Files
msd-core/tests
sim c1a2c33886 perf(#4012): two subprocess spawns, not five
My instrumentation suite tipped ubuntu shard 1/3 over its 15-minute job cap.
Measured, not guessed: baseline on next (c8f08b61f) passed that shard in
14m21s — 39 seconds of headroom — and the chunk-timeout instrumentation suite
I added costs 31,621ms, about 80% of what was left. The job ran 15m09s and
GitHub reported the cap as a cancel, which failed the required-tests rollup.

Cause is spawn count, not test content. The suite booted scripts/run-tests.cjs
five separate times — three success-path, two timeout-path — and each boot
globs the suite and spawns node --test children before any assertion runs. The
direct-require tests beside it cost milliseconds.

Now two spawns: one success run backing the elapsed-timing, temp-dir-non-leak
and no-EINVAL assertions, and one timeout run backing the in-flight-file
naming and the diagnostic wording. Every assertion is kept verbatim; only the
per-assertion subprocess boot is gone. Modelling per-boot overhead from the
measured total puts the saving around 18s, but that is an estimate derived
from one data point, not a measurement — the real number comes from CI.

The chunk timeout stays at 2000ms. It is already the lowest value used
anywhere in this file, and lowering it further would race a loaded CI box that
has to boot node --test, register the hang, and observe the kill inside the
window.

Worth recording separately: that lane has 39 seconds of margin on next, so it
is one cliff away from this happening to whoever adds the next test. The
per-chunk timing this PR adds is what made the attribution possible at all —
chunk 1/5 alone is 263s of a 900s budget, which was previously invisible.

Verification runs on the remote runner.

Refs #4012
2026-08-29 01:01:36 -04:00
..