1892850 - Bug Report - Scrolling lags on about:preferences in Firefox Snap (lubuntu 24.04 alpha)

Status: NEW

(Core :: Widget: Gtk, defect, P3)

Description

[mozilla.marshy790]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:125.0) Gecko/20100101 Firefox/125.0

Steps to reproduce:

How to reproduce:

1. Start up lubuntu alpha live-iso

2. Open Firefox

3. Install some add-ons (necessary?)

4. Go to settings (about:preferences)

5. Try to scroll quickly down or up with the middle mouse wheel.

Actual results:

What actually happens: Page lags for about a second and then scrolls.

Expected results:

What I expect: page should scroll up and down

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Toolkit::Add-ons Manager' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Alex Cornestean]

Hello,

Would you be able to check if the issue occurs in Troubleshoot Mode as well? To start Firefox in Troubleshoot Mode, refer to https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-troubleshoot-mode.

Thank you !

Comment 3

[mozilla.marshy790]

Tried in troubleshoot mode and the lag is the same.

I am also noticing that the help menu lags while the "about:preferences" tab is active as well. Maybe the lag is causing both symptoms

For instance:

-1. Start in troubleshoot mode
0. Go to about:preferences via settings menu item

• Try scrolling the page -- notice lag

1. Hamburger Menu > Help
2. Hover mouse on About Firefox (or any menu item)
3. Move mouse to any other menu item

What I expect: other menu item should be highlighted under mouse cursor
What actually happens: first menu item stays highlighted for a second or so delay, and then it highlights the currently hovered item.

This menu lag is not present on other pages that I tried, just about:preferences.

Comment 4

[Alex Cornestean]

Hello and thank you for checking in Troubleshoot mode !

Since the issue still occurs in Troubleshoot mode (which disables any installed add-ons) this means that it’s not caused by extensions. Instead, it’s an issue with Firefox.
I’ll change the product and component for the report to a more appropriate one so that my colleagues can take a better look at the issue.
This also means that step 3 from Comment 0 is not necessary since extensions do not cause the issue.

Thank you !

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:mak, could you have a look please?

For more information, please visit BugBot documentation.

Comment 6

[Marco Bonardo [:mak]]

It would be useful if you could record a Performance Profile using the Firefox Profiler instructions on how to do so are in the link. Shortly, you should start recording, reproduce the bug, stop recording... then upload the profile and share a link to that on this bug report.
I would probably suggest picking the Graphics preset for the profiler.
Also please attach a log from about:support to this bug report.

Comment 7

[BugBot [:suhaib / :marco/ :calixte]]

This bug was moved into the Performance component.

:mozilla.marshy790, could you make sure the following information is on this bug?

• For slowness or high CPU usage, capture a profile with http://profiler.firefox.com/, upload it and share the link here.
• For memory usage issues, capture a memory dump from about:memory and attach it to this bug.
• Troubleshooting information: Go to about:support, click "Copy raw data to clipboard", paste it into a file, save it, and attach the file here.

If the requested information is already in the bug, please confirm it is recent.

Thank you.

Comment 8

[mozilla.marshy790]

Hey, thanks for sticking with this bug report; First -- the slowdown is NO LONGER PRESENT in the Oracular Daily Iso. I went ahead and ran the profiler anyway, and the bug --came back-- with the additional load of the profiler in the Oracular Daily

No bug: Profiler on kubuntu 22.04)

https://profiler.firefox.com/from-browser/calltree/?globalTrackOrder=0wa&hiddenGlobalTracks=1wa&hiddenLocalTracksByPid=3515-1w468wg~3978-0&thread=0&v=10

Bug (Slowdown) Exists only when profiler is running:

https://profiler.firefox.com/from-browser/calltree/?globalTrackOrder=f0we&hiddenGlobalTracks=1we&hiddenLocalTracksByPid=2582-23~9108-0~2876-0~9139-0~8854-0w2~7611-0w2&thread=0&v=10

Comment 9

[mozilla.marshy790]

Attachment: oracular-daily-20240527

data from about:support on oracular daily

Comment 10

[Bas Schouten (:bas.schouten)]

(In reply to mozilla.marshy790 from comment #8)

Hey, thanks for sticking with this bug report; First -- the slowdown is NO LONGER PRESENT in the Oracular Daily Iso. I went ahead and ran the profiler anyway, and the bug --came back-- with the additional load of the profiler in the Oracular Daily

No bug: Profiler on kubuntu 22.04)

https://profiler.firefox.com/from-browser/calltree/?globalTrackOrder=0wa&hiddenGlobalTracks=1wa&hiddenLocalTracksByPid=3515-1w468wg~3978-0&thread=0&v=10

Bug (Slowdown) Exists only when profiler is running:

https://profiler.firefox.com/from-browser/calltree/?globalTrackOrder=f0we&hiddenGlobalTracks=1we&hiddenLocalTracksByPid=2582-23~9108-0~2876-0~9139-0~8854-0w2~7611-0w2&thread=0&v=10

Hi! Please upload and share the profile by using the button in the topleft. By default your profile is stored only on your local machine.

Comment 11

[mozilla.marshy790]

Thanks for the tip. Here is is (bug present). Was run with the settings tab as the only open tab. https://share.firefox.dev/3Rn3dKB

Comment 12

[Markus Stange [:mstange]]

The profile shows a lag of 4.0 seconds, spent inside nsGNOMEShellService::IsDefaultBrowser.

Comment 13

[Nazım Can Altınova [:canova][:canaltinova on phabricator]]

The Performance Impact Calculator has determined this bug's performance impact to be low. If you'd like to request re-triage, you can reset the Performance Impact flag to "?" or needinfo the triage sheriff.

Impact on browser: Causes noticeable jank
Configuration: Rare
[x] Affects animation smoothness

Comment 14

[Martin Stránský [:stransky] (ni? me)]

(In reply to Markus Stange [:mstange] from comment #12)

The profile shows a lag of 4.0 seconds, spent inside nsGNOMEShellService::IsDefaultBrowser.

In sandbox environment we need to ask portals/DBus for default browser so it's expected.

Comment 15

[Jan Horak [:jhorak]]

We can't check for default browser under flatpak, so this does not block flatpak.

Code also does not try that: https://searchfox.org/mozilla-central/source/browser/components/shell/nsGNOMEShellService.cpp#179