feat(bench): repeatable memory-footprint benchmark (mem-bench.mjs + advisory workflow) - #406
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….mjs) Measures server RSS at lifecycle checkpoints (after-initialize = reaper barrier, after-tools-list, session-cycle retention) across targets (dist / npx bundle / docker), with a synthesized busy-/proc docker scenario (N sleeper processes spawned before exec, server as PID 1) to exercise the startup orphan reapers under a realistic process count. 5-trial median + min..max sampling, JSON output, and a compare subcommand whose significance test is median-shift vs full spread. Advisory weekly/dispatch CI workflow (never a required check). Motivated by PR #395's finding that unbounded /proc scans leave a permanent RSS scar; this makes such claims measurable and repeatable. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
…ckout Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Description
PR #395 showed that a memory claim about this server ("startup /proc scan leaves a permanent ~200 MB RSS scar") was measurable, repeatable, and fixable — but we had no tooling to make such claims cheap to verify or to catch regressions. This adds a repeatable memory-footprint benchmark so footprint decisions are driven by data instead of chance.
scripts/mem-bench.mjs(zero new dependencies — drives the server with the already-vendored MCP SDK client):after-initialize(startup floor — a successful MCPinitializeis a guaranteed barrier for reaper completion, since both reapers are awaited before argv parsing),after-tools-list(prices the adapter availability probe, perf(adapters): first tools/list imports and instantiates all 9 adapter packages permanently #401),after-session-cycle+ per-session RSS delta (retention signal).busy-procscenario (docker): spawns Nsleep infinityprocesses inside the container before exec'ing the server, so exactly N sleepers exist in/procwhen the reapers run and node is PID 1 — a controlled, repeatable stand-in for a busy host, no--pid=hostnondeterminism. Each trial runs a 0-sleeper control and an N-sleeper variant; the within-trial delta isolates scan cost.procEntryCountis recorded per trial so a failed spawn is visible, not silently wrong./proc/<pid>/statusVmRSS + VmHWM on Linux (peak proves a spike was prevented, not released — V8 doesn't return grown arenas),Get-ProcessWorkingSet64/PeakWorkingSet64/PrivateMemorySize64 on Windows,pson darwin,docker exec cat /proc/1/statusfor containers. Settle = 3 consecutive samples within max(2%, 2 MB).--trials(default 5); JSON output with git/host/config provenance;compare a.json b.jsonsubcommand marks a delta significant only when the median shift exceeds both runs' full spreads.bench:mem/bench:mem:docker;bench-results/gitignored..github/workflows/mem-bench.yml: advisory only — weekly cron + workflow_dispatch, ubuntu-only, results to step summary + uploaded JSON artifact. Never a required check, no thresholds, no PR trigger (shared-runner memory numbers are noisy; the local harness is the source of truth).Baselines at this commit
Windows host, dist target, 5 trials (all settled):
Docker (linux), busy-proc, 5 trials — the #395 verification this harness was first used for:
a4d5737d🔄 Type of Change
🧪 Testing
pnpm lintclean (script is covered byscripts/**lint glob)Related: #399 #400 #401 #402 #403 #404 #405 (the footprint follow-ups this data supports)
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