1877007 - extremely high CPU usage even with one tab open on the splash screen

Status: RESOLVED INCOMPLETE

(Core :: Performance, defect)

Description

[Hain]

Attachment: memory-report.json.gz

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:122.0) Gecko/20100101 Firefox/122.0

Steps to reproduce:

Opening firefox, doesn't matter if I have 1 tab open with nothing rendering or 3 YouTube videos playing. Firefox opens very sluggishly like it's on a computer with a mechanical hard drive and 4GB of RAM

Actual results:

2 CPU cores go to 100%, Firefox total CPU usage is roughly 50% on a 11800H Mobile CPU

Expected results:

not that

Comment 1

[Hain]

Attachment: about:support

Comment 2

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

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

Comment 3

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

This bug was moved into the Performance component.

:hai_ho090, 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 4

[Hain]

Attachment: about:support

https://profiler.firefox.com/public/n62qpztghppzgb5s0zzj7b5pdsax6vvf1k0h5b8/flame-graph/?globalTrackOrder=0w3&thread=1&v=10

Comment 5

[Mike Conley (:mconley) (:⚙️)]

Hi Hain,

Sorry for the delay getting back to you. What I see in that performance profile actually looks like a browser sitting there doing nothing - just waiting for user input events. Did you capture this performance profile while CPU usage was high? If so, you might need to capture more threads to help us identify which one is doing all of the work.

You can configure the profiler to capture more threads by visiting about:profiling and making sure "Bypass selections above and record all registered threads" is checked. Then start the profiler, and dump the profile after a few seconds of high CPU usage.

Comment 6

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

A needinfo is requested from the reporter, however, the reporter is inactive on Bugzilla. Given that the bug is still UNCONFIRMED, closing the bug as incomplete.

For more information, please visit BugBot documentation.