1666177 - Slow page scroll on forum.xda-developers.com

Status: RESOLVED WORKSFORME

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

Description

[Asif Youssuff]

Basic information

Steps to Reproduce:

1. Navigate to https://forum.xda-developers.com/hp-touchpad/development
2. Use touchpad to scroll up and down

Expected Results:

Smooth scrolling.

Actual Results:

Very slow scrolling, a lot of jank.

---

More information

This is worse on WebRender than Basic compositing.

Profile URL: https://share.firefox.dev/3cidsdi

Basic systems configuration:

OS version: Fedora Rawhide

GPU model: Intel(R) UHD Graphics 600

Number of cores: 2

Amount of memory (RAM): 8GB

Thanks so much for your help.

Comment 1

[Asif Youssuff]

Attachment: about:support

Comment 2

[Jamie Nicol [:jnicol]]

There appear to be some very long glFlushes, and some very log glTexStorage3Ds.

Asif, could you try enabling gfx.webrender.debug.texture-cache and see if it shows anything useful. Perhaps the number of textures repeatedly growing/shrinking.

Also, separately from the texture cache, try enabling gfx.webrender.debug.gpu-time-queries and gfx.webrender.debug.profiler, and see where the GPU is spending a lot of time (which presumably is causing the long flushes).

Comment 3

[Asif Youssuff]

Attachment: gfx.webrender.debug.texture-cache.png

Jamie, I am not sure what I was looking for after enabling gfx.webrender.debug.texture-cache - the "bar" seemed to slowly be getting longer, but that is about all I really noticed. I took a screenshot so you can see what I saw.

I enabled gfx.webrender.debug.gpu-time-queries and gfx.webrender.debug.profiler and I am attaching screenshots of what I saw after some scrolling (timed screenshot).

Hope this helps!

Comment 4

[Asif Youssuff]

Attachment: Screenshot from 2020-09-23 00-41-33.png

Comment 5

[Asif Youssuff]

Attachment: Screenshot from 2020-09-23 00-42-16.png

Comment 6

[Jamie Nicol [:jnicol]]

Thanks Asif, I'm not realy sure what I was expecting the texture-cache debug view to show. Maybe it would increase in size at the same time as a stutter in the scrolling? Or it would suddenly get a lot less blue, as more texture cache items were allocated at once, but it's too small to really be useful for that.

Unfortunately the bit of the profiler I'm interested in isn't visible, could you additionally set gfx.webrender.debug.small-screen true and try again?

Comment 7

[Asif Youssuff]

Attachment: Screenshot from 2020-09-23 14-32-22.png

(In reply to Jamie Nicol [:jnicol] from comment #6)

Unfortunately the bit of the profiler I'm interested in isn't visible, could you additionally set gfx.webrender.debug.small-screen true and try again?

I went ahead and added a new screenshot with gfx.webrender.debug.small-screen true. Hope this helps!

Comment 8

[Robert Mader [:rmader]]

Asif, did this get better? It looks smooth here now.

Comment 9

[Asif Youssuff]

This page changed significantly since the initial report, so this issue doesn't exist anymore.