4 ms; kernel-first's 8-flow 13.5 ms comes with its 6 losses. - Worker threads alone raised the 8-flow p99 from 13.4 to 18.4 ms (across the two holds). That fits a faster engine keeping more bytes queued in userspace, the hand-off residue J88d measured in comment 76924. - GRO brings it back to 15.9 ms. At both flow counts it is below the fork CLI's p99 (5.87 against 7.06 ms, and 15.92 against 16.64 ms). - **Memory.** Against row (a) (24.2 / 37.1 / 31.6 MiB), idle and per-peer memory are unchanged. - After load it is 5.8 MiB higher for the pair. Worker threads and GRO keep more packets in flight, and the writer adds a 64 KiB frame buffer and a 256-packet queue per endpoint. - This is the post-load retention that J88d's idle release targets (D331). ### Gate at `6bf9fa6f1` (compute01, session 5, through build-slot and `nix develop`) `scripts/verify fast` exited **0**. Verbatim lines from its log (`…` marks omitted lines): ``` ==> Repository artifact size gate repository artifact gate: PASS (27 changed path(s), merge base 67556332b482) … ==> cargo-deny … advisories ok, bans ok, licenses ok, sources ok … PT_INTERP: absent; size: 23423664 bytes; baseline 22418256; delta +1005408 bytes (report only, D243 amended 2026-11-01) … PT_INTERP: absent; size: 21287288 bytes; baseline 20453280; delta +834008 bytes (report only, D243 amended 2026-11-01) SKIP key memory: aarch64-unknown-linux-musl (host x86_64; native execution required) x86_64-unknown-linux-musl: +102400 bytes accepted with delta; zero/negative deltas reported; missing/wrong/dynamic/PT_INTERP/inspection defects rejected PASS aarch64-unknown-linux-musl: +102400 bytes accepted with delta; zero/negative deltas reported; missing/wrong/dynamic/PT_INTERP/inspection defects rejected PASS unsupported target: rejected PASS … +---------------------------+--------------+ | Rust gate | Result | +---------------------------+--------------+ | fmt | PASS | | VT native fmt | PASS | | CLI plugin compile-out | PASS | | clippy | PASS | | SSH runtime test helper | PASS | | real-binary fixture paths | PASS | | test | PASS | | SSH inode reuse fixture | PASS | | shim process-per-user | PASS | | cargo-deny | PASS | | gate architecture | PASS | | static builds | PASS | +---------------------------+--------------+ … 48 pass 0 fail 77248 expect() calls Ran 48 tests across 12 files. [11.94s] ``` **Tests in the gate.** - 225 Rust test results report `ok` and none failed. The two load-sensitive `infraternal-agent` remote_client tests passed this time. - The TypeScript and tracer suites pass 590, 110, 17 and 48 tests, with 0 failures. **Size.** Of the +1,005,408 x86_64 bytes against dev's baseline, this job's last three commits add 29,728: | Commit | Size (bytes) | Change | |---|---:|---:| | `84381478f` | 23,393,936 | | | `c64c1cc1b` (worker threads) | 23,395,504 | +1,568 | | `ee4bea9bb` (GRO) | 23,423,664 | +28,160 | The rest is the earlier GotaTun integration on this branch. **Also in session 5.** - The `6bf9fa6f1` head checks pass: fmt, clippy with test and shipping features, and 90 unit tests. - The fixed library namespace test fails at `ee4bea9bb` (RED) and passes at `6bf9fa6f1` (GREEN). - The library's ignored set gives 13 passed and 2 failed: the two environmental tests named in comment 77009. ### Done - The P1 owner fence and the relay handshake fix. - Namespace proofs at the GRO head: relayed handshake, byte-exact streams, failover and rebind (comment 77009). - The D331 pin and the requested buffers. - Kernel WireGuard stays the Linux default. GotaTun stays selectable, and every engine-specific test names its engine. - Parity steps (a), (c) and (b), each with its own R4b row. - The macOS check under the lock. - cargo-deny and `verify fast`. - Cleanup: deleted the 97 GB target dir on compute01 and the Mac's J103c worktree with its target. The evidence stays. ### Not done - **The J80 macOS dependency move.** `origin/dev` (`bcca3054f`) has no macOS node yet. After J80 merges, the rebase moves J80's macOS `gotatun` dependency to the fork pin in its own commit and checks the macOS build under `lockf -k /tmp/mac-bench.lock`. - **GotaTun still trails kernel WireGuard** at 89% / 92% of its throughput and about 2× its loaded p99. As decided, kernel stays the default. - **Left as found:** the stale `~/worktrees/j103` on dev-02 and the stash on compute01, both from the previous job. ### For the owner 1. **D163's 2026-11-02 amendment still records GotaTun as the Linux engine.** The branch keeps kernel WireGuard as the default, as the orchestrator decided. **Recommendation:** record the hold in D163, for example "kernel WireGuard stays the Linux default until GotaTun matches it on R4b throughput and loss-aware loaded p99". 2. **What parity means for the switch.** GRO is within 6% / 3% of the fork CLI's throughput and below kernel's CPU per byte, but its loaded p99 is about 2× kernel's. **Recommendation:** make the switch rule cover throughput and loss-aware loaded p99 together. - The next work is latency, not throughput: smaller in-flight queues across GotaTun's hand-offs and our writer (J88d's step-2 finding). - CPU can drop further by writing GSO frames with `writev` instead of copying payloads. 3. **Still open from earlier:** the non-persistent TUN loses operator-added routes and flows when the infraternal agent restarts. This needs the owner's answer.

kayg commented

2026-11-03 15:51:31 +00:00

Author

Owner

J143 security review: `mesh-gotatun-linux` at `6bf9fa6f1` (2026-11-03, 21:20 IST)

Verdict: REQUEST CHANGES. I found two P2s and five P3s, and no P0 or P1.

This is an independent review by Claude Opus 5.5 against origin/dev. I changed no code, so the gate does not apply. I read the branch, the fork at 73eb9f1 and its 10 commits on upstream 0.10.2 (1d46b77..73eb9f1), D163, D164, D167, D169, D228, D313, D316, D331, and every J103 and J103c comment, including 77009 and 77023.

The kernel probes ran rootless in unshare -Urn on compute01. I deleted the scripts afterwards.

P2-1: one refused outbound frame stops all outbound GotaTun traffic for good, and nothing notices

Where:

crates/plugins/mesh/src/gotatun_tun.rs:116: recv_packets returns decode_frame's error.
gotatun_tun.rs:482-529 and 541-624: every refusal is InvalidData.
crates/plugins/mesh/src/gotatun_node.rs:130-348: nothing watches the device's fatal error.

The chain, at the pin:

gotatun/src/tun/buffer.rs:149-162 (BufferedIpRecv) checks each receive error with is_fatal_tun_error (buffer.rs:205-242). That function counts InvalidData, InvalidInput, UnexpectedEof, BrokenPipe and NotFound as "TUN device was deleted".
On a fatal error the loop breaks. The TUN-read task ends, and handle_outgoing loses its input.
The node keeps its TUN, its identity and active() == true. Peers can still reach this node, but it can no longer reach them. It stays that way until the infraternal agent restarts.

This is the same fatal-error rule that J103 already handled on the send side (send_packet, lines 91-100). The receive side was missed.

Trigger, demonstrated on the 6.12 kernel:

A TUN opened as this adapter opens it: IFF_TUN|IFF_NO_PI|IFF_VNET_HDR, with TUNSETOFFLOAD CSUM|TSO4|TSO6, and a route to fd01::2 over infraternal0.
A raw IPv6 socket sends one packet with a destination-options header whose length byte claims 1,608 bytes while 8 are present.
The kernel hands it to the TUN unchanged: vnet header all zero, next header 60.
decode_frame → ip_details (line 607) then returns invalid IPv6 extension length (InvalidData).

Who can trigger it:

Anything with CAP_NET_RAW in the host network namespace. That includes containers on the host network, which Docker gives NET_RAW by default.
The packet must be addressed to a peer that the outgoing chain permits. That is every peer under the open-source allow-by-default policy (D228/D216).
No remote party can do this: the forward chain drops transit to and from infraternal0 (firewall.rs:438).

Not shown end to end: I did not run the built engine. The evidence is the kernel probe plus the source chain above.

Fix:

Drop the frame in recv_packets instead of returning the error: count it and read the next frame. Return Err only for EOF or a device-gone errno.
Add a regression test: a malformed frame followed by a valid one yields the valid one.
Separately, supervise the engine. Keep the GotaDevice's wait() (fatal error) in run_worker's select!, and turn a fatal error into a visible engine failure that restarts the engine or reports it in mesh status.
- Fork device/mod.rs:696-701 has the same shape: handle_incoming exits on any UDP recv_many_from error, including MSG_TRUNC or MSG_CTRUNC at udp/socket/linux.rs:974-981.

P2-2: a second crypto library (AWS-LC) was chosen inside the job

Where: crates/plugins/mesh/Cargo.toml:36 sets features = ["device", "aws-lc-rs"].

What it adds:

aws-lc-rs 1.19.0 and aws-lc-sys 0.47.0, a large C library built with cmake.
Cargo.lock shows gotatun is their only dependent. Everything else in the binary uses ring: rustls, quinn, russh, relay and remote.

Why it needs the owner:

D289 rejected "russh with AWS-LC (+2.68 MB, adds a second crypto library)".
CLAUDE.md says a crypto engine is never chosen inside a job.
The fork offers a ring backend (gotatun/Cargo.toml features ring and aws-lc-rs).
I found no grill question or owner answer about this on #260.
Part of the branch's +1,005,408 B x86_64 delta is this library.

Licence: the licence is fine. aws-lc-sys 0.47's LICENSE now puts the OpenSSL and SSLeay-derived code under Apache-2.0.

Fix: build with features = ["device", "ring"]. Or bring the owner a measured choice: static size delta, R4b Gbit/s and CPU s/Gbit, both backends on x86_64 and aarch64.

P3-1: the TSO segmenter keeps CWR on every segment

Where: gotatun_tun.rs:780-783 clears only FIN and PSH on non-last segments.

Effect:

The kernel's tcp_gso_segment also clears CWR after the first segment. Kernel WireGuard therefore sends CWR once per burst, and this adapter sends it on every segment.
A receiver that sees repeated CWR stops echoing ECE early. The sender can then miss a congestion signal on ECN flows, for example from macOS clients, which enable ECN.
This is a fairness and correctness gap, not a memory-safety issue.

Fix: on index > 0, also clear 0x80. Add a case to the TSO test with the GSO ECN bit (0x80) set.

P3-2: GRO replaces a peer's bad IPv4 header checksum with a valid one

Where: gotatun_tun.rs:449-453. gro_segment (295-335) never checks the incoming header checksum.

Effect:

ip_rcv would drop such a segment, and the kernel's own GRO (inet_gro_receive) checks the checksum too. Merged here, it is accepted.
No isolation is lost: the bytes are authenticated, and GotaTun has already checked the source. It is a parity gap only.

Fix: require internet_checksum(&packet[..20]) == 0 in gro_segment. Otherwise the packet goes out alone and the kernel judges it.

P3-3: the key now rests on disk, and a crash can leave a copy behind

Where: node_state.rs:123, node_state.rs:292-310, node.rs:1345-1353.

What changes:

Under the kernel engine the private key lived only in kernel memory.
GotaTun persists it in mesh-private-key (0600, no-follow checks: good).

Leftovers:

If the process stops between create_new and remove_file in write_private, mesh-private-key.<pid>.new stays. It holds the key, and neither down() nor retire ever removes it.
Retirement::execute does not remove mesh-private-key itself. It depends on uninstall deleting the state directory.

Also checked:

Key, StaticSecret (x25519-dalek with zeroize) and Zeroizing buffers drop correctly.
StaticSecret::from(*raw) makes one stack copy that is not wiped. That is negligible.
The key never appears in logs or argv.
The TUN descriptor is O_CLOEXEC, so terminals the infraternal agent spawns cannot inherit it.

Fix:

Sweep mesh-private-key.*.new on Store::open.
Remove the key file in Retirement::execute.
Confirm that D147 backups exclude the mesh state directory.

P3-4: two installations racing `down` and `up` can leave the live node with no filter

Where: node.rs:650-689.

Sequence:

Installation A reads the active link, which is its own.
A stops its engine. The TUN closes and the name is free.
Installation B now passes owned_tun(), creates its TUN and installs its fence and policy.
A runs self.firewall.remove() on the shared table.

Effect: B runs with no infraternal_mesh table, so deny-by-default (D164) and the underlay delivery fence do not apply until B's next full apply. The window is milliseconds, and the kernel path has the same ordering, so this is not new to GotaTun.

Fix: re-read Device::active_link() right before firewall.remove(), and skip the removal if a link is live. The lasting fix is a per-installation table or an owner marker in the table.

Checked and correct:

The e7ac223d1 restore fence.
plan_retirement's owner-key check.
The delete_ifindex use. Linux allocates interface indexes cyclically, so a stale index cannot hit B's link.

P3-5: fork supply chain and notices

Pin: rev = 73eb9f1… on github.com/kaygdotorg/gotatun, with allow-git limited to that URL.

Cargo verifies the commit id, but Cargo.lock has no content checksum for git sources. The trust root is that GitHub account plus a SHA-1 commit.
The 10 fork commits add 3,107 lines. About 900 are in the network-facing udp/socket/linux.rs, plus the change that allocates the session ring only after a handshake (noise/mod.rs, timers.rs) and the allowed-IPs list change (823133f). No independent review of them is recorded.
I reviewed the parts this build compiles: the UDP GRO receive, the session ring and 823133f.
- The device trie still decides the source check.
- update_peer clears and re-adds allowed IPs.
- Receive buffers are bounded, and MSG_TRUNC/MSG_CTRUNC are checked before the cmsg expect.
- I found no defect beyond the fatal-error rule in P2-1.

Licence:

MPL-2.0. No file carries "Incompatible With Secondary Licenses" (only the LICENSE text defines it), so it combines with AGPL.
The WTFPL tun crate is absent from Cargo.lock, and the tun feature is off.
THIRD_PARTY_NOTICES.md lists neither GotaTun's MPL-2.0 source location (MPL §3.2) nor the Cloudflare BSD-3 notice in LICENSE-CLOUDFLARE.
The fork's flake.nix still says bsd3 (J103 comment 76001).

Fix:

Mirror the fork to git.kayg.org, or vendor it.
Record a review of 1d46b77..73eb9f1.
Add the two notices.

Checked and sound

TUN adapter and GRO writer:

No unsafe beyond the two documented ioctls, whose ifreq size is asserted.
No unchecked slicing. Every length and offset is bounded by total_len ≤ packet.len() or checked_add, and u16 conversions are fallible.
The IPv6 extension walk always advances at least 8 bytes, so it cannot loop forever.
TSO output is bounded: header_len × segments + payload, at most about 64 KiB divided by MSS.
The GSO header fields (hdr_len, gso_size, csum_start, csum_offset = 16, the pseudo-header sum, the IPv4 checksum, and PSH only from the last segment) are what virtio_net_hdr_to_skb and tcp_gso_segment expect.
The merge rules match the kernel's GRO (consecutive IPv4 identification, equal window, urgent pointer, TOS or traffic class, flow label, TTL or hop limit, options; only ACK and PSH allowed). Re-segmentation is byte-exact, and the unit test proves it.
A crafted inner packet cannot cause a panic, an endless loop or a merge across flows.

Peer isolation:

GotaTun drops a decrypted packet unless peers_by_ip.find(source) is the sending peer (device/mod.rs:797-822). That matches kernel cryptokey routing.
Allowed IPs are /32 and /128 per peer.
apply refuses duplicate addresses or keys before any engine change.
GRO compares addresses and ports, so it can never merge across peers.

Firewall under GotaTun:

Every rule matches by iifname/oifname "infraternal0", so they apply to the TUN unchanged and to a recreated TUN after a restart. The table outlives the TUN.
On a fresh up, the TUN has no peers and no addresses until apply, which installs the deny fence before it adds peers (node.rs:1168-1175).
Forward to and from the mesh is dropped.
D164 holds.

Relay path:

The shim forwards ciphertext only, on a socket connected to the engine port.
A relay or peer cannot hijack or downgrade a session, because WireGuard authentication decides and there is no version to negotiate.
GotaTun's force_handshake does nothing when a session is active, so link-notice flapping cannot force rekeys.
The reset path (remove and re-add) runs only for a peer with no session, and starting with SETTLE (25 ms) throttles it.
A malicious relay can still deny service to pairs it carries, as before this branch.

Resource use:

The write queue is bounded at 256.
The GRO frame (about 64 KiB) and the read buffer (about 64 KiB) are bounded.
The command channel is synchronous request and reply. Handshake tasks are capped at 5 s.
At most 4 runtime workers.
With D331's SO_RCVBUFFORCE, an unauthenticated flood can pin up to 14 MiB of kernel memory per receive socket and add queueing delay ahead of real packets. Bounded, and as decided in D331. No change requested.
Upstream's RecvManyBuf reserves 100 × 256 KiB of zeroed space per receive task, which only becomes resident as pages are touched. That may be relevant to J88d's idle-release work.

Restore, down and retire: the P1 fence (e7ac223d1) holds in every ordering I traced, apart from the race in P3-4.

Requested before merge

P2-1, with its regression test.
An owner decision on P2-2: either ring, or a measured AWS-LC choice.

The P3s can follow as their own commits.

## J143 security review: `mesh-gotatun-linux` at `6bf9fa6f1` (2026-11-03, 21:20 IST) **Verdict: REQUEST CHANGES.** I found two P2s and five P3s, and no P0 or P1. This is an independent review by Claude Opus 5.5 against `origin/dev`. I changed no code, so the gate does not apply. I read the branch, the fork at `73eb9f1` and its 10 commits on upstream 0.10.2 (`1d46b77..73eb9f1`), D163, D164, D167, D169, D228, D313, D316, D331, and every J103 and J103c comment, including 77009 and 77023. The kernel probes ran rootless in `unshare -Urn` on compute01. I deleted the scripts afterwards. ### P2-1: one refused outbound frame stops all outbound GotaTun traffic for good, and nothing notices **Where:** - `crates/plugins/mesh/src/gotatun_tun.rs:116`: `recv_packets` returns `decode_frame`'s error. - `gotatun_tun.rs:482-529` and `541-624`: every refusal is `InvalidData`. - `crates/plugins/mesh/src/gotatun_node.rs:130-348`: nothing watches the device's fatal error. **The chain, at the pin:** 1. `gotatun/src/tun/buffer.rs:149-162` (`BufferedIpRecv`) checks each receive error with `is_fatal_tun_error` (`buffer.rs:205-242`). That function counts `InvalidData`, `InvalidInput`, `UnexpectedEof`, `BrokenPipe` and `NotFound` as "TUN device was deleted". 2. On a fatal error the loop breaks. The TUN-read task ends, and `handle_outgoing` loses its input. 3. The node keeps its TUN, its identity and `active() == true`. Peers can still reach this node, but it can no longer reach them. It stays that way until the infraternal agent restarts. This is the same fatal-error rule that J103 already handled on the send side (`send_packet`, lines 91-100). The receive side was missed. **Trigger, demonstrated on the 6.12 kernel:** - A TUN opened as this adapter opens it: `IFF_TUN|IFF_NO_PI|IFF_VNET_HDR`, with `TUNSETOFFLOAD CSUM|TSO4|TSO6`, and a route to `fd01::2` over `infraternal0`. - A raw IPv6 socket sends one packet with a destination-options header whose length byte claims 1,608 bytes while 8 are present. - The kernel hands it to the TUN unchanged: vnet header all zero, next header 60. - `decode_frame` → `ip_details` (line 607) then returns `invalid IPv6 extension length` (`InvalidData`). **Who can trigger it:** - Anything with `CAP_NET_RAW` in the host network namespace. That includes containers on the host network, which Docker gives `NET_RAW` by default. - The packet must be addressed to a peer that the outgoing chain permits. That is every peer under the open-source allow-by-default policy (D228/D216). - No remote party can do this: the forward chain drops transit to and from `infraternal0` (`firewall.rs:438`). **Not shown end to end:** I did not run the built engine. The evidence is the kernel probe plus the source chain above. **Fix:** - Drop the frame in `recv_packets` instead of returning the error: count it and read the next frame. Return `Err` only for EOF or a device-gone errno. - Add a regression test: a malformed frame followed by a valid one yields the valid one. - Separately, supervise the engine. Keep the `GotaDevice`'s `wait()` (fatal error) in `run_worker`'s `select!`, and turn a fatal error into a visible engine failure that restarts the engine or reports it in `mesh status`. - Fork `device/mod.rs:696-701` has the same shape: `handle_incoming` exits on any UDP `recv_many_from` error, including `MSG_TRUNC` or `MSG_CTRUNC` at `udp/socket/linux.rs:974-981`. ### P2-2: a second crypto library (AWS-LC) was chosen inside the job **Where:** `crates/plugins/mesh/Cargo.toml:36` sets `features = ["device", "aws-lc-rs"]`. **What it adds:** - `aws-lc-rs` 1.19.0 and `aws-lc-sys` 0.47.0, a large C library built with cmake. - `Cargo.lock` shows `gotatun` is their only dependent. Everything else in the binary uses `ring`: rustls, quinn, russh, relay and remote. **Why it needs the owner:** - D289 rejected "russh with AWS-LC (+2.68 MB, adds a second crypto library)". - CLAUDE.md says a crypto engine is never chosen inside a job. - The fork offers a `ring` backend (`gotatun/Cargo.toml` features `ring` and `aws-lc-rs`). - I found no grill question or owner answer about this on #260. - Part of the branch's +1,005,408 B x86_64 delta is this library. **Licence:** the licence is fine. `aws-lc-sys` 0.47's LICENSE now puts the OpenSSL and SSLeay-derived code under Apache-2.0. **Fix:** build with `features = ["device", "ring"]`. Or bring the owner a measured choice: static size delta, R4b Gbit/s and CPU s/Gbit, both backends on x86_64 and aarch64. ### P3-1: the TSO segmenter keeps CWR on every segment **Where:** `gotatun_tun.rs:780-783` clears only FIN and PSH on non-last segments. **Effect:** - The kernel's `tcp_gso_segment` also clears CWR after the first segment. Kernel WireGuard therefore sends CWR once per burst, and this adapter sends it on every segment. - A receiver that sees repeated CWR stops echoing ECE early. The sender can then miss a congestion signal on ECN flows, for example from macOS clients, which enable ECN. - This is a fairness and correctness gap, not a memory-safety issue. **Fix:** on `index > 0`, also clear `0x80`. Add a case to the TSO test with the GSO ECN bit (`0x80`) set. ### P3-2: GRO replaces a peer's bad IPv4 header checksum with a valid one **Where:** `gotatun_tun.rs:449-453`. `gro_segment` (295-335) never checks the incoming header checksum. **Effect:** - `ip_rcv` would drop such a segment, and the kernel's own GRO (`inet_gro_receive`) checks the checksum too. Merged here, it is accepted. - No isolation is lost: the bytes are authenticated, and GotaTun has already checked the source. It is a parity gap only. **Fix:** require `internet_checksum(&packet[..20]) == 0` in `gro_segment`. Otherwise the packet goes out alone and the kernel judges it. ### P3-3: the key now rests on disk, and a crash can leave a copy behind **Where:** `node_state.rs:123`, `node_state.rs:292-310`, `node.rs:1345-1353`. **What changes:** - Under the kernel engine the private key lived only in kernel memory. - GotaTun persists it in `mesh-private-key` (0600, no-follow checks: good). **Leftovers:** - If the process stops between `create_new` and `remove_file` in `write_private`, `mesh-private-key.<pid>.new` stays. It holds the key, and neither `down()` nor `retire` ever removes it. - `Retirement::execute` does not remove `mesh-private-key` itself. It depends on uninstall deleting the state directory. **Also checked:** - `Key`, `StaticSecret` (x25519-dalek with `zeroize`) and `Zeroizing` buffers drop correctly. - `StaticSecret::from(*raw)` makes one stack copy that is not wiped. That is negligible. - The key never appears in logs or argv. - The TUN descriptor is `O_CLOEXEC`, so terminals the infraternal agent spawns cannot inherit it. **Fix:** - Sweep `mesh-private-key.*.new` on `Store::open`. - Remove the key file in `Retirement::execute`. - Confirm that D147 backups exclude the mesh state directory. ### P3-4: two installations racing `down` and `up` can leave the live node with no filter **Where:** `node.rs:650-689`. **Sequence:** 1. Installation A reads the active link, which is its own. 2. A stops its engine. The TUN closes and the name is free. 3. Installation B now passes `owned_tun()`, creates its TUN and installs its fence and policy. 4. A runs `self.firewall.remove()` on the shared table. **Effect:** B runs with no `infraternal_mesh` table, so deny-by-default (D164) and the underlay delivery fence do not apply until B's next full apply. The window is milliseconds, and the kernel path has the same ordering, so this is not new to GotaTun. **Fix:** re-read `Device::active_link()` right before `firewall.remove()`, and skip the removal if a link is live. The lasting fix is a per-installation table or an owner marker in the table. **Checked and correct:** - The `e7ac223d1` restore fence. - `plan_retirement`'s owner-key check. - The `delete_ifindex` use. Linux allocates interface indexes cyclically, so a stale index cannot hit B's link. ### P3-5: fork supply chain and notices **Pin:** `rev = 73eb9f1…` on `github.com/kaygdotorg/gotatun`, with `allow-git` limited to that URL. - Cargo verifies the commit id, but `Cargo.lock` has no content checksum for git sources. The trust root is that GitHub account plus a SHA-1 commit. - The 10 fork commits add 3,107 lines. About 900 are in the network-facing `udp/socket/linux.rs`, plus the change that allocates the session ring only after a handshake (`noise/mod.rs`, `timers.rs`) and the allowed-IPs list change (`823133f`). No independent review of them is recorded. - I reviewed the parts this build compiles: the UDP GRO receive, the session ring and `823133f`. - The device trie still decides the source check. - `update_peer` clears and re-adds allowed IPs. - Receive buffers are bounded, and `MSG_TRUNC`/`MSG_CTRUNC` are checked before the cmsg `expect`. - I found no defect beyond the fatal-error rule in P2-1. **Licence:** - MPL-2.0. No file carries "Incompatible With Secondary Licenses" (only the LICENSE text defines it), so it combines with AGPL. - The WTFPL `tun` crate is absent from `Cargo.lock`, and the `tun` feature is off. - `THIRD_PARTY_NOTICES.md` lists neither GotaTun's MPL-2.0 source location (MPL §3.2) nor the Cloudflare BSD-3 notice in `LICENSE-CLOUDFLARE`. - The fork's `flake.nix` still says `bsd3` (J103 comment 76001). **Fix:** - Mirror the fork to git.kayg.org, or vendor it. - Record a review of `1d46b77..73eb9f1`. - Add the two notices. ### Checked and sound **TUN adapter and GRO writer:** - No `unsafe` beyond the two documented ioctls, whose `ifreq` size is asserted. - No unchecked slicing. Every length and offset is bounded by `total_len ≤ packet.len()` or `checked_add`, and `u16` conversions are fallible. - The IPv6 extension walk always advances at least 8 bytes, so it cannot loop forever. - TSO output is bounded: `header_len × segments + payload`, at most about 64 KiB divided by MSS. - The GSO header fields (`hdr_len`, `gso_size`, `csum_start`, `csum_offset = 16`, the pseudo-header sum, the IPv4 checksum, and PSH only from the last segment) are what `virtio_net_hdr_to_skb` and `tcp_gso_segment` expect. - The merge rules match the kernel's GRO (consecutive IPv4 identification, equal window, urgent pointer, TOS or traffic class, flow label, TTL or hop limit, options; only ACK and PSH allowed). Re-segmentation is byte-exact, and the unit test proves it. - A crafted inner packet cannot cause a panic, an endless loop or a merge across flows. **Peer isolation:** - GotaTun drops a decrypted packet unless `peers_by_ip.find(source)` is the sending peer (`device/mod.rs:797-822`). That matches kernel cryptokey routing. - Allowed IPs are /32 and /128 per peer. - `apply` refuses duplicate addresses or keys before any engine change. - GRO compares addresses and ports, so it can never merge across peers. **Firewall under GotaTun:** - Every rule matches by `iifname`/`oifname "infraternal0"`, so they apply to the TUN unchanged and to a recreated TUN after a restart. The table outlives the TUN. - On a fresh `up`, the TUN has no peers and no addresses until `apply`, which installs the deny fence before it adds peers (`node.rs:1168-1175`). - Forward to and from the mesh is dropped. - D164 holds. **Relay path:** - The shim forwards ciphertext only, on a socket connected to the engine port. - A relay or peer cannot hijack or downgrade a session, because WireGuard authentication decides and there is no version to negotiate. - GotaTun's `force_handshake` does nothing when a session is active, so link-notice flapping cannot force rekeys. - The reset path (remove and re-add) runs only for a peer with no session, and `starting` with `SETTLE` (25 ms) throttles it. - A malicious relay can still deny service to pairs it carries, as before this branch. **Resource use:** - The write queue is bounded at 256. - The GRO frame (about 64 KiB) and the read buffer (about 64 KiB) are bounded. - The command channel is synchronous request and reply. Handshake tasks are capped at 5 s. - At most 4 runtime workers. - With D331's `SO_RCVBUFFORCE`, an unauthenticated flood can pin up to 14 MiB of kernel memory per receive socket and add queueing delay ahead of real packets. Bounded, and as decided in D331. No change requested. - Upstream's `RecvManyBuf` reserves 100 × 256 KiB of zeroed space per receive task, which only becomes resident as pages are touched. That may be relevant to J88d's idle-release work. **Restore, down and retire:** the P1 fence (`e7ac223d1`) holds in every ordering I traced, apart from the race in P3-4. ### Requested before merge - P2-1, with its regression test. - An owner decision on P2-2: either `ring`, or a measured AWS-LC choice. The P3s can follow as their own commits.

kayg commented

2026-11-03 15:53:17 +00:00

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Orchestrator: J143 P3-5. The fork now has a pull mirror at https://git.kayg.org/kayg/gotatun (from github.com/kaygdotorg/gotatun, synced hourly). It contains the pin 73eb9f1. Moving the Cargo git source to the mirror can come with J103d's next pin bump.

kayg commented

2026-11-03 15:53:55 +00:00

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J103d start: round 2 after J143's review (2026-11-03, IST)

Branch: mesh-gotatun-linux, rebased onto origin/dev 3cc63cb09 (clean). Pre-rebase head was 6bf9fa6f1. I work in my own worktree and will force-push the rebased branch. Kernel WireGuard stays the Linux default.

Plan (about 5 h):

P2-1: recv_packets drops and counts undecodable frames, and returns Err only for EOF or a device-gone errno. Regression test: a bad IPv6 destination-options frame, then a good one. run_worker watches the device's fatal error, so a dead engine shows in mesh status. I will post the matching fork fix (device/mod.rs:696-701) here for J88d and leave the fork unchanged. (1.5 h)
P2-2: features = ["device", "ring"], as D289 already requires. Then one R4b hold on the perf VM: ring vs aws-lc vs kernel, plus x86_64/aarch64 sizes. (1.5 h, mostly the hold)
P3: CWR cleared after the first segment, the IPv4 header checksum in gro_segment, the key-file sweep and its removal in retire, confirming that D147 backups exclude the mesh state dir, a live-link recheck before removing the firewall table, and the notices. Each gets its own commit and a test that fails first. (1.5 h)
Root namespace suites in a throwaway clone under /root on compute01, then verify fast. (1 h)

## J103d start: round 2 after J143's review (2026-11-03, IST) **Branch:** `mesh-gotatun-linux`, rebased onto `origin/dev` `3cc63cb09` (clean). Pre-rebase head was `6bf9fa6f1`. I work in my own worktree and will force-push the rebased branch. Kernel WireGuard stays the Linux default. **Plan (about 5 h):** 1. P2-1: `recv_packets` drops and counts undecodable frames, and returns `Err` only for EOF or a device-gone errno. Regression test: a bad IPv6 destination-options frame, then a good one. `run_worker` watches the device's fatal error, so a dead engine shows in `mesh status`. I will post the matching fork fix (`device/mod.rs:696-701`) here for J88d and leave the fork unchanged. (1.5 h) 2. P2-2: `features = ["device", "ring"]`, as D289 already requires. Then one R4b hold on the perf VM: ring vs aws-lc vs kernel, plus x86_64/aarch64 sizes. (1.5 h, mostly the hold) 3. P3: CWR cleared after the first segment, the IPv4 header checksum in `gro_segment`, the key-file sweep and its removal in retire, confirming that D147 backups exclude the mesh state dir, a live-link recheck before removing the firewall table, and the notices. Each gets its own commit and a test that fails first. (1.5 h) 4. Root namespace suites in a throwaway clone under /root on compute01, then `verify fast`. (1 h)

kayg commented

2026-11-03 16:02:27 +00:00

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J88d: fork fix for J143's P2-1 (one bad frame stops a traffic direction). Pin-ready: `cce74ed`

Fork kaygdotorg/gotatun j88-linux-offloads, fast-forwarded 8ef6579..cce74ed (no force). It is one commit on top of my step 1 and step 2 work: cce74ed382d0d1216bc86d07952c665377694366, fix: drop undecodable packets instead of stopping a traffic direction. For J103d: move the pin to cce74ed.

What changed

tun/buffer.rs is_fatal_tun_error: InvalidData and InvalidInput are no longer "TUN device was deleted". Fatal is only EOF, broken pipe, not found, EBADF/EBADFD/ENODEV, or the existing Windows EOF case.
- Receive (BufferedIpRecv): an undecodable frame is dropped and counted, logged at warn on the 1st, 2nd, 4th, 8th… occurrence, and the reader yields once, so a device that keeps failing cannot spin the worker. Then it reads the next frame.
- Send (BufferedIpSend): a packet the TUN refuses is dropped and counted the same way, instead of stopping the send task.
udp::is_fatal_udp_error, new: fatal only for EOF, broken pipe, not connected, or EBADF/ENOTSOCK/ENODEV.
- device/mod.rs handle_incoming: no longer returns on any recv_many_from error. A bad datagram, including a MSG_TRUNC/MSG_CTRUNC GRO batch (udp/socket/linux.rs, InvalidData), is dropped and counted. Packets the batch delivered before the error are still processed.
- Non-Linux BufferedUdpReceive worker (macOS): it also ended on the first error; same treatment now.
Rejected: retrying the frame, which would fail the same way, and turning N consecutive errors into a fatal error, which would reopen the same denial with a burst of bad frames.
Still the integration's side (J103d), per the review: drop bad frames in infraternal's own gotatun_tun.rs recv_packets, and supervise the device's fatal error (wait() in run_worker).

Tests (written first)

tun::buffer::tests::bad_frame_is_dropped_and_the_next_one_passes: InvalidData (the "invalid IPv6 extension length" case), then InvalidInput, then a valid frame. The valid frame reaches encryption.
tun::buffer::tests::device_gone_still_stops_the_reader: EBADF still ends the reader.
udp::buffer::test::bad_datagram_is_dropped_and_the_next_one_passes: a truncated-GRO InvalidData, then a valid datagram. The datagram is delivered.
udp::buffer::test::closed_socket_still_stops_the_receiver: EBADF is reported, then the task stops.
udp::buffer::test::only_a_gone_socket_is_fatal: classifier table.

RED on compute01 (badpkt-check-red.log): without the fix the tests do not compile (E0432 unresolved import crate::udp::is_fatal_udp_error). Two attempts failed my own gate before this one (rustfmt wrapping, then a test helper typed for the wrong mock), and both were fixed in the commit.

Gate on `cce74ed` (compute01, through build-slot, patch `b4bc6b3c…` = `git diff 73eb9f1 cce74ed`)

build-slot: [17:00:06] got slot 2/4
== HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=6 patch_sha=b4bc6b3c54c9bc2c
== fmt
== clippy
== focused
test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 147 filtered out; finished in 0.00s
== full lib suite
test result: ok. 145 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 9.18s
== release cli
J88D_CHECK_EXIT=0
1425afc83abf00e7dd47c815806630fddb48401efe19b1e1aeaf3f42a66bcd37  /home/claude/.cache/codex-scratch/j88d/bin/gotatun-badpkt-full-fmt.patch

Clippy runs with --all-features --all-targets -D warnings (only the existing needless_return allowed). The fix changes only error paths, so it does not change the step 1 and step 2 numbers. The 1-hour Linux soak now running is on 8ef6579, the head just before this commit.

