RFR: 8336707: Contention of ForkJoinPool grows when stealing works [v24]

[Viktor Klang]

On Mon, 11 Nov 2024 16:39:47 GMT, Doug Lea <dl at openjdk.org> wrote:

>> This addresses tendencies in previous update to increase fencing, scanning, and signalling that can increase contention, and slow down performance especially on ARM platforms. It also uses more ARM-friendly constructions to reduce overhead (leading to several changes that all of the same form),
>
> Doug Lea has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address review comments

src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java line 2078:

> 2076:         w.phase = p;
> 2077:         if (!compareAndSetCtl(pc, qc))        // try to enqueue
> 2078:             return w.phase = phase;           // back out on possible signal

@DougLea We don't back out the stackPred change here, is that still valid? 🤔

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/21507#discussion_r1838226013