Crippling Firefox Bug On Mac OS X
Wednesday, November 30th, 2005 by Mike Rundle
As I’m sure you all know, Firefox v1.5 has been officially released and is available for download. Got a G5 processor? Check out this page to download a G5-optimized version of the Fox that is a bit faster. You would think all is gravy in Mozilla-land, but that is definitely not the case.
There is a major bug in Firefox where if you hold down the mouse button to select text, or scroll, or anything inside the browser window, the Firefox CPU usage shoots up to nearly 100% and hogs your entire system until you let go. I just tested it using top and can verify that the CPU usage jumps to between 75-95% depending on the other applications in use at the time. For Powerbook or iBook users this is a major issue, considering your fans will probably turn on and you’ll battery will drain much quicker.
This issue only affects Firefox on Mac OS X, and is unique to the FF application in that other OS X apps like Safari or Mail don’t exhibit this bug. Cocoa applications don’t exhibit this bug, but I’ve learned it’s a problem with the Carbon frameworks that Firefox uses. Other applications that utilize this framework exhibit similar processor hogging. I’m wondering what this bug does to Flock considering there are more things to click on in that interface — this bug might affect Flock more than Firefox because of the user mousing patterns with the updated UI.
I’m not sure why the Bugzilla report isn’t jumped up to high priority considering the major blocking mechanism apparent here, but I hope this is resolved soon. The bug report has now been open for about three years with no one apparently working on a solution.
Update: Think that you won’t be clicking and scrolling much? If you’re using Google Maps, your CPU usage will go to max as soon as you start scrolling the map. I just tried it and top reported my CPU usage sustained at 80-90% throughout the whole time I was using it. Not good at all, especially since so many damn “web 2.0″ applications/companies use the Google Maps API to do their stuff.
2nd Update: Front page of Digg!
Thanks to Chris for pointing this out to me in a comment. This is something every Mac OS X user needs to know. Digg this story »
Reader Comments
31 Responses to “Crippling Firefox Bug On Mac OS X”
This bug has been open since 2002, which kind of implies the team does not feel it is significant.
And it is not listened as a known issue with the release.
And 1.5 is supposed to have better Mac support.
November 30th, 2005 at 3:17 pm
Tyme - The new version of FF brings the CPU usage up to about 75-85%, while previous versions bring it right up to the full 100%. A slight improvement, but it is still a major issue for laptop users. It boggles my mind too :)
November 30th, 2005 at 3:20 pm
Why is this a major bug? How how could you possibly hold a mouse button down for? A couple of seconds here and there? Where’s the blood?
November 30th, 2005 at 3:28 pm
Mike - As soon as you click it immediately jumps to 100%. Hold it down for more than an instant and threads are locked and waiting. Some people have reported it freezing FF as well.
This bug is much worse for laptop users, since clicks on links and buttons within your web browser can add up to a lot of battery drain over the course of your browsing experience.
November 30th, 2005 at 3:30 pm
That vacuums! I just got an iBook and had just decided to use Firefox as my main browser. Safari in my ddesktop. I remember that even in my desktop, I was experienceng randow slowdowns, althou I never would have realized it was clicking on text! I have had to shut down FF acouple of times on my portable, due to freezez, but I just shrugged it off as another bug. I was using the beta version for testing. I did submit a report every time it happened. hope they fix it soon.
November 30th, 2005 at 11:59 pm
in what way is this bug “crippling”? i just now verified that it’s happening on my machine, but i’ve been using ff on my ibook, powermac, and 2 powerbooks for next to forever (something like firebird 0.7), and i’ve never even *noticed* this bug, much less had it cripple me.
sensationalize why don’t you! you sound like you think you’re secunia breaking the next big security hole story. who are you a fanboi of? ie7? opera? or are you just bored?
yes, it’s a bug. yes, it needs fixing. no, it’s not crippling.
December 1st, 2005 at 5:59 am
sorry to post twice… i’m not gettin’ rabid or anything, but i thought i should share the comments of another digger, astrosmash:
“Total BS.
I’m a longtime Mozilla and Firefox user on Windows and Linux, but I rarely use Firefox on OS X. Firefox has some serious issues on OS X, but this isn’t one of them.
This is just an artifact of how older Carbon apps work. Appleworks does the same thing. And the Firefox people are in the process of upgrading their framework to use more modern Cocoa APIs anyway.
Furthermore, there is no slowdown. It’s just a low-priorty thread that spins while tracking the mouse. That’s just how classic Mac OS did things before OS X. It’s not an issue for laptop users or anyone else.”
i just confirmed this on my ibook as well, if you open an appleworks 6 document and hold down the mouse button in it, the exact same thing happens: 85-95% cpu usage, w/ no slow down.
December 1st, 2005 at 6:09 am
This is not specific to FF, i’ve had this problem for years in IE on OSX.
“This is just an artifact of how older Carbon apps work. Appleworks does the same thing. And the Firefox people are in the process of upgrading their framework to use more modern Cocoa APIs anyway.”