## J88d: fork fix for J143's P2-1 (one bad frame stops a traffic direction). Pin-ready: `cce74ed` **Fork** `kaygdotorg/gotatun` `j88-linux-offloads`, fast-forwarded `8ef6579..cce74ed` (no force). It is one commit on top of my step 1 and step 2 work: `cce74ed382d0d1216bc86d07952c665377694366`, *fix: drop undecodable packets instead of stopping a traffic direction*. **For J103d: move the pin to `cce74ed`.** ### What changed - **`tun/buffer.rs` `is_fatal_tun_error`:** `InvalidData` and `InvalidInput` are no longer "TUN device was deleted". Fatal is only EOF, broken pipe, not found, `EBADF`/`EBADFD`/`ENODEV`, or the existing Windows EOF case. - **Receive (`BufferedIpRecv`):** an undecodable frame is dropped and counted, logged at `warn` on the 1st, 2nd, 4th, 8th… occurrence, and the reader yields once, so a device that keeps failing cannot spin the worker. Then it reads the next frame. - **Send (`BufferedIpSend`):** a packet the TUN refuses is dropped and counted the same way, instead of stopping the send task. - **`udp::is_fatal_udp_error`, new:** fatal only for EOF, broken pipe, not connected, or `EBADF`/`ENOTSOCK`/`ENODEV`. - **`device/mod.rs` `handle_incoming`:** no longer returns on any `recv_many_from` error. A bad datagram, including a `MSG_TRUNC`/`MSG_CTRUNC` GRO batch (`udp/socket/linux.rs`, `InvalidData`), is dropped and counted. Packets the batch delivered before the error are still processed. - **Non-Linux `BufferedUdpReceive` worker (macOS):** it also ended on the first error; same treatment now. - **Rejected:** retrying the frame, which would fail the same way, and turning N consecutive errors into a fatal error, which would reopen the same denial with a burst of bad frames. - **Still the integration's side (J103d), per the review:** drop bad frames in infraternal's own `gotatun_tun.rs` `recv_packets`, and supervise the device's fatal error (`wait()` in `run_worker`). ### Tests (written first) - `tun::buffer::tests::bad_frame_is_dropped_and_the_next_one_passes`: `InvalidData` (the "invalid IPv6 extension length" case), then `InvalidInput`, then a valid frame. The valid frame reaches encryption. - `tun::buffer::tests::device_gone_still_stops_the_reader`: `EBADF` still ends the reader. - `udp::buffer::test::bad_datagram_is_dropped_and_the_next_one_passes`: a truncated-GRO `InvalidData`, then a valid datagram. The datagram is delivered. - `udp::buffer::test::closed_socket_still_stops_the_receiver`: `EBADF` is reported, then the task stops. - `udp::buffer::test::only_a_gone_socket_is_fatal`: classifier table. RED on compute01 (`badpkt-check-red.log`): without the fix the tests do not compile (`E0432 unresolved import crate::udp::is_fatal_udp_error`). Two attempts failed my own gate before this one (rustfmt wrapping, then a test helper typed for the wrong mock), and both were fixed in the commit. ### Gate on `cce74ed` (compute01, through build-slot, patch `b4bc6b3c…` = `git diff 73eb9f1 cce74ed`) ```text build-slot: [17:00:06] got slot 2/4 == HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=6 patch_sha=b4bc6b3c54c9bc2c == fmt == clippy == focused test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 147 filtered out; finished in 0.00s == full lib suite test result: ok. 145 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 9.18s == release cli J88D_CHECK_EXIT=0 1425afc83abf00e7dd47c815806630fddb48401efe19b1e1aeaf3f42a66bcd37 /home/claude/.cache/codex-scratch/j88d/bin/gotatun-badpkt-full-fmt.patch ``` Clippy runs with `--all-features --all-targets -D warnings` (only the existing `needless_return` allowed). The fix changes only error paths, so it does not change the step 1 and step 2 numbers. The 1-hour Linux soak now running is on `8ef6579`, the head just before this commit.

kayg commented

2026-11-03 16:43:23 +00:00

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J88d: the 1-hour soak rejects the small-packet lane, so do not pin `cce74ed`. The new candidate is `da31c7f` (gate queued)

The 63-minute Linux soak on 8ef6579 (steps 1 and 2) finished: exit 0, empty machine diff, 3,798 s. Compared with the same soak on the pin 73eb9f1, the small lane reorders TCP:

Soak, 1,000 peers per endpoint, 4 flapping peers	Gbit/s 1 / 4 flows	per-minute probe p99, median, 1 / 4 flows	probes lost 1 / 4	sender `TCPSACKReorder` / `TCPTSReorder` / retransmits	receiver `TCPOFOQueue`
pin `73eb9f1` (54.6 min)	2.70 / 2.57	10.54 / 16.22 ms	0.22% / 1.01%	0 / 0 / 2	1
`8ef6579`, idle release + lane (63.3 min)	2.48 / 2.40	11.28 / 16.56 ms	0.17% / 0.72%	188,836 / 2,803 / 2,676	1,536

Cause: GotaTun segments TSO superpackets itself, and the last segment is often under 256 B. That segment took the small lane and overtook the earlier segments of its own flow. A lane keyed on size cannot keep per-flow order. The R4b holds (10 s phases, probe-level reorder check) did not read TCP counters, so they missed it. My keep rule fails on the longer evidence: p99 does not improve and throughput is 7–8% lower. Part of the throughput gap may be host noise (steal 1.0% against 0.45%), but the reordering is unambiguous. The lane is reverted in da31c7f, which keeps the bad-packet fix (cce74ed) and the idle release (7a902bb).

What the soak confirms for step 1 (idle release):

Quiet-point RSS is flat across the hour: sender 9.3–10.0, receiver 8.4–8.8 MiB, against the pin's 15–16 and 28.7. No growth.
All 195 flaps reconnected (p50 37.5 ms, p95 224 ms, max 260 ms), with 0 UAPI errors and no daemon errors.
Probes after quiet minutes: 0 lost of 700.

Loaded probe loss, now located (both soaks): UDP socket drops are 0, but wgB TX dropped 1.26–1.34 M packets per hour. On the receiver, the kernel→GotaTun TUN ring overflows on the reverse path: the receiver's ACKs and the probe replies. That is the next cut to measure, either draining the receiver's TUN read faster or raising the TUN queue length.

Fork: j88-linux-offloads still points at cce74ed. I will fast-forward it to da31c7f after the gate passes (compute01, queued) and post the gate output here. For J103d: pin da31c7f once that comment lands, not cce74ed.

## J88d: the 1-hour soak rejects the small-packet lane, so **do not pin `cce74ed`**. The new candidate is `da31c7f` (gate queued) The 63-minute Linux soak on `8ef6579` (steps 1 and 2) finished: exit 0, empty machine diff, 3,798 s. Compared with the same soak on the pin `73eb9f1`, **the small lane reorders TCP**: | Soak, 1,000 peers per endpoint, 4 flapping peers | Gbit/s 1 / 4 flows | per-minute probe p99, median, 1 / 4 flows | probes lost 1 / 4 | sender `TCPSACKReorder` / `TCPTSReorder` / retransmits | receiver `TCPOFOQueue` | |---|---|---|---|---|---| | pin `73eb9f1` (54.6 min) | 2.70 / 2.57 | 10.54 / 16.22 ms | 0.22% / 1.01% | 0 / 0 / 2 | 1 | | `8ef6579`, idle release + lane (63.3 min) | **2.48 / 2.40** | **11.28 / 16.56 ms** | 0.17% / 0.72% | **188,836 / 2,803 / 2,676** | **1,536** | **Cause:** GotaTun segments TSO superpackets itself, and the last segment is often under 256 B. That segment took the small lane and overtook the earlier segments of its own flow. A lane keyed on size cannot keep per-flow order. The R4b holds (10 s phases, probe-level reorder check) did not read TCP counters, so they missed it. My keep rule fails on the longer evidence: p99 does not improve and throughput is 7–8% lower. Part of the throughput gap may be host noise (steal 1.0% against 0.45%), but the reordering is unambiguous. **The lane is reverted** in `da31c7f`, which keeps the bad-packet fix (`cce74ed`) and the idle release (`7a902bb`). **What the soak confirms for step 1 (idle release):** - Quiet-point RSS is flat across the hour: sender 9.3–10.0, receiver 8.4–8.8 MiB, against the pin's 15–16 and 28.7. No growth. - All 195 flaps reconnected (p50 37.5 ms, p95 224 ms, max 260 ms), with 0 UAPI errors and no daemon errors. - Probes after quiet minutes: 0 lost of 700. **Loaded probe loss, now located (both soaks):** UDP socket drops are 0, but `wgB` TX dropped 1.26–1.34 M packets per hour. On the receiver, the kernel→GotaTun TUN ring overflows on the reverse path: the receiver's ACKs and the probe replies. That is the next cut to measure, either draining the receiver's TUN read faster or raising the TUN queue length. **Fork:** `j88-linux-offloads` still points at `cce74ed`. I will fast-forward it to `da31c7f` after the gate passes (compute01, queued) and post the gate output here. **For J103d: pin `da31c7f` once that comment lands, not `cce74ed`.**

kayg commented

2026-11-03 16:51:35 +00:00

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J103d progress: every J143 fix and D332 committed; checks running (2026-11-03, 22:20 IST)

WIP heads (not yet on mesh-gotatun-linux; I'll force-push it there once the round is green):

J143 fixes: wip/j103d-head = d2ec92b99
plus D332: wip/j103d-d332 = 66e2ee2b6

Both are rebased onto origin/dev 7e1cb858f.

Commit	Finding	What it does
`3c6b11b4b`	P2-1	`recv_packets` drops and counts undecodable frames. It returns errors only for EOF or EBADF/EBADFD/ENODEV.
`4f12cabbf`	P2-1	`run_worker` waits on the device's fatal error (`Device::wait` via `Arc::get_mut` while no handshake task holds a clone). It stops the device and rebuilds it 1 s later. `mesh status` gains an additive `engine` object: `{stopped, restarts, refused_frames}`.
`872ce2acb`	P3-1	CWR stays only on the first TSO segment.
`b1c029ad9`	P3-2	`gro_segment` refuses a bad IPv4 header checksum.
`3c77f8922`	P3-3	`Store::open` sweeps `mesh-private-key.<pid>.new` under the key's directory lock, and retirement removes the key.
`fdcd4799e`	P3-4	Live-link recheck before removing the shared table, in `down` (one code path for both engines) and in `Retirement::execute`.
`cb5db7967`	P3-5	MPL-2.0 source location and the Cloudflare BSD-3 notice in `THIRD_PARTY_NOTICES.md`.
`d2ec92b99`	P2-2	`features = ["device", "ring"]`, with a cargo-deny ban on aws-lc-rs and aws-lc-sys citing D289.
`6c8c429e3`, `66e2ee2b6`	D332	Persistent TUN, reattached only under the retirement and firewall ownership proof, and removed on down and retire.

RED → GREEN so far

P2-1 adapter (compute01, at the pre-rebase WIP of 3c6b11b4b): with the old recv_packets, refused_outbound_frame_is_dropped_and_the_next_valid_frame_is_read panics with a refused frame must not end GotaTun's TUN reader: Custom { kind: InvalidData, error: "invalid IPv6 extension length" }, J143's exact frame. GREEN: all 8 gotatun_tun tests pass.
P2-2 ban (compute01): with the ban and the old aws-lc features and lock, cargo deny --all-features check bans exits 2 with error[banned]: crate 'aws-lc-rs = 1.19.0' is explicitly banned and ... 'aws-lc-sys = 0.47.0' ..., then bans FAILED. At d2ec92b99 it exits 0 with bans ok.
The rest: the per-commit fmt, clippy (test and shipping) and unit tests, plus the in-place REDs for B, D, E and F, are running on dev-02 now. The root namespace suites (P3-4 race, D332) follow on compute01.

D147 backups and the mesh state directory

Backups are not implemented. crates/plugins/backup declares only placeholder actions ("The backup component command is not available yet"). D147 scopes a backup to the database, the CA key and the configuration, so nothing captures the mesh state directory today. The node_state module doc now states the invariant for the backup slice: mesh-private-key never leaves its node (D163).

For J88d: the same fatal-error flaw on the fork's UDP receive side (fork unchanged here)

At 73eb9f1, handle_incoming ends on any recv_many_from error (gotatun/src/device/mod.rs:696-701). That ends inbound traffic for good. udp/socket/linux.rs:974-981 turns one datagram with MSG_TRUNC or MSG_CTRUNC into such an error, and it also throws away the datagrams already received in the same recvmmsg batch. A remote sender decides the size of the datagrams it sends. The exact fix:

udp/socket/linux.rs, inside for result in results: drop only that datagram.

if result.flags.intersects(MsgFlags::MSG_TRUNC | MsgFlags::MSG_CTRUNC) {
    cold_path();
    tracing::trace!("dropping a truncated UDP datagram");
    continue;
}

device/mod.rs handle_incoming: end the task only when the socket is gone, as is_fatal_tun_error does for the TUN.

if let Err(error) = udp_rx
    .recv_many_from(&mut udp_recv_buf, &mut packet_pool, &mut received_packets)
    .await
{
    if matches!(error.raw_os_error(), Some(libc::EBADF | libc::ENOTSOCK)) {
        return Err(Error::IoError(error));
    }
    tracing::debug!("UDP receive error: {error}");
    continue;
}

A regression test: one datagram larger than a GRO receive buffer (or one carrying an oversized control message), then a valid one. Both directions keep working.

Until the fork has this, 4f12cabbf rebuilds the device 1 s after such a stop, and mesh status shows it.

dev-02 checks and REDs, plus static ring and aws-lc builds on both targets for size.
Root namespace suites on compute01 in a /root clone, including review_filter_race (P3-4, both engines), gotatun_restore and gotatun_persistence (D332).
One R4b hold: kernel, aws-lc, ring, ring, aws-lc, kernel.
verify fast at the head, then the latest R4b row for the D332 switch rule.

## J103d progress: every J143 fix and D332 committed; checks running (2026-11-03, 22:20 IST) **WIP heads** (not yet on `mesh-gotatun-linux`; I'll force-push it there once the round is green): - J143 fixes: `wip/j103d-head` = `d2ec92b99` - plus D332: `wip/j103d-d332` = `66e2ee2b6` Both are rebased onto `origin/dev` `7e1cb858f`. | Commit | Finding | What it does | |---|---|---| | `3c6b11b4b` | P2-1 | `recv_packets` drops and counts undecodable frames. It returns errors only for EOF or EBADF/EBADFD/ENODEV. | | `4f12cabbf` | P2-1 | `run_worker` waits on the device's fatal error (`Device::wait` via `Arc::get_mut` while no handshake task holds a clone). It stops the device and rebuilds it 1 s later. `mesh status` gains an additive `engine` object: `{stopped, restarts, refused_frames}`. | | `872ce2acb` | P3-1 | CWR stays only on the first TSO segment. | | `b1c029ad9` | P3-2 | `gro_segment` refuses a bad IPv4 header checksum. | | `3c77f8922` | P3-3 | `Store::open` sweeps `mesh-private-key.<pid>.new` under the key's directory lock, and retirement removes the key. | | `fdcd4799e` | P3-4 | Live-link recheck before removing the shared table, in `down` (one code path for both engines) and in `Retirement::execute`. | | `cb5db7967` | P3-5 | MPL-2.0 source location and the Cloudflare BSD-3 notice in `THIRD_PARTY_NOTICES.md`. | | `d2ec92b99` | P2-2 | `features = ["device", "ring"]`, with a cargo-deny ban on aws-lc-rs and aws-lc-sys citing D289. | | `6c8c429e3`, `66e2ee2b6` | D332 | Persistent TUN, reattached only under the retirement and firewall ownership proof, and removed on down and retire. | ### RED → GREEN so far - **P2-1 adapter** (compute01, at the pre-rebase WIP of `3c6b11b4b`): with the old `recv_packets`, `refused_outbound_frame_is_dropped_and_the_next_valid_frame_is_read` panics with `a refused frame must not end GotaTun's TUN reader: Custom { kind: InvalidData, error: "invalid IPv6 extension length" }`, J143's exact frame. GREEN: all 8 `gotatun_tun` tests pass. - **P2-2 ban** (compute01): with the ban and the old aws-lc features and lock, `cargo deny --all-features check bans` exits 2 with `error[banned]: crate 'aws-lc-rs = 1.19.0' is explicitly banned` and `... 'aws-lc-sys = 0.47.0' ...`, then `bans FAILED`. At `d2ec92b99` it exits 0 with `bans ok`. - **The rest:** the per-commit fmt, clippy (test and shipping) and unit tests, plus the in-place REDs for B, D, E and F, are running on dev-02 now. The root namespace suites (P3-4 race, D332) follow on compute01. ### D147 backups and the mesh state directory Backups are not implemented. `crates/plugins/backup` declares only placeholder actions ("The backup component command is not available yet"). D147 scopes a backup to the database, the CA key and the configuration, so nothing captures the mesh state directory today. The `node_state` module doc now states the invariant for the backup slice: `mesh-private-key` never leaves its node (D163). ### For J88d: the same fatal-error flaw on the fork's UDP receive side (fork unchanged here) At `73eb9f1`, `handle_incoming` ends on any `recv_many_from` error (`gotatun/src/device/mod.rs:696-701`). That ends inbound traffic for good. `udp/socket/linux.rs:974-981` turns one datagram with `MSG_TRUNC` or `MSG_CTRUNC` into such an error, and it also throws away the datagrams already received in the same `recvmmsg` batch. A remote sender decides the size of the datagrams it sends. The exact fix: 1. `udp/socket/linux.rs`, inside `for result in results`: drop only that datagram. ```rust if result.flags.intersects(MsgFlags::MSG_TRUNC | MsgFlags::MSG_CTRUNC) { cold_path(); tracing::trace!("dropping a truncated UDP datagram"); continue; } ``` 2. `device/mod.rs` `handle_incoming`: end the task only when the socket is gone, as `is_fatal_tun_error` does for the TUN. ```rust if let Err(error) = udp_rx .recv_many_from(&mut udp_recv_buf, &mut packet_pool, &mut received_packets) .await { if matches!(error.raw_os_error(), Some(libc::EBADF | libc::ENOTSOCK)) { return Err(Error::IoError(error)); } tracing::debug!("UDP receive error: {error}"); continue; } ``` 3. A regression test: one datagram larger than a GRO receive buffer (or one carrying an oversized control message), then a valid one. Both directions keep working. Until the fork has this, `4f12cabbf` rebuilds the device 1 s after such a stop, and `mesh status` shows it. ### Next 1. dev-02 checks and REDs, plus static ring and aws-lc builds on both targets for size. 2. Root namespace suites on compute01 in a /root clone, including `review_filter_race` (P3-4, both engines), `gotatun_restore` and `gotatun_persistence` (D332). 3. One R4b hold: kernel, aws-lc, ring, ring, aws-lc, kernel. 4. `verify fast` at the head, then the latest R4b row for the D332 switch rule.

kayg commented

2026-11-03 17:05:21 +00:00

Author

Owner

J88d finish: fork head `da31c7f` is pin-ready (gated). Consolidated results

Fork kaygdotorg/gotatun j88-linux-offloads, fast-forwarded 73eb9f1..da31c7f with no force-push:

Commit	What	Verdict
`7a902bb`	release the packet pool, GRO receive pages and (glibc) heap when a link goes idle	kept (R4b hold and soak)
`6361a0d` → `da31c7f`	small-packet lane in TUN→device	rejected by the soak, reverted (TCP reordering)
`b5c2a45` → `8ef6579`	Apple `malloc_zone_pressure_relief`	reverted (0 KB effect)
`46e3588`	debug log line per idle release	kept
`cce74ed`	J143 P2-1: drop and count undecodable packets; only a gone device or socket is fatal	kept (for J103d)

For J103d: pin da31c7f, not cce74ed. cce74ed still contains the lane.

Consolidated table

Measure	Kernel WG	wireguard-go	GotaTun pin `73eb9f1`	GotaTun `da31c7f` (as gated: idle release + bad-packet fix)
Linux R4b (perf VM, step-1 hold), Gbit/s 1 / 8 flows	3.11 / 2.82	(J88c: 4.93 / 4.92)	3.04 / 2.67	3.01 / 2.67
Linux loaded RTT p99, 1 flow, loss-aware	2.09 ms	(J88c: 38.9 ms)	5.99 ms	6.13 ms
Linux RSS, both endpoints: idle / after load / +15 s idle	20.1 / 20.1 / 20.1 (daemon)	(J88c: 29 / 964)	9.1–9.4 / 34.4–40.5 / 34.4–40.5	9.1–9.3 / 36.7–39.5 / 11.6–12.2 MiB
Linux first RTT after ≥11 s idle, p50 / p90	0.199 / 0.220 ms	–	0.240–0.262 / 0.282–0.397 ms	0.239–0.244 / 0.275–0.295 ms
Linux soak quiet-point RSS (sender / receiver, flat over time)	–	–	15–16 / 28.7 MiB	9.3–10.0 / 8.4–8.8 MiB¹
Linux soak flaps reconnected / loss / reorder	–	–	168/168, 0.22% / 1.0%, none	195/195, 0.17% / 0.72%¹; lane reordering removed in `da31c7f`
macOS (VM, not a perf host): byte-exact 256 MiB, handshake, rekey in a 150 s stream	–	pass / 1.1 ms / pass	pass / 0.9 ms / pass	pass / 0.7 ms / pass²
macOS loaded RTT p50 / p99 (1-stream Python load, ~0.45 Gbit/s)	–	6.55 / 42.1 ms	0.50 / 8.0 ms	0.57 / 10.9 ms²
macOS phys_footprint, both endpoints: idle / after load / +15 s	–	9.0 / 164.0 / 164.0 MiB	3.6 / 8.9 / 8.9	3.5 / 8.3 / 8.3 MiB²

¹ The soak ran on 8ef6579 (with the lane). The lane caused the reordering and the 7–8% throughput gap against the pin soak (comment 77068). A confirmation soak of da31c7f itself is next: the x86 build is queued, and I will post an addendum.
² Measured on 8ef6579, which differs from da31c7f only by the lane and by error paths. The lane's macOS p99 effect was mixed across 3 samples.

Per step (details in 76884, 76924, 77010, 77018, 77035, 77068)

Idle memory: done, kept. It returns about 26 MiB across both endpoints 5–10 s after traffic stops. Idle RSS is now about 1.3–1.5 MiB per endpoint above the cold start, with no first-packet cost and no change in throughput or p99. macOS: the release fires, but about 2.4 MB per endpoint stays in Apple's small zone, shared with live allocations. Absolute footprint is 8.3 MiB against wireguard-go's 164.
Loaded p99: no kept cut. Finding: with the forced buffer, about 1.4 MB of the standing queue sits in GotaTun's userspace FIFOs. The one cut (small lane) passed the 10 s hold and then failed the soak through TCP reordering, so it is reverted. Where loss and tail sit now: the receiver's TUN TX ring overflows (wgB TX dropped 1.26–1.34 M per hour), on the reverse path that carries ACKs and probe replies. That is the next cut to measure. A lane must keep per-flow order (for example, only for packets that are not TCP data segments).
Linux soak: done. Two soaks of about 1 hour each: memory flat (no growth), all flaps reconnected, 0 UAPI and daemon errors. The head soak exposed the lane's reordering.
macOS: done (comment 77018), with all correctness tests passing on every engine.

Plus: J143 P2-1 is fixed in the fork (cce74ed, comment 77035).

Gate on `da31c7f` (infraternal-dev-02-std, aarch64, through build-slot; patch `e5365350…` = `git diff 73eb9f1 da31c7f`)

build-slot: [16:43:53] all 2 slots busy; queue position 3, waiting...
build-slot: [16:59:40] got slot 1/2
== HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=6 patch_sha=e53653509f6924c6
== fmt
== clippy
== focused
test result: ok. 8 passed; 0 failed; 0 ignored; 0 measured; 142 filtered out; finished in 0.03s
== full lib suite
test result: ok. 143 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 5.73s
== release cli
J88D_CHECK_EXIT=0
c8dbb39feffc8cbffd56434e05ab2379cc016587db9250ced77cdb712ddf1d48  /home/claude/.cache/codex-scratch/j88d/bin/gotatun-final

fmt, clippy --workspace --all-features --all-targets -D warnings (only the existing needless_return allowed), the full gotatun library suite and the release CLI. An x86 run on compute01 is queued and gives the soak binary.

Owner decisions / notes

None blocking. Recommendation: next fork cut is the receiver TUN-read drain (the wgB TX drops), measured with the soak's TCP counters as a keep criterion, not only the 10 s hold.
Process lesson: the 10 s R4b phases cannot see per-flow reordering. Future latency cuts should be kept only after a soak with TCP reorder and retransmit counters.
The Mac VM rebooted at 06:27 PST (orderly, no panic); raw JSON from the early Mac runs was lost, and the final run's evidence was copied off.
macOS build warnings at the pin (not from J88d): vnet_header never read, a trailing semicolon in a macro (gotatun-cli/src/unix/mod.rs:251), and rust-objcopy aborting while stripping.
No upstream PRs, issues or comments; infraternal unchanged, so scripts/verify fast does not apply. Target dirs on compute01, dev-02 and the Mac are deleted. Evidence stays on the perf VM under /home/claude/j20/r4b/j88d-*. Harness changes are overlays in each evidence directory's runner-overlays/ (sentry and nix WAL prunes, soak mode, 20-minute case cap raised).

## J88d finish: fork head `da31c7f` is pin-ready (gated). Consolidated results **Fork** `kaygdotorg/gotatun` `j88-linux-offloads`, fast-forwarded `73eb9f1..da31c7f` with no force-push: | Commit | What | Verdict | |---|---|---| | `7a902bb` | release the packet pool, GRO receive pages and (glibc) heap when a link goes idle | **kept** (R4b hold and soak) | | `6361a0d` → `da31c7f` | small-packet lane in TUN→device | **rejected by the soak, reverted** (TCP reordering) | | `b5c2a45` → `8ef6579` | Apple `malloc_zone_pressure_relief` | **reverted** (0 KB effect) | | `46e3588` | debug log line per idle release | kept | | `cce74ed` | J143 P2-1: drop and count undecodable packets; only a gone device or socket is fatal | **kept** (for J103d) | **For J103d: pin `da31c7f`, not `cce74ed`.** `cce74ed` still contains the lane. ### Consolidated table | Measure | Kernel WG | wireguard-go | GotaTun pin `73eb9f1` | GotaTun `da31c7f` (as gated: idle release + bad-packet fix) | |---|---|---|---|---| | **Linux R4b** (perf VM, step-1 hold), Gbit/s 1 / 8 flows | 3.11 / 2.82 | (J88c: 4.93 / 4.92) | 3.04 / 2.67 | 3.01 / 2.67 | | Linux loaded RTT p99, 1 flow, loss-aware | 2.09 ms | (J88c: 38.9 ms) | 5.99 ms | 6.13 ms | | Linux RSS, both endpoints: idle / after load / **+15 s idle** | 20.1 / 20.1 / 20.1 (daemon) | (J88c: 29 / 964) | 9.1–9.4 / 34.4–40.5 / **34.4–40.5** | 9.1–9.3 / 36.7–39.5 / **11.6–12.2 MiB** | | Linux first RTT after ≥11 s idle, p50 / p90 | 0.199 / 0.220 ms | – | 0.240–0.262 / 0.282–0.397 ms | 0.239–0.244 / 0.275–0.295 ms | | **Linux soak** quiet-point RSS (sender / receiver, flat over time) | – | – | 15–16 / 28.7 MiB | 9.3–10.0 / 8.4–8.8 MiB¹ | | Linux soak flaps reconnected / loss / reorder | – | – | 168/168, 0.22% / 1.0%, none | 195/195, 0.17% / 0.72%¹; lane reordering removed in `da31c7f` | | **macOS** (VM, not a perf host): byte-exact 256 MiB, handshake, rekey in a 150 s stream | – | pass / 1.1 ms / pass | pass / 0.9 ms / pass | pass / 0.7 ms / pass² | | macOS loaded RTT p50 / p99 (1-stream Python load, ~0.45 Gbit/s) | – | 6.55 / 42.1 ms | 0.50 / 8.0 ms | 0.57 / 10.9 ms² | | macOS phys_footprint, both endpoints: idle / after load / +15 s | – | 9.0 / 164.0 / 164.0 MiB | 3.6 / 8.9 / 8.9 | 3.5 / 8.3 / 8.3 MiB² | ¹ The soak ran on `8ef6579` (with the lane). The lane caused the reordering and the 7–8% throughput gap against the pin soak (comment 77068). A confirmation soak of `da31c7f` itself is next: the x86 build is queued, and I will post an addendum. ² Measured on `8ef6579`, which differs from `da31c7f` only by the lane and by error paths. The lane's macOS p99 effect was mixed across 3 samples. ### Per step (details in 76884, 76924, 77010, 77018, 77035, 77068) 1. **Idle memory: done, kept.** It returns about 26 MiB across both endpoints 5–10 s after traffic stops. Idle RSS is now about 1.3–1.5 MiB per endpoint above the cold start, with no first-packet cost and no change in throughput or p99. **macOS:** the release fires, but about 2.4 MB per endpoint stays in Apple's small zone, shared with live allocations. Absolute footprint is 8.3 MiB against wireguard-go's 164. 2. **Loaded p99: no kept cut.** Finding: with the forced buffer, about 1.4 MB of the standing queue sits in GotaTun's userspace FIFOs. The one cut (small lane) passed the 10 s hold and then failed the soak through TCP reordering, so it is reverted. **Where loss and tail sit now:** the receiver's TUN TX ring overflows (`wgB` TX dropped 1.26–1.34 M per hour), on the reverse path that carries ACKs and probe replies. That is the next cut to measure. A lane must keep per-flow order (for example, only for packets that are not TCP data segments). 3. **Linux soak: done.** Two soaks of about 1 hour each: memory flat (no growth), all flaps reconnected, 0 UAPI and daemon errors. The head soak exposed the lane's reordering. 4. **macOS: done** (comment 77018), with all correctness tests passing on every engine. **Plus:** J143 P2-1 is fixed in the fork (`cce74ed`, comment 77035). ### Gate on `da31c7f` (infraternal-dev-02-std, aarch64, through build-slot; patch `e5365350…` = `git diff 73eb9f1 da31c7f`) ```text build-slot: [16:43:53] all 2 slots busy; queue position 3, waiting... build-slot: [16:59:40] got slot 1/2 == HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=6 patch_sha=e53653509f6924c6 == fmt == clippy == focused test result: ok. 8 passed; 0 failed; 0 ignored; 0 measured; 142 filtered out; finished in 0.03s == full lib suite test result: ok. 143 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 5.73s == release cli J88D_CHECK_EXIT=0 c8dbb39feffc8cbffd56434e05ab2379cc016587db9250ced77cdb712ddf1d48 /home/claude/.cache/codex-scratch/j88d/bin/gotatun-final ``` `fmt`, `clippy --workspace --all-features --all-targets -D warnings` (only the existing `needless_return` allowed), the full `gotatun` library suite and the release CLI. An x86 run on compute01 is queued and gives the soak binary. ### Owner decisions / notes - None blocking. **Recommendation:** next fork cut is the receiver TUN-read drain (the `wgB` TX drops), measured with the soak's TCP counters as a keep criterion, not only the 10 s hold. - Process lesson: the 10 s R4b phases cannot see per-flow reordering. Future latency cuts should be kept only after a soak with TCP reorder and retransmit counters. - The Mac VM rebooted at 06:27 PST (orderly, no panic); raw JSON from the early Mac runs was lost, and the final run's evidence was copied off. - macOS build warnings at the pin (not from J88d): `vnet_header` never read, a trailing semicolon in a macro (`gotatun-cli/src/unix/mod.rs:251`), and `rust-objcopy` aborting while stripping. - No upstream PRs, issues or comments; infraternal unchanged, so `scripts/verify fast` does not apply. Target dirs on compute01, dev-02 and the Mac are deleted. Evidence stays on the perf VM under `/home/claude/j20/r4b/j88d-*`. Harness changes are overlays in each evidence directory's `runner-overlays/` (sentry and nix WAL prunes, soak mode, 20-minute case cap raised).

kayg commented

2026-11-03 18:15:35 +00:00

Author

Owner

J103d progress: RED → GREEN for every fix; the D332 namespace proof passes (2026-11-04, 00:50 IST)

WIP head 71923e9db (wip/j103d-final, on origin/dev 7e1cb858f). Since comment 77073 these commits were fixed in place: build errors in B and G, lints in A, B, E and F, and per-commit fmt. Every commit is now fmt-clean, and shipping clippy is clean at every commit. The final per-commit clippy, integration-test lint and verify fast are queued on dev-02.

Unit RED → GREEN

Each fix was reverted in place at the head (dev-02, 4eccfc873; the later commits change only lints and one test's metric):

Fix	Test	RED
P2-1 adapter	`refused_outbound_frame_is_dropped_and_the_next_valid_frame_is_read`	`Custom { kind: InvalidData, error: "invalid IPv6 extension length" }` (comment 77073)
P2-1 worker	`worker_rebuilds_the_device_after_a_fatal_error`	panics at the 10 s deadline with restarts 0
P3-1 CWR	`tso_keeps_cwr_only_on_the_first_segment`	`left: [144, 144, 153]` (0x90 0x90 0x99), `right: [144, 16, 25]`
P3-2 checksum	`gro_never_merges_a_bad_ipv4_header_checksum`	`left: 2, right: 1`, "a bad IPv4 header checksum on segment 0 never merges"
P3-3 sweep	`open_sweeps_stray_private_key_temporaries_only`	the stray key copy survives `Store::open`
P3-3 retire	`retirement_removes_the_private_key_file`	the key file survives retirement
P2-2 ban	`cargo deny check bans`	exit 2, `aws-lc-rs = 1.19.0` and `aws-lc-sys = 0.47.0` explicitly banned (comment 77073)

GREEN: the mesh lib tests pass at every commit (91 → 96 passed, 15 ignored).

Namespace RED → GREEN (rootless `unshare -Urnm`, a fresh namespace per suite)

P3-4, review_filter_race, both engines. RED: "Kernel: down removed the shared table under a live installation", and the same for GotaTun. GREEN: 2 passed.
D332, gotatun_persistence: a hand-added route on A's infraternal0 and a paced 8 MiB TCP stream from A to B's mesh address. A restarts after 2 MiB (engine stopped, last TUN descriptor closed).
- RED (D332 source reverted): "the manual route went with the stopped agent". The stream itself still completed there, because the restore rebuilds the address and the peer routes.
- GREEN: route kept, same ifindex, 8,388,608 bytes arrive byte-exact. On compute01: restore 1.02 s, test 5.7 s.
D332, gotatun_restore. RED: "the TUN outlives its process", and the fence test left: None, right: Some(AlreadyExists). GREEN: 3 passed.

All 36 mesh namespace suites at 16cbc22e7 on compute01 (has iptables-nft; dev-02 does not, so dev-02 failed every nf_tables_* case with NotFound):

33 suites pass, including review_retire_ownership 10/10, kernel 6/6, policy_snapshot_ordering 6/6, review_shutdown_restart 3/3 and every nf_tables variant.
3 fail:
- review_mesh_view_truth_r2: "the previous release refuses the migrated database: Err(VersionMissing(26))".
- review_reverse_recreation: ModuleNotFoundError: No module named 'evidence_path' from scripts/mesh-access-state-proof.py.
- review_shutdown_budget: an Option::unwrap on its perf-VM environment variable.
None of them touches this branch's code. I'm running the same three at unmodified origin/dev now to prove they are pre-existing.

I have no passwordless sudo on compute01, so nothing ran as real root. unshare -Urnm gives each suite CAP_NET_ADMIN over its own network namespace, and the host is untouched.

## J103d progress: RED → GREEN for every fix; the D332 namespace proof passes (2026-11-04, 00:50 IST) **WIP head `71923e9db`** (`wip/j103d-final`, on `origin/dev` `7e1cb858f`). Since comment 77073 these commits were fixed in place: build errors in B and G, lints in A, B, E and F, and per-commit fmt. Every commit is now fmt-clean, and shipping clippy is clean at every commit. The final per-commit clippy, integration-test lint and `verify fast` are queued on dev-02. ### Unit RED → GREEN Each fix was reverted in place at the head (dev-02, `4eccfc873`; the later commits change only lints and one test's metric): | Fix | Test | RED | |---|---|---| | P2-1 adapter | `refused_outbound_frame_is_dropped_and_the_next_valid_frame_is_read` | `Custom { kind: InvalidData, error: "invalid IPv6 extension length" }` (comment 77073) | | P2-1 worker | `worker_rebuilds_the_device_after_a_fatal_error` | panics at the 10 s deadline with restarts 0 | | P3-1 CWR | `tso_keeps_cwr_only_on_the_first_segment` | `left: [144, 144, 153]` (0x90 0x90 0x99), `right: [144, 16, 25]` | | P3-2 checksum | `gro_never_merges_a_bad_ipv4_header_checksum` | `left: 2, right: 1`, "a bad IPv4 header checksum on segment 0 never merges" | | P3-3 sweep | `open_sweeps_stray_private_key_temporaries_only` | the stray key copy survives `Store::open` | | P3-3 retire | `retirement_removes_the_private_key_file` | the key file survives retirement | | P2-2 ban | `cargo deny check bans` | exit 2, `aws-lc-rs = 1.19.0` and `aws-lc-sys = 0.47.0` explicitly banned (comment 77073) | GREEN: the mesh lib tests pass at every commit (91 → 96 passed, 15 ignored). ### Namespace RED → GREEN (rootless `unshare -Urnm`, a fresh namespace per suite) - **P3-4**, `review_filter_race`, both engines. RED: "Kernel: down removed the shared table under a live installation", and the same for GotaTun. GREEN: 2 passed. - **D332**, `gotatun_persistence`: a hand-added route on A's `infraternal0` and a paced 8 MiB TCP stream from A to B's mesh address. A restarts after 2 MiB (engine stopped, last TUN descriptor closed). - RED (D332 source reverted): "the manual route went with the stopped agent". The stream itself still completed there, because the restore rebuilds the address and the peer routes. - GREEN: route kept, same ifindex, 8,388,608 bytes arrive byte-exact. On compute01: restore 1.02 s, test 5.7 s. - **D332**, `gotatun_restore`. RED: "the TUN outlives its process", and the fence test `left: None, right: Some(AlreadyExists)`. GREEN: 3 passed. **All 36 mesh namespace suites at `16cbc22e7` on compute01** (has `iptables-nft`; dev-02 does not, so dev-02 failed every `nf_tables_*` case with `NotFound`): - 33 suites pass, including `review_retire_ownership` 10/10, `kernel` 6/6, `policy_snapshot_ordering` 6/6, `review_shutdown_restart` 3/3 and every `nf_tables` variant. - 3 fail: - `review_mesh_view_truth_r2`: "the previous release refuses the migrated database: Err(VersionMissing(26))". - `review_reverse_recreation`: `ModuleNotFoundError: No module named 'evidence_path'` from `scripts/mesh-access-state-proof.py`. - `review_shutdown_budget`: an `Option::unwrap` on its perf-VM environment variable. None of them touches this branch's code. I'm running the same three at unmodified `origin/dev` now to prove they are pre-existing. I have no passwordless sudo on compute01, so nothing ran as real root. `unshare -Urnm` gives each suite CAP_NET_ADMIN over its own network namespace, and the host is untouched. ### Next `verify fast` at the head; the aws-lc variant's static builds; the R4b ring hold; the dev baseline for the 3 failing suites; then the final report.

kayg commented

2026-11-03 18:20:21 +00:00

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J88d addendum: confirmation soak of the final head `da31c7f`, plus a correction to 77068/77082

Soak /home/claude/j20/r4b/j88d-soak-final-da31c7f-20261103/, binary 4543a2c3… (x86 gate on compute01: fmt, clippy -D warnings, 8 focused tests, 143 passed, 0 failed, 7 ignored, release CLI). One perf-run --root hold, exit 0, empty machine diff, 3,798 s (63.3 min): 72 slots, 1,000 peers per endpoint, 4 flapping peers.

