CPU hogging in version 3.0.5




9 years ago
9 years ago


(Reporter: Michael Jennings, Unassigned)


3.0 Branch
Windows XP

Firefox Tracking Flags

(Not tracked)




9 years ago
User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv: Gecko/2008120122 Firefox/3.0.5
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv: Gecko/2008120122 Firefox/3.0.5

CPU hogging bug in version 3.0.5 is MUCH worse than in 3.0.4. This is a chance to understand this particular bug by examining the differences between 3.0.4 and 3.0.5.

Possibly the bug is in the keyboard handler, or the way the keyboard handler interacts with Windows XP SP3, all patches applied up to January 12, 2009.

Reproducible: Always

Steps to Reproduce:
1. Open many windows and tabs, a common occurrence for those who do research.
2. Hibernate the OS several times.

Actual Results:  
After the CPU hogging starts, when opening a new window, it takes about 15 seconds until the new window will accept typing into the URL box. Until then, no keyboard input is accepted.

This bug also slows all computer operations.

Expected Results:  
Normally a new window accepts keyboard input immediately after it is opened. 

Process Explorer version v11.32 shows in the "CPU Time" column that Firefox CPU usage is far greater than any other program that is running. At present, on the computer I am using to file this bug, Firefox is peaking at 77.8% CPU usage with no activity, shown in the "CPU" column. There is sometimes a delay between the time I type a character and the time the character is displayed.

Process Explorer is available free:

Firefox 3.0.4 was not perfect, but it was far better than 3.0.5. The old 2.0 versions of Firefox were far worse.

This bug is different than the CPU hogging caused by faulty interaction with Flash-based videos (.FLV file extension). (Yes, I know that Flash has a history of being very poorly written.)

These things seem important: 

1) There is the likelihood that finding what causes this bug will be far easier because the problem became abruptly worse in the transition from 3.0.4 to 3.0.5.

2) This bug has existed since the 0.9 versions of Mozilla, the old name for Firefox. In those versions it was much more severe.

3) Firefox's CPU hogging bug causes the destruction of laptops. The CPU hogging causes laptop fans to operate far more than they otherwise would. The CPU fan is normally the first part in a laptop that fails. The fans are generally very expensive to replace. Many users just buy a new laptop.

4) Possibly some resource is being overused. In this installation that is failing, the bookmarks.html file is 2,498,314 bytes. The places.sqlite file is 7,278,592 bytes.

5) Since this bug seems to concern a major misunderstanding of how Firefox works, it seems that fixing it may cure other problems also.

6) I recently completely removed Firefox 3.0.4 from this computer and re-installed it. That cured a bug of not being able to display Google maps.

7) Conditions: Default theme. Windows XP SP3, all patches applied except those provided by Microsoft last Tuesday, 2009-01-13.

Add-ons: Adblock Plus, Colorful Tabs, DownloadHelper, Firebug, Flashblock, JSView, NoScript, PDF Download, Session Manager, Tab Mix Plus, Web Developer, Web of Trust. All the latest versions, except Adblock Plus and DownloadHelper are the versions just before the latest.

However: Web Developer is disabled. Web Developer, JSView, and Firebug were added since Firefox 3.0.5 was installed.

8) If this bug is blamed on Add-ons, then there needs to be a way users can troubleshoot Add-on CPU use.

9) This bug is several years old, and in the past always occurred with no add-ons. Improvements in lessening CPU hogging occurred with improvements in Firefox. 

10) It is VERY inconvenient, before the research is finished, to close all the tabs and windows and restart the Windows OS to regain control of the computer. In the past, letting Session Manager reload the Firefox windows and tabs only brought back a CPU-hogging session. I have not tried that often, because in the past Session Manager would throw away URLS if they took too long to load.

