1538469 - When using nVidia GPU, firefox scroll lags

Status: UNCONFIRMED

(Core :: Graphics, defect, P3)

Description

[Lyubomir [:mystiquewolf]]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:67.0) Gecko/20100101 Firefox/67.0

Steps to reproduce:

1. Use nVidia GPU (nVidia GeForce MX150) with Firefox 67.0b4
2. Open some pages
3. Scroll down a bit, stop, scroll down again a bit.

Actual results:

The page doesn't start scrolling smoothly, it jumps a little bit down and only then starts scrolling smoothly. Not happening with integrated Intel UHD 620 GPU.

Expected results:

This bug is happening since many months. I used to use Intel GPU for Firefox as it still doesn't lag videos on it but also scrolling is smoother. Only reason i selected Nvidia for Firefox is i want to test WebRender.

However, no matter if WebRender is enabled or not, since many months this bug exists. Guys and ladies, please take some action now. How can i help with info for fixing this? Tests, data, etc. Let's fix it. I always update GPU drivers with latest via GeForce experience app.

Comment 1

[Lyubomir [:mystiquewolf]]

Some screencasts:
https://www.youtube.com/watch?v=5rz79F30aLU&feature=youtu.be
https://www.youtube.com/watch?v=WLEd3GmJleY&feature=youtu.be

Although i also update Windows (or better said it updates whenever it likes :)), it reproduces on latest Windows 10 v1809 build 17763.379 and in all of the last 10 months or so. Maybe since i got the PC and tried the first time with Nvidia. Who knows from when does this appear!?!?!

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Can you confirm that the same problem happens with WebRender disabled?

Comment 3

[Lyubomir [:mystiquewolf]]

Yes, i can confirm. It appears on stable and i don't know since when. I think 4-5 months ago it was the same.

Comment 4

[Lyubomir [:mystiquewolf]]

I believe it happens when i leave the site for about 5-10 seconds without scrolling, then the next scroll has this initial lag.

Comment 5

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

(In reply to Lyubomir Parvanov from comment #4)

I believe it happens when i leave the site for about 5-10 seconds without scrolling, then the next scroll has this initial lag.

If you go to about:config and change apz.displayport_expiry_ms upwards (say to 60000 from the default of 15000) does that help? I suspect with that change you will need to leave the site for a whole minute without scrolling before the next scroll has the lag. Can you confirm that?

Comment 6

[Lyubomir [:mystiquewolf]]

I changed it, then restarted the browser, but saw no change. It was still taking about the same time for the lags to appear. Also why does it appear only when nVidia is the GPU for Firefox?

It seems like it never appears when i switch from another tab, the one that was switched to scrolls okay. If i scroll and leave it for a little time it appears.

Comment 7

[Lyubomir [:mystiquewolf]]

Attachment: Nvidia settings

Nvidia settings for Firefox. I'm using balanced profile and it cascades from global settings.

Comment 8

[Lyubomir [:mystiquewolf]]

Attachment: nvidia2.png

Comment 9

[Lyubomir [:mystiquewolf]]

Attachment: nvidia3.png

Comment 10

[Lyubomir [:mystiquewolf]]

Scroll issues also happen when reading PDFs.

Comment 11

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

Ok, thanks. In that case getting a Gecko profile (see instructions) might help. Probably best to do it with WebRender disabled since then the default thread selection should have all the relevant information. If you enable WebRender you'll want to also enable the "Renderer" and "RenderBackend" threads in the profiler add-on settings before starting the profiler.

Comment 12

[Lyubomir [:mystiquewolf]]

Here are captures. I pressed Ctrl+Shift+2 as soon as i could after the issue appeared.

http://bit.ly/2HUVn7T
http://bit.ly/2HWU20r

Comment 13

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

The jank is likely caused by the hundreds of milliseconds spent in DXGI AcquireSync.

Comment 14

[Jeff Muizelaar [:jrmuizel]]

Can you try disabling Direct2D by setting gfx.direct2d.disabled to true?

Comment 15

[Lyubomir [:mystiquewolf]]

Disabled it, but the issue still occurs. :-/

Comment 16

[Lyubomir [:mystiquewolf]]

I guess this has something to do with #1383563, as it's the exact same symptoms.