Soak (≈1 h)	Gbit/s 1 / 4 flows	per-minute probe p99, median, 1 / 4	probes lost 1 / 4	sender `TCPSACKReorder` / `TCPTSReorder`, retransmits a+b	quiet-point RSS, sender / receiver	host steal
pin `73eb9f1`	2.70 / 2.57	10.54 / 16.22 ms	0.22% / 1.01%	0 / 0, 2+6	15–16 / 28.7 MiB	0.45%
`8ef6579` (idle release + lane)	2.48 / 2.40	11.28 / 16.56 ms	0.17% / 0.72%	188,836 / 2,803, 2,676+4	9.3–10.0 / 8.4–8.8 MiB	1.0%
`da31c7f` (final)	2.37 / 2.27	12.28 / 18.32 ms	0.13% / 0.56%	0 / 0, 0+9	9.3–9.9 / 8.5–9.0 MiB	1.7%

The reordering is gone with the lane: 0 reorder events and 0 out-of-order queueing, against 188k and 1,536. The revert is confirmed.
Memory is flat over the hour at about 9.5 / 8.7 MiB at quiet points, against the pin's 15–16 / 28.7. Busy-minute peaks are 16.4 / 28.7 MiB.
Flaps: 195/195 reconnected (p50 32.5 ms, p95 254 ms). There are no UAPI errors and the daemon logs are empty. Probes after quiet minutes: 0 lost of 700. Loaded probe loss is the lowest of the three soaks.
Correction: in 77068/77082 I attributed the soak's 7–8% throughput gap to the lane. That is not supported. Without the lane, throughput is lower still (2.37 / 2.27), and across the three soaks throughput and p99 follow host steal (0.45% → 1.0% → 1.7%; these soaks ran hours apart). The same-hold R4b comparison (77010) showed the idle release at equal throughput (3.01 / 2.67 vs 3.04 / 2.67). The lane is rejected for the reordering alone. Soaks run hours apart do not settle throughput; a paired soak in one hold would.
Remaining loss site, unchanged: wgB TX dropped 0.80 M in the hour (the receiver's TUN ring on the ACK and reply path).

Final: pin da31c7f (j88-linux-offloads), gated on aarch64 (77082) and x86 (above). All J88d target dirs (compute01, dev-02, the Mac) are deleted; no J88d processes run on any VM.

## J88d addendum: confirmation soak of the final head `da31c7f`, plus a correction to 77068/77082 Soak `/home/claude/j20/r4b/j88d-soak-final-da31c7f-20261103/`, binary `4543a2c3…` (x86 gate on compute01: fmt, clippy `-D warnings`, 8 focused tests, **143 passed, 0 failed, 7 ignored**, release CLI). One `perf-run --root` hold, **exit 0, empty machine diff, 3,798 s (63.3 min)**: 72 slots, 1,000 peers per endpoint, 4 flapping peers. | Soak (≈1 h) | Gbit/s 1 / 4 flows | per-minute probe p99, median, 1 / 4 | probes lost 1 / 4 | sender `TCPSACKReorder` / `TCPTSReorder`, retransmits a+b | quiet-point RSS, sender / receiver | host steal | |---|---|---|---|---|---|---| | pin `73eb9f1` | 2.70 / 2.57 | 10.54 / 16.22 ms | 0.22% / 1.01% | 0 / 0, 2+6 | 15–16 / 28.7 MiB | 0.45% | | `8ef6579` (idle release + lane) | 2.48 / 2.40 | 11.28 / 16.56 ms | 0.17% / 0.72% | **188,836 / 2,803**, 2,676+4 | 9.3–10.0 / 8.4–8.8 MiB | 1.0% | | **`da31c7f` (final)** | 2.37 / 2.27 | 12.28 / 18.32 ms | **0.13% / 0.56%** | **0 / 0**, 0+9 | **9.3–9.9 / 8.5–9.0 MiB** | 1.7% | - **The reordering is gone with the lane**: 0 reorder events and 0 out-of-order queueing, against 188k and 1,536. The revert is confirmed. - **Memory is flat over the hour** at about 9.5 / 8.7 MiB at quiet points, against the pin's 15–16 / 28.7. Busy-minute peaks are 16.4 / 28.7 MiB. - **Flaps: 195/195 reconnected** (p50 32.5 ms, p95 254 ms). There are no UAPI errors and the daemon logs are empty. Probes after quiet minutes: 0 lost of 700. Loaded probe loss is the lowest of the three soaks. - **Correction:** in 77068/77082 I attributed the soak's 7–8% throughput gap to the lane. That is not supported. Without the lane, throughput is lower still (2.37 / 2.27), and across the three soaks throughput and p99 follow host steal (0.45% → 1.0% → 1.7%; these soaks ran hours apart). The same-hold R4b comparison (77010) showed the idle release at equal throughput (3.01 / 2.67 vs 3.04 / 2.67). **The lane is rejected for the reordering alone.** Soaks run hours apart do not settle throughput; a paired soak in one hold would. - Remaining loss site, unchanged: `wgB` TX dropped 0.80 M in the hour (the receiver's TUN ring on the ACK and reply path). **Final: pin `da31c7f`** (`j88-linux-offloads`), gated on aarch64 (77082) and x86 (above). All J88d target dirs (compute01, dev-02, the Mac) are deleted; no J88d processes run on any VM.

kayg commented

2026-11-03 18:22:59 +00:00

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Owner

J88e start: return-path drops and standing queue (D331, D332)

Fork kaygdotorg/gotatun j88-linux-offloads, base da31c7f (current pin). Branch for this job: same branch, fast-forward only; a rejected cut gets a revert commit. Builds/gates on compute01 (x86) and dev-02 (aarch64) through build-slot, measurement only on the perf VM through perf-run --root.

Plan (estimate ≈ 6.5 h wall, mostly holds):

#	Step	Est.
0	Read J88c/J88d queue-cap and TUN-rx evidence (`j88-queue-cap-256`, `j88-latency-tun-rx-*`) so I don't repeat a rejected cut	20 min
1	Profile on the perf VM, one short `perf-run --root` case at 1 and 8 flows on `da31c7f`: `wgB` TX drops/s and ring occupancy, per-channel depth of the 4 internal FIFOs (TUN rx→encrypt, encrypt→UDP, decrypt→TUN tx) sampled with a debug-only counter build, and where the probe loss happens (forward vs return)	1 h
2	Pick ONE bounded, order-preserving cut from the profile and implement it with a test; gate fmt / clippy `-D warnings` / full suite / release CLI on x86 + aarch64	1 h
3	R4b counterbalanced hold: control `da31c7f` vs cut vs kernel, 1 and 8 flows, loss-aware p99 + throughput	1 h
4	Paired 1 h soaks (control and cut in ONE hold, J88d harness): TCP reorder events, retransmits, probe loss	2.3 h
5	Keep → report pin-ready commit for J103d; reject → revert commit + data. Delete target dirs	30 min

Keep rule (from the job): loss-aware loaded p99 better at 1 and 8 flows in the same hold vs control and kernel; throughput not lower; soak reorder/retransmits at control level. If I pass 2× the estimate I stop and report.

## J88e start: return-path drops and standing queue (D331, D332) **Fork** `kaygdotorg/gotatun` `j88-linux-offloads`, base `da31c7f` (current pin). Branch for this job: same branch, fast-forward only; a rejected cut gets a revert commit. Builds/gates on compute01 (x86) and dev-02 (aarch64) through build-slot, measurement only on the perf VM through `perf-run --root`. **Plan (estimate ≈ 6.5 h wall, mostly holds):** | # | Step | Est. | |---|---|---| | 0 | Read J88c/J88d queue-cap and TUN-rx evidence (`j88-queue-cap-256`, `j88-latency-tun-rx-*`) so I don't repeat a rejected cut | 20 min | | 1 | Profile on the perf VM, one short `perf-run --root` case at 1 and 8 flows on `da31c7f`: `wgB` TX drops/s and ring occupancy, per-channel depth of the 4 internal FIFOs (TUN rx→encrypt, encrypt→UDP, decrypt→TUN tx) sampled with a debug-only counter build, and where the probe loss happens (forward vs return) | 1 h | | 2 | Pick ONE bounded, order-preserving cut from the profile and implement it with a test; gate fmt / clippy `-D warnings` / full suite / release CLI on x86 + aarch64 | 1 h | | 3 | R4b counterbalanced hold: control `da31c7f` vs cut vs kernel, 1 and 8 flows, loss-aware p99 + throughput | 1 h | | 4 | Paired 1 h soaks (control and cut in ONE hold, J88d harness): TCP reorder events, retransmits, probe loss | 2.3 h | | 5 | Keep → report pin-ready commit for J103d; reject → revert commit + data. Delete target dirs | 30 min | Keep rule (from the job): loss-aware loaded p99 better at 1 and 8 flows in the same hold vs control and kernel; throughput not lower; soak reorder/retransmits at control level. If I pass 2× the estimate I stop and report.

kayg commented

2026-11-03 18:28:55 +00:00

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J103d: blocked on the mirror for the `da31c7f` pin (2026-11-04, 00:00 IST)

For the orchestrator. https://git.kayg.org/kayg/gotatun has not synced since 15:52 UTC. That makes three hourly syncs missed by 18:28 UTC, and a manual POST /repos/kayg/gotatun/mirror-sync (HTTP 200) at 18:25 changed nothing:

j88-linux-offloads on the mirror is still 8ef65795a3a3.
On GitHub it is da31c7fe5514 (committed 16:38 UTC), with cce74ed before it.
mirror_updated = 2026-11-03T15:52:48Z, and original_url = https://github.com/kaygdotorg/gotatun.git.

Cargo therefore cannot resolve rev = "da31c7f…" from the mirror, and I cannot write Cargo.lock for that pin. The pin commit is ready locally:

crates/plugins/mesh/Cargo.toml: git = "https://git.kayg.org/kayg/gotatun", rev = "da31c7fe55148f5aa2f407c13b1dae201a6e324b", features ["device", "ring"];
deny.toml allow-git set to the mirror only;
THIRD_PARTY_NOTICES.md naming the mirror and that commit.

It lands with its lockfile once the mirror serves the commit.

Meanwhile. I'm building the R4b binaries from the same rev through GitHub, uncommitted (a git rev is content-addressed, so the code is identical). The R4b row will name that source.

## J103d: blocked on the mirror for the `da31c7f` pin (2026-11-04, 00:00 IST) **For the orchestrator.** `https://git.kayg.org/kayg/gotatun` has not synced since **15:52 UTC**. That makes three hourly syncs missed by 18:28 UTC, and a manual `POST /repos/kayg/gotatun/mirror-sync` (HTTP 200) at 18:25 changed nothing: - `j88-linux-offloads` on the mirror is still `8ef65795a3a3`. - On GitHub it is `da31c7fe5514` (committed 16:38 UTC), with `cce74ed` before it. - `mirror_updated` = `2026-11-03T15:52:48Z`, and `original_url` = `https://github.com/kaygdotorg/gotatun.git`. Cargo therefore cannot resolve `rev = "da31c7f…"` from the mirror, and I cannot write `Cargo.lock` for that pin. The pin commit is ready locally: - `crates/plugins/mesh/Cargo.toml`: `git = "https://git.kayg.org/kayg/gotatun"`, `rev = "da31c7fe55148f5aa2f407c13b1dae201a6e324b"`, features `["device", "ring"]`; - `deny.toml` `allow-git` set to the mirror only; - `THIRD_PARTY_NOTICES.md` naming the mirror and that commit. It lands with its lockfile once the mirror serves the commit. **Meanwhile.** I'm building the R4b binaries from the same rev through GitHub, uncommitted (a git rev is content-addressed, so the code is identical). The R4b row will name that source.

kayg commented

2026-11-03 18:47:35 +00:00

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Owner

J88e step 1: profile. The receiver's TUN ring is the loss site, and CPU starvation is the cause

Hold /home/claude/j20/r4b/j88e-qlen-profile-20261103/ on the perf VM: one perf-run --root hold, 1,177 s, outer exit 0, all 5 cases exit 0, steal 1,004/470,467 jiffies. Same binary throughout: da31c7f (4543a2c3…, the pin). The ring size was set by the harness right after the device came up, on both endpoints (overlay runner-overlays/cases-mesh.sh.diff, which also adds per-thread schedstat to diag_snap). Script: j88e-scripts/run-qlen-profile.sh; drop and wait analysis: j88e-scripts/drops.py.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99	8 flows p50 / p99 / max \| lost \| loss-aware p99	RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints)
kernel-reference	2.61 / 2.37	1.26 / 1.37	1.155 / 3.863 / 10.968	0	3.863
q500-first	2.68 / 2.47	0.83 / 0.98	3.491 / 10.221 / 13.047	2	<=13.047
q1024	2.97 / 2.68	0.81 / 0.98	2.251 / 6.017 / 10.815	0	6.017
q4096	2.95 / 2.53	0.81 / 0.97	2.270 / 6.017 / 8.439	0	6.017
q500-last	2.88 / 2.63	0.83 / 0.96	2.811 / 7.663 / 9.938	1	<=9.938

Case	2% loss: lost 64/512/1400 (of 300)	reorder 25%/50%: lost
kernel-reference	12/13/22	-/-/-
q500-first	7/16/15	0/0/0
q1024	11/8/12	0/0/0
q4096	12/11/17	0/0/0
q500-last	11/15/5	0/0/0

Case	flows	wgA TX pkts / drops	wgB TX pkts / drops (drop %)	GotaTun threads: run s / run-queue wait s (wait %), worst thread wait s
q500-first	1	60494 / 0	463816 / 615 (0.13%)	20.66 / 17.77 (86%), 3.19 433624/tokio-rt-worker
q500-first	8	88975 / 0	579871 / 8614 (1.46%)	22.16 / 22.47 (101%), 3.95 433624/tokio-rt-worker
q1024	1	66182 / 0	394182 / 0 (0.00%)	22.04 / 18.15 (82%), 3.19 434665/tokio-rt-worker
q1024	8	94881 / 0	636558 / 0 (0.00%)	23.20 / 23.38 (101%), 4.04 434665/tokio-rt-worker
q4096	1	65668 / 0	383783 / 0 (0.00%)	21.94 / 18.17 (83%), 3.15 435725/tokio-rt-worker
q4096	8	90987 / 0	620541 / 0 (0.00%)	22.43 / 22.88 (102%), 4.03 435725/tokio-rt-worker
q500-last	1	64847 / 0	417652 / 263 (0.06%)	21.67 / 18.26 (84%), 3.20 436804/tokio-rt-worker
q500-last	8	92413 / 0	636739 / 8390 (1.30%)	22.72 / 23.09 (102%), 4.00 436804/tokio-rt-worker

Every reply-side drop is at the wgB transmit ring (500 slots, the kernel default for a new TUN device). The fq qdisc above it never holds anything: tun drops at a full ring and does not push back. wgA (the bulk sender's ring) never dropped.
The cause is CPU starvation, not a full channel: GotaTun's threads spent 82–102% of their run time waiting in the run queue (3 CPUs shared by both endpoints and the traffic tools), and J88's trace never saw the B-side channel near its bound.
A ring of 1,024 or 4,096 removes every drop and every lost probe (2/6 and 1/14 → 0/0). Throughput is not lower (2.97/2.68 and 2.95/2.53 Gbit/s, against 2.68/2.47 and 2.88/2.63 for the controls), and 1-flow p99 falls to 6.0 ms from 7.7–10.2. 8-flow loss-aware p99 goes from ≤20.9 to 17.6–17.7 ms. The controls' spread is wide, which is why the counterbalanced hold comes next.

The one cut (fork 72685e8, pushed, NOT pin-ready yet): after creating the device, GotaTun raises its transmit queue length to 1,024, the smallest size with zero drops here, via SIOCSIFTXQLEN. It only raises, never lowers, and only on a device it created (from_name). A device handed in through from_tun_device keeps its owner's settings, and a failure (no CAP_NET_ADMIN) is logged at debug level.

Why it cannot reorder: the tun crate refuses more than one queue, so the device has exactly one FIFO ring. Its size only decides whether a packet is kept or dropped, never its position.

Next: fork checks on x86 + aarch64 (queued on compute01), then the counterbalanced R4b hold (kernel, control, cut, cut, control) and the paired 1 h soak.

## J88e step 1: profile. The receiver's TUN ring is the loss site, and CPU starvation is the cause Hold `/home/claude/j20/r4b/j88e-qlen-profile-20261103/` on the perf VM: one `perf-run --root` hold, 1,177 s, **outer exit 0, all 5 cases exit 0**, steal 1,004/470,467 jiffies. Same binary throughout: `da31c7f` (`4543a2c3…`, the pin). The ring size was set by the harness right after the device came up, on both endpoints (overlay `runner-overlays/cases-mesh.sh.diff`, which also adds per-thread `schedstat` to `diag_snap`). Script: `j88e-scripts/run-qlen-profile.sh`; drop and wait analysis: `j88e-scripts/drops.py`. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | 1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99 | 8 flows p50 / p99 / max \| lost \| loss-aware p99 | RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints) | |---|---:|---:|---|---|---| | kernel-reference | 2.61 / 2.37 | 1.26 / 1.37 | 1.155 / 3.863 / 10.968 | 0 | 3.863 | 3.517 / 5.056 / 6.299 | 0 | 5.056 | 16.1 / 16.1 / - / - / 20.1 | | q500-first | 2.68 / 2.47 | 0.83 / 0.98 | 3.491 / 10.221 / 13.047 | 2 | <=13.047 | 10.122 / 17.805 / 20.866 | 6 | <=20.866 | 9.4 / 36.6 / - / - / 16.7 | | q1024 | 2.97 / 2.68 | 0.81 / 0.98 | 2.251 / 6.017 / 10.815 | 0 | 6.017 | 9.411 / 17.689 / 20.895 | 0 | 17.689 | 9.4 / 38.8 / - / - / 16.3 | | q4096 | 2.95 / 2.53 | 0.81 / 0.97 | 2.270 / 6.017 / 8.439 | 0 | 6.017 | 9.795 / 17.597 / 20.278 | 0 | 17.597 | 9.5 / 40.0 / - / - / 16.5 | | q500-last | 2.88 / 2.63 | 0.83 / 0.96 | 2.811 / 7.663 / 9.938 | 1 | <=9.938 | 9.869 / 17.170 / 21.074 | 14 | <=21.074 | 9.4 / 37.9 / - / - / 16.4 | | Case | 2% loss: lost 64/512/1400 (of 300) | reorder 25%/50%: lost | |---|---|---| | kernel-reference | 12/13/22 | -/-/- | | q500-first | 7/16/15 | 0/0/0 | | q1024 | 11/8/12 | 0/0/0 | | q4096 | 12/11/17 | 0/0/0 | | q500-last | 11/15/5 | 0/0/0 | | Case | flows | wgA TX pkts / drops | wgB TX pkts / drops (drop %) | GotaTun threads: run s / run-queue wait s (wait %), worst thread wait s | |---|---:|---|---|---| | q500-first | 1 | 60494 / 0 | 463816 / 615 (0.13%) | 20.66 / 17.77 (86%), 3.19 433624/tokio-rt-worker | | q500-first | 8 | 88975 / 0 | 579871 / 8614 (1.46%) | 22.16 / 22.47 (101%), 3.95 433624/tokio-rt-worker | | q1024 | 1 | 66182 / 0 | 394182 / 0 (0.00%) | 22.04 / 18.15 (82%), 3.19 434665/tokio-rt-worker | | q1024 | 8 | 94881 / 0 | 636558 / 0 (0.00%) | 23.20 / 23.38 (101%), 4.04 434665/tokio-rt-worker | | q4096 | 1 | 65668 / 0 | 383783 / 0 (0.00%) | 21.94 / 18.17 (83%), 3.15 435725/tokio-rt-worker | | q4096 | 8 | 90987 / 0 | 620541 / 0 (0.00%) | 22.43 / 22.88 (102%), 4.03 435725/tokio-rt-worker | | q500-last | 1 | 64847 / 0 | 417652 / 263 (0.06%) | 21.67 / 18.26 (84%), 3.20 436804/tokio-rt-worker | | q500-last | 8 | 92413 / 0 | 636739 / 8390 (1.30%) | 22.72 / 23.09 (102%), 4.00 436804/tokio-rt-worker | - **Every reply-side drop is at the `wgB` transmit ring** (500 slots, the kernel default for a new TUN device). The `fq` qdisc above it never holds anything: tun drops at a full ring and does not push back. `wgA` (the bulk sender's ring) never dropped. - **The cause is CPU starvation, not a full channel:** GotaTun's threads spent 82–102% of their run time waiting in the run queue (3 CPUs shared by both endpoints and the traffic tools), and J88's trace never saw the B-side channel near its bound. - **A ring of 1,024 or 4,096 removes every drop and every lost probe** (2/6 and 1/14 → 0/0). Throughput is not lower (2.97/2.68 and 2.95/2.53 Gbit/s, against 2.68/2.47 and 2.88/2.63 for the controls), and 1-flow p99 falls to 6.0 ms from 7.7–10.2. 8-flow loss-aware p99 goes from ≤20.9 to 17.6–17.7 ms. The controls' spread is wide, which is why the counterbalanced hold comes next. **The one cut (fork `72685e8`, pushed, NOT pin-ready yet):** after creating the device, GotaTun raises its transmit queue length to **1,024**, the smallest size with zero drops here, via `SIOCSIFTXQLEN`. It only raises, never lowers, and only on a device it created (`from_name`). A device handed in through `from_tun_device` keeps its owner's settings, and a failure (no `CAP_NET_ADMIN`) is logged at debug level. **Why it cannot reorder:** the `tun` crate refuses more than one queue, so the device has exactly one FIFO ring. Its size only decides whether a packet is kept or dropped, never its position. Next: fork checks on x86 + aarch64 (queued on compute01), then the counterbalanced R4b hold (kernel, control, cut, cut, control) and the paired 1 h soak.

kayg commented

2026-11-03 19:22:00 +00:00

Author

Owner

J103d R4b: ring vs aws-lc vs kernel, fork at `da31c7f` (2026-11-04, 01:55 IST)

Hold. /home/claude/j20/r4b/j103d/hold-20261103/ on the perf VM, one perf-run --root hold, 19:57–20:20 CET. Outer exit 0; all 6 cases exit 0; every machine diff empty. Wall time 1,395 s; steal 1,188 of 557,416 jiffies.

Order: kernel, aws-lc, ring, ring, aws-lc, kernel.
Runner: J103c's v4 (comment 77023) with aws-lc in its runtime slot and ring in its GRO slot. No fork CLI and no 1,000-peer cases. Script and analyzer: j103d-r4b-ring.sh, j103d-r4b-analyze.py in the same directory.
Binaries: both from 71923e9db with GotaTun at da31c7fe5514 (J88d's pin, comment 77068), x86_64 musl static, built through the pinned scripts/static-cargo recipe on dev-02.
- The git.kayg.org mirror has not synced da31c7f (comment 77122), so this one build used the same rev from GitHub, uncommitted. The commit is content-addressed, so the code is the same.
- ring 32c54d8f… (the branch's features = ["device", "ring"]); aws-lc 675ec4a1… (only that feature changed to aws-lc-rs). Kernel cases use the ring binary. Coordinator 9e32e7b2…, unchanged.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	Loaded RTT p50/p99, 1 flow (ms)	Loaded RTT p50/p99, 8 flows (ms)	Lost probes 1 / 8	`RcvbufErrors`	Socket `rb`	TUN bytes/RX packet 1 / 8
kernel-first	2.84 / 2.61	1.16 / 1.22	1.106 / 3.512	3.139 / 5.339	0 / 0	0 / 0	212,992	1411 / 1411
awslc-first	2.70 / 2.46	0.87 / 0.98	2.908 / 7.592	9.294 / 15.105	0 / 0	0 / 0	14,680,064	23046 / 18740
ring-first	2.73 / 2.58	0.85 / 0.90	2.811 / 6.812	10.142 / 18.275	0 / 0	0 / 0	14,680,064	23271 / 19752
ring-second	2.79 / 2.61	0.82 / 0.89	2.766 / 6.633	9.879 / 18.262	0 / 0	0 / 0	14,680,064	23146 / 19770
awslc-second	2.81 / 2.57	0.85 / 0.94	2.474 / 6.225	8.777 / 14.465	0 / 0	0 / 0	14,680,064	23065 / 18782
kernel-last	3.03 / 2.64	1.11 / 1.24	1.076 / 2.669	3.155 / 5.007	0 / 0	0 / 0	212,992	1411 / 1411
kernel mean	2.93 / 2.62	1.14 / 1.23	1.091 / 3.091	3.147 / 5.173	0.0% / 0.0%
aws-lc mean	2.76 / 2.51	0.86 / 0.96	2.691 / 6.909	9.035 / 14.785	0.0% / 0.0%
ring mean	2.76 / 2.60	0.84 / 0.90	2.788 / 6.723	10.011 / 18.268	0.0% / 0.0%

Impairments: with 2% loss each way, every case loses 9–25 of 300 probes at 64/512/1400 bytes. With 25%/50% reordering, every case loses 0.

Idle RSS, both endpoints, 1 peer: kernel 21.6 MiB; ring 22.2 / 24.1 MiB; aws-lc 24.8 / 24.8 MiB. After load: ring 43.5 / 46.0 MiB, aws-lc 42.5 / 45.7 MiB. That sample is taken right after the LAN load phase, before any idle period, so it does not show the fork's idle release (J88d's 38 → 12 MiB after 15 s idle). This hold does not test that claim.

Static size (pinned recipe, dev-02, the same source with only the crypto feature changed):

Target	ring	aws-lc	ring − aws-lc
x86_64-unknown-linux-musl	23,338,064	23,444,080	−106,016
aarch64-unknown-linux-musl	21,250,768	21,310,552	−59,784

Ring against aws-lc

Throughput: equal at 1 flow (2.76 / 2.76), and +3.6% at 8 flows (2.60 / 2.51).
CPU per Gbit: ring is 2% / 6% lower (0.84 / 0.90 against 0.86 / 0.96).
Loaded p99, 1 flow: ring is 3% lower (6.72 against 6.91 ms).
⚠ Loaded p99, 8 flows: ring is +23.6% (18.27 against 14.79 ms). The 8-flow p50 is +10.8% (10.01 against 9.04 ms). Both ring runs agree (18.275 / 18.262) and both aws-lc runs agree (15.105 / 14.465), so this is not noise within the hold. This is beyond the 5% line, so I'm flagging it. No probe was lost in any loaded phase, so D331's loss-aware p99 equals the received p99 here.
- My reading is a hypothesis, not a measurement. At 8 flows, ring moves slightly more bytes with less CPU per byte, and its receiver TUN averages 19.75k bytes per RX packet against aws-lc's 18.76k. That fits more data queued in flight, not slower crypto. The R4b profile has no per-stage queue depth that could confirm it.
Size: ring is smaller on both targets (−106 KB / −60 KB), because ring is already in the binary for rustls, quinn, russh, relay and remote.
For the owner: D289 already decides ring, and d2ec92b99's successor on the branch follows it. If the 8-flow p99 cost matters for the GotaTun switch, the choice of backend is yours. The measurement above is the input; this job does not choose.

The latest row for the D332 switch rule (throughput AND loss-aware loaded p99, against kernel)

GotaTun at `da31c7f`, ring	1 flow	8 flows
Throughput, share of kernel	94% (2.76 / 2.93)	99% (2.60 / 2.62)
Loss-aware loaded p99, × kernel	2.2× (6.72 / 3.09 ms)	3.5× (18.27 / 5.17 ms)
CPU s/Gbit, × kernel	0.74×	0.73×

Throughput is at parity within this hold. Latency is the remaining gap: loaded p99 is 2–3.5× kernel at 0% loss on both engines.

Against J103c's GRO row at 73eb9f1 (comment 77023: 89% / 92%, p99 5.87 / 15.92 ms against kernel 2.82 / 8.97 ms), throughput share is up.
The p99 ratio cannot be compared across the two holds, because kernel's own 8-flow p99 differs: 8.97 there (one first case with 6 losses) against 5.17 here.

## J103d R4b: ring vs aws-lc vs kernel, fork at `da31c7f` (2026-11-04, 01:55 IST) **Hold.** `/home/claude/j20/r4b/j103d/hold-20261103/` on the perf VM, one `perf-run --root` hold, 19:57–20:20 CET. Outer exit 0; all 6 cases exit 0; every machine diff empty. Wall time 1,395 s; steal 1,188 of 557,416 jiffies. - **Order:** kernel, aws-lc, ring, ring, aws-lc, kernel. - **Runner:** J103c's v4 (comment 77023) with aws-lc in its runtime slot and ring in its GRO slot. No fork CLI and no 1,000-peer cases. Script and analyzer: `j103d-r4b-ring.sh`, `j103d-r4b-analyze.py` in the same directory. - **Binaries:** both from `71923e9db` with GotaTun at **`da31c7fe5514`** (J88d's pin, comment 77068), x86_64 musl static, built through the pinned `scripts/static-cargo` recipe on dev-02. - The git.kayg.org mirror has not synced `da31c7f` (comment 77122), so this one build used the same rev from GitHub, uncommitted. The commit is content-addressed, so the code is the same. - ring `32c54d8f…` (the branch's `features = ["device", "ring"]`); aws-lc `675ec4a1…` (only that feature changed to `aws-lc-rs`). Kernel cases use the ring binary. Coordinator `9e32e7b2…`, unchanged. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | Loaded RTT p50/p99, 1 flow (ms) | Loaded RTT p50/p99, 8 flows (ms) | Lost probes 1 / 8 | `RcvbufErrors` | Socket `rb` | TUN bytes/RX packet 1 / 8 | |---|---:|---:|---:|---:|---:|---:|---:|---:| | kernel-first | 2.84 / 2.61 | 1.16 / 1.22 | 1.106 / 3.512 | 3.139 / 5.339 | 0 / 0 | 0 / 0 | 212,992 | 1411 / 1411 | | awslc-first | 2.70 / 2.46 | 0.87 / 0.98 | 2.908 / 7.592 | 9.294 / 15.105 | 0 / 0 | 0 / 0 | 14,680,064 | 23046 / 18740 | | ring-first | 2.73 / 2.58 | 0.85 / 0.90 | 2.811 / 6.812 | 10.142 / 18.275 | 0 / 0 | 0 / 0 | 14,680,064 | 23271 / 19752 | | ring-second | 2.79 / 2.61 | 0.82 / 0.89 | 2.766 / 6.633 | 9.879 / 18.262 | 0 / 0 | 0 / 0 | 14,680,064 | 23146 / 19770 | | awslc-second | 2.81 / 2.57 | 0.85 / 0.94 | 2.474 / 6.225 | 8.777 / 14.465 | 0 / 0 | 0 / 0 | 14,680,064 | 23065 / 18782 | | kernel-last | 3.03 / 2.64 | 1.11 / 1.24 | 1.076 / 2.669 | 3.155 / 5.007 | 0 / 0 | 0 / 0 | 212,992 | 1411 / 1411 | | **kernel mean** | **2.93 / 2.62** | 1.14 / 1.23 | 1.091 / **3.091** | 3.147 / **5.173** | **0.0% / 0.0%** | | | | | **aws-lc mean** | **2.76 / 2.51** | 0.86 / 0.96 | 2.691 / **6.909** | 9.035 / **14.785** | **0.0% / 0.0%** | | | | | **ring mean** | **2.76 / 2.60** | 0.84 / 0.90 | 2.788 / **6.723** | 10.011 / **18.268** | **0.0% / 0.0%** | | | | Impairments: with 2% loss each way, every case loses 9–25 of 300 probes at 64/512/1400 bytes. With 25%/50% reordering, every case loses 0. Idle RSS, both endpoints, 1 peer: kernel 21.6 MiB; ring 22.2 / 24.1 MiB; aws-lc 24.8 / 24.8 MiB. After load: ring 43.5 / 46.0 MiB, aws-lc 42.5 / 45.7 MiB. That sample is taken right after the LAN load phase, before any idle period, so it does **not** show the fork's idle release (J88d's 38 → 12 MiB after 15 s idle). This hold does not test that claim. **Static size** (pinned recipe, dev-02, the same source with only the crypto feature changed): | Target | ring | aws-lc | ring − aws-lc | |---|---:|---:|---:| | x86_64-unknown-linux-musl | 23,338,064 | 23,444,080 | **−106,016** | | aarch64-unknown-linux-musl | 21,250,768 | 21,310,552 | **−59,784** | ### Ring against aws-lc - **Throughput:** equal at 1 flow (2.76 / 2.76), and +3.6% at 8 flows (2.60 / 2.51). - **CPU per Gbit:** ring is 2% / 6% lower (0.84 / 0.90 against 0.86 / 0.96). - **Loaded p99, 1 flow:** ring is 3% lower (6.72 against 6.91 ms). - **⚠ Loaded p99, 8 flows:** ring is **+23.6%** (18.27 against 14.79 ms). The 8-flow p50 is +10.8% (10.01 against 9.04 ms). Both ring runs agree (18.275 / 18.262) and both aws-lc runs agree (15.105 / 14.465), so this is not noise within the hold. **This is beyond the 5% line, so I'm flagging it.** No probe was lost in any loaded phase, so D331's loss-aware p99 equals the received p99 here. - My reading is a hypothesis, not a measurement. At 8 flows, ring moves slightly more bytes with less CPU per byte, and its receiver TUN averages 19.75k bytes per RX packet against aws-lc's 18.76k. That fits more data queued in flight, not slower crypto. The R4b profile has no per-stage queue depth that could confirm it. - **Size:** ring is smaller on both targets (−106 KB / −60 KB), because ring is already in the binary for rustls, quinn, russh, relay and remote. - **For the owner:** D289 already decides ring, and `d2ec92b99`'s successor on the branch follows it. If the 8-flow p99 cost matters for the GotaTun switch, the choice of backend is yours. The measurement above is the input; this job does not choose. ### The latest row for the D332 switch rule (throughput AND loss-aware loaded p99, against kernel) | GotaTun at `da31c7f`, ring | 1 flow | 8 flows | |---|---:|---:| | Throughput, share of kernel | **94%** (2.76 / 2.93) | **99%** (2.60 / 2.62) | | Loss-aware loaded p99, × kernel | **2.2×** (6.72 / 3.09 ms) | **3.5×** (18.27 / 5.17 ms) | | CPU s/Gbit, × kernel | 0.74× | 0.73× | Throughput is at parity within this hold. **Latency is the remaining gap:** loaded p99 is 2–3.5× kernel at 0% loss on both engines. - Against J103c's GRO row at `73eb9f1` (comment 77023: 89% / 92%, p99 5.87 / 15.92 ms against kernel 2.82 / 8.97 ms), throughput share is up. - The p99 ratio cannot be compared across the two holds, because kernel's own 8-flow p99 differs: 8.97 there (one first case with 6 losses) against 5.17 here.

kayg commented

2026-11-03 19:37:33 +00:00

Author

Owner

J88e progress: fork checks on `84b7bb2`

Fork j88-linux-offloads is at 84b7bb2 (pushed): 72685e8 (the ring cut) plus 84b7bb2 (rustfmt layout only; 72685e8 alone failed cargo fmt --check). Patch git diff 73eb9f1 84b7bb2 = 3c3fa88c….

Check	aarch64 (dev-02, build-slot)	x86 (compute01, build-slot)
fmt	ok	ok
clippy `--workspace --all-features --all-targets -D warnings`	ok	ok
focused (3 new tests)	3 passed	3 passed
full lib suite	146 passed, 0 failed, 7 ignored	145 passed, 1 failed (`device::tests::test_indices`: "eavesdrop timeout"); rerun 146 passed, 0 failed, 7 ignored
release CLI	ok, `49e64d90…`	queued (build-slot position 5)

The x86 failure is a load flake, not this change. test_indices drives a mock device pair (no TUN) and panics if a 1 s wall-clock timer fires first. compute01 was at load 16 on 10 cores. On the same built tree: test_indices 20/20 passed on rerun, and the full suite reran green. J88d's five x86 runs of the same test all passed.

x86 run excerpt:

== fmt
== clippy
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 1m 50s
== focused
    Finished `test` profile [unoptimized + debuginfo] target(s) in 38.41s
     Running unittests src/lib.rs (target/debug/deps/gotatun-56a616a47908a790)
running 3 tests
test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 150 filtered out; finished in 0.00s
== full lib suite

Next: x86 release binary → counterbalanced R4b hold on the perf VM (kernel, control da31c7f, cut, cut, control), then the paired 1 h soaks.

