RFR: 8336707: Contention of ForkJoinPool grows when stealing works [v29]

[Viktor Klang]

On Wed, 20 Nov 2024 08:11:34 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> src/java.base/share/classes/java/util/concurrent/ForkJoinWorkerThread.java line 247:
>> 
>>> 245:         = U.objectFieldOffset(Thread.class, "threadLocals");
>>> 246:     private static final long INHERITABLETHREADLOCALS
>>> 247:         = U.objectFieldOffset(Thread.class, "inheritableThreadLocals");
>> 
>> @AlanBateman Thoughts here? 🤔
>
> resetThreadLocals looks good although. A discussion point is whether reset should be done for all FJP instances, not just the common pool but not this PR.

Thanks Alan. Yes, I think it should be considered to do it for all FJP instances.

>> src/java.base/share/classes/java/util/concurrent/ForkJoinWorkerThread.java line 270:
>> 
>>> 268:         @SuppressWarnings("removal")
>>> 269:         public void setContextClassLoader(ClassLoader cl) {
>>> 270:             if (System.getSecurityManager() != null &&
>> 
>> @AlanBateman Alternatives for this? 🤔
>
> I don't think it needs an alternative, instead L270-272 will be removed as part of the SM cleanup.

Sounds like a good plan 👍

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PR Review Comment: https://git.openjdk.org/jdk/pull/21507#discussion_r1850053209
PR Review Comment: https://git.openjdk.org/jdk/pull/21507#discussion_r1850054254