1690673 - We can get into a state where the compositor keeps compositing even though there's nothing to do

Status: NEW

(Core :: Graphics, defect)

Description

[Markus Stange [:mstange]]

This bug was encountered in bug 1689215 and in bug 1690619 and in bug 1646976:

Sometimes, we seem to get stuck in a state where the compositor keeps running compositing at 60Hz even though there is nothing to do.
I don't have steps to reproduce for this.

See also bug 1690619 which is about making it easier to find out why this is happening once we have entered that state.

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+1]]

I just got a base CPU usage of around 20% again. Here a captured profile: https://share.firefox.dev/2NCh1TC

There are a lot of Runnables referencing VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::ParentProcessVsyncNotifier(unlabeled).

Is that related here to the 60Hz refresh rate?

Comment 2

[Markus Stange [:mstange]]

(In reply to Henrik Skupin (:whimboo) [⌚️UTC+1] from comment #1)

Here a captured profile: https://share.firefox.dev/2NCh1TC

This profile doesn't show any composites, it only shows parent process main thread refresh ticks. So it's a different issue. I've filed bug 1693176 about it.