1515412 - Even simple animations lead to 100% GPU utilization with 4k display

Status: RESOLVED WORKSFORME

(Core :: Graphics: WebRender, defect, P3)

Description

[Clemens Eisserer]

Attachment: inteL-gpu_top_webrender.png

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:66.0) Gecko/20100101 Firefox/66.0

Steps to reproduce:

enabled webrender on my Linux system which is equipped with a 4k screen.
It consists of intel core-i5 6300U (skylake) with HD 520 running Fedora 29 (Mesa 18.2.6),


Actual results:

almost all sites cause extremly high utilization, as soon as there are simple animations (even the loading animation of the tab causes this to happen).




Expected results:

My suspicion is that webrender's design causes a lot of overdraw.
WebRender should only repaint areas where changes happen.
4k screen = 16MB of data per frame  @ 60Hz = 960mb/s bandwidth

and memory bandwidth - especially on mobile devices - translates directly to power consumption.

However this is just the memory bandwidth consumed by webrender itself, desktop compositor (which at leat on linux are capable of compositing only changed area) multiply this at least by a factor of 2x.

Comment 1

[Clemens Eisserer]

updated: the intel_gpu_top screenshot was taken with the animation shown in https://www.w3schools.com/csSref/tryit.asp?filename=trycss3_animation running

Comment 2

[Kartikaya Gupta (email:[e-mail])]

This should still block wr-intel, although it doesn't need to block intel-mvp because the MVP won't include 4k displays.

Comment 3

[Jessie [:jbonisteel] pls NI]

Potentially will be resolved with partial present.

Comment 4

[Glenn Watson [:gw]]

Partial present is enabled now, so this should be much better. Please reopen if still relevant.