1417968 - Firefox has a high idle CPU load (~4-10%) which severely shortens battery life

Status: RESOLVED DUPLICATE of bug 1396481

(Core :: General, defect)

Description

[u524404]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0
Build ID: 20171112125346

Steps to reproduce:

Run Firefox. See bug 1396481. Issue has been reported again for newer Firefox version.

The CPU usage is high enough 8-9hrs of on time (sleep time included) is reduced to 2hrs. This makes my device unusable. I am forced to close Firefox when AC power is not available.


Actual results:

Firefox has a high idle CPU usage.

In previous reports the high idle CPU usage was blamed on my extensions, but disabling them had no effect and now they have been forcefully disabled.


Expected results:

Ideally, idle CPU usage should be zero, as no processing should occur when a user is not interacting with the program.

Comment 1

[Ben Kelly [:bkelly, not reviewing]]

If you could install the addon here and collect a profile it would be helpful:

https://perf-html.io/

More info on how to use the profiler here:

https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Profiling_with_the_Built-in_Profiler

Also, what pages do you have open?  Does the CPU usage change if you close particular ones or keep a simple html page like example.com in the foreground?