On Fri, 10 May 2024 12:20:27 GMT, Doug Lea <d...@openjdk.org> wrote: >> src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java line 978: >> >>> 976: * of two, at least 2. See above. >>> 977: */ >>> 978: static final int INITIAL_QUEUE_CAPACITY = 1 << 7; >> >> @DougLea Interesting change—what impact did you notice when doubling this? > > The goal is to reduce the worst form of contention: when queue arrays are > laid out adjacently in memory. Increasing sizes has some impact but with > diminishing returns. Thanks for the comment as a reminder that I haven't > rechecked this lately in light of other layout changes. Will do.
After recheckiing, the best policy is to leave internal queues the same, but initialize external queues larger. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/19131#discussion_r1597634199
