1435365 - Scrolling gmail's label list is slower / more cpu intensive with WebRender

Status: RESOLVED WORKSFORME

(Core :: Graphics: WebRender, defect, P2)

Description

[Clemens Eisserer]

Attachment: top_webrender.png

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0
Build ID: 20180202102708

Steps to reproduce:

1. Logged in to gmail (account has  ~100-200 labels)
2. scrolled through gmail's label list quickly



Actual results:

noticed scrolling is a little bit more laggy with webrender enabled.

Further investiation showed, that WebRender causes higher load. Without WebRender (normal opengl compositor) I see one WebContent Process consume 20-30% and firefox-bin 20-30% cpu. With WebRender enabled, firefox-bin consumes >100%, while the WebContent Process is at about 12-20%.

Comment 1

[Clemens Eisserer]

Attachment: top_opengl.png

Comment 2

[Clemens Eisserer]

Please find a system-wide sysprof profile at: http://93.83.133.214/profile_webrender.syscap

A lot of time seems to be spent in webrender code itself, not the opengl drivers

Comment 3

[Clemens Eisserer]

This seems to be not limited to gmail - scrolling in general seems to perform worse with WebRender enabled compared to the old OpenGL compositor (higher CPU useage, less FPS)

Comment 4

[Jeff Muizelaar [:jrmuizel]]

Is it possible for you to get a profile of this using the Gecko profiler?

Comment 5

[Clemens Eisserer]

strange - while scrolling the main firefox process is almost at 100%, yet the profile looks rather idle: https://perfht.ml/2F2amvW

Comment 6

[Jeff Muizelaar [:jrmuizel]]

You should add these threads to the "Threads:" list of the profiler "RenderBackend,Renderer,WebRender"

Comment 7

[Jeff Muizelaar [:jrmuizel]]

A lot has improved in WebRender since this was reported. Can you still reproduce this?