perf: resident serve process — desktop panel fetches drop from ~7s to milliseconds - #956
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…illiseconds
Every CLI spawn on a large corpus pays seconds of fixed cost before any
query work: node boot, a 100MB+ session-cache JSON.parse, the discovery +
fingerprint sweep, and serve-time classification. The desktop app spawns
one CLI per panel fetch, so it pays that cost per panel.
codeburn serve --stdio is the same CLI kept warm: the app holds one child,
sends {id, args} per line, and gets the command's stdout back. Three layers
make it fast, each disabled outside serve so one-shot runs stay byte-exact:
- loadCache memo (session-cache.ts): the parsed cache object is reused
while a stat() shows the file unchanged; saveCache updates it
write-through. A rewrite by another process still forces a fresh read.
- burst reuse (parser.ts, CODEBURN_PARSE_BURST_MS, serve sets 10s): panel
bursts anchor their range ends at their own new Date(), so the exact-key
memo never hits in real traffic; within the window a re-anchored range is
served by trimming the previous parse instead of re-running discovery.
- fresh commander program per request (main.ts buildProgram factory),
because commander option state is sticky across parses.
The server allows only the app's read queries (status/overview/models/
sessions/compare/yield/spend/optimize/audit), refuses everything else
(client falls back to a spawn), serializes requests, and converts
process.exit into a caught signal. The app starts the child once at
startup; requests route through it only when warm, cold-start keeps the
spawn path with its progress events, any serve failure falls back to a
spawn, and three child deaths disable serve for the app run.
Measured on a real 17B-token corpus: panel fetches drop from ~7.4s per
spawn to 5-900ms warm (sessions/spend 5ms, status 898ms). One-shot CLI
output verified byte-identical against the pre-branch baseline.
This was referenced Aug 10, 2026
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The fetching-is-slow complaint, fixed for the release. Full design and measurements in the commit message; highlights:
Measured warm panel fetches: 5-900ms vs ~7,400ms per spawn (17B-token corpus). One-shot CLI output byte-identical to baseline (diffed); full suite 2,612 green, app suite 468 green, serve protocol + burst + memo covered by new tests.