December 1st, 2005 at 6:31 am
Thanks for the post, now I know why I can’t use Firefox on my Powerbook. Recently switched to Opera, since it works fine on my PB.
I was beginning to wonder if there was something wrong with my computer, so thanks for clearing it up for me. Firefox 1.0.7 is certainly worse than Firefox 1.5, but nevertheless they both die on me when I enter sites where I need to scroll or click on the page (even worse on pages littered with flash)
Mike D, yes this is major for people like me who can’t use FireFox on their laptops at all! You should try it out for a while and see if you’re ok with it or not.
December 1st, 2005 at 6:59 am
This is a bug in the widget code for the Mozilla Suite, which means that it’s not only Firefox, but Thunderbird too.
It is not present in Camino, but that uses a completely different widget set.
I’ve reported the issue on bugzilla and I suggest to everyone who reads this to vote for this bug. Hopefully, if it gathers enough votes, someone will notice it and fix it.
December 1st, 2005 at 7:15 am
I don’t know if this is the same bug, but sometimes (regardless of platform Windows, OSX, or Linux) sometimes Mozilla or Firefox will jump to 100 CPU. I can close the various tabs, but that changes nothing. The only way to stop it is to exit Mozilla or Firefox. It is down right annoying…
December 1st, 2005 at 7:16 am
I have installed Firefox 1.5 on W2k and also freeze with 100% of CPU. With the previous version this didn´t happend.
December 1st, 2005 at 7:32 am
This is very strange.
Interestingly, it doesn’t seem to happen when I use the new tab-dragging feature, or even when I’m scrolling (clicking and holding the scrollbar that is). It only seems to happen a) when clicking over an actual webpage (not sure what the technical name is for the window in which pages render) or b) when I click and hold on the bookmarks toolbar…
As for this problem being on Mozilla’s to-do list for a while - I’m sure we can count on the open source community to do something about it! Surely this sort of problem is exactly why open source is so much better than relying on the likes of Micro$oft!
December 1st, 2005 at 8:40 am
This is a carbon app thing, due to the way carbon allocated resources. It’s really not a big deal. Photoshop on Mac OS X does the same thing, and I can’t say I’ve ever noticed it causing a problem there (where you’re pretty likely to click and drag).
December 1st, 2005 at 9:02 am
* Why is this a major bug? How how could you possibly hold a mouse button down for? A couple of seconds here and there? Where’s the blood? *
Alot of people ust their mouse to grab scroll bars which move the page up and down. Some people do this slowly some people do this quickly. Other times people use their mouse to click drag and select text on webpages.
The blood? Anytime any application takes over your processor things aren’t good. And especially when it is for a menial task like a mouse button hold. I’ve had FF crash numerous times while movies are playing.. working in photoshop.. using iPhoto.. a flash website is flashing… I never knew about this.. I may think twice about exclusively using FF..
December 1st, 2005 at 9:10 am
It’s important to remember this behaviour is *not* exhibited with the scroll bar. Only by clicking and holding in the rendered web page itself. The amount of battery this wastes is negligable. You also have to hold down for quite some time for Mac OS to allocate up the CPU % to Firefox to a point where it’s a large amount (80%+). Other programs won’t be affected by this.
December 1st, 2005 at 9:16 am
First, you have to hold the mouse button down for several seconds before CPU usage approaches 75-95%. I’ve not seen any instances where that great a jump has occurred “as soon as you click” on the mouse.
Second, even if doing so “hogs the entire system until you let go,” what else would you be doing while holding down a mouse button anyway?
Third, who are these “some people” who’ve reported that holding down the mosue button freezes FF, and where are their reports?
I agree that this bug should receive attention and ultimate resolution, but if FF users comprise 10% of web surfers, and Mac users comprise 10% of computer users, that would mean that ~1% of web surfers are running Mac FF. Of those, how many hold the mouse button down for several seconds during any given online session? So we’re talking about a relatively minuscule number of web surfers here. Are you sure that this problem warrants the semi-hysterical tone of your subject header?
Chill, d00d. Way worse things are happening in Mac software, and almost all of them are coming from Apple Computer, Inc. these days. We’re going to have a lot more to worry about than such minor FF bugs….
December 1st, 2005 at 9:18 am
How can this be? Everyone knows that MAC is 1000% more stable than Windows.
Just had to do it, sorry.
December 1st, 2005 at 9:32 am
Carbon gets a bad rap. It’s possible to do this in both Cocoa and Carbon (and Windows GDI controls, for that matter).
All you have to do to pin the CPU is run continuously in a loop without blocking. The correct way to handle mouse drags is to block the current thread (thus using no CPU time) until the next mouse-moved event. Carbon provides several easy ways to do this without requiring major code changes. It’s a bug in the Firefox support framework that they don’t take advantage of Carbon.
Exercise: drag a scrollbar in the Finder while watching your CPU usage. There’s a small hit for redraw when you move it, but that’s normal, and that’s all. Finder is Carbon-based.
