1789153 - Reported high CPU use on reddit "Shop Avatars" widget

Status: NEW

(Core :: Graphics: WebRender, defect, P3)

Description

[Asif Youssuff]

Attachment: jsbin.qinoxidila.2.html

From: https://www.reddit.com/r/firefox/comments/wzvufu/new_reddits_sparkling_shop_avatars_navbar_toolbar/

As I had a single Reddit tab open this morning and I noticed 30% idle CPU usage across 4 logical processors on my laptop's Intel Core i5, I had an idea: I right-clicked the silly sparkly "Shop Avatars" button in the website's navbar at the top, chose "Block element..." to block it using uBlock Origin and boom! CPU usage dropped to between 0 and 1%*, and my temperatures dropped by about 10 degrees Celsius on my laptop running Firefox 104 on Fedora Linux with Intel Sandybridge graphics on Xorg/X11.

I'm not sure I can reproduce the issue on Firefox Nightly, but I extracted the widget into a testcase (attached) for further analysis.

Comment 1

[BugBot [:suhaib / :marco]]

The Bugbug bot thinks this bug should belong to the 'Core::Graphics: WebRender' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Tim Connors]

Reading the original reddit thread, which is now archived and can't be commented on, this, Linux+X11+backgrounded tabs sounds awfully like bug #1693513 which is affecting my bug #1820096 too.

Comment 3

[Wayne Mery (:wsmwk)]

(In reply to Tim Connors from comment #2)

Reading the original reddit thread, which is now archived and can't be commented on, this, Linux+X11+backgrounded tabs sounds awfully like bug #1693513 which is affecting my bug #1820096 too.

Fixed in v123 Bug 1693513 - X11-only: CPU usage does not decline if window is open but hidden behind others.

Tim can you reproduce this with comment 0 steps?