1667165 - Slow scrolling with two or more windows open

Status: NEW

(Core :: Graphics: WebRender, defect)

Description

[lucaswilm]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:81.0) Gecko/20100101 Firefox/81.0

Steps to reproduce:

I opened a window and went to https://news.google.com (for example). So I opened another window on any random website.

Actual results:

Firefox scrolling was slow in both open windows. However, with only one window open, scrolling is normal. Or when one window is minimized and the other is open, scrolling is also normal.

Expected results:

Scrolling should be fluid regardless of the number of windows open.

Comment 1

[Botond Ballo [:botond]]

Thanks for the report. Could you please provide the following information:

1. How many monitors you have, and their resolutions (and if any of them are HiDPI).
2. The contents of about:support.
3. If possible, a performance profile during a slow scroll (just a few seconds) taken using profiler.firefox.com?

Thanks!

Comment 2

[lucaswilm]

Attachment: about:support contents

(In reply to Botond Ballo [:botond] from comment #1)
> Thanks for the report. Could you please provide the following information:
> 
>   1. How many monitors you have, and their resolutions (and if any of them are HiDPI).
>   2. The contents of `about:support`.
>   3. If possible, a performance profile during a slow scroll (just a few seconds) taken using [profiler.firefox.com](https://profiler.firefox.com/)?
> 
> Thanks!

Thanks for the answer! I will try to give all of this information correctly.

1. I have only 1 monitor, model Flatron E2260 with resolution 1920x1080 and 60,0 Hz.
2.

Comment 3

[lucaswilm]

(In reply to Botond Ballo [:botond] from comment #1)

Thanks for the report. Could you please provide the following information:

1. How many monitors you have, and their resolutions (and if any of them are HiDPI).
2. The contents of about:support.
3. If possible, a performance profile during a slow scroll (just a few seconds) taken using profiler.firefox.com?

Thanks!

Thanks for the answer! I will try to give all of this information correctly.

1. I have only 1 monitor, model Flatron E2260 with resolution 1920x1080 and 60,0 Hz.
2. Guess I attached it somewhere?
3. https://share.firefox.dev/3kPlq0u (first I opened a website in a window and scrolled the page. Then I opened another window on another website and scrolled the page in both)

Comment 4

[lucaswilm]

I'm sorry for the inconvenience, I think I sent two responses. The first incomplete, with the about: support attached and the other with the continuation. I fumbled.

Comment 5

[Botond Ballo [:botond]]

Thanks! Could I ask you to try something, and let me know if it improves the performance?

1. Go to about:config. Click past the warning if necessary.
2. Type gfx.webrender.force-disabled into the search box.
3. Toggle the pref to "true".
4. Restart Firefox.

Comment 6

[lucaswilm]

(In reply to Botond Ballo [:botond] from comment #5)

Thanks! Could I ask you to try something, and let me know if it improves the performance?

1. Go to about:config. Click past the warning if necessary.
2. Type gfx.webrender.force-disabled into the search box.
3. Toggle the pref to "true".
4. Restart Firefox.

It does not improve performance. If I disable WebRender, scrolling is bad in any scenario, even with a single window open.

Comment 7

[Botond Ballo [:botond]]

Thanks! One more question: if you open about:support with WebRender disabled, and look for "Compositing" ("Composição"), does it say "OpenGL" or "Basic"?

Comment 8

[lucaswilm]

It say "Basic" when WebRender is disabled.

Comment 9

[lucaswilm]

Something curious:

My operating system is Linux and the distribution is Xubuntu. That is, I am using the Xfce desktop environment and it has virtual desktops, usually I use 4, as it comes in the standard.

If I move the second window to another virtual desktop, scrolling is nice and smooth across all windows while they are in different virtual desktops.

Comment 10

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

Jeff, are there any known issues with multiple WR windows being visible on Linux+NVidia? It sounds like if both windows are visible scrolling is bad, but if one window is minimized or moved to a different virtual desktop then things are good again. This feels more like a WR bug than an APZ bug.

Comment 11

[Jeff Muizelaar [:jrmuizel]]

I've not heard of anything, but Andrew and Nical have been watching Linux closer than me.

Comment 12

[Nicolas Silva [:nical]]

We know that alternativng between multiple GL context presenting is very slow with nvidia proprietary drivers on Linux, we don't know why. I can easily reproduce the issue, for example by having a video play with picture-in-picture and scrolling a page at the same time.