On Fri, 10 May 2024 08:11:52 GMT, Viktor Klang <vkl...@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 1830:
>
>> 1828: phase = w.phase;
>> 1829: if ((src = w.source) != DROPPED) {
>> 1830: w.source = DROPPED; // else already dropped
>
> @DougLea Would there be any gain in atomically swapping out `w.source` to
> `DROPPED`?
No the source field is only written by owner. (With one harmless exception --
cascading idle timeouts, where an invalid value is set to check that no tasks
were taken by successor.) I should note this somewhere.
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PR Review Comment: https://git.openjdk.org/jdk/pull/19131#discussion_r1596661400
