[libcxx-commits] [PATCH] D114119: [libcxx] Fix potential lost wake-up in counting semaphore

[Fabian Wolff via Phabricator via libcxx-commits]

fwolff marked 2 inline comments as done.
fwolff added inline comments.


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Comment at: libcxx/test/std/thread/thread.semaphore/lost_wakeup.pass.cpp:1
+//===----------------------------------------------------------------------===//
+//
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ldionne wrote:
> Do you think this test is the reason why the CI nodes timed out after running for 2 hours? It seems like it's not consistently slow (I just restarted the macOS CI and it finished quickly, but before that it froze for 2 hours, which I've never seen). https://buildkite.com/llvm-project/libcxx-ci/builds/6835#4278d152-fa4d-482f-a12e-e9697caa99e3
I don't see what could be causing this, but I agree that it looks suspicious.

The fix itself should be uncontroversial, though, at least as far as correctness is concerned, because we are always waking up //at least as many// threads as before, so if anything, we're making deadlocks //less// likely to occur.

What options do we have regarding this test? Could the problem also lie with, say, `std::barrier`?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D114119/new/

https://reviews.llvm.org/D114119