Artem S. Tashkinov Reporter
	Description • 8 years ago

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0
Build ID: 20160905130425

Steps to reproduce:

All recent GTK3 based official Firefox'es are painfully slow to scroll any pages, while consuming 100% of CPU.

Steps to reproduce:

* Have a PC with a NVIDIA GPU
* Install Fedora 24 64 + all updates.
* Install binary NVIDIA drivers 370.28
* Download and unpack https://ftp.mozilla.org/pub/firefox/releases/49.0.1/linux-x86_64-EME-free/en-US/firefox-49.0.1.tar.bz2
* Visit slashdot.org and try to scroll using your mouse while holding the scroll bar

I have zero add ons installed.
GTK2 based Firefox 45.4ESR is blazing fast.


Actual results:

100% CPU usage, very jerky movement, heavy tearing


Expected results:

Smooth scrolling

	Artem S. Tashkinov Reporter
	Comment 1 • 8 years ago

firefox-49.0-2.fc24.x86_64.rpm from Fedora exhibits the same problem.

I cannot test nouveau on this PC because my GPU (Pascal based) is not supported by the open source driver.

	Artem S. Tashkinov Reporter
	Comment 2 • 8 years ago

My only GTK3 setting is:

$ cat /home/birdie/.config/gtk-3.0/settings.ini
[Settings]
gtk-primary-button-warps-slider=false

The only additional theme package installed is adwaita-gtk2-theme-3.20.2-1.fc24.x86_64.rpm, i.e. I'm running the default GTK3 theme.

I'm running XFCE. This problem is reproducible *with* and *without* compositing enabled.

	Artem S. Tashkinov Reporter
	Comment 3 • 8 years ago

This issue is reproducible under the plain X.org server (i.e. with no WM running).

`top` for Firefox 49:

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND    
10849 root      20   0  208532  65280  49700 R  77.5  0.4   1:10.09 Xorg       
11035 birdie    20   0  905080 249196 126828 S  19.2  1.5   0:31.77 Web Content
10949 birdie    20   0 1392976 447536 166708 S  17.9  2.7   0:36.88 firefox    

`top` for Firefox 45.4ESR:

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND    
11488 birdie    20   0 1188956 349984  81472 S  25.3  2.1   0:18.60 firefox    
10849 root      20   0  193812  50808  33608 S   8.0  0.3   1:21.62 Xorg

both taken while scrolling this bug report webpage.

	Artem S. Tashkinov Reporter
	Comment 4 • 8 years ago

Is there a build of Firefox 49 for GTK2? I'd love to use it. Meanwhile I'm reverting back to the ESR tree because I cannot tolerate such a horrible performance.

	Jan Alexander Steffens [:heftig]
	Comment 5 • 8 years ago

Does it resolve if you enable "gfx.xrender.enabled" ?

	Artem S. Tashkinov Reporter
	Comment 6 • 8 years ago

(In reply to Jan Steffens from comment #5)
> Does it resolve if you enable "gfx.xrender.enabled" ?

It helps a lot, thank you!

It doesn't completely resolve the bug because even though scrolling becomes almost as smooth as with GTK2, overall CPU usage is still at least twice as large:

`top` for Firefox 49 + gfx.xrender.enabled = true:

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
10849 root      20   0  198172  51988  33340 S  34.0  0.3   1:53.36 Xorg       
11888 birdie    20   0  850868 230184 100532 S  28.0  1.4   0:11.81 Web Content
11815 birdie    20   0 1217516 364332 109548 S  21.0  2.2   0:16.33 firefox

	Artem S. Tashkinov Reporter
	Comment 7 • 8 years ago

With gfx.xrender.enabled = true, the performance of https://testdrive-archive.azurewebsites.net/Performance/PsychedelicBrowsing/Default.html falls 100fold (from 1500fps to 15fps).

Is there a middle ground so that scrolling was smooth and HTML rendering was properly accelerated?

