RFR: 8373118: Test java/lang/Thread/virtual/Starvation.java timed out [v5]

[Alan Bateman]

On Mon, 15 Dec 2025 11:32:00 GMT, Viktor Klang <vklang at openjdk.org> wrote:

>> Doug Lea has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Adjust runworker for previous update
>
> src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java line 1865:
> 
>> 1863:             long ac = (c + RC_UNIT) & RC_MASK, nc;
>> 1864:             int sp = (int)c, i = sp & SMASK;
>> 1865:             if ((short)(c >>> RC_SHIFT) >= pc)
> 
> I'm wondering if it might make sense to re-read `parallelism` on each new loop, since if we have a parallelism resize *during this loop* we want to exit early?
> 
> 
> Suggestion:
> 
>         for (long c = ctl;;) {
>             WorkQueue[] qs = queues;
>             long ac = (c + RC_UNIT) & RC_MASK, nc;
>             int sp = (int)c, i = sp & SMASK, pc;
>             if ((short)(c >>> RC_SHIFT) >= (pc = parallelism))

Maybe but it should also be rare to adjust parallelism, and setParallelism changed recently to signal.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28797#discussion_r2619087486