Bug 208709

Summary:

Break out of timer loop on display refresh

Product:

WebKit

Reporter:

Antti Koivisto <koivisto>

Component:

Platform

Assignee:

Nobody <webkit-unassigned>

Status:

NEW ---

Severity:

Normal

CC:

ggaren, simon.fraser

Priority:

Version:

WebKit Nightly Build

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
wip	none

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.