December 1st, 2005 at 10:59 am
1. This doesn’t affect click and hold on scroll bars, just the content window.
2. Dragging around in google maps already consumes 80-90% CPU without this ‘bug’, so the difference in CPU usage between Safari and Firefox is negligible.
While it’s not pretty, this behavior is consistent with other apps that have been ported from classic Mac OS. It doesn’t slow down Firefox (Firefox doesn’t block itself) and it pales in comparison to CPU usage Firefox (or any browser) uses render content on a regular basis. It’s a non-issue.
A much bigger issue regarding resource usage and web browsing is increasing use of Flash plugins that consume 30-80% CPU just sitting there while a web page is open.
December 1st, 2005 at 11:02 am
If you like Gecko, don’t want to use memory/cpu-hog Firefox, and would rather not use Safari (which has poor tab-loading, IMHO), then give Camino a try. It’s Cocoa-based, so the CPU bug won’t affect it like Firefox, and it’s much faster than Safari. http://www.caminobrowser.org/
December 1st, 2005 at 11:32 am
Seems like this might be linked to these two unconfirmed critical 1.5 bugs:
https://bugzilla.mozilla.org/show_bug.cgi?id=318215
https://bugzilla.mozilla.org/show_bug.cgi?id=315467
Firefox has become unusable for me under OS X. It’s a shame, too. The one thing that has kept me coming back to FF is the extensibility of it, but what good are the extra bells and whistles if it won’t stay open long enough to use them?
Looks like I’m back to Safari and Opera.
December 1st, 2005 at 12:08 pm
Just because the CPU is running at 100% doesn’t mean that all other processes are starved for CPU time. The CPU usage here is taken up by a *low-priority* thread, as previously mentioned. This means that any thread that wants more time will get it, as the default priority is higher than this one.
Yes, this is a bug. Yes, it should be fixed. NO! it is NOT crippling.
December 1st, 2005 at 3:03 pm
One thing I am really pleased to see has been resolved is that scrolling left on the scrollwheel of the MightyMouse (and perhaps others too) would cause Firefox to go back a page. This was extremely annoying when working in a content-management system because simply trying to scroll down in a text box would cause the page to go back and lose all the text that had just been typed. I had disabled the horizontal scrolling of the MightyMouse just because of Firefox but it now works correctly.
December 1st, 2005 at 3:43 pm
I tried this and I don’t see the problem. If I click and select text on the page and move the mouse rapidly, then I can get the Firefox CPU up to 40-50%, but if I stop moving, then it goes back down to ~5%. (I’m not sure why 5% is it’s base CPU usage, but I have a bunch of pages open in tabs.)
Also, it’s not the case that this is an inherent part of Carbon. It will occur if a Carbon app polls for events, but there are Carbon APIs that do not require polling.
December 1st, 2005 at 10:46 pm
So, first I should mention that applications that waste CPU cycles are are very much an annoyance for me. I’m surprised that so many people seem to think this is a non-issue. It wears out your CPU, slows down your system, and possibly drains your battery.
Secondly, iTunes for Windows does this as well, and it’s actually worse because it happens during scrolling as well. So Mozilla isn’t the only culprit here.
Oh, and now that I think about it, Paint Shop Pro also does it, which is particularly bad because photo editing involves a lot of dragging. Fix your software, people!
December 2nd, 2005 at 1:53 am
I just installed Firefox 1.5.0.1 , and I can report that this bug is totally crippling. I’ve never experienced such a bug in any other browser. I’ve got OSX 10.2.8
February 16th, 2006 at 7:53 am
yeah, i’ve just upgraded to 1.5.01 and now i’ve got this happening with the latest FF on winxp as well ha ha :( as soon as you open the program, it hogs cpu between 85-96%, and shoots back up there any time it’s slightly active. Darn frustrating.
(yes, you’re right about iTunes for windows, that’s why i went back to winamp)
February 23rd, 2006 at 4:53 pm
I have a similar experience in 1.5.0.1, but I’m performing another action.
I use Google a lot, and most of my queries begin with “.
With the new Firefox, 1 in 10 times I type ” in the Google searchbox (and the autoprompt box appears) and Firefox locks up completely. I can’t bookmark, I can’t save or perform any function in Firefox at all. All I can do is Force Quit.
I’ve been using Firefox for ages, but I’m now looking for a new browser.
March 1st, 2006 at 7:57 am
We have a similar problem with a G4 IMac running OSX. The problem happens when you type in the google search box. Just typing causes FireFox (1.5) to pinwheel. You have to force kill it. It happens so much of the time to cripple Firefox. It’s hard to believe this hasn’t been fixed. I’ve tried removing all the extensions but to no avail. It still happens. Extremely frustrating.
March 5th, 2006 at 7:28 pm
Firefox is unbearable for me. Well over half the time when I load a link into a new tab firefox completely freezes. It also freezes when I scroll, right before I hit the bottom of the page. Heck, every time I tried coming to this site FireFox locked up.
I’ve got a 2.33 GHz Intel Macbook Pro 2 GB RAM
As much as I love FireFox, I find myself having to use safari more and more to look up websites.
July 19th, 2007 at 6:40 pm
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