RFR: 8322732: ForkJoinPool may underutilize cores in async mode

[Doug Lea]

On Fri, 10 May 2024 08:15:59 GMT, Viktor Klang <vklang at openjdk.org> wrote:

>> This set of changes address causes of poor utilization with small numbers of cores due to overly aggressive contention avoidance. A number of further adjustments were needed to still avoid most contention effects in deployments with large numbers of cores
>
> src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java line 1883:
> 
>> 1881:             if (qs == null)
>> 1882:                 break;
>> 1883:             if (qs.length <= i)
> 
> @DougLea Any particular reason why these are not or-branches of a single if?

An old trick to save bytecode branches, reducing code size. I haven't checked lately whether this is still true though.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19131#discussion_r1596670378