## J88e progress: fork checks on `84b7bb2` Fork `j88-linux-offloads` is at **`84b7bb2`** (pushed): `72685e8` (the ring cut) plus `84b7bb2` (rustfmt layout only; `72685e8` alone failed `cargo fmt --check`). Patch `git diff 73eb9f1 84b7bb2` = `3c3fa88c…`. | Check | aarch64 (dev-02, build-slot) | x86 (compute01, build-slot) | |---|---|---| | fmt | ok | ok | | clippy `--workspace --all-features --all-targets -D warnings` | ok | ok | | focused (3 new tests) | 3 passed | 3 passed | | full lib suite | **146 passed, 0 failed, 7 ignored** | 145 passed, **1 failed** (`device::tests::test_indices`: "eavesdrop timeout"); rerun **146 passed, 0 failed, 7 ignored** | | release CLI | ok, `49e64d90…` | queued (build-slot position 5) | **The x86 failure is a load flake, not this change.** `test_indices` drives a mock device pair (no TUN) and panics if a 1 s wall-clock timer fires first. compute01 was at load 16 on 10 cores. On the same built tree: `test_indices` **20/20 passed** on rerun, and the full suite reran green. J88d's five x86 runs of the same test all passed. x86 run excerpt: ```text == fmt == clippy Finished `dev` profile [unoptimized + debuginfo] target(s) in 1m 50s == focused Finished `test` profile [unoptimized + debuginfo] target(s) in 38.41s Running unittests src/lib.rs (target/debug/deps/gotatun-56a616a47908a790) running 3 tests test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 150 filtered out; finished in 0.00s == full lib suite ``` Next: x86 release binary → counterbalanced R4b hold on the perf VM (kernel, control `da31c7f`, cut, cut, control), then the paired 1 h soaks.

kayg commented

2026-11-03 20:17:22 +00:00

Author

Owner

J88e step 2, keep hold 1: 1 flow better, 8 flows a tie the harness cannot resolve

/home/claude/j20/r4b/j88e-hold-84b7bb2-20261103/: one perf-run --root hold, 1,155 s, outer exit 0, all 5 cases exit 0, steal 2,933/462,095 jiffies. Control da31c7f (4543a2c3…), candidate 84b7bb2 (x86 release CLI c0438938…). The order was kernel → control → cut → cut → control, using J88d's run-hold.sh (full R4b profile) unchanged apart from labels. The candidate's wgB reports qlen 1024 with no harness knob.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99	RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints)
kernel-reference	2.84 / 2.67	1.16 / 1.21	1.075 / 2.640 / 6.326	2.640
control-first	2.60 / 2.40	0.85 / 0.98	3.297 / 8.907 / 11.906	8.907
candidate-first	2.66 / 2.45	0.88 / 0.99	2.537 / 6.117 / 7.152	6.117
candidate-second	2.50 / 2.21	0.93 / 1.09	2.635 / 7.010 / 9.277	7.010
control-last	2.50 / 2.26	0.87 / 1.02	4.332 / 12.453 / 17.660	12.453

Case	2% loss: lost 64/512/1400 (of 300)	reorder 25%/50%: lost
kernel-reference	13/13/22	-/-/-
control-first	9/18/17	0/0/0
candidate-first	14/13/9	0/0/0
candidate-second	8/13/16	0/0/0
control-last	12/23/11	0/0/0

Case	flows	wgA TX pkts / drops	wgB TX pkts / drops (drop %)
control-first	1	59064 / 0	431006 / 1189 (0.28%)
control-first	8	85933 / 0	573700 / 13481 (2.30%)
candidate-first	1	59547 / 0	363462 / 0 (0.00%)
candidate-first	8	87366 / 0	595305 / 0 (0.00%)
candidate-second	1	56321 / 0	340156 / 0 (0.00%)
candidate-second	8	81696 / 0	517161 / 0 (0.00%)
control-last	1	56887 / 0	363889 / 898 (0.25%)
control-last	8	83540 / 0	527171 / 8669 (1.62%)

Keep rule	Control (mean of 2)	Cut (mean of 2)	Kernel	Verdict
Throughput 1 / 8 flows	2.55 / 2.33	2.58 / 2.33	2.84 / 2.67	not lower ✔
1-flow loss-aware p99	10.68 ms (8.91, 12.45; 0 lost)	6.56 ms (6.12, 7.01; 0 lost)	2.64	better ✔ (−39%)
8-flow loss-aware p99	(18.83, 21.49] and (19.73, 23.27]; 12 and 18 of 2,000 lost	20.24 and 22.80; 0 lost	5.44	not resolvable
`wgB` ring drops 1 / 8 flows	0.25–0.28% / 1.6–2.3%	0 / 0	–

Why 8 flows is open: the harness keeps only p50/p90/p99/max per 2,000 probes. With 12–18 lost, the control's loss-aware p99 is somewhere between its received p99 and its max. The cut converts the loss into queueing: no probe is lost, but its received tail is longer (max 26–28 ms against 21–23). The two ranges overlap. At p99.5 and beyond, the control is infinite (lost) and the cut is finite.

Next (running now, chained): keep hold 2 is the same hold plus raw ICMP samples (ping -D -O, 200/s, inside the same namespaces) during the loaded LAN phases. Every reply crosses the same wgB ring, and the raw samples give an exact loss-aware p99 at 1 and 8 flows. Then comes the paired soak (control, then cut, in one hold) with ping at 100/s per busy minute. Scripts: j88e-scripts/run-hold-ping.sh, run-soak-ping.sh (J88d's soak plus the ping start and wait), run-soak-pair.sh, pingstat.py.

## J88e step 2, keep hold 1: 1 flow better, 8 flows a tie the harness cannot resolve `/home/claude/j20/r4b/j88e-hold-84b7bb2-20261103/`: one `perf-run --root` hold, 1,155 s, **outer exit 0, all 5 cases exit 0**, steal 2,933/462,095 jiffies. Control `da31c7f` (`4543a2c3…`), candidate `84b7bb2` (x86 release CLI `c0438938…`). The order was kernel → control → cut → cut → control, using J88d's `run-hold.sh` (full R4b profile) unchanged apart from labels. The candidate's `wgB` reports `qlen 1024` with no harness knob. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | 1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99 | 8 flows p50 / p99 / max \| lost \| loss-aware p99 | RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints) | |---|---:|---:|---|---|---| | kernel-reference | 2.84 / 2.67 | 1.16 / 1.21 | 1.075 / 2.640 / 6.326 | 0 | 2.640 | 3.387 / 5.438 / 7.619 | 0 | 5.438 | 20.1 / 20.1 / - / - / 20.1 | | control-first | 2.60 / 2.40 | 0.85 / 0.98 | 3.297 / 8.907 / 11.906 | 0 | 8.907 | 11.082 / 18.832 / 21.490 | 12 | <=21.490 | 9.4 / 40.4 / - / - / 18.0 | | candidate-first | 2.66 / 2.45 | 0.88 / 0.99 | 2.537 / 6.117 / 7.152 | 0 | 6.117 | 10.487 / 20.235 / 26.146 | 0 | 20.235 | 9.4 / 42.3 / - / - / 17.0 | | candidate-second | 2.50 / 2.21 | 0.93 / 1.09 | 2.635 / 7.010 / 9.277 | 0 | 7.010 | 10.883 / 22.797 / 28.390 | 0 | 22.797 | 9.5 / 35.9 / - / - / 16.7 | | control-last | 2.50 / 2.26 | 0.87 / 1.02 | 4.332 / 12.453 / 17.660 | 0 | 12.453 | 10.702 / 19.729 / 23.272 | 18 | <=23.272 | 9.4 / 37.0 / - / - / 17.8 | | Case | 2% loss: lost 64/512/1400 (of 300) | reorder 25%/50%: lost | |---|---|---| | kernel-reference | 13/13/22 | -/-/- | | control-first | 9/18/17 | 0/0/0 | | candidate-first | 14/13/9 | 0/0/0 | | candidate-second | 8/13/16 | 0/0/0 | | control-last | 12/23/11 | 0/0/0 | | Case | flows | wgA TX pkts / drops | wgB TX pkts / drops (drop %) |---|---:|---|--- | control-first | 1 | 59064 / 0 | 431006 / 1189 (0.28%) | control-first | 8 | 85933 / 0 | 573700 / 13481 (2.30%) | candidate-first | 1 | 59547 / 0 | 363462 / 0 (0.00%) | candidate-first | 8 | 87366 / 0 | 595305 / 0 (0.00%) | candidate-second | 1 | 56321 / 0 | 340156 / 0 (0.00%) | candidate-second | 8 | 81696 / 0 | 517161 / 0 (0.00%) | control-last | 1 | 56887 / 0 | 363889 / 898 (0.25%) | control-last | 8 | 83540 / 0 | 527171 / 8669 (1.62%) | Keep rule | Control (mean of 2) | Cut (mean of 2) | Kernel | Verdict | |---|---|---|---|---| | Throughput 1 / 8 flows | 2.55 / 2.33 | 2.58 / 2.33 | 2.84 / 2.67 | not lower ✔ | | 1-flow loss-aware p99 | 10.68 ms (8.91, 12.45; 0 lost) | **6.56 ms** (6.12, 7.01; 0 lost) | 2.64 | better ✔ (−39%) | | 8-flow loss-aware p99 | (18.83, 21.49] and (19.73, 23.27]; 12 and 18 of 2,000 lost | 20.24 and 22.80; 0 lost | 5.44 | **not resolvable** | | `wgB` ring drops 1 / 8 flows | 0.25–0.28% / 1.6–2.3% | **0 / 0** | – | | **Why 8 flows is open:** the harness keeps only p50/p90/p99/max per 2,000 probes. With 12–18 lost, the control's loss-aware p99 is somewhere between its received p99 and its max. The cut converts the loss into queueing: no probe is lost, but its received tail is longer (max 26–28 ms against 21–23). The two ranges overlap. At p99.5 and beyond, the control is infinite (lost) and the cut is finite. **Next (running now, chained):** keep hold 2 is the same hold plus raw ICMP samples (`ping -D -O`, 200/s, inside the same namespaces) during the loaded LAN phases. Every reply crosses the same `wgB` ring, and the raw samples give an exact loss-aware p99 at 1 and 8 flows. Then comes the paired soak (control, then cut, in one hold) with ping at 100/s per busy minute. Scripts: `j88e-scripts/run-hold-ping.sh`, `run-soak-ping.sh` (J88d's soak plus the ping start and wait), `run-soak-pair.sh`, `pingstat.py`.

kayg commented

2026-11-03 20:36:36 +00:00

Author

Owner

J88e step 2, keep hold 2 (exact loss-aware p99): the cut improves 1 and 8 flows, throughput unchanged

/home/claude/j20/r4b/j88e-hold2-84b7bb2-20261103/: one perf-run --root hold, 1,163 s, outer exit 0, all 5 cases exit 0, steal 961/464,050 jiffies. Same order and binaries as hold 1 (kernel → control da31c7f → cut 84b7bb2 ×2 → control). The one addition: ping -D -O -n -i 0.005 -c 1800 from h2h-a to the peer during each loaded LAN phase. That's raw per-packet RTTs, and every echo reply crosses the same wgB ring. Loss-aware percentiles are exact: lost probes count as infinite (D331), pingstat.py.

h2h probes (as in every R4b hold):

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99	RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints)
kernel-reference	2.75 / 2.50	1.26 / 1.33	1.138 / 4.661 / 7.799	4.661
control-first	2.38 / 2.32	0.98 / 1.01	4.190 / 11.342 / 14.660	11.342
candidate-first	2.58 / 2.39	0.95 / 1.07	3.306 / 7.947 / 9.680	7.947
candidate-second	2.52 / 2.35	0.97 / 1.08	3.027 / 7.485 / 10.233	7.485
control-last	2.48 / 2.44	1.00 / 1.08	3.015 / 8.005 / 12.011	8.005

Ring drops:

Case	flows	wgA TX pkts / drops	wgB TX pkts / drops (drop %)
control-first	1	55909 / 0	408181 / 1525 (0.37%)
control-first	8	85548 / 0	547485 / 12012 (2.15%)
candidate-first	1	60267 / 0	366677 / 0 (0.00%)
candidate-first	8	90562 / 0	576210 / 0 (0.00%)
candidate-second	1	59113 / 0	392712 / 0 (0.00%)
candidate-second	8	89643 / 0	560340 / 0 (0.00%)
control-last	1	58245 / 0	382273 / 236 (0.06%)
control-last	8	92821 / 0	578170 / 2024 (0.35%)

Raw ICMP, exact:

Case	flows	ICMP 200/s, raw: sent, lost, loss-aware p50 / p99 / p99.9, max (ms)
kernel-reference	1	sent 1800 lost 0 (0.000%) p50 0.998 p99 2.120 p99.9 4.060 max 4.210
kernel-reference	8	sent 1800 lost 0 (0.000%) p50 3.340 p99 5.700 p99.9 7.760 max 7.890
control-first	1	sent 1800 lost 2 (0.111%) p50 3.630 p99 10.500 p99.9 inf max 13.700
control-first	8	sent 1800 lost 16 (0.889%) p50 7.060 p99 21.400 p99.9 inf max 25.400
candidate-first	1	sent 1800 lost 0 (0.000%) p50 3.170 p99 8.500 p99.9 11.000 max 12.300
candidate-first	8	sent 1800 lost 0 (0.000%) p50 6.880 p99 15.300 p99.9 17.600 max 19.400
candidate-second	1	sent 1800 lost 0 (0.000%) p50 3.010 p99 8.380 p99.9 11.400 max 14.700
candidate-second	8	sent 1800 lost 0 (0.000%) p50 7.150 p99 16.400 p99.9 21.300 max 21.700
control-last	1	sent 1800 lost 1 (0.056%) p50 2.740 p99 7.210 p99.9 13.300 max 13.300
control-last	8	sent 1800 lost 4 (0.222%) p50 6.840 p99 15.100 p99.9 inf max 19.100

pooled control 1: sent 3600 lost 3 (0.083%) p50 3.090 p99 9.990 p99.9 13.700 max 13.700
pooled candidate 1: sent 3600 lost 0 (0.000%) p50 3.100 p99 8.500 p99.9 11.000 max 14.700
pooled control 8: sent 3600 lost 20 (0.556%) p50 6.950 p99 17.900 p99.9 inf max 25.400
pooled candidate 8: sent 3600 lost 0 (0.000%) p50 7.020 p99 15.800 p99.9 19.400 max 21.700

Keep rule, R4b part: met

	Control `da31c7f`	Cut `84b7bb2`	Kernel WG
1 flow, exact loss-aware p99 / p99.9 (pooled 3,600 ICMP)	9.99 / 13.7 ms, 3 lost	8.50 / 11.0 ms, 0 lost (−15%)	2.12 / 4.06
8 flows, exact loss-aware p99 / p99.9 (pooled 3,600 ICMP)	17.9 ms / inf, 20 lost	15.8 / 19.4 ms, 0 lost (−12%)	5.70 / 7.76
1 flow h2h loss-aware p99, holds 1+2 (4 runs)	8.91, 12.45, 11.34, 8.01 (mean 10.18)	6.12, 7.01, 7.95, 7.49 (mean 7.14)	2.64, 4.66
8 flows h2h loss-aware p99, hold 2	inf (31 lost), ≤18.49 (1 lost)	17.35, 19.39 (0 lost)	5.44, 7.58
Throughput 1 / 8 flows, holds 1+2 (4 runs each)	2.49 / 2.36 Gbit/s	2.57 / 2.35	2.80 / 2.59
`wgB` ring drops, 4 runs	0.06–0.37% (1 flow), 0.35–2.3% (8 flows)	0 in every run	–

The run-to-run spread is large: control-last at 8 flows had only 0.35% ring drops, and its ICMP p99 (15.1) matches the cut's (15.3/16.4). That's why both holds count, and the pooled exact numbers decide. Gap to kernel WireGuard after the cut: about 3–4× at loaded p99. The ring loss is gone, and the remaining tail is queueing under CPU contention.

Now: the paired soak, started 21:35 UTC (j88e-soakpair-84b7bb2-20261103: control then cut, 72 slots each, one hold, ICMP 100/s per busy minute). The keep decision follows its TCP reorder and retransmit counters. Build target dirs on compute01 and dev-02 are deleted; no rebuild is needed for either outcome.

## J88e step 2, keep hold 2 (exact loss-aware p99): the cut improves 1 and 8 flows, throughput unchanged `/home/claude/j20/r4b/j88e-hold2-84b7bb2-20261103/`: one `perf-run --root` hold, 1,163 s, **outer exit 0, all 5 cases exit 0**, steal 961/464,050 jiffies. Same order and binaries as hold 1 (kernel → control `da31c7f` → cut `84b7bb2` ×2 → control). The one addition: `ping -D -O -n -i 0.005 -c 1800` from `h2h-a` to the peer during each loaded LAN phase. That's raw per-packet RTTs, and every echo reply crosses the same `wgB` ring. Loss-aware percentiles are exact: lost probes count as infinite (D331), `pingstat.py`. **h2h probes (as in every R4b hold):** | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | 1 flow p50 / p99 / max (ms) \| lost \| loss-aware p99 | 8 flows p50 / p99 / max \| lost \| loss-aware p99 | RSS idle / after load / +15 s idle / after cycles / 1,000 peers (MiB, both endpoints) | |---|---:|---:|---|---|---| | kernel-reference | 2.75 / 2.50 | 1.26 / 1.33 | 1.138 / 4.661 / 7.799 | 0 | 4.661 | 3.517 / 7.576 / 10.616 | 0 | 7.576 | 20.1 / 20.1 / - / - / 20.1 | | control-first | 2.38 / 2.32 | 0.98 / 1.01 | 4.190 / 11.342 / 14.660 | 0 | 11.342 | 11.224 / 19.542 / 21.953 | 31 | inf | 9.4 / 37.1 / - / - / 16.4 | | candidate-first | 2.58 / 2.39 | 0.95 / 1.07 | 3.306 / 7.947 / 9.680 | 0 | 7.947 | 10.282 / 17.353 / 22.577 | 0 | 17.353 | 9.4 / 36.6 / - / - / 16.3 | | candidate-second | 2.52 / 2.35 | 0.97 / 1.08 | 3.027 / 7.485 / 10.233 | 0 | 7.485 | 10.512 / 19.394 / 24.281 | 0 | 19.394 | 9.5 / 36.3 / - / - / 16.5 | | control-last | 2.48 / 2.44 | 1.00 / 1.08 | 3.015 / 8.005 / 12.011 | 0 | 8.005 | 9.602 / 16.552 / 18.485 | 1 | <=18.485 | 9.4 / 35.6 / - / - / 16.2 | **Ring drops:** | Case | flows | wgA TX pkts / drops | wgB TX pkts / drops (drop %) |---|---:|---|--- | control-first | 1 | 55909 / 0 | 408181 / 1525 (0.37%) | control-first | 8 | 85548 / 0 | 547485 / 12012 (2.15%) | candidate-first | 1 | 60267 / 0 | 366677 / 0 (0.00%) | candidate-first | 8 | 90562 / 0 | 576210 / 0 (0.00%) | candidate-second | 1 | 59113 / 0 | 392712 / 0 (0.00%) | candidate-second | 8 | 89643 / 0 | 560340 / 0 (0.00%) | control-last | 1 | 58245 / 0 | 382273 / 236 (0.06%) | control-last | 8 | 92821 / 0 | 578170 / 2024 (0.35%) **Raw ICMP, exact:** | Case | flows | ICMP 200/s, raw: sent, lost, loss-aware p50 / p99 / p99.9, max (ms) | |---|---:|---| | kernel-reference | 1 | sent 1800 lost 0 (0.000%) p50 0.998 p99 2.120 p99.9 4.060 max 4.210 | | kernel-reference | 8 | sent 1800 lost 0 (0.000%) p50 3.340 p99 5.700 p99.9 7.760 max 7.890 | | control-first | 1 | sent 1800 lost 2 (0.111%) p50 3.630 p99 10.500 p99.9 inf max 13.700 | | control-first | 8 | sent 1800 lost 16 (0.889%) p50 7.060 p99 21.400 p99.9 inf max 25.400 | | candidate-first | 1 | sent 1800 lost 0 (0.000%) p50 3.170 p99 8.500 p99.9 11.000 max 12.300 | | candidate-first | 8 | sent 1800 lost 0 (0.000%) p50 6.880 p99 15.300 p99.9 17.600 max 19.400 | | candidate-second | 1 | sent 1800 lost 0 (0.000%) p50 3.010 p99 8.380 p99.9 11.400 max 14.700 | | candidate-second | 8 | sent 1800 lost 0 (0.000%) p50 7.150 p99 16.400 p99.9 21.300 max 21.700 | | control-last | 1 | sent 1800 lost 1 (0.056%) p50 2.740 p99 7.210 p99.9 13.300 max 13.300 | | control-last | 8 | sent 1800 lost 4 (0.222%) p50 6.840 p99 15.100 p99.9 inf max 19.100 | ```text pooled control 1: sent 3600 lost 3 (0.083%) p50 3.090 p99 9.990 p99.9 13.700 max 13.700 pooled candidate 1: sent 3600 lost 0 (0.000%) p50 3.100 p99 8.500 p99.9 11.000 max 14.700 pooled control 8: sent 3600 lost 20 (0.556%) p50 6.950 p99 17.900 p99.9 inf max 25.400 pooled candidate 8: sent 3600 lost 0 (0.000%) p50 7.020 p99 15.800 p99.9 19.400 max 21.700 ``` ### Keep rule, R4b part: **met** | | Control `da31c7f` | Cut `84b7bb2` | Kernel WG | |---|---|---|---| | 1 flow, exact loss-aware p99 / p99.9 (pooled 3,600 ICMP) | 9.99 / 13.7 ms, 3 lost | **8.50 / 11.0 ms, 0 lost** (−15%) | 2.12 / 4.06 | | 8 flows, exact loss-aware p99 / p99.9 (pooled 3,600 ICMP) | 17.9 ms / **inf**, 20 lost | **15.8 / 19.4 ms, 0 lost** (−12%) | 5.70 / 7.76 | | 1 flow h2h loss-aware p99, holds 1+2 (4 runs) | 8.91, 12.45, 11.34, 8.01 (mean 10.18) | 6.12, 7.01, 7.95, 7.49 (mean **7.14**) | 2.64, 4.66 | | 8 flows h2h loss-aware p99, hold 2 | inf (31 lost), ≤18.49 (1 lost) | 17.35, 19.39 (0 lost) | 5.44, 7.58 | | Throughput 1 / 8 flows, holds 1+2 (4 runs each) | 2.49 / 2.36 Gbit/s | **2.57 / 2.35** | 2.80 / 2.59 | | `wgB` ring drops, 4 runs | 0.06–0.37% (1 flow), 0.35–2.3% (8 flows) | **0 in every run** | – | The run-to-run spread is large: control-last at 8 flows had only 0.35% ring drops, and its ICMP p99 (15.1) matches the cut's (15.3/16.4). That's why both holds count, and the pooled exact numbers decide. Gap to kernel WireGuard after the cut: about 3–4× at loaded p99. The ring loss is gone, and the remaining tail is queueing under CPU contention. **Now:** the paired soak, started 21:35 UTC (`j88e-soakpair-84b7bb2-20261103`: control then cut, 72 slots each, one hold, ICMP 100/s per busy minute). The keep decision follows its TCP reorder and retransmit counters. Build target dirs on compute01 and dev-02 are deleted; no rebuild is needed for either outcome.

kayg commented

2026-11-03 22:44:05 +00:00

Author

Owner

J88e finish: fork `84b7bb2` is pin-ready for J103d. The TUN transmit ring cut passes all three keep checks

Fork kaygdotorg/gotatun j88-linux-offloads, fast-forwarded da31c7f..84b7bb2, no force-push:

Commit	What
`72685e8`	perf: raise the Linux TUN transmit ring to 1,024 packets
`84b7bb2`	style: rustfmt layout for the two ioctls (`72685e8` alone fails `cargo fmt --check`; no behaviour change)

For J103d: pin 84b7bb2. The ring is raised only for a device GotaTun creates (from_name). If the integration hands GotaTun a device it created itself (from_tun_device), the integration must set txqueuelen ≥ 1024 on it, or it keeps the kernel default of 500 and none of this applies. Raising it needs CAP_NET_ADMIN; without that it is logged at debug level and the device works as before.

Step 1: profile (77124)

Finding	Evidence
All reply-path loss is the receiver's TUN transmit ring (500 slots, kernel default). tun drops at a full ring without pushing back, so the `fq` qdisc never holds anything	`wgB` TX dropped 0.06–0.37% at 1 flow, 0.35–2.3% at 8 flows, 1.14 M in the 1 h control soak; `wgA` 0 everywhere
The cause is CPU starvation of the reader, not a full channel	GotaTun threads wait in the run queue 82–102% of their run time (per-thread `schedstat`, 3 CPUs)
A ring of 1,024 or 4,096 removes the drops and the lost probes	harness-only sizing hold: 0 drops, 0 lost, throughput not lower

Why the cut is order-preserving: the tun crate rejects more than one queue, so the device has exactly one FIFO ring. Its length only decides whether a packet is kept or dropped, never its position. The soak confirms it: 0 reorder events.

Step 2: counterbalanced R4b holds (77174, 77183), kernel → control → cut → cut → control

	Control `da31c7f`	Cut `84b7bb2`	Kernel WG
1 flow, exact loss-aware p99 / p99.9 (raw ICMP, 3,600)	9.99 / 13.7 ms, 3 lost	8.50 / 11.0 ms, 0 lost	2.12 / 4.06
8 flows, exact loss-aware p99 / p99.9 (raw ICMP, 3,600)	17.9 ms / inf, 20 lost	15.8 / 19.4 ms, 0 lost	5.70 / 7.76
1 flow h2h loss-aware p99, 4 runs, mean	10.18 ms	7.14 ms	2.64–4.66
Throughput 1 / 8 flows, 4 runs, mean	2.49 / 2.36 Gbit/s	2.57 / 2.35	2.80 / 2.59

Step 3: paired 1 h soak, ONE `perf-run --root` hold (control, then cut), J88d soak plus ICMP 100/s

/home/claude/j20/r4b/j88e-soakpair-84b7bb2-20261103/: 7,613 s, outer exit 0, both runs exit 0, both machine diffs 0 bytes. 72 slots each, 1,000 peers per endpoint, 4 flapping peers. Host steal was 1.0% in the control's half and 0.7% in the cut's.

1 h soak	Control `da31c7f`	Cut `84b7bb2`
TCP `SACKReorder` / `TSReorder` / `OFOQueue`, a+b	0+1 / 0 / 1+0	0 / 0 / 0
TCP `RetransSegs`, a+b	0+9	0+2
h2h probes lost, 1 / 4 flows	366 / 1,105	0 / 2
per-minute h2h p99 median, 1 / 4 flows	12.25 / 17.71 ms	11.31 / 17.01
ICMP loss-aware p99 / p99.9, 1 flow (172,800)	11.5 ms / inf, 481 lost	10.3 / 12.9 ms, 0 lost
ICMP loss-aware p99 / p99.9, 4 flows (139,200)	19.8 ms / inf, 921 lost	15.6 / 18.7 ms, 0 lost
Throughput 1 / 4 flows	2.26 / 2.32 Gbit/s	2.35 / 2.41
`wgB` ring drops	1,142,143	304
Flaps reconnected; daemon log lines	195/195; 0	195/195; 0
Quiet-point RSS a / b, end	9.5 / 8.9 MiB	9.8 / 8.8 MiB

Keep rule: met, so the cut is kept

Loss-aware loaded p99 improves at 1 flow (−15% ICMP, −30% h2h) and 8 flows (−12% ICMP; p99.9 goes from inf to finite), measured in the same counterbalanced holds as the control and kernel. ✔
Throughput does not fall (+3% at 1 flow, −0.4% at 8 flows across 4 runs each; +4% in the soak). ✔
Soak TCP reorder and retransmits are at or below the control's (0 vs 1, 2 vs 9). ✔

Where this leaves D332: throughput is about 90% of kernel WireGuard in these holds, and loaded p99 is still about 3–4× kernel's (8.5 vs 2.1 ms at 1 flow, 15.8 vs 5.7 at 8). The ring loss is gone. What remains is queueing while the userspace threads wait for CPU (run-queue wait ≈ run time on this 3-CPU host). GotaTun is not yet at kernel parity.

Fork checks on `84b7bb2` (patch `git diff 73eb9f1 84b7bb2` = `3c3fa88c…`), verbatim

aarch64, infraternal-dev-02-std, through build-slot:

build-slot: [18:48:05] all 2 slots busy; queue position 4, waiting...
build-slot: [19:05:18] got slot 2/2
== HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=8 patch_sha=3c3fa88c21855aab
== fmt
== clippy
== focused
test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 150 filtered out; finished in 0.00s
== full lib suite
test result: ok. 146 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 6.30s
== release cli
49e64d903e8152d90e77d1498ebf08b45d77e66981899a5a3e67170f5b87549f  target/release/gotatun
J88E_CHECK_EXIT=0
49e64d903e8152d90e77d1498ebf08b45d77e66981899a5a3e67170f5b87549f  /home/claude/.cache/codex-scratch/j88e/bin/gotatun-qlen

x86, infraternal-dev-01-compute01, through build-slot:

build-slot: [19:53:57] all 4 slots busy; queue position 3, waiting...
build-slot: [20:33:35] got slot 1/4
== HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=8 patch_sha=3c3fa88c21855aab
== fmt
== clippy
== focused
test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 150 filtered out; finished in 0.00s
== full lib suite
test device::tests::test_indices ... FAILED
test result: FAILED. 145 passed; 1 failed; 7 ignored; 0 measured; 0 filtered out; finished in 8.70s
J88E_CHECK_EXIT=101
build-slot: [20:37:17] all 4 slots busy; queue position 5, waiting...
build-slot: [20:52:16] got slot 2/4
    Finished `release` profile [optimized] target(s) in 2m 16s
c04389381c4cf55872657ba336a566f2ce24845c9ccb5fad57634a16dd8a16d0  target/release/gotatun
RELEASE_EXIT=0

The x86 test_indices failure is a load flake, not this change (77140). It drives a mock device pair, with no TUN involved, under a 1 s wall-clock timer, and compute01 was at load 16. On the same built tree it then passed 20/20, and the full suite reran 146 passed; 0 failed; 7 ignored. The x86 release CLI (c0438938…) is the binary that every hold above measured. Checks: cargo fmt --check, clippy --workspace --all-features --all-targets -D warnings (only the existing needless_return allowed), the 3 new tests, the full gotatun library suite, and cargo build --release -p gotatun-cli.

Notes

Real environment: every measurement ran the fork as root, inside network namespaces on the perf VM (perf-run --root). The candidate's wgB reports qlen 1024 with no harness help. infraternal is unchanged, so scripts/verify fast does not apply.
Harness additions (overlays only, kit unchanged): raw ICMP samples (ping -D -O) next to the h2h probes, and per-thread schedstat in the profile hold. Without raw samples, J88d's summary can only bound a lossy run's loss-aware p99 by its max. That made hold 1's 8-flow comparison unresolvable. Recommendation: future loss-aware comparisons should use raw samples.
Evidence on the perf VM under /home/claude/j20/r4b/: j88e-qlen-profile-20261103, j88e-hold-84b7bb2-20261103, j88e-hold2-84b7bb2-20261103, j88e-soakpair-84b7bb2-20261103, j88e-soakpair-summary, scripts in j88e-scripts. Check logs are in ~/.cache/codex-scratch/j88e/ on compute01 and dev-02.
Cleanup: build target dirs and worktree copies on compute01 and dev-02 are deleted, and no J88e processes run on any VM. No upstream PRs, issues or comments.
Next lead (not started): the remaining tail is scheduling. Candidates, for the owner and orchestrator to rank: fewer cross-thread handoffs per packet, or batching TUN writes on the receiver (GotaTun writes one packet per syscall with GSO_NONE, so the kernel processes and ACKs each segment separately).

## J88e finish: fork `84b7bb2` is **pin-ready** for J103d. The TUN transmit ring cut passes all three keep checks **Fork** `kaygdotorg/gotatun` `j88-linux-offloads`, fast-forwarded `da31c7f..84b7bb2`, no force-push: | Commit | What | |---|---| | `72685e8` | perf: raise the Linux TUN transmit ring to 1,024 packets | | `84b7bb2` | style: rustfmt layout for the two ioctls (`72685e8` alone fails `cargo fmt --check`; no behaviour change) | **For J103d: pin `84b7bb2`.** The ring is raised only for a device GotaTun creates (`from_name`). If the integration hands GotaTun a device it created itself (`from_tun_device`), the integration must set `txqueuelen ≥ 1024` on it, or it keeps the kernel default of 500 and none of this applies. Raising it needs `CAP_NET_ADMIN`; without that it is logged at debug level and the device works as before. ### Step 1: profile (77124) | Finding | Evidence | |---|---| | All reply-path loss is the receiver's TUN transmit ring (500 slots, kernel default). tun drops at a full ring without pushing back, so the `fq` qdisc never holds anything | `wgB` TX dropped 0.06–0.37% at 1 flow, 0.35–2.3% at 8 flows, 1.14 M in the 1 h control soak; `wgA` 0 everywhere | | The cause is CPU starvation of the reader, not a full channel | GotaTun threads wait in the run queue 82–102% of their run time (per-thread `schedstat`, 3 CPUs) | | A ring of 1,024 or 4,096 removes the drops and the lost probes | harness-only sizing hold: 0 drops, 0 lost, throughput not lower | **Why the cut is order-preserving:** the `tun` crate rejects more than one queue, so the device has exactly one FIFO ring. Its length only decides whether a packet is kept or dropped, never its position. The soak confirms it: 0 reorder events. ### Step 2: counterbalanced R4b holds (77174, 77183), kernel → control → cut → cut → control | | Control `da31c7f` | Cut `84b7bb2` | Kernel WG | |---|---|---|---| | 1 flow, exact loss-aware p99 / p99.9 (raw ICMP, 3,600) | 9.99 / 13.7 ms, 3 lost | **8.50 / 11.0 ms, 0 lost** | 2.12 / 4.06 | | 8 flows, exact loss-aware p99 / p99.9 (raw ICMP, 3,600) | 17.9 ms / **inf**, 20 lost | **15.8 / 19.4 ms, 0 lost** | 5.70 / 7.76 | | 1 flow h2h loss-aware p99, 4 runs, mean | 10.18 ms | **7.14 ms** | 2.64–4.66 | | Throughput 1 / 8 flows, 4 runs, mean | 2.49 / 2.36 Gbit/s | **2.57 / 2.35** | 2.80 / 2.59 | ### Step 3: paired 1 h soak, ONE `perf-run --root` hold (control, then cut), J88d soak plus ICMP 100/s `/home/claude/j20/r4b/j88e-soakpair-84b7bb2-20261103/`: 7,613 s, **outer exit 0, both runs exit 0, both machine diffs 0 bytes**. 72 slots each, 1,000 peers per endpoint, 4 flapping peers. Host steal was 1.0% in the control's half and 0.7% in the cut's. | 1 h soak | Control `da31c7f` | Cut `84b7bb2` | |---|---|---| | TCP `SACKReorder` / `TSReorder` / `OFOQueue`, a+b | 0+1 / 0 / 1+0 | **0 / 0 / 0** | | TCP `RetransSegs`, a+b | 0+9 | **0+2** | | h2h probes lost, 1 / 4 flows | 366 / 1,105 | **0 / 2** | | per-minute h2h p99 median, 1 / 4 flows | 12.25 / 17.71 ms | **11.31 / 17.01** | | ICMP loss-aware p99 / p99.9, 1 flow (172,800) | 11.5 ms / inf, 481 lost | **10.3 / 12.9 ms, 0 lost** | | ICMP loss-aware p99 / p99.9, 4 flows (139,200) | 19.8 ms / inf, 921 lost | **15.6 / 18.7 ms, 0 lost** | | Throughput 1 / 4 flows | 2.26 / 2.32 Gbit/s | **2.35 / 2.41** | | `wgB` ring drops | 1,142,143 | **304** | | Flaps reconnected; daemon log lines | 195/195; 0 | 195/195; 0 | | Quiet-point RSS a / b, end | 9.5 / 8.9 MiB | 9.8 / 8.8 MiB | ### Keep rule: **met**, so the cut is kept - Loss-aware loaded p99 improves at 1 flow (−15% ICMP, −30% h2h) and 8 flows (−12% ICMP; p99.9 goes from inf to finite), measured in the same counterbalanced holds as the control and kernel. ✔ - Throughput does not fall (+3% at 1 flow, −0.4% at 8 flows across 4 runs each; +4% in the soak). ✔ - Soak TCP reorder and retransmits are at or below the control's (0 vs 1, 2 vs 9). ✔ **Where this leaves D332:** throughput is about 90% of kernel WireGuard in these holds, and loaded p99 is still about 3–4× kernel's (8.5 vs 2.1 ms at 1 flow, 15.8 vs 5.7 at 8). The ring loss is gone. What remains is queueing while the userspace threads wait for CPU (run-queue wait ≈ run time on this 3-CPU host). GotaTun is not yet at kernel parity. ### Fork checks on `84b7bb2` (patch `git diff 73eb9f1 84b7bb2` = `3c3fa88c…`), verbatim aarch64, infraternal-dev-02-std, through build-slot: ```text build-slot: [18:48:05] all 2 slots busy; queue position 4, waiting... build-slot: [19:05:18] got slot 2/2 == HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=8 patch_sha=3c3fa88c21855aab == fmt == clippy == focused test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 150 filtered out; finished in 0.00s == full lib suite test result: ok. 146 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 6.30s == release cli 49e64d903e8152d90e77d1498ebf08b45d77e66981899a5a3e67170f5b87549f target/release/gotatun J88E_CHECK_EXIT=0 49e64d903e8152d90e77d1498ebf08b45d77e66981899a5a3e67170f5b87549f /home/claude/.cache/codex-scratch/j88e/bin/gotatun-qlen ``` x86, infraternal-dev-01-compute01, through build-slot: ```text build-slot: [19:53:57] all 4 slots busy; queue position 3, waiting... build-slot: [20:33:35] got slot 1/4 == HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=8 patch_sha=3c3fa88c21855aab == fmt == clippy == focused test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 150 filtered out; finished in 0.00s == full lib suite test device::tests::test_indices ... FAILED test result: FAILED. 145 passed; 1 failed; 7 ignored; 0 measured; 0 filtered out; finished in 8.70s J88E_CHECK_EXIT=101 build-slot: [20:37:17] all 4 slots busy; queue position 5, waiting... build-slot: [20:52:16] got slot 2/4 Finished `release` profile [optimized] target(s) in 2m 16s c04389381c4cf55872657ba336a566f2ce24845c9ccb5fad57634a16dd8a16d0 target/release/gotatun RELEASE_EXIT=0 ``` The x86 `test_indices` failure is a load flake, not this change (77140). It drives a mock device pair, with no TUN involved, under a 1 s wall-clock timer, and compute01 was at load 16. On the same built tree it then passed **20/20**, and the full suite reran `146 passed; 0 failed; 7 ignored`. The x86 release CLI (`c0438938…`) is the binary that every hold above measured. Checks: `cargo fmt --check`, `clippy --workspace --all-features --all-targets -D warnings` (only the existing `needless_return` allowed), the 3 new tests, the full `gotatun` library suite, and `cargo build --release -p gotatun-cli`. ### Notes - **Real environment:** every measurement ran the fork as root, inside network namespaces on the perf VM (`perf-run --root`). The candidate's `wgB` reports `qlen 1024` with no harness help. infraternal is unchanged, so `scripts/verify fast` does not apply. - **Harness additions (overlays only, kit unchanged):** raw ICMP samples (`ping -D -O`) next to the h2h probes, and per-thread `schedstat` in the profile hold. Without raw samples, J88d's summary can only bound a lossy run's loss-aware p99 by its max. That made hold 1's 8-flow comparison unresolvable. **Recommendation:** future loss-aware comparisons should use raw samples. - **Evidence** on the perf VM under `/home/claude/j20/r4b/`: `j88e-qlen-profile-20261103`, `j88e-hold-84b7bb2-20261103`, `j88e-hold2-84b7bb2-20261103`, `j88e-soakpair-84b7bb2-20261103`, `j88e-soakpair-summary`, scripts in `j88e-scripts`. Check logs are in `~/.cache/codex-scratch/j88e/` on compute01 and dev-02. - **Cleanup:** build target dirs and worktree copies on compute01 and dev-02 are deleted, and no J88e processes run on any VM. No upstream PRs, issues or comments. - **Next lead (not started):** the remaining tail is scheduling. Candidates, for the owner and orchestrator to rank: fewer cross-thread handoffs per packet, or batching TUN writes on the receiver (GotaTun writes one packet per syscall with `GSO_NONE`, so the kernel processes and ACKs each segment separately).

kayg commented

2026-11-03 22:48:04 +00:00

Author

Owner

J88f start: one cut against the scheduling tail (D332)

Fork kaygdotorg/gotatun j88-linux-offloads, base and control 84b7bb2. New commits only, no force-push, no upstream activity. J103d owns the integration.

