1875496 - High cpu and thread usage

Status: UNCONFIRMED

(Core :: Audio/Video: Playback, defect)

Description

[github.dev]

Attachment: closed.png

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:121.0) Gecko/20100101 Firefox/121.0

Steps to reproduce:

I'm not sure the best way to report this but will happy provide any information that helps diagnose the issue. I stopped using Firefox earlier this year for the same reason, forgot why and recently switched back to find the same issue so figured I would report.

I typically have a browser window open to display security camera feeds while I am working. I switched back to Firefox from Brave browser about two weeks ago and today my system became very sluggish due to excessive CPU usage.

1. Open tab to a Unifi Protect "live view" webpage.
2. Occasionally clicking on the webpage requires re-authentication (not sure why, this also wasn't happening in brave)
3. Eventually, cpu usage increases drastically

Actual results:

CPU and thread usage becomes very high and causes system to slow down.
See the attached screenshot from btop. The sudden drop in CPU usage occurred when I closed the browser window that was connected to the video feed.
Prior to closing the window, Pid 13180 "RDD Process /usr/lib/firefox/firefox -contentproc -parentBuildID ..." was reporting lazy cpu usage at 54.3%.
After closing the window, as you can see in the screenshot, that Pid dropped to 0.0%.

However, Pid 11348 firefox /usr/lib/firefox/firefox" is still using 341 threads. This could be a separate issue.
There are only 7 windows open and 30 tabs... most of which are hibernated.

Expected results:

CPU usage should not have become excessive and thread count should be much lower. This does not happen when the websites are open using other browser, and their thread count is significantly lower.

Comment 1

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

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

Comment 2

[Mayank Bansal]

Can you

1. go to about:support in your Firefox brwser and copy its contents here
2. Capture a Firefox profile with the "media" preset using the instructions here : https://profiler.firefox.com/docs/#/

Comment 3

[github.dev]

(In reply to Mayank Bansal from comment #2)

Can you

1. go to about:support in your Firefox brwser and copy its contents here

121.0.1 (64-bit)
Mozilla Firefox for Manjaro Linux
Manjaro - 1.0

2. Capture a Firefox profile with the "media" preset using the instructions here : https://profiler.firefox.com/docs/#/

https://share.firefox.dev/429n57Z

Some context for the captured range. I had been running the profile and waiting for the issue to occur. This morning firefox was unresponsive and I had to kill the process tree. After restarting the browser, I started recording before logging into some sites. One of the first I opened was the video feed. Almost immediately, my cpu usage across all cores increased to near 100% (as reported by btop). I waited for several seconds before closing the site and capturing the profile. I was unable to include additional data using the checkboxes because the profiler reported that the file was too large.

Comment 4

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

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

For more information, please visit BugBot documentation.

Comment 5

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

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

For more information, please visit BugBot documentation.

Comment 6

[Jim Mathies [:jimm]]

https://share.firefox.dev/429n57Z

Not much activity going on here. There's a blip in the middle from some web extension activity but other than that Fx doesn't appear to be consuming a lot of cpu time.