Bug 208709 - Break out of timer loop on display refresh
Summary: Break out of timer loop on display refresh
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Platform (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-03-06 05:52 PST by Antti Koivisto
Modified: 2020-03-06 07:58 PST (History)
2 users (show)

See Also:

Attachments
wip (13.02 KB, patch)
2020-03-06 05:54 PST, Antti Koivisto 		no flags Details | Formatted Diff | Diff
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Antti Koivisto 2020-03-06 05:52:13 PST 
We currently process timers for 50ms in a loop. We should break out immediately when there is a display refresh to allow rendering update.
Comment 1 Antti Koivisto 2020-03-06 05:54:39 PST 
Created attachment 392711 [details]
wip
Comment 2 Simon Fraser (smfr) 2020-03-06 07:58:44 PST 
Comment on attachment 392711 [details]
wip

View in context: https://bugs.webkit.org/attachment.cgi?id=392711&action=review

> Source/WebCore/platform/ThreadTimers.cpp:129
> +        if (DisplayRefreshMonitorManager::sharedManager().hasPendingRefresh() && !m_didBreakForPendingDisplayRefreshWithoutFiringTimers) {

It's a bit gross for timers to know about DisplayRefreshMonitorManager, and we need something that works on iOS too.

> Source/WebCore/platform/graphics/DisplayRefreshMonitor.h:86
> +    WEBCORE_EXPORT void setIsPreviousFrameDone(bool);

I presume this is WEBCORE_EXPORT just to satisfy the linker, not because anyone else calls it (because it doesn't lock).

> Source/WebKit/WebProcess/WebPage/EventDispatcher.cpp:250
> +    DisplayRefreshMonitorManager::sharedManager().displayWasUpdated(displayID);

Which thread are we on here?

DisplayRefreshMonitorManager::displayWasUpdated() doesn't look thread safe.