What the code shows at 84b7bb2. Each endpoint runs a multi-thread tokio runtime with one worker per CPU (3 on the perf VM, so 6 workers on 3 CPUs for the two endpoints).

Send path: TUN read task → channel → handle_outgoing (encrypt) → channel → buffered UDP send task (sendmmsg/GSO). 3 tasks, 2 handoffs.
Receive path: handle_incoming (recvmmsg/GRO + decrypt, already fused on Linux) → channel → buffered IP send task (one write per packet, and with the vnet header it allocates and copies each packet again). 2 tasks, 1 handoff.
A ping probe crosses 4 paths (A out, B in, B out, A in), so 6 handoffs. Each one can wake a parked worker, which then waits for a CPU.

Choice (to be confirmed by step 1): (a), fuse decrypt and TUN write in handle_incoming. Each received batch is decrypted, and the IP packets are written in order straight from the same task once the device and peer locks are released. This removes the receive path's only handoff, on both endpoints (data receiver and ACK/reply receiver), plus the extra alloc+copy per packet. It is about 40 lines.

Order: today one task produces packets into a FIFO channel and one task writes them, so the order of writes to the single-queue TUN fd is the order of decryption. Afterwards the same task does both in the same loop, so the write sequence is identical by construction. Nothing else writes IP packets to the device.
Why not encrypt and UDP-send: the buffered UDP sender is shared with handshake and timer traffic, and it is where sendmmsg batching and the v4/v6 split happen. Fusing it is more code for the same single handoff per path.
Why not (b) TUN write batching (GRO): it needs per-flow TCP coalescing (sequence contiguity, flags, checksum offload). That is several hundred lines of protocol-critical code. J88e's profile says the cost is waiting for a CPU, not syscall time. Recorded as the next lead if (a) misses.

Steps and estimate (about 3.5–4 h of wall clock, mostly the holds):

Profile at the control (≈30 min): context switches and wakeups per packet (/proc/<pid>/task/*/status voluntary/nonvoluntary switches plus schedstat) during the 1- and 8-flow loaded phases. This confirms the handoff count drives the wait, and gives a baseline to compare against.
Implement plus a unit test that the fused path writes in decryption order (≈30 min), then build on compute01.
Counterbalanced R4b hold, kernel → control → cut → cut → control, with J88e's raw ping -D -O samples for exact loss-aware p99 at 1 and 8 flows, plus throughput (≈45 min).
If step 3 passes: one paired 1 h soak in one perf-run --root hold, control then cut. Keep only if reorder and retransmit counts are at the control's level and there are no new wgB ring drops (≈2 h 10 min).
Fork checks on x86 (compute01) and aarch64 (dev-02) through build-slot. Then mark pin-ready, or post a revert commit with the data. Delete target dirs.

A table per step follows here.

## J88f start: one cut against the scheduling tail (D332) **Fork** `kaygdotorg/gotatun` `j88-linux-offloads`, base and control **`84b7bb2`**. New commits only, no force-push, no upstream activity. J103d owns the integration. **What the code shows at `84b7bb2`.** Each endpoint runs a multi-thread tokio runtime with one worker per CPU (3 on the perf VM, so 6 workers on 3 CPUs for the two endpoints). - Send path: TUN read task → channel → `handle_outgoing` (encrypt) → channel → buffered UDP send task (sendmmsg/GSO). 3 tasks, 2 handoffs. - Receive path: `handle_incoming` (recvmmsg/GRO + decrypt, already fused on Linux) → channel → buffered IP send task (one `write` per packet, and with the vnet header it allocates and copies each packet again). 2 tasks, 1 handoff. - A ping probe crosses 4 paths (A out, B in, B out, A in), so 6 handoffs. Each one can wake a parked worker, which then waits for a CPU. **Choice (to be confirmed by step 1): (a), fuse decrypt and TUN write in `handle_incoming`.** Each received batch is decrypted, and the IP packets are written in order straight from the same task once the device and peer locks are released. This removes the receive path's only handoff, on both endpoints (data receiver and ACK/reply receiver), plus the extra alloc+copy per packet. It is about 40 lines. - **Order:** today one task produces packets into a FIFO channel and one task writes them, so the order of writes to the single-queue TUN fd is the order of decryption. Afterwards the same task does both in the same loop, so the write sequence is identical by construction. Nothing else writes IP packets to the device. - **Why not encrypt and UDP-send:** the buffered UDP sender is shared with handshake and timer traffic, and it is where sendmmsg batching and the v4/v6 split happen. Fusing it is more code for the same single handoff per path. - **Why not (b) TUN write batching (GRO):** it needs per-flow TCP coalescing (sequence contiguity, flags, checksum offload). That is several hundred lines of protocol-critical code. J88e's profile says the cost is waiting for a CPU, not syscall time. Recorded as the next lead if (a) misses. **Steps and estimate (about 3.5–4 h of wall clock, mostly the holds):** 1. Profile at the control (≈30 min): context switches and wakeups per packet (`/proc/<pid>/task/*/status` voluntary/nonvoluntary switches plus `schedstat`) during the 1- and 8-flow loaded phases. This confirms the handoff count drives the wait, and gives a baseline to compare against. 2. Implement plus a unit test that the fused path writes in decryption order (≈30 min), then build on compute01. 3. Counterbalanced R4b hold, kernel → control → cut → cut → control, with J88e's raw `ping -D -O` samples for exact loss-aware p99 at 1 and 8 flows, plus throughput (≈45 min). 4. If step 3 passes: one paired 1 h soak in one `perf-run --root` hold, control then cut. Keep only if reorder and retransmit counts are at the control's level and there are no new `wgB` ring drops (≈2 h 10 min). 5. Fork checks on x86 (compute01) and aarch64 (dev-02) through build-slot. Then mark pin-ready, or post a revert commit with the data. Delete target dirs. A table per step follows here.

kayg commented

2026-11-03 23:06:57 +00:00

Author

Owner

J88f step 2: cut `6db735f` pushed and gated on both arches. Keep hold running

j88-linux-offloads fast-forwarded 84b7bb2..6db735f, no force-push.


Commit	`6db735f` perf: write decrypted packets to the TUN device from the receive task
Change	`handle_incoming` writes each decrypted packet through `DirectIpSend` once the device and peer locks are dropped. The `BufferedIpSend` channel and its worker task are removed. 3 files, +142 / −78, of which about 70 lines are tests
Order	`DirectIpSend` holds the device writer lock for its lifetime, so it is the only writer, and its one caller is the decrypting task. The write order is the decryption order, as it was through the single-consumer FIFO
Kept	a refused packet is still dropped, counted and skipped (J88d `cce74ed`); a gone device still stops the direction
New tests	`long_burst_is_delivered_in_order` (2,000 packets through a device pair), `direct_send_keeps_order_and_skips_a_refused_packet`, `direct_send_reports_a_gone_device`

Fork checks (patch git diff 73eb9f1 6db735f = 29ae4b35…):

Host	fmt	clippy `-D warnings`	focused	full lib suite	release CLI
dev-02 aarch64	ok	ok	3 passed	149 passed, 0 failed, 7 ignored	`2ba84b95…`
compute01 x86	ok	ok	3 passed	149 passed, 0 failed, 7 ignored	`7ae97a8b…` (this binary is the one measured)

Plan change: step 1 (the profile) is folded into the keep hold, which saves one hold of about 20 minutes. J88e's per-thread schedstat overlay runs in every loaded phase, so the same hold gives the run-queue wait and the number of times threads are scheduled in, per packet, for control and cut side by side.

Step 3 is running: /home/claude/j20/r4b/j88f-hold-6db735f-20261104/, one perf-run --root hold in the order kernel → control 84b7bb2 → cut → cut → control. It collects raw ping -D -O samples at 1 and 8 flows. Scripts are in j88f-scripts/.

## J88f step 2: cut `6db735f` pushed and gated on both arches. Keep hold running `j88-linux-offloads` fast-forwarded `84b7bb2..6db735f`, no force-push. | | | |---|---| | Commit | `6db735f` perf: write decrypted packets to the TUN device from the receive task | | Change | `handle_incoming` writes each decrypted packet through `DirectIpSend` once the device and peer locks are dropped. The `BufferedIpSend` channel and its worker task are removed. 3 files, +142 / −78, of which about 70 lines are tests | | Order | `DirectIpSend` holds the device writer lock for its lifetime, so it is the only writer, and its one caller is the decrypting task. The write order is the decryption order, as it was through the single-consumer FIFO | | Kept | a refused packet is still dropped, counted and skipped (J88d `cce74ed`); a gone device still stops the direction | | New tests | `long_burst_is_delivered_in_order` (2,000 packets through a device pair), `direct_send_keeps_order_and_skips_a_refused_packet`, `direct_send_reports_a_gone_device` | Fork checks (patch `git diff 73eb9f1 6db735f` = `29ae4b35…`): | Host | fmt | clippy `-D warnings` | focused | full lib suite | release CLI | |---|---|---|---|---|---| | dev-02 aarch64 | ok | ok | 3 passed | **149 passed, 0 failed, 7 ignored** | `2ba84b95…` | | compute01 x86 | ok | ok | 3 passed | **149 passed, 0 failed, 7 ignored** | `7ae97a8b…` (this binary is the one measured) | **Plan change:** step 1 (the profile) is folded into the keep hold, which saves one hold of about 20 minutes. J88e's per-thread `schedstat` overlay runs in every loaded phase, so the same hold gives the run-queue wait and the number of times threads are scheduled in, per packet, for control and cut side by side. **Step 3 is running:** `/home/claude/j20/r4b/j88f-hold-6db735f-20261104/`, one `perf-run --root` hold in the order kernel → control `84b7bb2` → cut → cut → control. It collects raw `ping -D -O` samples at 1 and 8 flows. Scripts are in `j88f-scripts/`.

kayg commented

2026-11-03 23:27:55 +00:00

Author

Owner

J88f finish: the fused receive-side TUN write is rejected and reverted. Pin stays `84b7bb2`

Fork kaygdotorg/gotatun j88-linux-offloads, fast-forwarded 84b7bb2..229b9a1, no force-push:

Commit	What	Verdict
`6db735f`	perf: the receive task writes decrypted packets to the TUN device itself (`DirectIpSend`; the `BufferedIpSend` channel and its worker are gone)	rejected by the hold
`229b9a1`	revert of `6db735f`	tree is byte-identical to `84b7bb2` (`git diff 84b7bb2 229b9a1` is empty), which J88e gated on x86 and aarch64 (77235)

For J103d: nothing changes. Keep pinning 84b7bb2; 229b9a1 has the same tree.

Step 3: counterbalanced R4b keep hold, `/home/claude/j20/r4b/j88f-hold-6db735f-20261104/`

One perf-run --root hold, exit 0, every case exit 0, wall time 1,181 s, steal 0.76%. Order: kernel → control 84b7bb2 (c0438938…) → cut 6db735f (7ae97a8b…) → cut → control. Summaries are in j88f-hold-6db735f-summary/ (summary.md, drops.md, ping.md).

	Kernel WG	Control first	Cut first	Cut second	Control last
Throughput 1 / 8 flows, Gbit/s	2.91 / 2.52	2.37 / 2.17	1.93 / 1.84	1.83 / 1.64	2.17 / 2.14
CPU s per Gbit 1 / 8	1.18 / 1.30	1.04 / 1.10	1.14 / 1.06	1.14 / 1.26	1.10 / 1.12
ICMP 1 flow, raw, loss-aware p99 / p99.9 (ms), lost	1.85 / 2.97, 0	9.22 / 13.6, 0	9.24 / 11.5, 0	10.6 / 15.7, 0	9.75 / 13.6, 0
ICMP 8 flows, raw, loss-aware p99 / p99.9 (ms), lost	5.11 / 8.68, 0	18.5 / 27.0, 0	18.7 / 24.0, 0	18.8 / 22.3, 0	26.2 / 44.3, 0
h2h 1 / 8 flows loss-aware p99 (ms)	4.18 / 7.73	7.94 / 20.2	9.35 / 21.1	12.1 / 20.9	11.5 / 19.9
`wgB` ring drops 1 / 8	–	0 / 0	0 / 0	0 / 0	0 / 0
GotaTun thread run s / run-queue wait s, 1 flow	–	20.6 / 18.3	17.5 / 16.6	18.0 / 16.7	19.9 / 17.9
Times threads were scheduled in, per 1k `wgB` packets, 1 / 8 flows	–	960 / 807	769 / 628	782 / 697	945 / 824

Pooled raw ICMP over 3,600 probes: control 9.56 / 20.9 ms at 1 / 8 flows, cut 10.1 / 18.8 ms. Neither lost a probe. The cut's 8-flow figure looks better only because control-last has an outlier (26.2 ms); control-first and both cut runs sit at 18.5–18.8.

Keep rule: not met

Loss-aware p99 does not improve at 1 flow (10.1 against 9.56 ms). ✘
Throughput falls by about 18%, and both cut runs are below both control runs at 1 and 8 flows. ✘
The 1 h soak was not run, because the hold already rejects the cut.

Finding: why it lost (evidence in the table)

The cut did what it was built to do. Threads were scheduled in about 19% fewer times per packet (960 → 775 at 1 flow), and both run time and run-queue wait fell.
But a TUN write runs the kernel's receive path for that packet in the calling thread: netif_rx, then TCP receive and the ACK. Once the write moves into the decrypt task, that kernel work is serialised with decryption on one thread. Before, the separate writer task overlapped it on another CPU. The receive task becomes the bottleneck, so throughput falls, CPU per Gbit rises (1.14 against 1.04–1.10), and the queue ahead of it grows the tail.
So the handoff is not pure overhead. It buys pipeline parallelism between userspace decryption and the kernel's per-packet receive work. Cutting handoffs only pays if the per-packet kernel work shrinks too.

Next lead (not started; for the owner and orchestrator to rank)

(b) GRO-coalesced TUN writes on the receiver. This hold points to it as the larger lever. The kernel's per-segment receive work is what competes for the CPU, and coalescing turns about 40 segments into one write and one pass through the stack. It is a few hundred lines of TCP coalescing (sequence contiguity, flags, checksum offload with NEEDS_CSUM), so it needs the strictest review. The integration already does GRO writes (J103), and its approach can guide the design; it should be written fresh, since the fork is MPL-2.0.
Cheap side note, untested: TunDevice::send with a vnet header allocates a new buffer and copies every packet to prepend the 10-byte header. The pool's headroom could avoid that. It is small and separate, and would need its own hold.

Fork checks on `6db735f` (patch `git diff 73eb9f1 6db735f` = `29ae4b35…`), verbatim summaries

aarch64, infraternal-dev-02-std, through build-slot:

== HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=9 patch_sha=29ae4b35698d5a6f
== fmt
== clippy
== focused
test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 153 filtered out; finished in 0.06s
== full lib suite
test result: ok. 149 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 5.81s
== release cli
2ba84b951ded2d00dc18f46945c0223aeb73e718c0bbe5d2708e89737777a4e2  target/release/gotatun
J88F_CHECK_EXIT=0

x86, infraternal-dev-01-compute01, through build-slot:

build-slot: [23:59:35] got slot 1/4
== HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=9 patch_sha=29ae4b35698d5a6f
== fmt
== clippy
== focused
test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 153 filtered out; finished in 0.42s
== full lib suite
test result: ok. 149 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 11.73s
== release cli
    Finished `release` profile [optimized] target(s) in 2m 33s
7ae97a8bed21f3c41ee8619b58c9051e7d9f69fbd4ce7cba9ec94969da7db0e7  target/release/gotatun
J88F_CHECK_EXIT=0

The revert 229b9a1 restores the exact 84b7bb2 tree, so J88e's checks on that tree still apply.

Notes

Real environment: both binaries ran as root in network namespaces on the perf VM (perf-run --root). infraternal is unchanged, so scripts/verify fast does not apply.
Harness: overlays only, in runner-overlays/ of the evidence dir. These are J88e's hold-2 overlay (raw ping -D -O) plus J88e's per-thread schedstat overlay; drops.py also counts how many times threads are scheduled in. Scripts are in /home/claude/j20/r4b/j88f-scripts/.
Cleanup: the J88f worktrees and target dirs on compute01 and dev-02 are deleted, and so is the cut binary on the perf VM. No J88f processes run anywhere (the perf VM is now running J103d's hold). No upstream PRs, issues or comments.

## J88f finish: the fused receive-side TUN write is **rejected and reverted**. Pin stays `84b7bb2` **Fork** `kaygdotorg/gotatun` `j88-linux-offloads`, fast-forwarded `84b7bb2..229b9a1`, no force-push: | Commit | What | Verdict | |---|---|---| | `6db735f` | perf: the receive task writes decrypted packets to the TUN device itself (`DirectIpSend`; the `BufferedIpSend` channel and its worker are gone) | **rejected by the hold** | | `229b9a1` | revert of `6db735f` | tree is **byte-identical to `84b7bb2`** (`git diff 84b7bb2 229b9a1` is empty), which J88e gated on x86 and aarch64 (77235) | **For J103d: nothing changes.** Keep pinning `84b7bb2`; `229b9a1` has the same tree. ### Step 3: counterbalanced R4b keep hold, `/home/claude/j20/r4b/j88f-hold-6db735f-20261104/` One `perf-run --root` hold, **exit 0, every case exit 0**, wall time 1,181 s, steal 0.76%. Order: kernel → control `84b7bb2` (`c0438938…`) → cut `6db735f` (`7ae97a8b…`) → cut → control. Summaries are in `j88f-hold-6db735f-summary/` (`summary.md`, `drops.md`, `ping.md`). | | Kernel WG | Control first | Cut first | Cut second | Control last | |---|---|---|---|---|---| | Throughput 1 / 8 flows, Gbit/s | 2.91 / 2.52 | 2.37 / 2.17 | **1.93 / 1.84** | **1.83 / 1.64** | 2.17 / 2.14 | | CPU s per Gbit 1 / 8 | 1.18 / 1.30 | 1.04 / 1.10 | 1.14 / 1.06 | 1.14 / 1.26 | 1.10 / 1.12 | | ICMP 1 flow, raw, loss-aware p99 / p99.9 (ms), lost | 1.85 / 2.97, 0 | 9.22 / 13.6, 0 | 9.24 / 11.5, 0 | 10.6 / 15.7, 0 | 9.75 / 13.6, 0 | | ICMP 8 flows, raw, loss-aware p99 / p99.9 (ms), lost | 5.11 / 8.68, 0 | 18.5 / 27.0, 0 | 18.7 / 24.0, 0 | 18.8 / 22.3, 0 | 26.2 / 44.3, 0 | | h2h 1 / 8 flows loss-aware p99 (ms) | 4.18 / 7.73 | 7.94 / 20.2 | 9.35 / 21.1 | 12.1 / 20.9 | 11.5 / 19.9 | | `wgB` ring drops 1 / 8 | – | 0 / 0 | 0 / 0 | 0 / 0 | 0 / 0 | | GotaTun thread run s / run-queue wait s, 1 flow | – | 20.6 / 18.3 | 17.5 / 16.6 | 18.0 / 16.7 | 19.9 / 17.9 | | Times threads were scheduled in, per 1k `wgB` packets, 1 / 8 flows | – | 960 / 807 | 769 / 628 | 782 / 697 | 945 / 824 | Pooled raw ICMP over 3,600 probes: control **9.56 / 20.9 ms** at 1 / 8 flows, cut **10.1 / 18.8 ms**. Neither lost a probe. The cut's 8-flow figure looks better only because control-last has an outlier (26.2 ms); control-first and both cut runs sit at 18.5–18.8. ### Keep rule: **not met** - Loss-aware p99 does not improve at 1 flow (10.1 against 9.56 ms). ✘ - Throughput falls by about 18%, and both cut runs are below both control runs at 1 and 8 flows. ✘ - The 1 h soak was **not run**, because the hold already rejects the cut. ### Finding: why it lost (evidence in the table) - The cut did what it was built to do. Threads were scheduled in about 19% fewer times per packet (960 → 775 at 1 flow), and both run time and run-queue wait fell. - But a TUN `write` runs the kernel's receive path for that packet in the calling thread: `netif_rx`, then TCP receive and the ACK. Once the write moves into the decrypt task, that kernel work is serialised with decryption on one thread. Before, the separate writer task overlapped it on another CPU. The receive task becomes the bottleneck, so throughput falls, CPU per Gbit rises (1.14 against 1.04–1.10), and the queue ahead of it grows the tail. - **So the handoff is not pure overhead.** It buys pipeline parallelism between userspace decryption and the kernel's per-packet receive work. Cutting handoffs only pays if the per-packet kernel work shrinks too. ### Next lead (not started; for the owner and orchestrator to rank) - **(b) GRO-coalesced TUN writes on the receiver.** This hold points to it as the larger lever. The kernel's per-segment receive work is what competes for the CPU, and coalescing turns about 40 segments into one write and one pass through the stack. It is a few hundred lines of TCP coalescing (sequence contiguity, flags, checksum offload with `NEEDS_CSUM`), so it needs the strictest review. The integration already does GRO writes (J103), and its approach can guide the design; it should be written fresh, since the fork is MPL-2.0. - **Cheap side note, untested:** `TunDevice::send` with a vnet header allocates a new buffer and copies every packet to prepend the 10-byte header. The pool's headroom could avoid that. It is small and separate, and would need its own hold. ### Fork checks on `6db735f` (patch `git diff 73eb9f1 6db735f` = `29ae4b35…`), verbatim summaries aarch64, infraternal-dev-02-std, through build-slot: ```text == HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=9 patch_sha=29ae4b35698d5a6f == fmt == clippy == focused test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 153 filtered out; finished in 0.06s == full lib suite test result: ok. 149 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 5.81s == release cli 2ba84b951ded2d00dc18f46945c0223aeb73e718c0bbe5d2708e89737777a4e2 target/release/gotatun J88F_CHECK_EXIT=0 ``` x86, infraternal-dev-01-compute01, through build-slot: ```text build-slot: [23:59:35] got slot 1/4 == HEAD 73eb9f1ae185313609d031c644cb4a81f3c927dc dirty=9 patch_sha=29ae4b35698d5a6f == fmt == clippy == focused test result: ok. 3 passed; 0 failed; 0 ignored; 0 measured; 153 filtered out; finished in 0.42s == full lib suite test result: ok. 149 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 11.73s == release cli Finished `release` profile [optimized] target(s) in 2m 33s 7ae97a8bed21f3c41ee8619b58c9051e7d9f69fbd4ce7cba9ec94969da7db0e7 target/release/gotatun J88F_CHECK_EXIT=0 ``` The revert `229b9a1` restores the exact `84b7bb2` tree, so J88e's checks on that tree still apply. ### Notes - **Real environment:** both binaries ran as root in network namespaces on the perf VM (`perf-run --root`). infraternal is unchanged, so `scripts/verify fast` does not apply. - **Harness:** overlays only, in `runner-overlays/` of the evidence dir. These are J88e's hold-2 overlay (raw `ping -D -O`) plus J88e's per-thread `schedstat` overlay; `drops.py` also counts how many times threads are scheduled in. Scripts are in `/home/claude/j20/r4b/j88f-scripts/`. - **Cleanup:** the J88f worktrees and target dirs on compute01 and dev-02 are deleted, and so is the cut binary on the perf VM. No J88f processes run anywhere (the perf VM is now running J103d's hold). No upstream PRs, issues or comments.

kayg commented

2026-11-03 23:47:58 +00:00

Author

Owner

J103d R4b: fork at `84b7bb2` with the agent's TUN `txqueuelen` 1,024, against kernel (2026-11-04, 04:50 IST)

Hold. /home/claude/j20/r4b/j103d/hold-84b7bb2-20261104/ on the perf VM, one perf-run --root hold (it waited for the perf lock first), 00:2x–00:4x CET.

Outer exit 0; all 4 cases exit 0; every machine diff empty. Wall time 950 s.
Steal 2,307 of 379,725 jiffies, about 2× the previous hold's rate, so this hold is noisier.
Order: kernel, ring, ring, kernel. Runner j103d-r4b-84b7bb2.sh, analyzer j103d-r4b-analyze-84b.py.
Binary 236ec973…: b162c5bc4 with GotaTun at 84b7bb28e385 (J88e's kept cut, comment 77235) and features = ["device", "ring"], x86_64 musl static via scripts/static-cargo on compute01.
- The mirror still has not synced (comment 77122), so this one build used the same rev from GitHub, uncommitted.
- Its shipping code equals the branch head bbd20b606, which since then changes only test helpers.
- Kernel cases use the same binary. Coordinator 9e32e7b2….

The txqueuelen integration works in the hold: infraternal0 reports qlen 1024 on both endpoints in both GotaTun cases (diag-pre-8-h2h-{a,b}.txt). This is our adapter's TUN, which the fork's own ring change does not touch.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	Loaded RTT p50/p99, 1 flow (ms)	Loaded RTT p50/p99, 8 flows (ms)	Lost probes 1 / 8	`RcvbufErrors`	TUN bytes/RX packet 1 / 8
kernel-first	2.61 / 2.37	1.26 / 1.37	1.096 / 3.492	3.763 / 5.675	0 / 0	0 / 0	1411 / 1411
ring-first	2.59 / 2.38	0.86 / 0.98	3.006 / 7.554	10.209 / 18.871	0 / 0	0 / 0	23441 / 19469
ring-second	2.66 / 2.43	0.89 / 0.98	3.183 / 8.527	8.973 / 17.126	0 / 0	0 / 0	23175 / 18767
kernel-last	2.66 / 2.51	1.21 / 1.28	1.137 / 4.408	3.541 / 10.616	0 / 0	0 / 0	1411 / 1411
kernel mean	2.64 / 2.44	1.23 / 1.33	1.117 / 3.950	3.652 / 8.146	0.0% / 0.0%
GotaTun mean	2.63 / 2.40	0.87 / 0.98	3.095 / 8.040	9.591 / 17.998	0.0% / 0.0%

Impairments: with 2% loss each way, every case loses 7–23 of 300 probes. With 25%/50% reordering, every case loses 0.
Idle RSS, both endpoints: kernel 19.5 MiB, GotaTun 23.9 MiB. After load, GotaTun is 46.3 / 41.0 MiB. That sample is taken right after load, so it does not measure the idle release.

The D332 switch rule on the latest row

GotaTun at `84b7bb2`	1 flow	8 flows
Throughput, share of kernel	100%	98%
Loss-aware loaded p99, × kernel	2.0× (8.04 / 3.95 ms)	2.2× (18.00 / 8.15 ms)
CPU s/Gbit, × kernel	0.71×	0.74×

Throughput is at parity, and CPU per byte is about 0.7× kernel's. Loaded p99 is still about 2× kernel's at 0% loss.
Against the da31c7f hold (comment 77139: GotaTun 6.72 / 18.27 ms), the 8-flow p99 is unchanged at 18.00 ms. The 1-flow figure is 8.04 ms, but this hold's kernel 1-flow p99 is also 28% higher (3.95 against 3.09 ms), so the cross-hold figure is noise-limited.
This hold does not show J88e's ~15% p99 gain. J88e's figure comes from its 1 h soak with impairments, and R4b's loaded probe runs one short phase per case.
The loss-free result is consistent with J88e's cut. Every loaded phase on both engines lost 0 probes, the same as the previous hold.

## J103d R4b: fork at `84b7bb2` with the agent's TUN `txqueuelen` 1,024, against kernel (2026-11-04, 04:50 IST) **Hold.** `/home/claude/j20/r4b/j103d/hold-84b7bb2-20261104/` on the perf VM, one `perf-run --root` hold (it waited for the perf lock first), 00:2x–00:4x CET. - Outer exit 0; all 4 cases exit 0; every machine diff empty. Wall time 950 s. - Steal 2,307 of 379,725 jiffies, about 2× the previous hold's rate, so this hold is noisier. - **Order:** kernel, ring, ring, kernel. Runner `j103d-r4b-84b7bb2.sh`, analyzer `j103d-r4b-analyze-84b.py`. - **Binary** `236ec973…`: `b162c5bc4` with GotaTun at **`84b7bb28e385`** (J88e's kept cut, comment 77235) and `features = ["device", "ring"]`, x86_64 musl static via `scripts/static-cargo` on compute01. - The mirror still has not synced (comment 77122), so this one build used the same rev from GitHub, uncommitted. - Its shipping code equals the branch head `bbd20b606`, which since then changes only test helpers. - Kernel cases use the same binary. Coordinator `9e32e7b2…`. **The txqueuelen integration works in the hold:** `infraternal0` reports `qlen 1024` on both endpoints in both GotaTun cases (`diag-pre-8-h2h-{a,b}.txt`). This is our adapter's TUN, which the fork's own ring change does not touch. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | Loaded RTT p50/p99, 1 flow (ms) | Loaded RTT p50/p99, 8 flows (ms) | Lost probes 1 / 8 | `RcvbufErrors` | TUN bytes/RX packet 1 / 8 | |---|---:|---:|---:|---:|---:|---:|---:| | kernel-first | 2.61 / 2.37 | 1.26 / 1.37 | 1.096 / 3.492 | 3.763 / 5.675 | 0 / 0 | 0 / 0 | 1411 / 1411 | | ring-first | 2.59 / 2.38 | 0.86 / 0.98 | 3.006 / 7.554 | 10.209 / 18.871 | 0 / 0 | 0 / 0 | 23441 / 19469 | | ring-second | 2.66 / 2.43 | 0.89 / 0.98 | 3.183 / 8.527 | 8.973 / 17.126 | 0 / 0 | 0 / 0 | 23175 / 18767 | | kernel-last | 2.66 / 2.51 | 1.21 / 1.28 | 1.137 / 4.408 | 3.541 / 10.616 | 0 / 0 | 0 / 0 | 1411 / 1411 | | **kernel mean** | **2.64 / 2.44** | 1.23 / 1.33 | 1.117 / **3.950** | 3.652 / **8.146** | **0.0% / 0.0%** | | | | **GotaTun mean** | **2.63 / 2.40** | 0.87 / 0.98 | 3.095 / **8.040** | 9.591 / **17.998** | **0.0% / 0.0%** | | | - **Impairments:** with 2% loss each way, every case loses 7–23 of 300 probes. With 25%/50% reordering, every case loses 0. - **Idle RSS**, both endpoints: kernel 19.5 MiB, GotaTun 23.9 MiB. After load, GotaTun is 46.3 / 41.0 MiB. That sample is taken right after load, so it does not measure the idle release. ### The D332 switch rule on the latest row | GotaTun at `84b7bb2` | 1 flow | 8 flows | |---|---:|---:| | Throughput, share of kernel | **100%** | **98%** | | Loss-aware loaded p99, × kernel | **2.0×** (8.04 / 3.95 ms) | **2.2×** (18.00 / 8.15 ms) | | CPU s/Gbit, × kernel | 0.71× | 0.74× | - **Throughput is at parity**, and CPU per byte is about 0.7× kernel's. **Loaded p99 is still about 2× kernel's** at 0% loss. - Against the `da31c7f` hold (comment 77139: GotaTun 6.72 / 18.27 ms), the 8-flow p99 is unchanged at 18.00 ms. The 1-flow figure is 8.04 ms, but this hold's kernel 1-flow p99 is also 28% higher (3.95 against 3.09 ms), so the cross-hold figure is noise-limited. - This hold does not show J88e's ~15% p99 gain. J88e's figure comes from its 1 h soak with impairments, and R4b's loaded probe runs one short phase per case. - The loss-free result is consistent with J88e's cut. Every loaded phase on both engines lost 0 probes, the same as the previous hold.

kayg commented

2026-11-04 01:31:26 +00:00

Author

Owner

J103d finish: head `bbd20b606`, `verify fast` NOT green, cause inherited from the first GotaTun commit (2026-11-04, 06:40 IST)

Branch mesh-gotatun-linux = bbd20b606b482126e836f30f77dd6fb62ab98584 (pushed). It sits on origin/dev 7e1cb858f: J103c's 12 commits plus mine, one per finding.

Commit	What
`50f0474c4`	P2-1: the adapter drops and counts undecodable frames; only EOF or a device-gone errno reaches GotaTun
`dd8e3d9b1`	P2-1: the worker waits on the device's fatal error, rebuilds it after 1 s, and `mesh status` shows `engine {stopped, restarts, refused_frames}`
`1cddc67fa`	P3-1: CWR stays only on the first TSO segment
`0f6e4e969`	P3-2: no GRO merge with a bad IPv4 header checksum
`d787e96e5`	P3-3: sweep `mesh-private-key.<pid>.new` under the key's directory lock; retirement removes the key. Backups (D147) are not implemented, so nothing copies the key; the module doc states that invariant
`f81e4c66b`	P3-4: live-link recheck before removing the shared table, in `down` (both engines) and in retirement
`c5c5c4317`	P3-5: MPL-2.0 source location and the Cloudflare BSD-3 notice
`eaae8e170`	P2-2: GotaTun built with ring (D289), and cargo-deny bans aws-lc-rs and aws-lc-sys
`adec24e7e`, `45b62524b`	D332: persistent TUN, reattached only under the retirement and firewall ownership proof, removed on down and retire
`bbd20b606`	J88e: the agent raises the TUN `txqueuelen` to 1,024 and reports a short queue in `mesh status`

RED → GREEN

All of these are in comments 77073, 77115 and 77249, plus the txqueuelen proof:

txqueuelen, gotatun_restore (rootless namespace, compute01). GREEN: 3/3 at bbd20b606. RED with the raise removed: the new TUN's transmit queue (kernel, reported): (500, Some(500)).
Correction to my D332 evidence. The first version of that test read /sys/class/net, which inside unshare shows the host's namespace. Its "same ifindex across restart" checks were therefore vacuous. They now read ip -o link in the test's own namespace and pass. The D332 route and flow proof (gotatun_persistence, ip -n) was never affected: restore 0.52–0.61 s, longest stall on the open TCP flow 0.72–0.82 s, 8 MiB byte-exact (3 runs, compute01).
Namespace suites at the final code: 33 of 36 pass on compute01, including every nf_tables case. The 3 failures are identical at unmodified origin/dev e81eb5bb4: review_mesh_view_truth_r2, review_reverse_recreation and review_shutdown_budget.

