From fc6a5ea88c913cbeb9af432c1ec16b4c72f4b4ba Mon Sep 17 00:00:00 2001 From: Rhys Hiltner Date: Tue, 23 Apr 2024 14:16:04 -0700 Subject: runtime: test mutex contention stacks and counts Fully testing the runtime's profiles and metrics for contention on its internal mutex values involves comparing two separate clocks (cputicks for the profile and nanotime for the metric), verifying its fractional sampling (when MutexProfileRate is greater than 1), and observing a very small critical section outside of the test's control (semrelease). Flakiness (#64253) from those parts of the test have led to skipping it entirely. But there are portions of the mutex profiling behavior that should have more consistent behavior: for a mutex under the test's control, the test and the runtime should be able to agree that the test successfully induced contention, and should agree on the call stack that caused the contention. Allow those more consistent parts to run. For #64253 Change-Id: I7f368d3265a5c003da2765164276fab616eb9959 Reviewed-on: https://go-review.googlesource.com/c/go/+/581296 LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Knyszek Reviewed-by: Joedian Reid Auto-Submit: Rhys Hiltner --- src/runtime/metrics_test.go | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/src/runtime/metrics_test.go b/src/runtime/metrics_test.go index 1d99b86fe6..859bc712f1 100644 --- a/src/runtime/metrics_test.go +++ b/src/runtime/metrics_test.go @@ -948,8 +948,6 @@ func TestSchedPauseMetrics(t *testing.T) { } func TestRuntimeLockMetricsAndProfile(t *testing.T) { - testenv.SkipFlaky(t, 64253) - old := runtime.SetMutexProfileFraction(0) // enabled during sub-tests defer runtime.SetMutexProfileFraction(old) if old != 0 { @@ -1181,12 +1179,17 @@ func TestRuntimeLockMetricsAndProfile(t *testing.T) { } const slop = 1.5 // account for nanotime vs cputicks - if profileGrowth > slop*metricGrowth || metricGrowth > slop*profileGrowth { - t.Errorf("views differ by more than %fx", slop) - } + t.Run("compare timers", func(t *testing.T) { + testenv.SkipFlaky(t, 64253) + if profileGrowth > slop*metricGrowth || metricGrowth > slop*profileGrowth { + t.Errorf("views differ by more than %fx", slop) + } + }) }) t.Run("sample-2", func(t *testing.T) { + testenv.SkipFlaky(t, 64253) + old := runtime.SetMutexProfileFraction(2) defer runtime.SetMutexProfileFraction(old) @@ -1218,6 +1221,8 @@ func TestRuntimeLockMetricsAndProfile(t *testing.T) { }) t.Run("runtime.semrelease", func(t *testing.T) { + testenv.SkipFlaky(t, 64253) + old := runtime.SetMutexProfileFraction(1) defer runtime.SetMutexProfileFraction(old) -- cgit v1.2.3-54-g00ecf