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perf(dashboard): replace blocking pgrep execSync with async execFile

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Two sync hot paths were stalling the dashboard event loop on a periodic
timer:

1. `pgrep -f vitest` ran via `execSync` in `getVitestProcessIds`
   (`/api/system-stats`, `/api/kill-vitest`) and `killVitestProcesses`
   (TUI memory-pressure check). On a busy machine pgrep walking the
   process table can take 100ms+; execSync blocks the entire Node event
   loop for that duration, so every concurrent dashboard request hangs
   while pgrep runs. The TUI variant fired on every memory-pressure tick
   (~2s when over threshold), the dashboard variant fired on every
   system-stats poll (5s while the modal is open). Both now use execFile
   with a callback wrapped in a Promise.

2. `discoverDashboardPiExtensions` (called from 3 /api/settings/pi-
   extensions routes) did 6+ blocking existsSync/readFileSync calls per
   invocation across legacy and fusion settings paths. Converted to
   fs.promises.readFile/access and parallelized via Promise.all.

Behavior preserved:
- TUI memory-pressure detection still works (sync os.totalmem path
  unchanged); auto-kill still fires on threshold breach.
- The `lastAutoKillAt` 30s re-fire gate is set before the async kill
  starts, so concurrent ticks can't trigger duplicate kills.
- system-stats still polls every 5s while the modal is open and still
  returns vitestProcessCount.
- All 7 system-stats / kill-vitest tests pass; all 6 settings/pi-
  extensions tests pass. Test mocks updated for the (err, stdout, stderr)
  callback signature.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
gsxdsm
2026-05-02 14:57:54 -07:00
parent c719720004
commit 3bafc48000
4 changed files with 123 additions and 60 deletions
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.changeset/dashboard-async-pgrep-and-fs.md Normal file
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---
"@runfusion/fusion": patch
---
Fix periodic dashboard event-loop stalls caused by synchronous shell-outs and filesystem reads on hot request paths.
Two distinct sources, both replaced with async equivalents:
- **`pgrep -f vitest`** ran via `execSync` in `getVitestProcessIds` (`/api/system-stats`, `/api/kill-vitest`) and `killVitestProcesses` (TUI memory-pressure check). On a busy machine `pgrep` walking the process table can take 100ms+; `execSync` blocks the entire Node event loop for that duration, so every concurrent dashboard request hangs while pgrep runs. The TUI variant fired on every memory-pressure tick (every 2s when over threshold), the dashboard variant fired on every system-stats poll (every 5s while the modal is open). Both now use `execFile` with a callback wrapped in a Promise.
- **`discoverDashboardPiExtensions`** (called from 3 `/api/settings/pi-extensions` routes) did 6+ blocking `existsSync`/`readFileSync` calls per invocation across legacy and fusion settings paths. Converted to `fs.promises.readFile`/`access` and parallelized via `Promise.all`.