User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

1. Open https://codepen.io/dropside/full/MYGKyj/ with FF 73, 74, 75.
2. Open any site with a lot of pictures, javascript.

Actual results:

1. Extreme drop in performance, the movement of the mouse cursor occurs with large lags, tab closed within 3-5 seconds after command.
2. Mouse scroll is laggy with comparision in FF 68.7.0 and 72 and earlear.

Expected results:

Ryzen 5 2600, GeForce 1650 Super 4 Gb, nvidia-drivers 440.64 and 440.82. Latest BIOS MOBO Asrock Fatal1ty B450 Gaming K4. No any overclocking.

This behavior checked with Gentoo (firefox-bin) and Xubuntu 20.04 beta, with old and new profiles.

Tested with Xfce-4.14, openbox with and without picom 7.5 and 9999 (glx render, xrender, experimental-backend), xcompmgr. No any special options in xorg.conf.

Tested with kernel 5.4.28 and 4.19.113, mesa 19.3.5 and 20.0.4, xorg-server 1.20.7 and 1.20.8.

gfx.webrender.all=true
layers.acceleration.force-enable=true

I downloaded the old versions and tested them - the problem starts with version 73.

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

KDE, X11, Debian Testing, Macbook Pro, Intel Iris 6100 (Broadwell GT3)
Confirmed performance problem with Basic, OpenGL, WebRender. Performance is worse than Chrome Dev. Stars are smooth with Chrome Dev.
Tabs close immediately. I don't see a regression, it is likewise worse with ESR 68.7.0esr-1.
Basic and OpenGL also suffer from a correctness bug: bug 1623548

The problem is not so much in this specific site as the responsiveness of FF as a whole has decreased, which is especially evident when scrolling on sites with a large number of images, with heavy javascript.

Hm. For me on Intel (Macbook Pro) it has gotten a lot better in the last months.

the movement of the mouse cursor occurs with large lags

https://www.gamingonlinux.com/articles/how-to-an-update-on-fixing-screen-tearing-on-linux-with-an-nvidia-gpu.8892/
"Force Full Composition Pipeline" helped a lot when I tested proprietary Nvidia. Would it improve overall performance for you, too?
It's the number one problem why I wouldn't recommend enabling WebRender by default for proprietary Nvidia, as users would likely blame the OpenGL application and not their driver. (bug 1560457) Nouveau was just fine.

Nouveau do not support my video card (GeForce 1650 Super) .
The same result as with Force Full Composition Pipeline and only with Force Composition Pipeline and without it all in Xfce and openbox.
This behavior started from FF 73. Version before not affected.

Could you try to find a regression range (between last day of Nightly 72 and last day of Nightly 73)?

$ pip install --user --upgrade mozregression
$ mozregression --good 2019-12-02 --bad 2020-01-06 --pref gfx.webrender.all:true -a https://codepen.io/dropside/full/MYGKyj/

You can also directly launch given dates:

$ mozregression --launch 2020-12-02 --pref gfx.webrender.all:true -a https://codepen.io/dropside/full/MYGKyj/

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=05327537443557099272b63ade89fe36f0ad05e1&tochange=3f9482614123972f6fcd8b6a1d99dc8db8cb6c07

Thank you!

Is there a patch applicable to FF 75 so I rebuild Firefox under Gentoo and check?

(In reply to jg.staffel from comment #10)

Is there a patch applicable to FF 75 so I rebuild Firefox under Gentoo and check?

In gfx/wr/webrender/src/device/gl.rs you can find the line let supports_nonzero_pbo_offsets = !is_amd_macos; and change it to let supports_nonzero_pbo_offsets = false; that should revert the behaviour.

It fairly easy to revert the behaviour to what it was before this patch for certain configurations. It's probably worth us investigating whether this affects all nvidia GPUs with the proprietary driver, whether it affects nouevau too, whether it affects nvidia GPUs on other OSes, etc.

(In reply to Jamie Nicol [:jnicol] from comment #12)

It fairly easy to revert the behaviour to what it was before this patch for certain configurations. It's probably worth us investigating whether this affects all nvidia GPUs with the proprietary driver, whether it affects nouevau too, whether it affects nvidia GPUs on other OSes, etc.

Can I help you?

Yes! Could you capture a profile of the slowness? Go to profiler.firefox.com, enable the profiler. Then in the settings make sure the "Renderer" thread is enabled. Thanks!

(In reply to Jamie Nicol [:jnicol] from comment #14)

Yes! Could you capture a profile of the slowness? Go to profiler.firefox.com, enable the profiler. Then in the settings make sure the "Renderer" thread is enabled. Thanks!

Please check - is everything done correctly?
https://perfht.ml/3eDP06U

Recompiled Firefox 75 with let supports_nonzero_pbo_offsets = false; works without regression.

(In reply to jg.staffel from comment #15)

Please check - is everything done correctly?
https://perfht.ml/3eDP06U

Yes, that's perfect thanks!