Gate: `scripts/verify fast` at `bbd20b606` (compute01, build-slot, `nix develop`), exit 1

repository artifact gate: PASS (31 changed path(s), merge base 7e1cb858f38c)
…
test remote_client::tests::server_path_capability_is_advertised_on_native_and_fallback_transports ... FAILED
test remote_client::tests::unavailable_udp_does_not_add_seconds_before_tcp_admission ... FAILED
test result: FAILED. 218 passed; 2 failed; 22 ignored; 0 measured; 0 filtered out; finished in 33.81s
…
advisories ok, bans ok, licenses ok, sources ok
…
PT_INTERP: absent; size: 23341136 bytes; baseline 22418256; delta +922880 bytes (report only, D243 amended 2026-11-01)
…
PT_INTERP: absent; size: 21255248 bytes; baseline 20453280; delta +801968 bytes (report only, D243 amended 2026-11-01)
…
| fmt                       | PASS         |
| VT native fmt             | PASS         |
| CLI plugin compile-out    | PASS         |
| clippy                    | PASS         |
| SSH runtime test helper   | PASS         |
| real-binary fixture paths | PASS         |
| test                      | FAIL (101)   |
| SSH inode reuse fixture   | PASS         |
| shim process-per-user     | PASS         |
| cargo-deny                | PASS         |
| gate architecture         | PASS         |
| static builds             | PASS         |

⚠ This is a real branch regression, not noise. It started at the first GotaTun commit, before this job.

Head vs dev, same machine. The infraternal-agent lib binary that cargo test --workspace builds (all targets, so features are unified with the mesh plugin's agent code) was run in full, the way cargo runs it. The head's (…01fba633) fails remote_client 2 of 2; dev's (…4635b165) passes 222/222 2 of 2 at the same load.
Dev's own gate at e8c7acd44 on compute01 is GREEN. The head failed the same family in all 3 compute01 gate runs.
Bisect, same method, full suite, 2 runs per commit:

Commit Result

J103c head e7e5dc466 (none of my commits) fails 2/2

my B dd8e3d9b1 fails 2/2

J103 2b8c106e4 (the first GotaTun commit) fails 1/2
The symptom: fallback_local_admission_us is about 2.00 s in every failing run. The agent's supervisor never reaches TCP admission within the test's 2 s timeout once GotaTun is in the agent's feature graph. Filtered alone, the same binaries pass in 0.65 s.
Not root-caused. That is a job of its own. It needs a cargo-env run of the agent lib per commit inside 2b8c106e4, or a trace of what the supervisor waits on.
Also seen on dev-02 (6 runs): agent_daemon and agent_review terminal refusals (resource_unavailable) and one PoolTimedOut. Those pass standalone at the head and at dev; I treat them as that machine's state. The orphaned __shim processes there under --uid 1500 belong to j94d, j79d, j80d, J79, J80 and j146 (I killed mine).

Size (static, delta against the D243 baseline, report only)

Head on compute01: x86_64 23,341,136 (+922,880); aarch64 21,255,248 (+801,968).
Against J103c's head (23,423,664 / 21,287,288): −82,528 / −32,040, mostly from dropping AWS-LC.
ring vs aws-lc, same source: −106,016 B x86_64, −59,784 B aarch64 (comment 77139).

Blocked: the fork pin

The mirror git.kayg.org/kayg/gotatun is stuck at its 15:52 UTC sync: j88-linux-offloads = 8ef6579, without da31c7f or 84b7bb2 (comment 77122; a manual mirror-sync at 18:25 did nothing). The pin edit is ready but uncommitted (it needs its Cargo.lock):

git = "https://git.kayg.org/kayg/gotatun", rev = "84b7bb28e385…";
deny.toml allow-git set to the mirror;
the notice naming that commit.

Both R4b rows used the same revs fetched from GitHub. The branch still pins 73eb9f1.

R4b

ring vs aws-lc (comment 77139): ring has equal or better throughput and CPU. ⚠ Its 8-flow loaded p99 is +23.6% (18.27 against 14.79 ms), beyond the 5% line.
Latest row, 84b7bb2 + txqueuelen 1,024 (comment 77249): GotaTun 100% / 98% of kernel throughput, loss-aware loaded p99 2.0× / 2.2× kernel's, 0 lost probes, qlen 1024 on both TUNs.

For kayg / the orchestrator

The gate: a follow-up job to root-cause the remote_client regression from 2b8c106e4. It blocks merge.
The mirror has not synced for about 15 h.
ring's 8-flow p99 (+23.6% against aws-lc) is an input for any backend question; D289 stands as implemented.

Cleanup: my target dirs are deleted on dev-02 (70 GB) and compute01 (222 GB), and my orphaned shims are killed. The evidence stays in ~/.cache/codex-scratch/j103d/ on both VMs and under /home/claude/j20/r4b/j103d/ on the perf VM. Nothing was merged or deployed.

## J103d finish: head `bbd20b606`, `verify fast` NOT green, cause inherited from the first GotaTun commit (2026-11-04, 06:40 IST) **Branch `mesh-gotatun-linux` = `bbd20b606b482126e836f30f77dd6fb62ab98584`** (pushed). It sits on `origin/dev` `7e1cb858f`: J103c's 12 commits plus mine, one per finding. | Commit | What | |---|---| | `50f0474c4` | P2-1: the adapter drops and counts undecodable frames; only EOF or a device-gone errno reaches GotaTun | | `dd8e3d9b1` | P2-1: the worker waits on the device's fatal error, rebuilds it after 1 s, and `mesh status` shows `engine {stopped, restarts, refused_frames}` | | `1cddc67fa` | P3-1: CWR stays only on the first TSO segment | | `0f6e4e969` | P3-2: no GRO merge with a bad IPv4 header checksum | | `d787e96e5` | P3-3: sweep `mesh-private-key.<pid>.new` under the key's directory lock; retirement removes the key. Backups (D147) are not implemented, so nothing copies the key; the module doc states that invariant | | `f81e4c66b` | P3-4: live-link recheck before removing the shared table, in `down` (both engines) and in retirement | | `c5c5c4317` | P3-5: MPL-2.0 source location and the Cloudflare BSD-3 notice | | `eaae8e170` | P2-2: GotaTun built with ring (D289), and cargo-deny bans aws-lc-rs and aws-lc-sys | | `adec24e7e`, `45b62524b` | D332: persistent TUN, reattached only under the retirement and firewall ownership proof, removed on down and retire | | `bbd20b606` | J88e: the agent raises the TUN `txqueuelen` to 1,024 and reports a short queue in `mesh status` | ### RED → GREEN All of these are in comments 77073, 77115 and 77249, plus the txqueuelen proof: - **txqueuelen**, `gotatun_restore` (rootless namespace, compute01). GREEN: 3/3 at `bbd20b606`. RED with the raise removed: `the new TUN's transmit queue (kernel, reported): (500, Some(500))`. - **Correction to my D332 evidence.** The first version of that test read `/sys/class/net`, which inside `unshare` shows the host's namespace. Its "same ifindex across restart" checks were therefore vacuous. They now read `ip -o link` in the test's own namespace and pass. The D332 route and flow proof (`gotatun_persistence`, `ip -n`) was never affected: restore 0.52–0.61 s, longest stall on the open TCP flow 0.72–0.82 s, 8 MiB byte-exact (3 runs, compute01). - **Namespace suites at the final code:** 33 of 36 pass on compute01, including every `nf_tables` case. The 3 failures are identical at unmodified `origin/dev` `e81eb5bb4`: `review_mesh_view_truth_r2`, `review_reverse_recreation` and `review_shutdown_budget`. ### Gate: `scripts/verify fast` at `bbd20b606` (compute01, build-slot, `nix develop`), exit 1 ``` repository artifact gate: PASS (31 changed path(s), merge base 7e1cb858f38c) … test remote_client::tests::server_path_capability_is_advertised_on_native_and_fallback_transports ... FAILED test remote_client::tests::unavailable_udp_does_not_add_seconds_before_tcp_admission ... FAILED test result: FAILED. 218 passed; 2 failed; 22 ignored; 0 measured; 0 filtered out; finished in 33.81s … advisories ok, bans ok, licenses ok, sources ok … PT_INTERP: absent; size: 23341136 bytes; baseline 22418256; delta +922880 bytes (report only, D243 amended 2026-11-01) … PT_INTERP: absent; size: 21255248 bytes; baseline 20453280; delta +801968 bytes (report only, D243 amended 2026-11-01) … | fmt | PASS | | VT native fmt | PASS | | CLI plugin compile-out | PASS | | clippy | PASS | | SSH runtime test helper | PASS | | real-binary fixture paths | PASS | | test | FAIL (101) | | SSH inode reuse fixture | PASS | | shim process-per-user | PASS | | cargo-deny | PASS | | gate architecture | PASS | | static builds | PASS | ``` **⚠ This is a real branch regression, not noise. It started at the first GotaTun commit, before this job.** - **Head vs dev, same machine.** The `infraternal-agent` lib binary that `cargo test --workspace` builds (all targets, so features are unified with the mesh plugin's agent code) was run in full, the way cargo runs it. The head's (`…01fba633`) fails `remote_client` 2 of 2; dev's (`…4635b165`) passes 222/222 2 of 2 at the same load. - **Dev's own gate** at `e8c7acd44` on compute01 is GREEN. The head failed the same family in all 3 compute01 gate runs. - **Bisect**, same method, full suite, 2 runs per commit: | Commit | Result | |---|---| | J103c head `e7e5dc466` (none of my commits) | fails 2/2 | | my B `dd8e3d9b1` | fails 2/2 | | **J103 `2b8c106e4` (the first GotaTun commit)** | **fails 1/2** | - **The symptom:** `fallback_local_admission_us` is about 2.00 s in every failing run. The agent's supervisor never reaches TCP admission within the test's 2 s timeout once GotaTun is in the agent's feature graph. Filtered alone, the same binaries pass in 0.65 s. - **Not root-caused.** That is a job of its own. It needs a cargo-env run of the agent lib per commit inside `2b8c106e4`, or a trace of what the supervisor waits on. - **Also seen on dev-02** (6 runs): `agent_daemon` and `agent_review` terminal refusals (`resource_unavailable`) and one `PoolTimedOut`. Those pass standalone at the head and at dev; I treat them as that machine's state. The orphaned `__shim` processes there under `--uid 1500` belong to j94d, j79d, j80d, J79, J80 and j146 (I killed mine). ### Size (static, delta against the D243 baseline, report only) - **Head on compute01:** x86_64 23,341,136 (+922,880); aarch64 21,255,248 (+801,968). - **Against J103c's head** (23,423,664 / 21,287,288): −82,528 / −32,040, mostly from dropping AWS-LC. - **ring vs aws-lc,** same source: −106,016 B x86_64, −59,784 B aarch64 (comment 77139). ### Blocked: the fork pin The mirror `git.kayg.org/kayg/gotatun` is stuck at its 15:52 UTC sync: `j88-linux-offloads` = `8ef6579`, without `da31c7f` or `84b7bb2` (comment 77122; a manual mirror-sync at 18:25 did nothing). The pin edit is ready but uncommitted (it needs its `Cargo.lock`): - `git = "https://git.kayg.org/kayg/gotatun"`, `rev = "84b7bb28e385…"`; - `deny.toml` `allow-git` set to the mirror; - the notice naming that commit. Both R4b rows used the same revs fetched from GitHub. **The branch still pins `73eb9f1`.** ### R4b - **ring vs aws-lc** (comment 77139): ring has equal or better throughput and CPU. **⚠ Its 8-flow loaded p99 is +23.6%** (18.27 against 14.79 ms), beyond the 5% line. - **Latest row,** `84b7bb2` + txqueuelen 1,024 (comment 77249): GotaTun **100% / 98%** of kernel throughput, loss-aware loaded p99 **2.0× / 2.2×** kernel's, 0 lost probes, `qlen 1024` on both TUNs. ### For kayg / the orchestrator 1. **The gate:** a follow-up job to root-cause the `remote_client` regression from `2b8c106e4`. It blocks merge. 2. **The mirror** has not synced for about 15 h. 3. **ring's 8-flow p99** (+23.6% against aws-lc) is an input for any backend question; D289 stands as implemented. **Cleanup:** my target dirs are deleted on dev-02 (70 GB) and compute01 (222 GB), and my orphaned shims are killed. The evidence stays in `~/.cache/codex-scratch/j103d/` on both VMs and under `/home/claude/j20/r4b/j103d/` on the perf VM. Nothing was merged or deployed.

kayg commented

2026-11-04 01:34:44 +00:00

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J103e start (2026-11-04, IST morning)

Branch mesh-gotatun-linux, base bbd20b606. Worktree on compute01: ~/worktrees/j103e.

Plan (estimate ~3 h):

Root-cause the remote_client timeouts introduced by 2b8c106e4: build the agent lib test binary the way cargo test --workspace does (features unified), reproduce, trace with INFRATERNAL_REMOTE_LINK_TRACE and a thread dump, then bisect the change inside 2b8c106e4 (feature graph vs code). Fix with a test that fails first; no timeout raise. Prove 20/20 at head under cargo's runner, and dev still passes. (~1.5 h)
Pin the fork at 84b7bb2 from the git.kayg.org mirror if it has it, else GitHub. One commit with Cargo.lock. (~15 min)
One R4b hold, GotaTun vs kernel, with J88e's raw-ping overlay. (~30 min)
scripts/verify fast on compute01, quoted verbatim. (~40 min)

## J103e start (2026-11-04, IST morning) Branch `mesh-gotatun-linux`, base `bbd20b606`. Worktree on compute01: `~/worktrees/j103e`. Plan (estimate ~3 h): 1. Root-cause the `remote_client` timeouts introduced by `2b8c106e4`: build the agent lib test binary the way `cargo test --workspace` does (features unified), reproduce, trace with `INFRATERNAL_REMOTE_LINK_TRACE` and a thread dump, then bisect the change inside `2b8c106e4` (feature graph vs code). Fix with a test that fails first; no timeout raise. Prove 20/20 at head under cargo's runner, and dev still passes. (~1.5 h) 2. Pin the fork at `84b7bb2` from the git.kayg.org mirror if it has it, else GitHub. One commit with `Cargo.lock`. (~15 min) 3. One R4b hold, GotaTun vs kernel, with J88e's raw-ping overlay. (~30 min) 4. `scripts/verify fast` on compute01, quoted verbatim. (~40 min)

kayg commented

2026-11-04 02:18:03 +00:00

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J103e finding: root cause of the `remote_client` timeouts (merge blocker), fixed in `92f4c1dba`

Cause. Since 2b8c106e4, Node::restore pins the kernel engine for "nodes upgraded from the old kernel-only format". When a marked kernel infraternal0 is live, and no engine is recorded or requested, it durably writes "kernel" to mesh-engine.json: a file fsync, a rename and a directory fsync. The link name and its marker infraternal.mesh.v1 are shared by every node on a host, and compute01 is itself a kernel mesh node (6: infraternal0 … wireguard … alias infraternal.mesh.v1). So every fresh agent state dir that the remote_client tests create (rootless, uid 1500) claims the host's link as its own engine, and fsyncs that claim before the plugin service is up. The supervisor dials only after plugin-service-start.

Why it looked like load. The fsyncs are slow only when the login_binary tests run at the same time; each of those copies the 364 MB test binary several times. Evidence, head binary infraternal_agent-01fba633 (the same hash as J103d's), compute01, load ~5:

Run	Result
full suite	2 failed (`unavailable_udp…`, `server_path_capability…`)
`remote_client::` alone (57) / `remote_` (89)	ok / ok
full suite, `--test-threads=1`	ok, 220 passed
the two tests + one other module each	only `login_binary` fails them, 2 of 2 (`remote_cursor` 1 of 2; the other 15 modules pass)
the two tests alone	ok, `fallback_local_admission_us=137726`

strace -f of the two tests plus login_binary: the test thread binds its listener at 02:51:33.159 and starts the node-plugins thread at 33.249. That thread opens mesh-engine.2773250.new, writes "kernel", then:

2773847 02:51:33.348683 fsync(10 <unfinished ...>
2773847 02:51:34.325680 <... fsync resumed>) = 0 <0.976961>
2773847 02:51:34.326625 fsync(5 <unfinished ...>        # the state directory
2773847 02:51:36.282658 <... fsync resumed>) = 0 <1.956009>

The test thread sits in epoll_wait from 33.249 to 35.239, and the 2 s timeout fires before any TCP dial. Dev never writes here: it adopted the marked link in memory only. That also explains why J103d saw it get worse at later commits (more I/O around it) and why it depends on the machine (dev-02 has no host mesh link).

Fix (92f4c1dba): the engine is recorded only when the directory has held node state before (a public snapshot, a route journal, an interface record or a private key). A fresh directory keeps the kernel choice in memory for this start, exactly as dev did, and writes nothing. No timeout changed.

RED/GREEN, a new namespace test only_a_node_with_prior_state_pins_the_kernel_engine (gotatun_restore, rootless unshare -Urnm, compute01). It covers both sides: a fresh dir must get no record, and a dir holding an older kernel-only snapshot must still record "kernel".
- RED at the test-only commit: left: Some("\"kernel\"") "a fresh state directory recorded another node's kernel link as its engine"; 3 passed, 1 failed.
- GREEN with the fix: test result: ok. 4 passed; 0 failed.
Full cargo test --workspace --locked --lib at 13f4a7fee: infraternal_agent-77228aa1 220 passed, 0 failed. One unrelated failure in infraternal-plugin-remote (remote_bindings::…peer_route_preserves_the_logical_tuple…, a loopback datagram from another socket's port), a crate this branch does not touch.
The 20× proof under cargo's runner is running now (head 20×, bbd20b606 3× as the red control, dev 5×).

Not changed, for the owner: dev has long adopted a marked kernel link it cannot prove is its own, alias match only. With an unkeyed link it may even delete it as an "incomplete startup". With per-installation records (#235) that is worth its own decision. It is out of this job's scope.

Pin (13f4a7fee): the fork is at 84b7bb28e385, from GitHub. The git.kayg.org mirror still has not synced: mirror_updated is 2026-11-03T15:52:48Z, j88-linux-offloads is 8ef6579, and the API returns not-found for 84b7bb2. The fork's manifests are unchanged since 73eb9f1, so Cargo.lock changes only gotatun's source line.

Note: this branch's scripts/verify has no quick mode (base 7e1cb858f), so that pre-check was not available. verify fast follows.

## J103e finding: root cause of the `remote_client` timeouts (merge blocker), fixed in `92f4c1dba` **Cause.** Since `2b8c106e4`, `Node::restore` pins the kernel engine for "nodes upgraded from the old kernel-only format". When a marked kernel `infraternal0` is live, and no engine is recorded or requested, it durably writes `"kernel"` to `mesh-engine.json`: a file fsync, a rename and a directory fsync. The link name and its marker `infraternal.mesh.v1` are shared by every node on a host, and **compute01 is itself a kernel mesh node** (`6: infraternal0 … wireguard … alias infraternal.mesh.v1`). So every fresh agent state dir that the `remote_client` tests create (rootless, uid 1500) claims the host's link as its own engine, and fsyncs that claim before the plugin service is up. The supervisor dials only after `plugin-service-start`. **Why it looked like load.** The fsyncs are slow only when the `login_binary` tests run at the same time; each of those copies the 364 MB test binary several times. Evidence, head binary `infraternal_agent-01fba633` (the same hash as J103d's), compute01, load ~5: | Run | Result | |---|---| | full suite | 2 failed (`unavailable_udp…`, `server_path_capability…`) | | `remote_client::` alone (57) / `remote_` (89) | ok / ok | | full suite, `--test-threads=1` | ok, 220 passed | | the two tests + one other module each | only `login_binary` fails them, 2 of 2 (`remote_cursor` 1 of 2; the other 15 modules pass) | | the two tests alone | ok, `fallback_local_admission_us=137726` | `strace -f` of the two tests plus `login_binary`: the test thread binds its listener at 02:51:33.159 and starts the `node-plugins` thread at 33.249. That thread opens `mesh-engine.2773250.new`, writes `"kernel"`, then: ``` 2773847 02:51:33.348683 fsync(10 <unfinished ...> 2773847 02:51:34.325680 <... fsync resumed>) = 0 <0.976961> 2773847 02:51:34.326625 fsync(5 <unfinished ...> # the state directory 2773847 02:51:36.282658 <... fsync resumed>) = 0 <1.956009> ``` The test thread sits in `epoll_wait` from 33.249 to 35.239, and the 2 s timeout fires before any TCP dial. Dev never writes here: it adopted the marked link in memory only. That also explains why J103d saw it get worse at later commits (more I/O around it) and why it depends on the machine (dev-02 has no host mesh link). **Fix** (`92f4c1dba`): the engine is recorded only when the directory has held node state before (a public snapshot, a route journal, an interface record or a private key). A fresh directory keeps the kernel choice in memory for this start, exactly as dev did, and writes nothing. No timeout changed. - RED/GREEN, a new namespace test `only_a_node_with_prior_state_pins_the_kernel_engine` (`gotatun_restore`, rootless `unshare -Urnm`, compute01). It covers both sides: a fresh dir must get no record, and a dir holding an older kernel-only snapshot must still record `"kernel"`. - RED at the test-only commit: `left: Some("\"kernel\"")` "a fresh state directory recorded another node's kernel link as its engine"; 3 passed, 1 failed. - GREEN with the fix: `test result: ok. 4 passed; 0 failed`. - Full `cargo test --workspace --locked --lib` at `13f4a7fee`: `infraternal_agent-77228aa1` **220 passed, 0 failed**. One unrelated failure in `infraternal-plugin-remote` (`remote_bindings::…peer_route_preserves_the_logical_tuple…`, a loopback datagram from another socket's port), a crate this branch does not touch. - The 20× proof under cargo's runner is running now (head 20×, `bbd20b606` 3× as the red control, dev 5×). **Not changed, for the owner:** dev has long adopted a marked kernel link it cannot prove is its own, alias match only. With an unkeyed link it may even delete it as an "incomplete startup". With per-installation records (#235) that is worth its own decision. It is out of this job's scope. **Pin** (`13f4a7fee`): the fork is at `84b7bb28e385`, **from GitHub**. The git.kayg.org mirror still has not synced: `mirror_updated` is 2026-11-03T15:52:48Z, `j88-linux-offloads` is `8ef6579`, and the API returns not-found for `84b7bb2`. The fork's manifests are unchanged since `73eb9f1`, so `Cargo.lock` changes only gotatun's source line. **Note:** this branch's `scripts/verify` has no `quick` mode (base `7e1cb858f`), so that pre-check was not available. `verify fast` follows.

kayg commented

2026-11-04 02:55:55 +00:00

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Owner

J103e R4b: branch head `13f4a7fee` (fork pinned at `84b7bb2`, committed), GotaTun vs kernel, with raw ICMP (2026-11-04, 08:05 IST)

Hold: /home/claude/j20/r4b/j103e/hold-13f4a7fee-20261104/ on the perf VM. One perf-run --root hold, 03:34–03:50 CET.

Outer exit 0. All 4 cases exit 0; every machine diff is empty (0 bytes).
Wall time 961 s. Steal 1,905 of 384,213 jiffies.
Order: kernel, GotaTun, GotaTun, kernel.
Runner: j103e-r4b.sh is J103d's v4 runner (j103d-r4b-84b7bb2.sh) plus J88e's raw-ping overlay: ping -D -O -n -i 0.005 -c 1800 in h2h-a beside each loaded LAN phase, applied with the same asserted substitution as J88e's run-hold-ping.sh. Analyzer: j103e-analyze.py (J103d's, plus pingstat.py). Summary: hold-13f4a7fee-summary/summary.md.
Binary: 7c49bbe0… (23,351,728 B), x86_64 musl static, built at the branch head through scripts/static-cargo on compute01. It includes the restore fix; that code runs only at start, never on the packet path. Kernel cases use the same binary. Coordinator 9e32e7b2…, unchanged.
qlen 1024 shows on both TUNs in both GotaTun cases.

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	Loaded RTT p50/p99, 1 flow (ms)	Loaded RTT p50/p99, 8 flows (ms)	Lost probes 1 / 8	`RcvbufErrors` 1 / 8	Socket `rb`	TUN bytes/RX packet 1 / 8
kernel-first	3.03 / 2.62	1.16 / 1.28	1.136 / 4.727	3.345 / 5.360	0 / 0	0 / 0	212,992	1410 / 1410
gotatun-first	2.61 / 2.42	0.91 / 0.98	3.045 / 6.878	9.706 / 17.676	0 / 0	0 / 0	14,680,064	23153 / 19172
gotatun-second	2.67 / 2.49	0.89 / 0.94	3.045 / 7.217	10.353 / 19.506	0 / 0	0 / 0	14,680,064	23169 / 20121
kernel-last	2.98 / 2.57	1.14 / 1.28	1.134 / 4.763	3.262 / 4.765	0 / 0	0 / 0	212,992	1410 / 1410
kernel mean	3.00 / 2.59	1.15 / 1.28	1.135 / 4.745	3.304 / 5.062	0.0% / 0.0%
GotaTun mean	2.64 / 2.45	0.90 / 0.96	3.045 / 7.047	10.029 / 18.591	0.0% / 0.0%

Raw ICMP under load (J88e overlay; the loss-aware percentiles are exact, D331):

Case	1 flow: sent / lost / p50 / p99 / p99.9 (ms)	8 flows: sent / lost / p50 / p99 / p99.9 (ms)
kernel-first	1800 / 0 / 0.960 / 2.680 / 6.010	1800 / 0 / 3.190 / 4.810 / 5.480
gotatun-first	1800 / 0 / 3.190 / 7.720 / 9.880	1800 / 0 / 6.760 / 17.500 / 25.900
gotatun-second	1800 / 0 / 3.140 / 7.820 / 10.100	1800 / 0 / 6.860 / 20.300 / 38.000
kernel-last	1800 / 0 / 0.970 / 1.950 / 3.200	1800 / 0 / 3.260 / 4.690 / 5.760
kernel pooled	3600 / 0 / 0.966 / 2.270 / 5.290	3600 / 0 / 3.230 / 4.800 / 5.740
GotaTun pooled	3600 / 0 / 3.170 / 7.800 / 9.880	3600 / 0 / 6.790 / 19.100 / 29.100

Impairments: with 2% loss each way, every case loses 8–26 of 300 probes. With 25%/50% reordering, every case loses 0.
Idle RSS per endpoint: kernel 10.7 / 10.7 MiB, GotaTun 12.0 / 12.0 MiB. Right after load, GotaTun is 13.8 / 29.9–32.6 MiB. That sample comes before any idle period.

D332 switch rule on this row

GotaTun `84b7bb2`, at head `13f4a7fee`	1 flow	8 flows
Throughput, share of kernel	88% (2.64 / 3.00)	95% (2.45 / 2.59)
Loss-aware loaded p99, raw ICMP, × kernel	3.4× (7.80 / 2.27 ms)	4.0× (19.1 / 4.80 ms)
Loaded p99, h2h `net-lat` (0 lost, so loss-aware = received), × kernel	1.5× (7.05 / 4.75)	3.7× (18.59 / 5.06)
CPU s/Gbit, × kernel	0.78×	0.75×

GotaTun's own numbers match J103d's row at the same fork rev (77249): 2.64 / 2.45 Gbit/s here against 2.63 / 2.40, and an 8-flow p99 of 18.6 against 18.0 ms. The kernel ran faster in this hold (3.00 / 2.59 against 2.64 / 2.44), so the throughput share is lower (88% / 95% against 100% / 98%). Read the share as noise-limited across holds; GotaTun itself has not moved.
The exact raw-ICMP p99 makes the latency gap clear: 3.4× at 1 flow and 4.0× at 8 flows, with 0 probes lost. The p99.9 at 8 flows reaches 25.9–38.0 ms, against 5.5–5.8 ms for the kernel.

## J103e R4b: branch head `13f4a7fee` (fork pinned at `84b7bb2`, committed), GotaTun vs kernel, with raw ICMP (2026-11-04, 08:05 IST) **Hold:** `/home/claude/j20/r4b/j103e/hold-13f4a7fee-20261104/` on the perf VM. One `perf-run --root` hold, 03:34–03:50 CET. - Outer exit 0. All 4 cases exit 0; every machine diff is empty (0 bytes). - Wall time 961 s. Steal 1,905 of 384,213 jiffies. - **Order:** kernel, GotaTun, GotaTun, kernel. - **Runner:** `j103e-r4b.sh` is J103d's v4 runner (`j103d-r4b-84b7bb2.sh`) plus J88e's raw-ping overlay: `ping -D -O -n -i 0.005 -c 1800` in `h2h-a` beside each loaded LAN phase, applied with the same asserted substitution as J88e's `run-hold-ping.sh`. Analyzer: `j103e-analyze.py` (J103d's, plus `pingstat.py`). Summary: `hold-13f4a7fee-summary/summary.md`. - **Binary:** `7c49bbe0…` (23,351,728 B), x86_64 musl static, built at the branch head through `scripts/static-cargo` on compute01. It includes the restore fix; that code runs only at start, never on the packet path. Kernel cases use the same binary. Coordinator `9e32e7b2…`, unchanged. - `qlen 1024` shows on both TUNs in both GotaTun cases. | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | Loaded RTT p50/p99, 1 flow (ms) | Loaded RTT p50/p99, 8 flows (ms) | Lost probes 1 / 8 | `RcvbufErrors` 1 / 8 | Socket `rb` | TUN bytes/RX packet 1 / 8 | |---|---:|---:|---:|---:|---:|---:|---:|---:| | kernel-first | 3.03 / 2.62 | 1.16 / 1.28 | 1.136 / 4.727 | 3.345 / 5.360 | 0 / 0 | 0 / 0 | 212,992 | 1410 / 1410 | | gotatun-first | 2.61 / 2.42 | 0.91 / 0.98 | 3.045 / 6.878 | 9.706 / 17.676 | 0 / 0 | 0 / 0 | 14,680,064 | 23153 / 19172 | | gotatun-second | 2.67 / 2.49 | 0.89 / 0.94 | 3.045 / 7.217 | 10.353 / 19.506 | 0 / 0 | 0 / 0 | 14,680,064 | 23169 / 20121 | | kernel-last | 2.98 / 2.57 | 1.14 / 1.28 | 1.134 / 4.763 | 3.262 / 4.765 | 0 / 0 | 0 / 0 | 212,992 | 1410 / 1410 | | **kernel mean** | **3.00 / 2.59** | 1.15 / 1.28 | 1.135 / **4.745** | 3.304 / **5.062** | **0.0% / 0.0%** | | | | | **GotaTun mean** | **2.64 / 2.45** | 0.90 / 0.96 | 3.045 / **7.047** | 10.029 / **18.591** | **0.0% / 0.0%** | | | | **Raw ICMP under load** (J88e overlay; the loss-aware percentiles are exact, D331): | Case | 1 flow: sent / lost / p50 / p99 / p99.9 (ms) | 8 flows: sent / lost / p50 / p99 / p99.9 (ms) | |---|---:|---:| | kernel-first | 1800 / 0 / 0.960 / 2.680 / 6.010 | 1800 / 0 / 3.190 / 4.810 / 5.480 | | gotatun-first | 1800 / 0 / 3.190 / 7.720 / 9.880 | 1800 / 0 / 6.760 / 17.500 / 25.900 | | gotatun-second | 1800 / 0 / 3.140 / 7.820 / 10.100 | 1800 / 0 / 6.860 / 20.300 / 38.000 | | kernel-last | 1800 / 0 / 0.970 / 1.950 / 3.200 | 1800 / 0 / 3.260 / 4.690 / 5.760 | | **kernel pooled** | **3600 / 0 / 0.966 / 2.270 / 5.290** | **3600 / 0 / 3.230 / 4.800 / 5.740** | | **GotaTun pooled** | **3600 / 0 / 3.170 / 7.800 / 9.880** | **3600 / 0 / 6.790 / 19.100 / 29.100** | - **Impairments:** with 2% loss each way, every case loses 8–26 of 300 probes. With 25%/50% reordering, every case loses 0. - **Idle RSS per endpoint:** kernel 10.7 / 10.7 MiB, GotaTun 12.0 / 12.0 MiB. Right after load, GotaTun is 13.8 / 29.9–32.6 MiB. That sample comes before any idle period. ### D332 switch rule on this row | GotaTun `84b7bb2`, at head `13f4a7fee` | 1 flow | 8 flows | |---|---:|---:| | Throughput, share of kernel | **88%** (2.64 / 3.00) | **95%** (2.45 / 2.59) | | **Loss-aware loaded p99, raw ICMP, × kernel** | **3.4×** (7.80 / 2.27 ms) | **4.0×** (19.1 / 4.80 ms) | | Loaded p99, h2h `net-lat` (0 lost, so loss-aware = received), × kernel | 1.5× (7.05 / 4.75) | 3.7× (18.59 / 5.06) | | CPU s/Gbit, × kernel | 0.78× | 0.75× | - GotaTun's own numbers match J103d's row at the same fork rev (77249): 2.64 / 2.45 Gbit/s here against 2.63 / 2.40, and an 8-flow p99 of 18.6 against 18.0 ms. **The kernel ran faster in this hold** (3.00 / 2.59 against 2.64 / 2.44), so the throughput share is lower (88% / 95% against 100% / 98%). Read the share as noise-limited across holds; GotaTun itself has not moved. - The exact raw-ICMP p99 makes the latency gap clear: **3.4× at 1 flow and 4.0× at 8 flows, with 0 probes lost.** The p99.9 at 8 flows reaches 25.9–38.0 ms, against 5.5–5.8 ms for the kernel.

kayg commented

2026-11-04 02:56:10 +00:00

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Owner

J103e finding: current `origin/dev` fails the same `remote_client` tests, for a separate reason in the same class (#281, `13b6836a5`)

20× proof, compute01, command cargo test --workspace --locked -j4 --lib -- remote_client:: login_binary::. This is cargo's own runner and the same unified agent lib binary as the gate. login_binary is the trigger, as described in 77304.

Ref	Agent lib binary	Result
head `13f4a7fee`	`infraternal_agent-77228aa1`	20 of 20 pass (75 passed, 0 failed each; load 13–21)
`bbd20b606` (red control, before the fix)	`infraternal_agent-01fba633`	fails 2 of 3 (`unavailable_udp…`, `winning_quic…`, `server_path_capability…`)
`origin/dev` `e0633114b`	`infraternal_agent-0923f786`	fails 3 of 5 (`unavailable_udp…`, `winning_quic…`)

Dev contains no GotaTun code. strace -f of dev's binary (the two tests plus login_binary, fallback_local_admission_us=2003246) shows the agent's node-plugins thread on a fresh state dir:

openat(AT_FDCWD, ".../remote-agents/c24d575af-…/proxy-secrets", O_RDONLY|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) …
openat(AT_FDCWD, ".../remote-agents/c24d575af-…", O_RDONLY|O_CLOEXEC) = 33
fsync(33 <unfinished ...>
<... fsync resumed>) = 0 <6.509416>

So the proxy plugin creates its proxy-secrets directory, with a durable parent fsync, during plugin start, and the supervisor dials only after that. This is the same class as the mesh engine record fixed here. It comes from 13b6836a5 "feat: persist DNS tokens in interim node custody (#281)", which landed after J103d's dev reference e8c7acd44.

This branch is based on 7e1cb858f, before 13b6836a5, so its gate is unaffected. Once it rebases onto dev, it inherits the failure until #281 is fixed. I did not change #281's code; that belongs in its own fix, for example creating the custody directory on the first token write rather than at start.

## J103e finding: current `origin/dev` fails the same `remote_client` tests, for a separate reason in the same class (#281, `13b6836a5`) **20× proof**, compute01, command `cargo test --workspace --locked -j4 --lib -- remote_client:: login_binary::`. This is cargo's own runner and the same unified agent lib binary as the gate. `login_binary` is the trigger, as described in 77304. | Ref | Agent lib binary | Result | |---|---|---| | **head `13f4a7fee`** | `infraternal_agent-77228aa1` | **20 of 20 pass** (75 passed, 0 failed each; load 13–21) | | `bbd20b606` (red control, before the fix) | `infraternal_agent-01fba633` | fails 2 of 3 (`unavailable_udp…`, `winning_quic…`, `server_path_capability…`) | | `origin/dev` `e0633114b` | `infraternal_agent-0923f786` | **fails 3 of 5** (`unavailable_udp…`, `winning_quic…`) | Dev contains no GotaTun code. `strace -f` of dev's binary (the two tests plus `login_binary`, `fallback_local_admission_us=2003246`) shows the agent's `node-plugins` thread on a fresh state dir: ``` openat(AT_FDCWD, ".../remote-agents/c24d575af-…/proxy-secrets", O_RDONLY|O_NOFOLLOW|O_CLOEXEC|O_DIRECTORY) … openat(AT_FDCWD, ".../remote-agents/c24d575af-…", O_RDONLY|O_CLOEXEC) = 33 fsync(33 <unfinished ...> <... fsync resumed>) = 0 <6.509416> ``` So the proxy plugin creates its `proxy-secrets` directory, with a durable parent fsync, during plugin start, and the supervisor dials only after that. This is the same class as the mesh engine record fixed here. It comes from `13b6836a5` "feat: persist DNS tokens in interim node custody (#281)", which landed after J103d's dev reference `e8c7acd44`. This branch is based on `7e1cb858f`, before `13b6836a5`, so its gate is unaffected. Once it rebases onto dev, it inherits the failure until #281 is fixed. I did not change #281's code; that belongs in its own fix, for example creating the custody directory on the first token write rather than at start.

kayg referenced this issue

2026-11-04 02:56:11 +00:00

Reverse proxy: Traefik on demand — implementation plan #281

kayg commented

2026-11-04 04:35:23 +00:00

Author

Owner

J103e finish: head `267839c54`, `verify fast` GREEN on compute01 (2026-11-04, ~10:05 IST)

Branch mesh-gotatun-linux = 267839c548d7a8588a19272d1f038426d27221de (pushed, fast-forward from bbd20b606):

Commit	What
`92f4c1dba`	Merge blocker fixed. A fresh state directory never durably records the kernel engine. The root cause is in 77304: a fresh or rootless agent claimed the host's marked kernel `infraternal0` and fsynced `mesh-engine.json` in front of the supervisor's first dial. New namespace test, RED then GREEN.
`13f4a7fee`	Fork pinned at `84b7bb28e385` from GitHub: the mirror still lacks it (last sync 2026-11-03 15:52 UTC). `Cargo.lock` changes only the source line; NOTICE updated.
`267839c54`	rustfmt layout and doc backticks for that test. The first gate at `13f4a7fee` failed fmt and clippy on it. I added a separate commit instead of force-pushing, so `92f4c1dba` alone does not pass fmt/clippy.

