1252342 - When starting nightly, high CPU usage while displaying the restore session page about:sessionrestore

Status: RESOLVED WORKSFORME

(Core :: General, defect)

Description

[Jean-Yves Avenard [:jya]]

Starting Nightly (debug build) takes a while to start.
After about 10s or so, it will display the page to restore the previous session.

CPU usage during this time oscillate between 120 to 160%, all this while nothing appears to happen and it is just displaying the restore session page.

After about 3.5 minutes CPU usage will got back down to a more reasonable 12%.

Attached is the profiler run for the first 127s.
It shows:
Running Time	Self (ms)		Symbol Name
102355.0ms   83.5%	0.0	 	nsThread::ProcessNextEvent  0x52cb69

the biggest blob in there is:
Running Time	Self (ms)		Symbol Name
5462.0ms    4.4%	0.0	 	                          InterSliceGCTimerFired(nsITimer*, void*)

next is:
Running Time	Self (ms)		Symbol Name
3255.0ms    2.6%	0.0	 	                            nsCycleCollector_collectSlice(js::SliceBudget&, bool)

it is difficult to comprehend what takes so much CPU just to display the page "Well, this is embarrassing." 

This is on a MBP 13" early 2015. i7 3.1GHz dual-core.

Comment 1

[Jean-Yves Avenard [:jya]]

attachment of the profile session failed (it's 17MB zipped)

Comment 2

[Wayne Mery (:wsmwk)]

jya, do you still see this problem?
Can you make a smaller profile?

Comment 3

[Jean-Yves Avenard [:jya]]

I haven't seen this problem in a while.

Sorry for the lack of answer in the mean time