Open Bug 878804 Opened 11 years ago Updated 2 years ago

Firefox spins with 100% of CPU in mach_message_trap

Categories

(Core :: General, defect)

defect

Tracking

()

People

(Reporter: justin.lebar+bug, Unassigned)

Details

(Keywords: perf)

http://people.mozilla.com/~bgirard/cleopatra/#report=5e274cf239170180d9f19367c2ef2443b3438d2a

I don't understand what's going on in this profile, but Firefox is sitting using 100% of one CPU with all but two bugzilla tabs closed.  That seems pretty bad!

Nightly built from http://hg.mozilla.org/mozilla-central/rev/b94e996b05fd
Mac OS 10.8.
You don't have js profiling enable (you should) but I'm going to guess that it's Firefox Sync (or maybe FHR but I think it got fixed) that's spinning the event loop. It looks like your main thread is mostly idle waiting on events with a nested event loop. Your CPU usage is likely coming from another thread. I suggest using Instruments.
I've restarted my browser (sorry), but the "js profiling" checkbox is checked.  Is there anything else I need to do to get that working?

If it happens again I'll use instruments.
> Firefox is sitting using 100% of one CPU

How did you measure this?
(In reply to Steven Michaud from comment #3)
> > Firefox is sitting using 100% of one CPU
> 
> How did you measure this?

Activity monitor.
Keywords: perf
Severity: normal → S3
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