On Fri, 10 May 2024 07:34:40 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 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. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/19131#discussion_r1596684587
