RFR: 8315442: Enable parallelism in vmTestbase/nsk/monitoring/stress/thread tests

[Aleksey Shipilev]

On Thu, 31 Aug 2023 15:21:52 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

>> Current vmTestbase/nsk/monitoring/stress/thread tests contains 21 tests, each running exclusively. This drags the tier4 test times up. There seem to be no reason to run these tests exclusively, though: they complete in reasonable time, are lightly-threaded, and consume the usual amount of memory.
>> 
>> We should consider enabling parallelism for them and get improved test performance. Currently it is blocked by TEST.properties with exclusiveAccess.dirs directives in them.
>> 
>> Current run on 18-core machine:
>>  1025.63s user 97.23s system 586% cpu 3:11.60 total
>> 
>> Fully parallel:
>>  1125.04s user 107.60s system 1583% cpu 1:17.83 total 
>> 
>> Additional testing:
>>  - [x]  50x iterations of Linux x86_64 fastdebug `vmTestbase/nsk/monitoring/stress/thread`
>
> Marked as reviewed by lmesnik (Reviewer).

> @lmesnik can you test this in our CI please? (I would but am starting vacation in a few hours).

Yes, that would be nice. I did my own stability testing (see PR "Additional testing"), and that passed well. 

Given the prior experience with these parallelism improvements, I expect no problems. ...and we can revert this change if found problematic. Which would also give us a bug trail why these needed to be sequential.

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PR Comment: https://git.openjdk.org/jdk/pull/15508#issuecomment-1704966526