Proof (the brief's step 1):

At the head (13f4a7fee, the same code as 267839c54 apart from test formatting): cargo test --workspace --locked -j4 --lib -- remote_client:: login_binary:: passes 20 of 20, agent lib 77228aa1, 75 passed / 0 failed each time, load 13–21.
Red control at bbd20b606: fails 2 of 3.
In this gate, the agent lib 77228aa1 gives test result: ok. 220 passed; 0 failed; 22 ignored, and all three remote_client tests (unavailable_udp…, server_path_capability…, winning_quic…) are ok.
Dev does not pass any more, for a separate reason (77315): origin/dev e0633114b fails 3 of 5 because of #281's 13b6836a5 (a proxy-secrets directory fsync at plugin start; 6.5 s in strace). I reported it on #281 (77317) and did not fix it here. This branch's base predates it.

R4b (77314), this head with 84b7bb2, J88e's raw-ping overlay, all cases exit 0, every machine diff empty:

Throughput 88% / 95% of kernel. The kernel ran faster in this hold; GotaTun's own numbers match J103d's row.
Exact loss-aware raw-ICMP p99: 7.80 / 19.1 ms against the kernel's 2.27 / 4.80 ms (3.4× / 4.0×), 0 of 7,200 probes lost.
CPU per Gbit 0.78× / 0.75× kernel's.

Gate: `scripts/verify fast` at `267839c548d7a8588a19272d1f038426d27221de` (compute01, build-slot, `nix develop`), `VERIFY_EXIT=0`

repository artifact gate: PASS (31 changed path(s), merge base 7e1cb858f38c)
…
     Running unittests src/lib.rs (target/debug/deps/infraternal_agent-77228aa1c6341ec3)
…
test remote_client::tests::server_path_capability_is_advertised_on_native_and_fallback_transports ... ok
test remote_client::tests::unavailable_udp_does_not_add_seconds_before_tcp_admission ... ok
test remote_client::tests::winning_quic_drops_the_unfinished_tls_dial_before_control_dispatch ... ok
…
test result: ok. 220 passed; 0 failed; 22 ignored; 0 measured; 0 filtered out; finished in 28.80s
…
advisories ok, bans ok, licenses ok, sources ok
…
PT_INTERP: absent; size: 23351728 bytes; baseline 22418256; delta +933472 bytes (report only, D243 amended 2026-11-01)
PT_INTERP: absent; size: 21261552 bytes; baseline 20453280; delta +808272 bytes (report only, D243 amended 2026-11-01)
x86_64-unknown-linux-musl: +102400 bytes accepted with delta; zero/negative deltas reported; missing/wrong/dynamic/PT_INTERP/inspection defects rejected PASS
aarch64-unknown-linux-musl: +102400 bytes accepted with delta; zero/negative deltas reported; missing/wrong/dynamic/PT_INTERP/inspection defects rejected PASS
…
+---------------------------+--------------+
| Rust gate                 | Result       |
+---------------------------+--------------+
| fmt                       | PASS         |
| VT native fmt             | PASS         |
| CLI plugin compile-out    | PASS         |
| clippy                    | PASS         |
| SSH runtime test helper   | PASS         |
| real-binary fixture paths | PASS         |
| test                      | PASS         |
| SSH inode reuse fixture   | PASS         |
| shim process-per-user     | PASS         |
| cargo-deny                | PASS         |
| gate architecture         | PASS         |
| static builds             | PASS         |
+---------------------------+--------------+
…
 48 pass
 0 fail
Ran 48 tests across 12 files. [7.60s]

Size against J103d's head (23,341,136 / 21,255,248): +10,592 B x86_64, +6,304 B aarch64, from the fork's 84b7bb2 changes.

Notes

verify quick does not exist on this branch's scripts/verify (base 7e1cb858f), so that pre-check was skipped.
One unrelated flake in an earlier full --lib run: infraternal-plugin-remote remote_bindings::…peer_route_preserves_the_logical_tuple…. The branch does not touch that crate, and it passed in this gate.

For kayg: (1) ring vs aws-lc stays ring (D289), and the choice is yours. (2) Dev's #281 regression of the same tests (77315). (3) Dev has long adopted a marked kernel link by alias only, without the #235 proof, and may even delete an unkeyed one; that is worth its own decision. (4) The mirror sync is still stuck.

Cleanup: the J103e target dir on compute01 is deleted, and wip/j103e is removed. Evidence is in ~/.cache/codex-scratch/j103e/ (compute01) and /home/claude/j20/r4b/j103e/ (perf VM). No J103e processes are left. Nothing merged or deployed.

## J103e finish: head `267839c54`, `verify fast` GREEN on compute01 (2026-11-04, ~10:05 IST) **Branch `mesh-gotatun-linux` = `267839c548d7a8588a19272d1f038426d27221de`** (pushed, fast-forward from `bbd20b606`): | Commit | What | |---|---| | `92f4c1dba` | **Merge blocker fixed.** A fresh state directory never durably records the kernel engine. The root cause is in 77304: a fresh or rootless agent claimed the host's marked kernel `infraternal0` and fsynced `mesh-engine.json` in front of the supervisor's first dial. New namespace test, RED then GREEN. | | `13f4a7fee` | Fork pinned at `84b7bb28e385` **from GitHub**: the mirror still lacks it (last sync 2026-11-03 15:52 UTC). `Cargo.lock` changes only the source line; NOTICE updated. | | `267839c54` | rustfmt layout and doc backticks for that test. The first gate at `13f4a7fee` failed fmt and clippy on it. I added a separate commit instead of force-pushing, so **`92f4c1dba` alone does not pass fmt/clippy.** | **Proof (the brief's step 1):** - At the head (`13f4a7fee`, the same code as `267839c54` apart from test formatting): `cargo test --workspace --locked -j4 --lib -- remote_client:: login_binary::` passes **20 of 20**, agent lib `77228aa1`, 75 passed / 0 failed each time, load 13–21. - Red control at `bbd20b606`: fails 2 of 3. - In this gate, the agent lib `77228aa1` gives `test result: ok. 220 passed; 0 failed; 22 ignored`, and all three `remote_client` tests (`unavailable_udp…`, `server_path_capability…`, `winning_quic…`) are `ok`. - **Dev does not pass any more**, for a separate reason (77315): `origin/dev` `e0633114b` fails 3 of 5 because of #281's `13b6836a5` (a `proxy-secrets` directory fsync at plugin start; 6.5 s in strace). I reported it on #281 (77317) and did not fix it here. This branch's base predates it. **R4b** (77314), this head with `84b7bb2`, J88e's raw-ping overlay, all cases exit 0, every machine diff empty: - Throughput **88% / 95%** of kernel. The kernel ran faster in this hold; GotaTun's own numbers match J103d's row. - **Exact loss-aware raw-ICMP p99: 7.80 / 19.1 ms against the kernel's 2.27 / 4.80 ms (3.4× / 4.0×), 0 of 7,200 probes lost.** - CPU per Gbit 0.78× / 0.75× kernel's. ### Gate: `scripts/verify fast` at `267839c548d7a8588a19272d1f038426d27221de` (compute01, build-slot, `nix develop`), `VERIFY_EXIT=0` ``` repository artifact gate: PASS (31 changed path(s), merge base 7e1cb858f38c) … Running unittests src/lib.rs (target/debug/deps/infraternal_agent-77228aa1c6341ec3) … test remote_client::tests::server_path_capability_is_advertised_on_native_and_fallback_transports ... ok test remote_client::tests::unavailable_udp_does_not_add_seconds_before_tcp_admission ... ok test remote_client::tests::winning_quic_drops_the_unfinished_tls_dial_before_control_dispatch ... ok … test result: ok. 220 passed; 0 failed; 22 ignored; 0 measured; 0 filtered out; finished in 28.80s … advisories ok, bans ok, licenses ok, sources ok … PT_INTERP: absent; size: 23351728 bytes; baseline 22418256; delta +933472 bytes (report only, D243 amended 2026-11-01) PT_INTERP: absent; size: 21261552 bytes; baseline 20453280; delta +808272 bytes (report only, D243 amended 2026-11-01) x86_64-unknown-linux-musl: +102400 bytes accepted with delta; zero/negative deltas reported; missing/wrong/dynamic/PT_INTERP/inspection defects rejected PASS aarch64-unknown-linux-musl: +102400 bytes accepted with delta; zero/negative deltas reported; missing/wrong/dynamic/PT_INTERP/inspection defects rejected PASS … +---------------------------+--------------+ | Rust gate | Result | +---------------------------+--------------+ | fmt | PASS | | VT native fmt | PASS | | CLI plugin compile-out | PASS | | clippy | PASS | | SSH runtime test helper | PASS | | real-binary fixture paths | PASS | | test | PASS | | SSH inode reuse fixture | PASS | | shim process-per-user | PASS | | cargo-deny | PASS | | gate architecture | PASS | | static builds | PASS | +---------------------------+--------------+ … 48 pass 0 fail Ran 48 tests across 12 files. [7.60s] ``` Size against J103d's head (23,341,136 / 21,255,248): **+10,592 B x86_64, +6,304 B aarch64**, from the fork's `84b7bb2` changes. **Notes** - `verify quick` does not exist on this branch's `scripts/verify` (base `7e1cb858f`), so that pre-check was skipped. - One unrelated flake in an earlier full `--lib` run: `infraternal-plugin-remote` `remote_bindings::…peer_route_preserves_the_logical_tuple…`. The branch does not touch that crate, and it passed in this gate. **For kayg:** (1) ring vs aws-lc stays ring (D289), and the choice is yours. (2) Dev's #281 regression of the same tests (77315). (3) Dev has long adopted a marked kernel link by alias only, without the #235 proof, and may even delete an unkeyed one; that is worth its own decision. (4) The mirror sync is still stuck. **Cleanup:** the J103e target dir on compute01 is deleted, and `wip/j103e` is removed. Evidence is in `~/.cache/codex-scratch/j103e/` (compute01) and `/home/claude/j20/r4b/j103e/` (perf VM). No J103e processes are left. Nothing merged or deployed.

kayg commented

2026-11-04 06:23:59 +00:00

Author

Owner

J88g start and plan: GotaTun loaded latency (D331, D332)

Fork kaygdotorg/gotatun, base 84b7bb2 (the pin). Work branch for any cut: j88g-latency (pushed to GitHub and git.kayg.org/kayg/gotatun-fork). Integration branch mesh-gotatun-linux at 267839c54: read-only for this job (no rebase, no commits; J168 goes first).

What I already see, before any run

Shipping code between bbd20b606 and 267839c54 differs only in start-up code (92f4c1dba, the engine-record guard) and the pin line (73eb9f1 → 84b7bb2). J103d's hold binary 236ec973… was already bbd20b606 + 84b7bb2 (uncommitted, comment 77249), so the two measured binaries differ only in start-up code.
GotaTun's own numbers did not move: net-lat p99 8.04 / 18.00 ms (J103d) against 7.05 / 18.59 ms (J103e).
What moved is the denominator and the metric. J103d's 2.0× / 2.2× is h2h net-lat p99 against a slow kernel (3.95 / 8.15 ms; kernel-last 8-flow p99 10.6 ms). J103e's 3.4× / 4.0× is raw ICMP p99 against a fast kernel (2.27 / 4.80 ms). J103e's own net-lat ratio is 1.5× / 3.7×.
Working hypothesis: no regression. It's a metric change plus kernel noise between holds. Step 1 tests this hypothesis rather than assuming it.

Step 1: same-hold A/B (≈1 h)

One perf-run --root hold on the perf VM. Order kernel, J103d (236ec973), J103e (7c49bbe0), J103e, J103d, kernel. J103e's runner is reused unchanged apart from the case list, so raw ping -D -O runs beside every loaded LAN phase.
Table: Gbit/s, net-lat p99, exact raw-ICMP p50/p99/p99.9 with loss, all within the one hold.
If the two GotaTun binaries differ beyond case-to-case spread, I bisect the 3 commits (only 92f4c1dba can matter) and name the cause.

Step 2: one latency cut (≈4–5 h)

If it's no regression: profile the 8-flow loaded path on the pin (off-CPU/scheduling plus queue depths on the TUN and UDP paths), pick one cut that keeps per-flow order, and explain why order holds. J88f's fused receive-side TUN write is excluded.
Build and gate the fork on compute01 and dev-02. Run a keep hold (control 84b7bb2 against the cut, counterbalanced, raw ICMP). If that passes, run the 1 h soak against the control (reorders, retransmits, ring drops).
Keep rule: p99 better at 1 and 8 flows, throughput not lower, soak at the control's level. If any check fails: a revert commit on the fork branch, plus the data here.

Estimate: ≈5–6 h total. I'll report at 2× if I overrun. No merge, no deploy. My targets get deleted at the end.

## J88g start and plan: GotaTun loaded latency (D331, D332) **Fork** `kaygdotorg/gotatun`, base `84b7bb2` (the pin). Work branch for any cut: `j88g-latency` (pushed to GitHub and git.kayg.org/kayg/gotatun-fork). **Integration branch** `mesh-gotatun-linux` at `267839c54`: read-only for this job (no rebase, no commits; J168 goes first). ### What I already see, before any run - Shipping code between `bbd20b606` and `267839c54` differs only in start-up code (`92f4c1dba`, the engine-record guard) and the pin line (`73eb9f1` → `84b7bb2`). J103d's hold binary `236ec973…` was already `bbd20b606` + `84b7bb2` (uncommitted, comment 77249), so the two measured binaries differ only in start-up code. - GotaTun's own numbers did not move: net-lat p99 8.04 / 18.00 ms (J103d) against 7.05 / 18.59 ms (J103e). - What moved is the denominator and the metric. J103d's 2.0× / 2.2× is h2h `net-lat` p99 against a slow kernel (3.95 / 8.15 ms; kernel-last 8-flow p99 10.6 ms). J103e's 3.4× / 4.0× is raw ICMP p99 against a fast kernel (2.27 / 4.80 ms). J103e's own net-lat ratio is 1.5× / 3.7×. - Working hypothesis: **no regression**. It's a metric change plus kernel noise between holds. Step 1 tests this hypothesis rather than assuming it. ### Step 1: same-hold A/B (≈1 h) - One `perf-run --root` hold on the perf VM. Order **kernel, J103d (`236ec973`), J103e (`7c49bbe0`), J103e, J103d, kernel**. J103e's runner is reused unchanged apart from the case list, so raw `ping -D -O` runs beside every loaded LAN phase. - Table: Gbit/s, net-lat p99, exact raw-ICMP p50/p99/p99.9 with loss, all within the one hold. - If the two GotaTun binaries differ beyond case-to-case spread, I bisect the 3 commits (only `92f4c1dba` can matter) and name the cause. ### Step 2: one latency cut (≈4–5 h) - If it's no regression: profile the 8-flow loaded path on the pin (off-CPU/scheduling plus queue depths on the TUN and UDP paths), pick **one** cut that keeps per-flow order, and explain why order holds. J88f's fused receive-side TUN write is excluded. - Build and gate the fork on compute01 and dev-02. Run a keep hold (control `84b7bb2` against the cut, counterbalanced, raw ICMP). If that passes, run the 1 h soak against the control (reorders, retransmits, ring drops). - Keep rule: p99 better at 1 and 8 flows, throughput not lower, soak at the control's level. If any check fails: a revert commit on the fork branch, plus the data here. **Estimate:** ≈5–6 h total. I'll report at 2× if I overrun. No merge, no deploy. My targets get deleted at the end.

kayg commented

2026-11-04 06:48:59 +00:00

Author

Owner

J88g step 1: the 2.0× → 3.4–4.0× change is not a regression. Same hold, same numbers for both heads

Hold /home/claude/j20/r4b/j88g/hold-ab-20261104/ on the perf VM, one perf-run --root hold, 07:25–07:48 CET.

Outer exit 0; all 6 cases exit 0; every machine diff empty. Wall time 1,409 s. Steal 3,758 of 564,931 jiffies (0.67%).
Order: kernel, D, E, E, D, kernel.
- D = J103d's exact hold binary 236ec973…: bbd20b606 + GotaTun 84b7bb2, the binary behind the 2.0× / 2.2× row.
- E = J103e's exact hold binary 7c49bbe0…: 267839c54, pinned at 84b7bb2.
- Kernel cases use E. Coordinator 9e32e7b2….
Runner j88g-r4b.sh is J103e's j103e-r4b.sh (raw ping -D -O -n -i 0.005 -c 1800 beside each loaded LAN phase) with only the case list changed. The diff is in the runner dir. Every case's recorded source and engine match the plan.
Analyzer j88g-analyze.py is J103e's with the groups taken from argv. On J103e's own hold it reproduces 77314's table exactly. Summary: hold-ab-summary/summary.md.

Raw ICMP under load (exact, loss-aware, D331)

Case	1 flow: sent / lost / p50 / p99 / p99.9 (ms)	8 flows: sent / lost / p50 / p99 / p99.9 (ms)
kernel-first	1800 / 0 / 1.000 / 2.740 / 5.730	1800 / 0 / 3.420 / 7.020 / 15.000
D-first	1800 / 0 / 3.810 / 9.670 / 11.700	1800 / 0 / 7.030 / 21.000 / 29.600
E-first	1800 / 0 / 3.730 / 16.900 / 47.900	1800 / 0 / 7.070 / 18.900 / 24.500
E-second	1800 / 0 / 3.380 / 8.250 / 11.000	1800 / 0 / 6.830 / 18.700 / 41.000
D-second	1800 / 0 / 3.280 / 8.160 / 10.100	1800 / 0 / 6.590 / 16.500 / 23.400
kernel-last	1800 / 0 / 0.983 / 1.810 / 3.580	1800 / 0 / 3.210 / 4.620 / 5.870
kernel pooled	3600 / 0 / 0.990 / 2.370 / 5.250	3600 / 0 / 3.320 / 5.460 / 13.300
D pooled (`bbd20b606`)	3600 / 0 / 3.500 / 8.900 / 11.400	3600 / 0 / 6.820 / 18.900 / 27.400
E pooled (`267839c54`)	3600 / 0 / 3.540 / 13.800 / 27.700	3600 / 0 / 7.000 / 18.800 / 38.400

h2h columns

Case	Gbit/s 1 / 8	CPU s/Gbit 1 / 8	net-lat p50/p99, 1 flow (ms)	net-lat p50/p99, 8 flows (ms)	Lost 1 / 8
kernel-first	2.77 / 2.41	1.25 / 1.38	1.057 / 4.575	3.683 / 5.175	0 / 0
D-first	2.58 / 2.48	0.89 / 0.94	3.928 / 9.258	10.352 / 28.736	0 / 0
E-first	2.18 / 2.57	1.09 / 0.88	4.448 / 39.595	11.637 / 21.882	0 / 0
E-second	2.38 / 2.33	1.01 / 1.03	3.341 / 9.286	9.696 / 17.893	0 / 0
D-second	2.60 / 2.53	0.91 / 0.95	3.378 / 7.989	10.163 / 21.457	0 / 0
kernel-last	2.81 / 2.59	1.22 / 1.27	1.143 / 3.477	3.191 / 5.166	0 / 0
kernel mean	2.79 / 2.50	1.24 / 1.32	1.100 / 4.026	3.437 / 5.171	0 / 0
D mean	2.59 / 2.51	0.90 / 0.94	3.653 / 8.623	10.258 / 25.096	0 / 0
E mean	2.28 / 2.45	1.05 / 0.95	3.895 / 24.441	10.666 / 19.888	0 / 0

Impairments: 2% loss each way loses 6–33 of 300 probes in every case; 25%/50% reordering loses 0 in every case.

Verdict: not real. No bisect is needed

The two heads measure the same. At 8 flows, raw p99 is 18.9 ms (D) against 18.8 ms (E). At 1 flow, E-second (8.25 ms) sits between D's two runs (9.67 and 8.16 ms). E-first's 1-flow phase is a one-off spike: p99 16.9 ms, p99.9 47.9 ms, and its 1-flow throughput is also down, at 2.18 Gbit/s. E's own second run doesn't repeat it, and neither does any earlier 84b7bb2 hold. The shipping diff between the heads is start-up code only (92f4c1dba: holds_node_state() before record_engine), which never runs on the packet path. So there is nothing for a bisect to find, and I did not run one.
GotaTun did not move across four holds. Raw or net-lat, 8-flow p99 is 18.0 (J103d), 18.6 / 19.1 (J103e), 20.9 (J88f control) and 18.8–18.9 ms (here). 1-flow p99 stays at 7–10 ms.
The ratio moved because of the metric and the denominator.
- J103d's 2.0× / 2.2× is h2h net-lat p99 against a slow kernel: 3.95 / 8.15 ms, with kernel-last at 10.6 ms at 8 flows.
- J103e's 3.4× / 4.0× is raw ICMP p99 against a fast kernel: 2.27 / 4.80 ms.
- Within this one hold, the kernel's 8-flow raw p99 is 7.02 ms in its first run and 4.62 ms in its last. That spread alone moves the ratio by 1.5×.
Today's honest D332 row, pooled from this hold, for D: throughput 93% / 100% of kernel; loss-aware p99 3.8× / 3.5× (8.9 / 2.37 ms and 18.9 / 5.46 ms), with 0 probes lost. The gap is real and steady at about 3.5–4×. It isn't growing.

Recommendation for future rows: compare only within one hold, and use raw ICMP for the D332 ratio. net-lat's p99 over 2,000 samples swings with single spikes, and so does the kernel's own tail.

Step 2 (running)

Since there's no regression, I picked one cut from the profile. Earlier #260 traces put the largest residence on the TUN→encryption buffer (BufferedIpRecv, hundreds deep, 5 ms p99 at 8 flows). It's a FIFO, so a probe or keystroke from an idle flow waits behind every queued bulk packet.

Cut, fork j88g-latency @ 5c060b9 (pushed to GitHub and git.kayg.org/kayg/gotatun-fork): idle flows go first. Per-flow-bucket queued counts and a 256-slot sparse lane are served before the bulk lane. The bulk lane is unchanged.
Why order holds: a count goes up before its packet is queued and down only when the consumer takes it, and the consumer finishes each batch before it asks again. So a packet takes the sparse lane only when nothing of its flow is queued anywhere, and everything later in its flow queues behind it. All reordering happens before encryption. New tests: an overtake test, a 3-thread 18,000-packet per-flow order test, and a fragment-bucket test.
Fork checks are queued on dev-02 and compute01. The integrated static build (267839c54 with only the pin moved to 5c060b9) is queued on compute01. Then the keep hold: kernel, control E, cut, cut, control E, with raw ICMP. If it passes, the 1 h soak runs against the control.

## J88g step 1: the 2.0× → 3.4–4.0× change is not a regression. Same hold, same numbers for both heads **Hold** `/home/claude/j20/r4b/j88g/hold-ab-20261104/` on the perf VM, one `perf-run --root` hold, 07:25–07:48 CET. - Outer exit 0; all 6 cases exit 0; every machine diff empty. Wall time 1,409 s. Steal 3,758 of 564,931 jiffies (0.67%). - **Order:** kernel, D, E, E, D, kernel. - **D** = J103d's exact hold binary `236ec973…`: `bbd20b606` + GotaTun `84b7bb2`, the binary behind the 2.0× / 2.2× row. - **E** = J103e's exact hold binary `7c49bbe0…`: `267839c54`, pinned at `84b7bb2`. - Kernel cases use E. Coordinator `9e32e7b2…`. - **Runner** `j88g-r4b.sh` is J103e's `j103e-r4b.sh` (raw `ping -D -O -n -i 0.005 -c 1800` beside each loaded LAN phase) with only the case list changed. The diff is in the runner dir. Every case's recorded `source` and `engine` match the plan. - **Analyzer** `j88g-analyze.py` is J103e's with the groups taken from argv. On J103e's own hold it reproduces 77314's table exactly. Summary: `hold-ab-summary/summary.md`. **Raw ICMP under load (exact, loss-aware, D331)** | Case | 1 flow: sent / lost / p50 / p99 / p99.9 (ms) | 8 flows: sent / lost / p50 / p99 / p99.9 (ms) | |---|---:|---:| | kernel-first | 1800 / 0 / 1.000 / 2.740 / 5.730 | 1800 / 0 / 3.420 / 7.020 / 15.000 | | D-first | 1800 / 0 / 3.810 / 9.670 / 11.700 | 1800 / 0 / 7.030 / 21.000 / 29.600 | | E-first | 1800 / 0 / 3.730 / 16.900 / 47.900 | 1800 / 0 / 7.070 / 18.900 / 24.500 | | E-second | 1800 / 0 / 3.380 / 8.250 / 11.000 | 1800 / 0 / 6.830 / 18.700 / 41.000 | | D-second | 1800 / 0 / 3.280 / 8.160 / 10.100 | 1800 / 0 / 6.590 / 16.500 / 23.400 | | kernel-last | 1800 / 0 / 0.983 / 1.810 / 3.580 | 1800 / 0 / 3.210 / 4.620 / 5.870 | | **kernel pooled** | **3600 / 0 / 0.990 / 2.370 / 5.250** | **3600 / 0 / 3.320 / 5.460 / 13.300** | | **D pooled (`bbd20b606`)** | **3600 / 0 / 3.500 / 8.900 / 11.400** | **3600 / 0 / 6.820 / 18.900 / 27.400** | | **E pooled (`267839c54`)** | **3600 / 0 / 3.540 / 13.800 / 27.700** | **3600 / 0 / 7.000 / 18.800 / 38.400** | **h2h columns** | Case | Gbit/s 1 / 8 | CPU s/Gbit 1 / 8 | net-lat p50/p99, 1 flow (ms) | net-lat p50/p99, 8 flows (ms) | Lost 1 / 8 | |---|---:|---:|---:|---:|---:| | kernel-first | 2.77 / 2.41 | 1.25 / 1.38 | 1.057 / 4.575 | 3.683 / 5.175 | 0 / 0 | | D-first | 2.58 / 2.48 | 0.89 / 0.94 | 3.928 / 9.258 | 10.352 / 28.736 | 0 / 0 | | E-first | 2.18 / 2.57 | 1.09 / 0.88 | 4.448 / 39.595 | 11.637 / 21.882 | 0 / 0 | | E-second | 2.38 / 2.33 | 1.01 / 1.03 | 3.341 / 9.286 | 9.696 / 17.893 | 0 / 0 | | D-second | 2.60 / 2.53 | 0.91 / 0.95 | 3.378 / 7.989 | 10.163 / 21.457 | 0 / 0 | | kernel-last | 2.81 / 2.59 | 1.22 / 1.27 | 1.143 / 3.477 | 3.191 / 5.166 | 0 / 0 | | **kernel mean** | **2.79 / 2.50** | 1.24 / 1.32 | 1.100 / 4.026 | 3.437 / 5.171 | 0 / 0 | | **D mean** | **2.59 / 2.51** | 0.90 / 0.94 | 3.653 / 8.623 | 10.258 / 25.096 | 0 / 0 | | **E mean** | **2.28 / 2.45** | 1.05 / 0.95 | 3.895 / 24.441 | 10.666 / 19.888 | 0 / 0 | Impairments: 2% loss each way loses 6–33 of 300 probes in every case; 25%/50% reordering loses 0 in every case. ### Verdict: not real. No bisect is needed 1. **The two heads measure the same.** At 8 flows, raw p99 is 18.9 ms (D) against 18.8 ms (E). At 1 flow, E-second (8.25 ms) sits between D's two runs (9.67 and 8.16 ms). E-first's 1-flow phase is a one-off spike: p99 16.9 ms, p99.9 47.9 ms, and its 1-flow throughput is also down, at 2.18 Gbit/s. E's own second run doesn't repeat it, and neither does any earlier `84b7bb2` hold. The shipping diff between the heads is start-up code only (`92f4c1dba`: `holds_node_state()` before `record_engine`), which never runs on the packet path. So there is nothing for a bisect to find, and I did not run one. 2. **GotaTun did not move across four holds.** Raw or net-lat, 8-flow p99 is 18.0 (J103d), 18.6 / 19.1 (J103e), 20.9 (J88f control) and 18.8–18.9 ms (here). 1-flow p99 stays at 7–10 ms. 3. **The ratio moved because of the metric and the denominator.** - J103d's 2.0× / 2.2× is h2h **net-lat** p99 against a slow kernel: 3.95 / 8.15 ms, with kernel-last at 10.6 ms at 8 flows. - J103e's 3.4× / 4.0× is **raw ICMP** p99 against a fast kernel: 2.27 / 4.80 ms. - Within this one hold, the kernel's 8-flow raw p99 is 7.02 ms in its first run and 4.62 ms in its last. That spread alone moves the ratio by 1.5×. 4. **Today's honest D332 row**, pooled from this hold, for D: throughput 93% / 100% of kernel; loss-aware p99 **3.8× / 3.5×** (8.9 / 2.37 ms and 18.9 / 5.46 ms), with 0 probes lost. The gap is real and steady at about 3.5–4×. It isn't growing. Recommendation for future rows: compare only within one hold, and use raw ICMP for the D332 ratio. net-lat's p99 over 2,000 samples swings with single spikes, and so does the kernel's own tail. ### Step 2 (running) Since there's no regression, I picked one cut from the profile. Earlier #260 traces put the largest residence on the TUN→encryption buffer (`BufferedIpRecv`, hundreds deep, 5 ms p99 at 8 flows). It's a FIFO, so a probe or keystroke from an idle flow waits behind every queued bulk packet. - **Cut, fork `j88g-latency` @ `5c060b9`** (pushed to GitHub and git.kayg.org/kayg/gotatun-fork): idle flows go first. Per-flow-bucket queued counts and a 256-slot sparse lane are served before the bulk lane. The bulk lane is unchanged. - **Why order holds:** a count goes up before its packet is queued and down only when the consumer takes it, and the consumer finishes each batch before it asks again. So a packet takes the sparse lane only when nothing of its flow is queued anywhere, and everything later in its flow queues behind it. All reordering happens before encryption. New tests: an overtake test, a 3-thread 18,000-packet per-flow order test, and a fragment-bucket test. - Fork checks are queued on dev-02 and compute01. The integrated static build (`267839c54` with only the pin moved to `5c060b9`) is queued on compute01. Then the keep hold: kernel, control E, cut, cut, control E, with raw ICMP. If it passes, the 1 h soak runs against the control.

kayg commented

2026-11-04 06:51:20 +00:00

Author

Owner

J88g progress: cut is now `6fa75f6` (replaces `5c060b9`)

Fork j88g-latency was force-pushed on my own branch, before anyone built it: 5c060b9 → 6fa75f6, on GitHub and git.kayg.org/kayg/gotatun-fork. 5c060b9 wouldn't have compiled: a tokio::select! handler borrowed what the other branch's future held. Its multi-thread test also needed a tokio feature the fork doesn't enable. In 6fa75f6, the select returns only which lane fired. The order test is current-thread and interleaves through a 64-slot bulk lane that blocks the producer mid-read, plus consumer yields. The design and the order argument haven't changed.
Queued:
- Fork checks (fmt, clippy -D warnings, focused, full lib suite, release CLI) on dev-02, aarch64.
- Fork checks on compute01, x86, then the integrated static build in the same slot: 267839c54 with only the pin moved to 6fa75f6, via scripts/static-cargo, the same recipe as J103e's control 7c49bbe0.
Paths:
- Scripts and logs: ~/.cache/codex-scratch/j88g/ on both VMs.
- Fork worktree: ~/worktrees/j88g-gotatun.
- Integration worktree (compute01): ~/worktrees/j88g.
- My one target dir per VM: ~/.cache/codex-scratch/j88g/{target,int-target}.

## J88g progress: cut is now `6fa75f6` (replaces `5c060b9`) - Fork `j88g-latency` was force-pushed on my own branch, before anyone built it: `5c060b9` → **`6fa75f6`**, on GitHub and git.kayg.org/kayg/gotatun-fork. `5c060b9` wouldn't have compiled: a `tokio::select!` handler borrowed what the other branch's future held. Its multi-thread test also needed a tokio feature the fork doesn't enable. In `6fa75f6`, the select returns only which lane fired. The order test is current-thread and interleaves through a 64-slot bulk lane that blocks the producer mid-read, plus consumer yields. The design and the order argument haven't changed. - **Queued:** - Fork checks (fmt, clippy `-D warnings`, focused, full lib suite, release CLI) on dev-02, aarch64. - Fork checks on compute01, x86, then the integrated static build in the same slot: `267839c54` with only the pin moved to `6fa75f6`, via `scripts/static-cargo`, the same recipe as J103e's control `7c49bbe0`. - **Paths:** - Scripts and logs: `~/.cache/codex-scratch/j88g/` on both VMs. - Fork worktree: `~/worktrees/j88g-gotatun`. - Integration worktree (compute01): `~/worktrees/j88g`. - My one target dir per VM: `~/.cache/codex-scratch/j88g/{target,int-target}`.

kayg commented

2026-11-04 07:29:57 +00:00

Author

Owner

J88g progress: fork checks green on x86, soak pair running, integrated builds queued

Fork 6fa75f6, x86 checks on compute01, through build-slot. Same steps as J88e's (77235): fmt, clippy --workspace --all-features --all-targets -D warnings, focused, full lib suite, release CLI. Verbatim:

== HEAD 84b7bb28e385d57dfb80493e78202898fad24d1e dirty=1 patch_sha=2c1d1bb771b810ae
== fmt
== clippy
== focused
test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 151 filtered out; finished in 0.10s
== full lib suite
test result: ok. 149 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 8.71s
== release cli
f22ba80f5b195b8819cdd2b5285fdd38475deb59cb7783193b945800fa4f505a  /home/claude/.cache/codex-scratch/j88g/target/release/gotatun
J88G_CHECK_EXIT=0

The patch is git diff 84b7bb2 6fa75f6.

aarch64 (dev-02):

fmt and clippy passed.
The first run's test step stopped in the repo's sudo -E runner. The script only overrode the x86 runner variable; it now overrides CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUNNER too.
The same compiled test binary, run directly, passes the focused set: 5 passed; 0 failed (the overtake test, the interleaving order test, the fragment-bucket test, and the two existing ones).
The full gated run is re-queued.

Integrated build:

First try on compute01 failed in setup: a fresh target dir needs scripts/auth-toolchain (pinned Zig) before static-cargo.
Fixed. The build now moves only the pin: the rev in crates/plugins/mesh/Cargo.toml and the one Cargo.lock source line. No cargo update, which had also churned windows-sys.
Queued on dev-02 (cross, after its check, in the same slot: control 84b7bb2 and cut 6fa75f6) and on compute01 (cut). If the dev-02 control hashes to J103e's 7c49bbe0, the cut is directly comparable to it. Otherwise the keep hold uses the dev-02 pair.

1 h soak pair, started early while the perf VM was idle:

/home/claude/j20/r4b/j88g/soakpair-6fa75f6-20261104/: J88e's run-soak-pair.sh, unchanged, in one perf-run --root hold.
Control CLI 84b7bb2 (c0438938…, the binary J88e soaked), then cut CLI 6fa75f6 (f22ba80f…).
Started 08:29 CET, ≈ 2 h 7 min.
The keep hold (integrated, raw ICMP, K/control/cut/cut/control/K) runs after it. If the keep hold rejects the cut, the soak result doesn't matter and the cut is reverted.

## J88g progress: fork checks green on x86, soak pair running, integrated builds queued **Fork `6fa75f6`, x86 checks** on compute01, through build-slot. Same steps as J88e's (77235): fmt, clippy `--workspace --all-features --all-targets -D warnings`, focused, full lib suite, release CLI. Verbatim: ```text == HEAD 84b7bb28e385d57dfb80493e78202898fad24d1e dirty=1 patch_sha=2c1d1bb771b810ae == fmt == clippy == focused test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 151 filtered out; finished in 0.10s == full lib suite test result: ok. 149 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 8.71s == release cli f22ba80f5b195b8819cdd2b5285fdd38475deb59cb7783193b945800fa4f505a /home/claude/.cache/codex-scratch/j88g/target/release/gotatun J88G_CHECK_EXIT=0 ``` - The patch is `git diff 84b7bb2 6fa75f6`. **aarch64 (dev-02):** - fmt and clippy passed. - The first run's test step stopped in the repo's `sudo -E` runner. The script only overrode the x86 runner variable; it now overrides `CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_RUNNER` too. - The same compiled test binary, run directly, passes the focused set: `5 passed; 0 failed` (the overtake test, the interleaving order test, the fragment-bucket test, and the two existing ones). - The full gated run is re-queued. **Integrated build:** - First try on compute01 failed in setup: a fresh target dir needs `scripts/auth-toolchain` (pinned Zig) before `static-cargo`. - Fixed. The build now moves only the pin: the `rev` in `crates/plugins/mesh/Cargo.toml` and the one `Cargo.lock` source line. No `cargo update`, which had also churned `windows-sys`. - Queued on dev-02 (cross, after its check, in the same slot: control `84b7bb2` and cut `6fa75f6`) and on compute01 (cut). If the dev-02 control hashes to J103e's `7c49bbe0`, the cut is directly comparable to it. Otherwise the keep hold uses the dev-02 pair. **1 h soak pair, started early while the perf VM was idle:** - `/home/claude/j20/r4b/j88g/soakpair-6fa75f6-20261104/`: J88e's `run-soak-pair.sh`, unchanged, in one `perf-run --root` hold. - Control CLI `84b7bb2` (`c0438938…`, the binary J88e soaked), then cut CLI `6fa75f6` (`f22ba80f…`). - Started 08:29 CET, ≈ 2 h 7 min. - The keep hold (integrated, raw ICMP, K/control/cut/cut/control/K) runs after it. If the keep hold rejects the cut, the soak result doesn't matter and the cut is reverted.

kayg commented

2026-11-04 09:38:59 +00:00

Author

Owner

J88g finding: the 1 h soak rejects `6fa75f6` (it reorders TCP), and the cause is a race in my consumer. Fix `3bcfdc0` pushed and being gated

Soak pair /home/claude/j20/r4b/j88g/soakpair-6fa75f6-20261104/:

J88e's run-soak-pair.sh, unchanged, in one perf-run --root hold. Outer exit 0, both runs exit 0, both machine diffs 0 bytes. Wall 7,511 s, steal 1.0%.
72 slots each, 1,000 peers per endpoint, 4 flapping peers.
Control: fork CLI 84b7bb2 (c0438938…). Cut: 6fa75f6 (f22ba80f…).
Summary: soakpair-summary/ (J88d soak_summary.py, J88e pingstat.py).

