1726915 - Condition variable waits fire extremely late on OS X testers

Status: NEW

(Testing :: GTest, defect, P3)

Description

[Byron Campen [:bwc]]

Noticed this over in bug 1726177, due to new test-cases:

https://bugzilla.mozilla.org/show_bug.cgi?id=1726177#c7

Seeing pretty consistent >100ms delays on TimerThread wakeups, and presumably that means anything else using mozilla::CondVar::Wait will be similarly effected.

FWIW, this does not appear to happen on a 2017 macbook pro running 11.5. It is possible that this is specific to the hardware we're using for CI, or the version of OS X we're using.

Grep this log for "was supposed to wait for": https://treeherder.mozilla.org/jobs?repo=try&revision=125a159265a776ce39c0a880c319e08d4370ab73&selectedTaskRun=S2tNywiBQ9Ou_AdzlXj8xA.0

Comment 1

[Jens Stutte [:jstutte]]

I can see this on Mac OS CCOV, too, grep the log for Encountered flaky timers. On successful runs (linux) the deviation is far below 5%, usually <1%.