	Artem S. Tashkinov Reporter
	Comment 8 • 8 years ago

This setting is apparently useless for https://www.linux.org.ru/tag/nvidia - on this page scrolling is horribly slow (in Firefox 49).

Damn. Let's go back to Firefox 45.4.

	Artem S. Tashkinov Reporter
	Comment 9 • 8 years ago

Firefox 45.4 + default settings:

 Scrolling:

 https://slashdot.org - fast, OK
 https://www.linux.org.ru/tag/nvidia - fast, OK
 https://bugzilla.mozilla.org/show_bug.cgi?id=1305367 - fast, OK

 Demos:

 https://testdrive-archive.azurewebsites.net/Performance/PsychedelicBrowsing/Default.html - 1890fps


Firefox 49:

 Scrolling is universally slow or very slow on https://www.linux.org.ru/tag/nvidia + gfx.xrender.enabled
 PsychedelicBrowsing is fast (1500fps) but terribly slow (15fps) with gfx.xrender.enabled


What's the exact purpose of the GTK3 build of Firefox? To drive people from Linux? It's a pain to use, it's broken in great many ways. I do understand it's the "future" but you should have enabled it only for alpha builds - not on production builds. When Firefox 45 ESR stops being supported and GTK3 build is still broken, I will either start compiling my own GTK2 builds or migrate to Chrome.

	Stebs
	Comment 10 • 8 years ago

FYI, Firefox 49.0.1 runs great here with all your examples on ARCH/Manjaro with Nvidia 370.28, latest Nightly is even faster (OpenGL composition on by default). Maybe the performance-regression is Fedora-specific?

	Artem S. Tashkinov Reporter
	Comment 11 • 8 years ago

(In reply to Stebs from comment #10)

If only I knew how to test your hypothesis. What I see is that Firefox 45.4 has zero performance related problems while Firefox 49 is barely usable.

	Loic
	Comment 12 • 8 years ago

AFAIK, FF45 doesn't have the support about Gtk3, it starts only since FF46.

	Artem S. Tashkinov Reporter
	Comment 13 • 8 years ago

Yep.

Anyways Fedora is quite a popular Linux distro, I'd even venture to say it's a major one, so this bug deserves at least a modicum of attention.

	Nicolas Silva [:nical]
	Comment 14 • 8 years ago

Could you capture a profile of the CPU usage while the performance issue is happening using gecko's builtin profiler?

There are instructions here: https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Profiling_with_the_Built-in_Profiler

It will point us to the parts of firefox that are consuming a lot of CPU resources.

	Artem S. Tashkinov Reporter
	Comment 15 • 8 years ago

(In reply to Nicolas Silva [:nical] from comment #14)

For some reasons the original bug report has autoresolved/disappeared (I've upgraded to Firefox 49.0.1: Mozilla/5.0 (X11; Linux x86_64; rv:49.0) Gecko/20100101 Firefox/49.0). Now I've got a slow down only while scrolling https://www.linux.org.ru/tag/nvidia

Here's profiling information.

	Artem S. Tashkinov Reporter
	Comment 16 • 8 years ago

Cannot reproduce with:

Firefox 50.0.2 x86-64
Fedora 25 x86-64
Kernel 4.8.10
NVIDIA drivers 375.10
Default Firefox Settings
More or less default NVIDIA settings:

Section "Device"
        Identifier      "Videocard0"
        BusID           "PCI:1:0:0"
        Driver          "nvidia"
        VendorName      "NVIDIA"
        BoardName       "NVIDIA Corporation GP106 [GeForce GTX 1060 6GB] (rev a1)"
        Option          "Coolbits" "28"
        Option          "RegistryDwords" "PowerMizerEnable=0x1; PerfLevelSrc=0x2222; PowerMizerLevel=0x3; PowerMizerDefault=0x3; PowerMizerDefaultAC=0x3"
        Option          "TripleBuffer" "On"
EndSection


Psychedelic Browsing ~ 1427 Revolutions per Minute.

Marking fixed then.