RFR: 8360046: Scalability issue when submitting virtual threads with almost empty tasks [v5]

[Viktor Klang]

On Thu, 7 Aug 2025 14:03:40 GMT, Doug Lea <dl at openjdk.org> wrote:

>> This set of updates reduces contention-based performance loss under heavy over-subscription, while also improving perfomance more generally.
>
> Doug Lea has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Avoid underutilization on resize

src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java line 1894:

> 1892:             if (a != null && k < a.length && k >= 0 && a[k] == null)
> 1893:                 break;
> 1894:             if (c == (c = ctl) && c == (c = compareAndExchangeCtl(c, nc))) {

CCAE to reduce cache traffic contention on `ctl` is good. 👍

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

PR Review Comment: https://git.openjdk.org/jdk/pull/26479#discussion_r2272690784