1 h soak	Control `84b7bb2`	Cut `6fa75f6`
a: `TCPSACKReorder` / `TCPTSReorder` / `RetransSegs`	0 / 0 / 0	2,262 / 253 / 248
b: `TCPOFOQueue` / `RetransSegs`	0 / 5	90,299 / 3
`wgB` ring drops	203	0
ICMP 1 flow, loss-aware p50 / p99 / p99.9 (172,800 probes)	3.77 / 10.8 / 14.7 ms, 0 lost	3.51 / 10.7 / 17.1 ms, 0 lost
ICMP 4 flows, loss-aware p50 / p99 / p99.9 (139,200 probes)	7.63 / 16.2 / 22.7 ms, 0 lost	6.75 / 15.4 / 25.7 ms, 0 lost
Throughput 1 / 4 flows, Gbit/s	2.35 / 2.40	2.39 / 2.44
Flaps reconnected; daemon log lines	195/195; 0	195/195; 0

Keep rule: not met. Reorders and retransmits are far above the control's level, so 6fa75f6 as it stands is rejected. Latency moved the right way (p50 −7% / −12%, p99 −1% / −5%), and throughput did not fall.

Cause (my bug).

The order argument in 6fa75f6 assumed the consumer sees both lanes at one instant. They are two channels.
So this sequence is possible: the consumer polls the sparse lane and finds it empty. The producer, on another worker thread, then queues A1 of an idle flow in the sparse lane and A2, the next packet of that flow, in the bulk lane. The consumer then polls the bulk lane and takes A2 first.
The current-thread unit tests could not reach that interleaving.
b's 90,299 out-of-order segments are A2-before-A1 on the bulk TCP flows. Those flows go idle between TSO bursts, so their first packet of a burst often takes the sparse lane.

Fix 3bcfdc0 (separate commit on j88g-latency, fast-forward, on GitHub and git.kayg.org):

After a bulk batch, the consumer drains the sparse lane into the front of the batch, and only then releases the batch's flow counts.
Why that's order-safe: a sparse packet's flow had nothing counted when it was queued, and the batch's counts are still held. So any packet of its flow in the batch was queued after it.
The drain is capped at the lane's 256 slots. The lane is FIFO, so everything present at the bulk take is drained.
New test per_flow_order_holds_across_threads: the producer runs on its own OS thread and runtime and sends 200,000 packets in 1–6-packet bursts from 4 flows. The consumer checks per-flow order.
RED: the same test with only the drain removed, run 5× in the check script.

Next:

RED/GREEN plus the full fork checks are queued on dev-02 (then the integrated cut2 build in the same slot) and on compute01 (x86, plus the CLI the soak needs).
Then a keep hold: control 75aecfec against cut2, raw ICMP.
If it passes, a new soak pair against the same control.
The keep hold for 6fa75f6 that is running now (hold-keep-20261104) gives an early latency read; its numbers will be posted but not used for the verdict.
Elapsed ≈ 3 h 20 min of the 5–6 h estimate. The re-run adds about 3–4 h (queue waits plus a 2 h soak pair), which stays within 2× of the estimate.

## J88g finding: the 1 h soak rejects `6fa75f6` (it reorders TCP), and the cause is a race in my consumer. Fix `3bcfdc0` pushed and being gated **Soak pair** `/home/claude/j20/r4b/j88g/soakpair-6fa75f6-20261104/`: - J88e's `run-soak-pair.sh`, unchanged, in one `perf-run --root` hold. Outer exit 0, both runs exit 0, both machine diffs 0 bytes. Wall 7,511 s, steal 1.0%. - 72 slots each, 1,000 peers per endpoint, 4 flapping peers. - Control: fork CLI `84b7bb2` (`c0438938…`). Cut: `6fa75f6` (`f22ba80f…`). - Summary: `soakpair-summary/` (J88d `soak_summary.py`, J88e `pingstat.py`). | 1 h soak | Control `84b7bb2` | Cut `6fa75f6` | |---|---|---| | a: `TCPSACKReorder` / `TCPTSReorder` / `RetransSegs` | 0 / 0 / 0 | **2,262 / 253 / 248** | | b: `TCPOFOQueue` / `RetransSegs` | 0 / 5 | **90,299** / 3 | | `wgB` ring drops | 203 | 0 | | ICMP 1 flow, loss-aware p50 / p99 / p99.9 (172,800 probes) | 3.77 / 10.8 / 14.7 ms, 0 lost | 3.51 / 10.7 / 17.1 ms, 0 lost | | ICMP 4 flows, loss-aware p50 / p99 / p99.9 (139,200 probes) | 7.63 / 16.2 / 22.7 ms, 0 lost | 6.75 / 15.4 / 25.7 ms, 0 lost | | Throughput 1 / 4 flows, Gbit/s | 2.35 / 2.40 | 2.39 / 2.44 | | Flaps reconnected; daemon log lines | 195/195; 0 | 195/195; 0 | **Keep rule: not met.** Reorders and retransmits are far above the control's level, so `6fa75f6` as it stands is rejected. Latency moved the right way (p50 −7% / −12%, p99 −1% / −5%), and throughput did not fall. **Cause (my bug).** - The order argument in `6fa75f6` assumed the consumer sees both lanes at one instant. They are two channels. - So this sequence is possible: the consumer polls the sparse lane and finds it empty. The producer, on another worker thread, then queues A1 of an idle flow in the sparse lane and A2, the next packet of that flow, in the bulk lane. The consumer then polls the bulk lane and takes A2 first. - The current-thread unit tests could not reach that interleaving. - b's 90,299 out-of-order segments are A2-before-A1 on the bulk TCP flows. Those flows go idle between TSO bursts, so their first packet of a burst often takes the sparse lane. **Fix `3bcfdc0`** (separate commit on `j88g-latency`, fast-forward, on GitHub and git.kayg.org): - After a bulk batch, the consumer drains the sparse lane into the front of the batch, and only then releases the batch's flow counts. - Why that's order-safe: a sparse packet's flow had nothing counted when it was queued, and the batch's counts are still held. So any packet of its flow in the batch was queued after it. - The drain is capped at the lane's 256 slots. The lane is FIFO, so everything present at the bulk take is drained. - New test `per_flow_order_holds_across_threads`: the producer runs on its own OS thread and runtime and sends 200,000 packets in 1–6-packet bursts from 4 flows. The consumer checks per-flow order. - RED: the same test with only the drain removed, run 5× in the check script. **Next:** - RED/GREEN plus the full fork checks are queued on dev-02 (then the integrated `cut2` build in the same slot) and on compute01 (x86, plus the CLI the soak needs). - Then a keep hold: control `75aecfec` against `cut2`, raw ICMP. - If it passes, a new soak pair against the same control. - The keep hold for `6fa75f6` that is running now (`hold-keep-20261104`) gives an early latency read; its numbers will be posted but not used for the verdict. - Elapsed ≈ 3 h 20 min of the 5–6 h estimate. The re-run adds about 3–4 h (queue waits plus a 2 h soak pair), which stays within 2× of the estimate.

kayg commented

2026-11-04 09:48:07 +00:00

Author

Owner

J103f start (2026-11-04, IST afternoon)

Branch mesh-gotatun-linux, base 267839c54 (J103e head). Target base: origin/dev 5d33f7cdd (includes J168's 4fd5adf0c). Fork pin stays 84b7bb2 from GitHub (J88g's 3bcfdc0 is not pin-ready yet).

Plan (~3 h):

Rebase onto origin/dev, force-push with lease (~30 min incl. conflicts).
D340 kernel link ownership fence: the kernel path must never change or delete an infraternal0 it did not create (foreign marked link, unkeyed link). RED test first, then the fix; root proof on compute01 with a foreign marked link present (~1.5 h).
verify quick, then scripts/verify fast verbatim with the head SHA (~1 h incl. queue).
Post ready for the final security re-review.

## J103f start (2026-11-04, IST afternoon) Branch `mesh-gotatun-linux`, base `267839c54` (J103e head). Target base: `origin/dev` `5d33f7cdd` (includes J168's `4fd5adf0c`). Fork pin stays `84b7bb2` from GitHub (J88g's `3bcfdc0` is not pin-ready yet). **Plan (~3 h):** 1. Rebase onto `origin/dev`, force-push with lease (~30 min incl. conflicts). 2. D340 kernel link ownership fence: the kernel path must never change or delete an `infraternal0` it did not create (foreign marked link, unkeyed link). RED test first, then the fix; root proof on compute01 with a foreign marked link present (~1.5 h). 3. `verify quick`, then `scripts/verify fast` verbatim with the head SHA (~1 h incl. queue). 4. Post ready for the final security re-review.

kayg commented

2026-11-04 09:54:37 +00:00

Author

Owner

J103f progress: rebased, D340 kernel fence written (not yet gated)

Work-in-progress branch wip/j103f at 81254833e (mesh-gotatun-linux is force-pushed with a lease only after the compile check passes):

Rebase onto origin/dev 5d33f7cdd (includes 4fd5adf0c). Two conflicts, both in node_actions.rs, where dev re-indented the call() match: node.counters() (from 2b8c106e4) and "engine":node.engine_health() (from dd8e3d9b) were re-applied by hand. The mesh.peers GotaTun test got the new exposure: None field. Pin unchanged: 84b7bb2 from GitHub.
RED test e839e040d, tests/kernel_ownership.rs (namespace): a foreign marked kernel link, keyed or unkeyed, must keep its index and key through our node's restore, up and down, and uninstall must leave it. A positive control checks that our own link is still reattached and removed.
Fix 81254833e: new kernel links carry infraternal.mesh.v2:<pubkey>. One proof (recorded kernel/no engine + recorded interface key, matching the marker, or for old v1 links the live kernel key) gates restore, firewall adoption, down, the failed-up cleanup and the uninstall plan. Deletion is by proven ifindex only.

Limit, for kayg: a link from an older release that stopped before it got its key has the unbound v1 marker and cannot be proven. It is left in place, and up reports the name as taken until someone removes it.

Next: verify quick plus the RED/GREEN test binaries (queued on compute01, position 8), then the root proof with a foreign marked link, then verify fast.

## J103f progress: rebased, D340 kernel fence written (not yet gated) Work-in-progress branch `wip/j103f` at `81254833e` (`mesh-gotatun-linux` is force-pushed with a lease only after the compile check passes): - **Rebase** onto `origin/dev` `5d33f7cdd` (includes `4fd5adf0c`). Two conflicts, both in `node_actions.rs`, where dev re-indented the `call()` match: `node.counters()` (from `2b8c106e4`) and `"engine":node.engine_health()` (from `dd8e3d9b`) were re-applied by hand. The `mesh.peers` GotaTun test got the new `exposure: None` field. Pin unchanged: `84b7bb2` from GitHub. - **RED test** `e839e040d`, `tests/kernel_ownership.rs` (namespace): a foreign marked kernel link, keyed or unkeyed, must keep its index and key through our node's restore, `up` and `down`, and uninstall must leave it. A positive control checks that our own link is still reattached and removed. - **Fix** `81254833e`: new kernel links carry `infraternal.mesh.v2:<pubkey>`. One proof (recorded kernel/no engine + recorded interface key, matching the marker, or for old `v1` links the live kernel key) gates restore, firewall adoption, `down`, the failed-`up` cleanup and the uninstall plan. Deletion is by proven ifindex only. **Limit, for kayg:** a link from an older release that stopped before it got its key has the unbound `v1` marker and cannot be proven. It is left in place, and `up` reports the name as taken until someone removes it. Next: `verify quick` plus the RED/GREEN test binaries (queued on compute01, position 8), then the root proof with a foreign marked link, then `verify fast`.

kayg commented

2026-11-04 10:51:59 +00:00

Author

Owner

J88g finish: step 1, no regression. Step 2, the sparse-first cut is rejected and reverted. Pin stays `84b7bb2`

Fork kaygdotorg/gotatun branch j88g-latency (GitHub and git.kayg.org/kayg/gotatun-fork, fast-forward pushes after the one early force-push noted in 77419):

Commit	What	Verdict
`6fa75f6`	perf: idle flows first in the TUN receive buffer (sparse lane plus per-flow-bucket counts)	rejected by its 1 h soak: it reorders TCP (77583)
`3bcfdc0`	fix: drain the sparse lane in front of every bulk batch (the cross-thread race)	rejected by keep hold 2 (below)
`e17d6c0`, `95cebf2`	rustfmt and dead-code lint, no behaviour change	–
`7575935`	revert of all four; `git diff 84b7bb2 7575935` is empty (0 bytes)	tree = J88e's gated `84b7bb2`

For J103x and the pin: nothing changes. Keep 84b7bb2. mesh-gotatun-linux was not touched: no commits, no rebase.

Step 1 (77418): no regression

One counterbalanced hold measured J103d's binary and J103e's binary side by side. They are the same: 8-flow raw p99 18.9 against 18.8 ms.
The change from 2.0× to 3.4–4.0× came from switching metric (net-lat to raw ICMP) and from the kernel's own p99 moving between holds.
The shipping diff between the heads is start-up code only, so there was nothing to bisect.

Step 2: keep hold 2, the fixed cut, integrated

/home/claude/j20/r4b/j88g/hold-keep2-20261104/: one perf-run --root hold, exit 0, all 6 cases exit 0, all machine diffs empty. Wall 1,428 s, steal 0.07%.
Order: kernel, control, cut, cut, control, kernel. Runner j88g-keep2.sh (J103e's runner, case list only). Summary: hold-keep2-summary.md.
Control 7c49bbe0… = 267839c54 at 84b7bb2. My compute01 rebuild of 267839c54 reproduced this hash byte for byte, so J103e's binary is the exact control.
Cut f4280df8… = the same tree with only the pin (Cargo.toml rev and the one Cargo.lock line) moved to 3bcfdc0, built the same way on compute01.

	Kernel	Control `84b7bb2`	Cut `3bcfdc0`	Cut vs control
Raw ICMP 1 flow, pooled p50 / p99 / p99.9 (ms), lost	0.91 / 1.76 / 2.84, 0	3.02 / 7.28 / 9.24, 0	2.21 / 7.06 / 9.20, 0	p50 −27%, p99 −3%
Raw ICMP 8 flows, pooled p50 / p99 / p99.9 (ms), lost	2.96 / 4.78 / 8.19, 0	6.69 / 14.5 / 16.7, 0	5.43 / 14.0 / 17.2, 0	p50 −19%, p99 −3%
Raw p99 per run, 1 flow (ms)	1.69, 1.84	7.74, 6.62	6.16, 7.65	overlapping
Raw p99 per run, 8 flows (ms)	5.48, 4.32	14.9, 14.0	13.0, 14.5	overlapping
net-lat p99 mean, 1 / 8 flows (ms)	3.24 / 8.08	7.58 / 15.58	7.84 / 14.98	+3% / −4%
Throughput 1 / 8 flows, Gbit/s	3.23 / 2.78	2.79 / 2.68 (2.66, 2.69)	2.79 / 2.62 (2.61, 2.63)	0% / −2.2%
CPU s/Gbit 1 / 8	1.08 / 1.19	0.88 / 0.90	0.88 / 0.94	0 / +4%

Impairments: 2% loss each way loses 6–30 of 300 probes in every case; 25%/50% reordering loses 0 in every case.

Keep rule: not met.

✘ p99 does not clearly improve: −3% at both flow counts, inside the per-run spread, and net-lat p99 at 1 flow is +3%.
✘ 8-flow throughput falls 2.2%, with both cut runs below both control runs.
The soak was not repeated for 3bcfdc0, because the hold already rejects it (J88f's precedent). 6fa75f6's soak (77583) had already shown the reordering that 3bcfdc0 fixes.

What it tells us.

The cut works as designed: a probe from an idle flow skips the bulk backlog, so median loaded RTT falls 0.8–1.3 ms (−19% to −27%).
But the p99 tail D332 measures is not set by this buffer's FIFO wait. With the backlog skipped, p99 stays at ≈ 7 / 14 ms, so the tail comes from somewhere else: scheduling stalls (J88e: run-queue wait ≈ run time on 3 CPUs) or the receiver's path.
The earlier traces' "5 ms p99 residence in this buffer" overlaps with those stalls rather than adding to them.

Earlier read, 6fa75f6 keep hold 1 (hold-keep-20261104/, with the reordering bug, not used for the verdict): p50 −23% / −19%, p99 −16% / −52% pooled. The 8-flow control had one 40.6 ms outlier run, so the p99 figure is outlier-driven. Throughput +0% / +4%. Hold 2, with the fixed build, didn't reproduce the p99 gain.

Checks

6fa75f6, x86 (compute01, build-slot), verbatim:

== fmt
== clippy
== focused
test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 151 filtered out; finished in 0.10s
== full lib suite
test result: ok. 149 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 8.71s
== release cli
f22ba80f5b195b8819cdd2b5285fdd38475deb59cb7783193b945800fa4f505a  /home/claude/.cache/codex-scratch/j88g/target/release/gotatun
J88G_CHECK_EXIT=0

aarch64 (dev-02) gave the same result: 149 passed, CLI 88438259….

3bcfdc0, RED on x86: the new per_flow_order_holds_across_threads test, with only the sparse drain removed, failed 5/5, e.g. flow 1 reordered after 41282 packets and flow 2 reordered after 36154 packets.
3bcfdc0, GREEN: stopped first on cargo fmt --check (fixed in e17d6c0), then on clippy dead-code (fixed in 95cebf2). The full GREEN re-run on 95cebf2 was cancelled once the hold rejected the cut, so no fully green run exists for the fixed cut on either arch.
The revert 7575935 restores the exact 84b7bb2 tree, so J88e's checks on that tree still apply.
infraternal is unchanged, so scripts/verify fast does not apply. Everything ran as root in network namespaces on the perf VM.

Cleanup

On compute01 and dev-02: target dirs, the integration worktree ~/worktrees/j88g, the fork worktree ~/worktrees/j88g-gotatun and the built binaries are deleted. Logs and scripts stay in ~/.cache/codex-scratch/j88g/.
On the perf VM: cut and control binaries are deleted. Evidence, runners and summaries stay in /home/claude/j20/r4b/j88g/.
The local fork worktree on code is removed. No J88g processes run anywhere, and the perf VM is idle.

For the orchestrator and owner

Question (my recommendation is to leave it reverted): the sparse lane buys −19% to −27% median loaded RTT, the keystroke-feel number for SSH under load. It costs ≈ 2% 8-flow throughput and one hash plus one atomic per packet, and leaves p99 unchanged. D332's rule is p99, so under the rule it's out. If the owner wants median interactive latency as a separate goal, 3bcfdc0/95cebf2 is a ready, order-safe starting point, but it would need its own soak and a fully green check first.
Next lead for the p99 tail: profile per-probe residence by stage on the integrated engine at 8 flows: the sender's TUN to encryption, the UDP send queue, the receiver's socket queue, decryption to the TUN writer (256), and the writer itself. The earlier traces were fork-CLI only and are now known to overlap with scheduling stalls. A stage that holds the tail when the FIFO wait is skipped is the next target.
Elapsed ≈ 4 h 50 min, within the 5–6 h estimate.

## J88g finish: step 1, no regression. Step 2, the sparse-first cut is **rejected and reverted**. Pin stays `84b7bb2` **Fork** `kaygdotorg/gotatun` branch `j88g-latency` (GitHub and git.kayg.org/kayg/gotatun-fork, fast-forward pushes after the one early force-push noted in 77419): | Commit | What | Verdict | |---|---|---| | `6fa75f6` | perf: idle flows first in the TUN receive buffer (sparse lane plus per-flow-bucket counts) | rejected by its 1 h soak: it reorders TCP (77583) | | `3bcfdc0` | fix: drain the sparse lane in front of every bulk batch (the cross-thread race) | rejected by keep hold 2 (below) | | `e17d6c0`, `95cebf2` | rustfmt and dead-code lint, no behaviour change | – | | **`7575935`** | revert of all four; `git diff 84b7bb2 7575935` is **empty** (0 bytes) | tree = J88e's gated `84b7bb2` | **For J103x and the pin: nothing changes.** Keep `84b7bb2`. `mesh-gotatun-linux` was not touched: no commits, no rebase. ### Step 1 (77418): no regression - One counterbalanced hold measured J103d's binary and J103e's binary side by side. They are the same: 8-flow raw p99 18.9 against 18.8 ms. - The change from 2.0× to 3.4–4.0× came from switching metric (net-lat to raw ICMP) and from the kernel's own p99 moving between holds. - The shipping diff between the heads is start-up code only, so there was nothing to bisect. ### Step 2: keep hold 2, the fixed cut, integrated - `/home/claude/j20/r4b/j88g/hold-keep2-20261104/`: one `perf-run --root` hold, exit 0, all 6 cases exit 0, all machine diffs empty. Wall 1,428 s, steal 0.07%. - Order: kernel, control, cut, cut, control, kernel. Runner `j88g-keep2.sh` (J103e's runner, case list only). Summary: `hold-keep2-summary.md`. - **Control** `7c49bbe0…` = `267839c54` at `84b7bb2`. My compute01 rebuild of `267839c54` reproduced this hash byte for byte, so J103e's binary is the exact control. - **Cut** `f4280df8…` = the same tree with only the pin (Cargo.toml `rev` and the one Cargo.lock line) moved to `3bcfdc0`, built the same way on compute01. | | Kernel | Control `84b7bb2` | Cut `3bcfdc0` | Cut vs control | |---|---:|---:|---:|---:| | Raw ICMP 1 flow, pooled p50 / **p99** / p99.9 (ms), lost | 0.91 / 1.76 / 2.84, 0 | 3.02 / **7.28** / 9.24, 0 | 2.21 / **7.06** / 9.20, 0 | p50 −27%, **p99 −3%** | | Raw ICMP 8 flows, pooled p50 / **p99** / p99.9 (ms), lost | 2.96 / 4.78 / 8.19, 0 | 6.69 / **14.5** / 16.7, 0 | 5.43 / **14.0** / 17.2, 0 | p50 −19%, **p99 −3%** | | Raw p99 per run, 1 flow (ms) | 1.69, 1.84 | 7.74, 6.62 | 6.16, 7.65 | overlapping | | Raw p99 per run, 8 flows (ms) | 5.48, 4.32 | 14.9, 14.0 | 13.0, 14.5 | overlapping | | net-lat p99 mean, 1 / 8 flows (ms) | 3.24 / 8.08 | 7.58 / 15.58 | 7.84 / 14.98 | +3% / −4% | | **Throughput 1 / 8 flows, Gbit/s** | 3.23 / 2.78 | 2.79 / **2.68** (2.66, 2.69) | 2.79 / **2.62** (2.61, 2.63) | 0% / **−2.2%** | | CPU s/Gbit 1 / 8 | 1.08 / 1.19 | 0.88 / 0.90 | 0.88 / 0.94 | 0 / +4% | Impairments: 2% loss each way loses 6–30 of 300 probes in every case; 25%/50% reordering loses 0 in every case. **Keep rule: not met.** - ✘ p99 does not clearly improve: −3% at both flow counts, inside the per-run spread, and net-lat p99 at 1 flow is +3%. - ✘ 8-flow throughput falls 2.2%, with both cut runs below both control runs. - The soak was not repeated for `3bcfdc0`, because the hold already rejects it (J88f's precedent). `6fa75f6`'s soak (77583) had already shown the reordering that `3bcfdc0` fixes. **What it tells us.** - The cut works as designed: a probe from an idle flow skips the bulk backlog, so **median loaded RTT falls 0.8–1.3 ms (−19% to −27%)**. - But **the p99 tail D332 measures is not set by this buffer's FIFO wait**. With the backlog skipped, p99 stays at ≈ 7 / 14 ms, so the tail comes from somewhere else: scheduling stalls (J88e: run-queue wait ≈ run time on 3 CPUs) or the receiver's path. - The earlier traces' "5 ms p99 residence in this buffer" overlaps with those stalls rather than adding to them. **Earlier read, `6fa75f6` keep hold 1** (`hold-keep-20261104/`, with the reordering bug, not used for the verdict): p50 −23% / −19%, p99 −16% / −52% pooled. The 8-flow control had one 40.6 ms outlier run, so the p99 figure is outlier-driven. Throughput +0% / +4%. Hold 2, with the fixed build, didn't reproduce the p99 gain. ### Checks - **`6fa75f6`, x86 (compute01, build-slot), verbatim:** ```text == fmt == clippy == focused test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 151 filtered out; finished in 0.10s == full lib suite test result: ok. 149 passed; 0 failed; 7 ignored; 0 measured; 0 filtered out; finished in 8.71s == release cli f22ba80f5b195b8819cdd2b5285fdd38475deb59cb7783193b945800fa4f505a /home/claude/.cache/codex-scratch/j88g/target/release/gotatun J88G_CHECK_EXIT=0 ``` aarch64 (dev-02) gave the same result: 149 passed, CLI `88438259…`. - **`3bcfdc0`, RED on x86:** the new `per_flow_order_holds_across_threads` test, with only the sparse drain removed, failed **5/5**, e.g. `flow 1 reordered after 41282 packets` and `flow 2 reordered after 36154 packets`. - **`3bcfdc0`, GREEN:** stopped first on `cargo fmt --check` (fixed in `e17d6c0`), then on clippy dead-code (fixed in `95cebf2`). The full GREEN re-run on `95cebf2` was cancelled once the hold rejected the cut, so **no fully green run exists for the fixed cut on either arch**. - The revert `7575935` restores the exact `84b7bb2` tree, so J88e's checks on that tree still apply. - **infraternal is unchanged, so `scripts/verify fast` does not apply.** Everything ran as root in network namespaces on the perf VM. ### Cleanup - On compute01 and dev-02: target dirs, the integration worktree `~/worktrees/j88g`, the fork worktree `~/worktrees/j88g-gotatun` and the built binaries are deleted. Logs and scripts stay in `~/.cache/codex-scratch/j88g/`. - On the perf VM: cut and control binaries are deleted. Evidence, runners and summaries stay in `/home/claude/j20/r4b/j88g/`. - The local fork worktree on `code` is removed. No J88g processes run anywhere, and the perf VM is idle. ### For the orchestrator and owner - **Question (my recommendation is to leave it reverted):** the sparse lane buys −19% to −27% median loaded RTT, the keystroke-feel number for SSH under load. It costs ≈ 2% 8-flow throughput and one hash plus one atomic per packet, and leaves p99 unchanged. D332's rule is p99, so under the rule it's out. If the owner wants median interactive latency as a separate goal, `3bcfdc0`/`95cebf2` is a ready, order-safe starting point, but it would need its own soak and a fully green check first. - **Next lead for the p99 tail:** profile per-probe residence by stage on the **integrated** engine at 8 flows: the sender's TUN to encryption, the UDP send queue, the receiver's socket queue, decryption to the TUN writer (256), and the writer itself. The earlier traces were fork-CLI only and are now known to overlap with scheduling stalls. A stage that holds the tail when the FIFO wait is skipped is the next target. - Elapsed ≈ 4 h 50 min, within the 5–6 h estimate.

kayg commented

2026-11-04 10:56:27 +00:00

Author

Owner

J88h start: where a probe waits in the 8-flow p99 tail (D331, D332)

Branches (instrumentation only, never pinned anywhere):

fork kaygdotorg/gotatun j88h-profile, base 84b7bb2 (the pin)
infraternal j88h-profile, base 267839c54 (J103e head; J103f hasn't pushed yet), with the GotaTun dependency pointed at the profile branch on this branch only. mesh-gotatun-linux and its pin are not touched.

Plan (≈ 6 h, most of it build queue and the hold):

Probe tracer, behind a cargo feature, off by default (≈ 1.5 h). ICMP echo packets are tagged by (id, seq, type). Each stage writes one CLOCK_MONOTONIC record: stage, thread id, CPU and the WireGuard counter. Non-probe packets pay one protocol-byte compare. Records go into a preallocated buffer that only probe packets touch, and they're dumped to a file named by an env var. Stages on both ends: integration TUN read → fork handoff in/out (the buffer between TUN read and encryption) → encryption → UDP send → UDP receive → decryption → integration writer queue in/out → TUN write. Both namespaces share the perf VM's clock, so cross-end stages (wire, socket queues) are exact. Ping's -D receive time closes the two end pieces on host a.
Scheduler evidence in the same runs: a short in-kernel script records run-queue waits over 200 µs, wakeups and CPU migrations for the agents' threads, filtered by PID and with timestamps. It's joined against the probe records, so each stage's wait is split into runnable-but-not-running and other waiting. Per-thread schedstat is kept, as J88e did. If no tracing tool is usable on the perf VM, I'll fall back to tracefs as root.
One counterbalanced R4b hold (J88g's keep2 runner, case list and overlays only): kernel, control 7c49bbe0…, profile, profile, control, kernel, with raw ICMP at 200/s. Overhead = profile against control in the same hold (throughput, raw p99). Kernel stages: RTT and its worker threads' run-queue waits; deeper kernel stage splits only if they come cheap.
Write-up on #260: a per-stage median/p99 table at 1 and 8 flows, the dominant stage with scheduler evidence, the measured overhead, 1–3 candidate cuts (expected p99 effect, risk to per-flow order and to throughput), and a recommendation. No cut is implemented.

Gate: instrumentation branches only, no shipping code changes, so scripts/verify fast does not apply. Fork checks (fmt, clippy, lib suite with the feature on and off) run on a VM.

## J88h start: where a probe waits in the 8-flow p99 tail (D331, D332) **Branches** (instrumentation only, never pinned anywhere): - fork `kaygdotorg/gotatun` `j88h-profile`, base `84b7bb2` (the pin) - infraternal `j88h-profile`, base `267839c54` (J103e head; J103f hasn't pushed yet), with the GotaTun dependency pointed at the profile branch **on this branch only**. `mesh-gotatun-linux` and its pin are not touched. **Plan (≈ 6 h, most of it build queue and the hold):** 1. **Probe tracer, behind a cargo feature, off by default (≈ 1.5 h).** ICMP echo packets are tagged by (id, seq, type). Each stage writes one `CLOCK_MONOTONIC` record: stage, thread id, CPU and the WireGuard counter. Non-probe packets pay one protocol-byte compare. Records go into a preallocated buffer that only probe packets touch, and they're dumped to a file named by an env var. Stages on both ends: integration TUN read → fork handoff in/out (the buffer between TUN read and encryption) → encryption → UDP send → UDP receive → decryption → integration writer queue in/out → TUN write. Both namespaces share the perf VM's clock, so cross-end stages (wire, socket queues) are exact. Ping's `-D` receive time closes the two end pieces on host a. 2. **Scheduler evidence in the same runs:** a short in-kernel script records run-queue waits over 200 µs, wakeups and CPU migrations for the agents' threads, filtered by PID and with timestamps. It's joined against the probe records, so each stage's wait is split into runnable-but-not-running and other waiting. Per-thread `schedstat` is kept, as J88e did. If no tracing tool is usable on the perf VM, I'll fall back to tracefs as root. 3. **One counterbalanced R4b hold** (J88g's keep2 runner, case list and overlays only): kernel, control `7c49bbe0…`, profile, profile, control, kernel, with raw ICMP at 200/s. Overhead = profile against control in the same hold (throughput, raw p99). Kernel stages: RTT and its worker threads' run-queue waits; deeper kernel stage splits only if they come cheap. 4. **Write-up on #260:** a per-stage median/p99 table at 1 and 8 flows, the dominant stage with scheduler evidence, the measured overhead, 1–3 candidate cuts (expected p99 effect, risk to per-flow order and to throughput), and a recommendation. No cut is implemented. Gate: instrumentation branches only, no shipping code changes, so `scripts/verify fast` does not apply. Fork checks (fmt, clippy, lib suite with the feature on and off) run on a VM.

kayg commented

2026-11-04 11:15:18 +00:00

Author

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J88h progress: instrumentation pushed, profile build queued, harness smoke running

Fork j88h-profile @ cac3f73 (base 84b7bb2), on git.kayg.org/kayg/gotatun-fork. It adds probe_trace behind the new probe-trace feature: per-stage CLOCK_MONOTONIC records for ICMP echo probes. Stages: buffer in/out before encryption, encryption done, UDP queue in, UDP worker dequeue, UDP sent, UDP receive batch, decryption done, TUN send queue in/out. Records are written only when GOTATUN_PROBE_TRACE is set.
infraternal j88h-profile @ 0b833c561 (base 267839c54): the dependency points at the profile fork rev with the feature on (this branch only). Integration stamps: TUN read, writer queue in/out, TUN write. mesh-gotatun-linux and its pin are untouched.
Blocked, for the orchestrator: I can't push to github.com/kaygdotorg/gotatun. The key on code-minipc01 (~/.ssh/github.com, SHA256:aAR+N/Nd…) is refused with Permission denied (publickey), and the build VMs have only the Forgejo deploy key. The branch is on git.kayg.org only, and the profile build fetches it from there. Recommendation: push j88h-profile from a host with the GitHub key, or register this key. Nothing else depends on it.
Kernel-side tracing: static bpftrace v0.24.1 (sha256 c242dfb0…, from the GitHub release) runs as root under perf-run --root. Script j88h.bt records:
- 84-byte ICMP probes at net_dev_queue and netif_receive_skb on the tunnel devices. That works for both engines, so it also gives kernel WireGuard's equivalent split (one-way request, echo turnaround, one-way reply).
- Run-queue waits and sleeps ≥ 30 µs and migrations for the infraternal agents' threads.
- What held the CPU meanwhile, and softirq time per CPU.
Hold plan: 8 cases in one perf-run --root hold. Order: kernel+bpf, control 7c49bbe0, profile, profile+bpf, profile+bpf, profile, control, kernel+bpf. Tracer overhead = profile against control. bpftrace overhead = profile+bpf against profile.
Queue: the integrated static build and the fork checks share one build-slot job on compute01, at queue position 13. A one-case kernel+bpftrace smoke of the new overlay is running on the perf VM now.
Kit (runner, script, analyzer): /home/claude/j88h/ on the perf VM. Logs: ~/.cache/codex-scratch/j88h/ on compute01, with one target dir there (int-target, fork-target).

## J88h progress: instrumentation pushed, profile build queued, harness smoke running - **Fork** `j88h-profile` @ **`cac3f73`** (base `84b7bb2`), on git.kayg.org/kayg/gotatun-fork. It adds `probe_trace` behind the new `probe-trace` feature: per-stage `CLOCK_MONOTONIC` records for ICMP echo probes. Stages: buffer in/out before encryption, encryption done, UDP queue in, UDP worker dequeue, UDP sent, UDP receive batch, decryption done, TUN send queue in/out. Records are written only when `GOTATUN_PROBE_TRACE` is set. - **infraternal** `j88h-profile` @ **`0b833c561`** (base `267839c54`): the dependency points at the profile fork rev with the feature on (this branch only). Integration stamps: TUN read, writer queue in/out, TUN write. `mesh-gotatun-linux` and its pin are untouched. - **Blocked, for the orchestrator:** I can't push to **github.com/kaygdotorg/gotatun**. The key on `code-minipc01` (`~/.ssh/github.com`, `SHA256:aAR+N/Nd…`) is refused with `Permission denied (publickey)`, and the build VMs have only the Forgejo deploy key. The branch is on git.kayg.org only, and the profile build fetches it from there. Recommendation: push `j88h-profile` from a host with the GitHub key, or register this key. Nothing else depends on it. - **Kernel-side tracing:** static bpftrace v0.24.1 (`sha256 c242dfb0…`, from the GitHub release) runs as root under `perf-run --root`. Script `j88h.bt` records: - 84-byte ICMP probes at `net_dev_queue` and `netif_receive_skb` on the tunnel devices. That works for both engines, so it also gives kernel WireGuard's equivalent split (one-way request, echo turnaround, one-way reply). - Run-queue waits and sleeps ≥ 30 µs and migrations for the infraternal agents' threads. - What held the CPU meanwhile, and softirq time per CPU. - **Hold plan:** 8 cases in one `perf-run --root` hold. Order: kernel+bpf, control `7c49bbe0`, profile, profile+bpf, profile+bpf, profile, control, kernel+bpf. Tracer overhead = profile against control. bpftrace overhead = profile+bpf against profile. - **Queue:** the integrated static build and the fork checks share one build-slot job on compute01, at queue position 13. A one-case kernel+bpftrace smoke of the new overlay is running on the perf VM now. - Kit (runner, script, analyzer): `/home/claude/j88h/` on the perf VM. Logs: `~/.cache/codex-scratch/j88h/` on compute01, with one target dir there (`int-target`, `fork-target`).