test: avoid timer race in event loop delay test - #64728
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Stress tests on |
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Codecov Report✅ All modified and coverable lines are covered by tests. @@ Coverage Diff @@
## main #64728 +/- ##
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- Coverage 91.85% 90.15% -1.71%
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Files 400 752 +352
Lines 178855 251884 +73029
Branches 27331 47368 +20037
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+ Hits 164292 227078 +62786
- Misses 14234 16164 +1930
- Partials 329 8642 +8313 see 485 files with indirect coverage changes 🚀 New features to boost your workflow:
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Both of these are passing stress tests over main, not over this PR |
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panva
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LGTM but please stress test the PR head.
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Stress test on PR: https://ci.nodejs.org/job/node-stress-single-test/837/ |
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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 PR-URL: nodejs#64728 Refs: https://github.com/nodejs/reliability/issues?q=sort%3Aupdated-desc%20test-performance-eventloopdelay Reviewed-By: Filip Skokan <panva.ip@gmail.com>
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_check callback records a sample.
Previous fixes addressed related but distinct failures:
The failing samplePerIteration checks were added later by #62935 and still depend on elapsed time.
Solution
Drive a known number of event loop iterations using setImmediate before 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