1690621 - All content processes are notified of PCompositorBridge::Msg_DidComposite

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Florian Quèze [:florian]]

See this example profile: https://deploy-preview-3098--perf-html.netlify.app/public/rt3mdpvzcyxd6e21x3d1k0xk60zc5rwejz05swg/marker-chart/?globalTrackOrder=0-1-2-3-4-5-6-7-8-9-10-11-12&localTrackOrderByPid=23223-7-8-0-1-2-3-4-5-6~23224-0~23249-0~23230-0~23234-0~23232-0~23229-1-0~23227-1-0~23233-1-0~23231-1-0~23240-1-0~23235-1-0~23228-1-2-0~&thread=1&v=5

Compositing happens at 60Hz (I don't know why; I filed bug 1690619 to see if we could collect more information about it), and all content processes receive PCompositorBridge::Msg_DidComposite messages (see the Runnable markers).
This alone uses a bit more than 1% of a core per content process.

Comment 1

[Markus Stange [:mstange]]

This is a regression in WebRender compared to non-WebRender.

Same open tabs, WR: https://share.firefox.dev/3twpSGX Non-WR: https://share.firefox.dev/3oLztGf
Non-WebRender only notified visible tabs.

Comment 2

[Markus Stange [:mstange]]

Testcase: attachment 9089778 [details]

Comment 3

[Sotaro Ikeda [:sotaro]]

The problem seems to happen because DidComposite is notified to all clients that was notified by RendererOGL::FlushPipelineInfo().

• https://searchfox.org/mozilla-central/rev/d504494eab038fd1bbc82eb4191bb334b4de2c8d/gfx/webrender_bindings/RenderThread.cpp#431

It seems that CompositorBridgeParent::NotifyPipelineRendered() need to send DidComposite to client only when it is necessary.

Comment 4

[Sotaro Ikeda [:sotaro]]

Attachment: Bug 1690621 - Send DidComposite only when it is necessary

Comment 5

[Sotaro Ikeda [:sotaro]]

https://treeherder.mozilla.org/jobs?repo=try&revision=868fe2f6e31d7412ed40a4549843ba3f5f81009b

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f7e7db4cdf7d
Send DidComposite only when it is necessary r=nical

Comment 7

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/f7e7db4cdf7d

Comment 8

[Alexandru Ionescu (needinfo me) [:alexandrui]]

== Change summary for alert #28900 (as of Wed, 24 Feb 2021 06:53:45 GMT) ==

Improvements:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
6%	tart		linux1804-64-shippable-qr	e10s stylo webrender-sw	3.91 -> 3.67
4%	tp5o_scroll		linux1804-64-shippable-qr	e10s stylo webrender-sw	2.14 -> 2.06

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=28900