1415735 - CPU usage 100% for ~60s when visiting a site for the first time

Status: RESOLVED DUPLICATE of bug 1415387

(Core :: General, defect)

Description

[Fred Uggla]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:58.0) Gecko/20100101 Firefox/58.0
Build ID: 20171108110838

Steps to reproduce:

1. Created new profile
2. Installed performance profiler
3. Restarted Firefox
4. Visited page _not_ visited before (in this case twitter.com)
5. Waited for 100% CPU usage to drop down to normal levels (~60s later)
6. Visited page _not_ visited before (in this case reddit.com)



Actual results:

The CPU usage of the Firefox process stayed at 100% for about 60s after twitter.com loaded. It then dropped down to about 1 to 5%. I then visited reddit.com and the same thing happened again. That kind of CPU usage is not normal on my machine.

Profile: https://perfht.ml/2AmKdSH
~10s, opened twitter. CPU 100%
~60s, CPU returns to normal
~70s, opened reddit. CPU 100%



Expected results:

When a page is loading/rendering there's a spike in CPU usage. It then quickly drops down to normal. Currently with about 10 tabs open it's pedning between 5 to 15%. I don't have a supercomputer or anything, but 100% CPU for a single page for one min is beyond normal.

Comment 1

[Ekanan Ketunuti]

possible dupe of bug 1415387.