11) about:buildconfig

Build platform

Build tools
Compiler 	Version 	Compiler flags
cl 	14.00.50727.762 	-GL -wd4624 -wd4952 -TC -nologo -W3 -Gy -Fd$(PDBFILE)
cl 	14.00.50727.762 	-GR- -GL -wd4624 -wd4952 -TP -nologo -Zc:wchar_t- -W3 -Gy -Fd$(PDBFILE)

Configure arguments
--enable-application=browser --enable-update-channel=release --enable-optimize --disable-debug --disable-tests --enable-update-packaging --enable-official-branding --enable-jemalloc --with-crashreporter-enable-percent=10
Does the problem also happen in safe-mode? http://support.mozilla.com/en-US/kb/Safe+Mode
If so, can you test with the latest trunk nightly build for it may be fixed already: http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-mozilla-central/
And please give more exact steps to reproduce, with links to URLs.
Version: unspecified → 3.0 Branch


9 years ago
Whiteboard: DUPEME

Comment 2

9 years ago
This sounds like the problem I'm having. I started having problems last night, when I right-clicked on a flash game to toggle quality. All my FF windows hung and while other programs were working fine their windows would not go away when they were minimized or moved; if i moved a window i would get duplicates of it in it's old and new locations. FF windows wouldn't open up at all or would open sporadically. The problem was strangely alleviated by opening another FF window from the start menu, at which point everything returned to normal. This process repeated a few times until i gave up trying to change the quality of the flash game. At some point i opened task manager and noticed FF was consuming about 50% of the CPU usage. I did not do anything to fix the problem at the time.

Earlier today I was working fine with FF in the same session minus the page with the flash game. This time the hang happened when I opened a file browser window to upload a file. The same thing as before happened - FF was unresponsive but other programs worked fine, albeit with the UI glitch mentioned above. unlike before the problem did not resolve by opening another FF window. Instead, the window opened normally and behaved normally for about a second an then became unresponsive. I hadn't restarted my computer in a long time and figured that might help. Upon restarting the FF dialog box requesting whether i wanted to save and quit popped up just as it usually would have, but I do not know whether it actually processed my input (i clicked "yes" and the window still persisted, but this could have been a symptom of the general window persistence problem i was having). When the computer restarted and i opened FF, the old session restored and the problem was still there: FF hogged 50% of the CPU time and when i tried to open the file browser it hung in the same manner as before. I tried deleting my download history and that seemed to help: FF did not hog the CPU adn i was able to upload the file. Later tonight, however, i noticed FF was taking up 50% again even when minimized. I opened up the add ons box to look at the extensions but when i tried to drag it FF hung. this time was different tho; FF was unresponsive, and i could not access other programs or the start menu because the mouse would not move into the taskbar - it was stuck in the FF window. I pressed Ctrl+Alt+Del adn then pressed cancel and this immediately remedied the situation; FF worked normally (albeit still using 50% of the CPU time) and i could even manipulate the add ons box so long as i didn't move it. I have tried flashblocker and that did not relieve my CPU, and i have installed the latest Minefield build to no avail. The problem still persists. currently, I can still get the most recent error by doing the following:
1. have up many windows and tabs
2. go to tools -> add ons
3. i can interact with the add ons menu and change settings so long as i don't move it. after i move it a bit, FF hangs and my mouse will not scroll into the taskbar
4. by pressing ctrl+alt+del and then clicking "cancel", the computer returns to normal
this occurs every time. as for the performance FF consistently consumes 50% of the CPU and takes up about 150mb of RAM with the set of windows and tabs i've been using.

I have a Dell studio 1535 running Vista Home Premium SP1
Video Adapters 
Model Memory 
Mobile Intel(R) 965 Express Chipset Family 448 Mb  
Intel GMA X3100 Dynamic Video Memory Technology 4.0

Comment 3

9 years ago
Firefox is now hogging my resources so I nearly cannot do anything else when it is running. I am switching back to IE until resolved. Good by!
Have you tried with Firefox 3.5 and the steps in comment 1? We need accurate steps to reproduce as well
No reply, INCO. Please try using Firefox 3.5.2 or later in a new profile and report back if this still happens.
Last Resolved: 9 years ago
Resolution: --- → INCOMPLETE
Whiteboard: DUPEME
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