1692343 - firefox root process uses 10% of a core with all tabs suspended, and firefox being focused away from

Status: RESOLVED WORKSFORME

(Core :: Widget, defect)

Description

[Simonas Kazlauskas [:nagisa/:simukis]]

Attachment: perf recording output (note the usr time column)

I have a situation where I used the browser for a while and noticed my laptop getting slightly warm. Turns out the firefox process is constantly using 10-20% of a CPU core constantly. I see that Web Content and WebExtensions processes are mostly idle.

I unloaded all of the tabs, but the CPU utilization persisted.

I made a perf record run, but alas it could not collect callgraphs of any interesting functions for some reason.

I use sway so conceptually firefox should not be receiving any draw calls and should be very idle.

Comment 1

[Simonas Kazlauskas [:nagisa/:simukis]]

This does not happen anymore after a full browser restart, suggesting that whatever state that has caused this was entered after some extended use of the browser.

However it did continue happening after the browser was restarted via the File > Restart (Developer) menu. In the latter case I believe the parent-most firefox process is not actually replaced, or restarted.

Comment 2

[Stephen A Pohl [:spohl]]

I'm going to tentatively close this for now, but please reopen if this happens again.