Integrated: 8346120: VirtualThreadPinned event recorded for Object.wait may have wrong duration or may record second event

[Alan Bateman]

On Thu, 12 Dec 2024 17:09:09 GMT, Alan Bateman <alanb at openjdk.org> 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.

This pull request has now been integrated.

Changeset: fbbc7c35
Author:    Alan Bateman <alanb at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/fbbc7c35f422294090b8c7a02a19ab2fb67c7070
Stats:     490 lines in 2 files changed: 481 ins; 5 del; 4 mod

8346120: VirtualThreadPinned event recorded for Object.wait may have wrong duration or may record second event

Reviewed-by: dholmes, pchilanomate

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PR: https://git.openjdk.org/jdk/pull/22718