RFR: 8318986: Improve GenericWaitBarrier performance [v8]

[Patricio Chilano Mateo]

On Wed, 22 Nov 2023 16:02:28 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

>> Thanks for testing!
>> 
>>> I run Tiers[1-7] and there is one failure in tier5 in test vmTestbase/nsk/monitoring/stress/thread/strace016/TestDescription.java on windows-x64-debug. I re-run tier5 twice and the test alone 100 times but unfortunately couldn't reproduce the issue. I checked the history of failures and haven't seen this failed before. But it could also be that there is some race already in the test uncovered by this patch.
>> 
>> Yes, I think so too. I ran this test hundreds of times without failure. The output implies there is a thread that should be "blocked", but instead it is "runnable". I think the test itself contains the race condition, submitted: https://bugs.openjdk.org/browse/JDK-8320599. I would not treat this failure as integration blocker then.
>> 
>> Do you think we should wait for Mac pipeline to complete?
>
>> Thanks for testing!
>> 
>> > I run Tiers[1-7] and there is one failure in tier5 in test vmTestbase/nsk/monitoring/stress/thread/strace016/TestDescription.java on windows-x64-debug. I re-run tier5 twice and the test alone 100 times but unfortunately couldn't reproduce the issue. I checked the history of failures and haven't seen this failed before. But it could also be that there is some race already in the test uncovered by this patch.
>> 
>> Yes, I think so too. I ran this test hundreds of times without failure. The output implies there is a thread that should be "blocked", but instead it is "runnable". I think the test itself contains the race condition, submitted: https://bugs.openjdk.org/browse/JDK-8320599. I would not treat this failure as integration blocker then.
>> 
> Yes, I think the issue is in ThreadController.java with Blocker.block(). I'll keep investigating to see if I can reproduce it.
> 
>> Do you think we should wait for Mac pipeline to complete?
>>
> I'm not sure when this tasks will finish. I think we should be good with all the testing done so far.

> @pchilano you can change the waitBarrier.hpp so Linux also uses the generic one, as @shipilev did when he tested:
> 
> ```
> #if defined(LINUX)
> #include "waitBarrier_linux.hpp"
> ```
> 
> And just use "typedef GenericWaitBarrier WaitBarrierDefault;"
> 
> For better coverage.
>
I actually realized of this yesterday after the jobs have been running for a while. So I submitted extra runs with that change to test Linux too. I run Tiers[4-7]. Tier7 completed successfully, and Tiers[4-6] is almost done too with no failures. There are again some macos-x64 jobs that are pending.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/16404#issuecomment-1823057946