test: avoid timer race in event loop delay test#64728
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An expired timer can run before the first complete event loop iteration, disabling the histogram before it records any samples. Drive a known number of iterations with setImmediate before checking the histograms, and share the chain between resolution variants. Signed-off-by: Kamat, Trivikram <16024985+trivikr@users.noreply.github.com> Assisted-by: codex:gpt-5.6-sol
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Refs: https://github.com/nodejs/reliability/issues?q=sort%3Aupdated-desc%20test-performance-eventloopdelay
Problem
The test enables the histogram and checks it from a 20 ms timer.
On slow or contended systems, that timer can expire before the first complete event loop iteration.
The timer then disables the histogram before its
uv_checkcallback records a sample.Previous fixes addressed related but distinct failures:
The failing
samplePerIterationchecks were added later by #62935 and still depend on elapsed time.Solution
Drive a known number of event loop iterations using
setImmediatebefore disabling and checking each histogram.The default-resolution and large-resolution checks share one iteration chain, removing the duplicated timing logic.
Assisted-by: codex:gpt-5.6-sol