On Thu, 12 Dec 2024 17:09:09 GMT, Alan Bateman <[email protected]> wrote:
> A jdk.VirtualPinnedEvent JFR event is recorded by Object::wait when a virtual
> thread waits in Object.wait while pinned. The posting of the event in
> ObjectMonitor::wait is done after waiting but it can block again in
> enter/ReenterI before it re-acquires. If that happens then the event duration
> won't be accurate, and for the off-list case, the enter may be contended and
> a jdk.VirtualPinnedEvent event will be recorded for contended monitor enter.
> The changes to fix this are small: move the post of the event for Object.wait
> to end of the wait function, and only post an event for contended monitor
> enter when not waiting.
>
> I've added a test to check the pinned event that is recored for several
> contended monitor enter and Object.wait cases. It checks the event duration
> and that only one event is recorded for each case.
Looks good to me.
test/jdk/java/lang/Thread/virtual/MonitorPinnedEvents.java line 345:
> 343: vthread.interrupt();
> 344: } else {
> 345: synchronized (lock) {
Not sure if this was intentional but we already own the monitor.
-------------
Marked as reviewed by pchilanomate (Reviewer).
PR Review: https://git.openjdk.org/jdk/pull/22718#pullrequestreview-2502675830
PR Review Comment: https://git.openjdk.org/jdk/pull/22718#discussion_r1884181502
