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FireFox 6 Super Slow? Cache Settings Corruption


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For those of you that follow me on Twitter, you've probably seen some of my tweets regarding major performance problems I've seen with the install of FireFox 6.0. FireFox 6.0 was released a couple of weeks ago and is treated as a 'force feed' update for FireFox 5.0. I'm not sure what the deal is with this braindead versioning that Mozilla is doing with major version releases coming out, what now every other month? Seriously that's retarded especially given the limited number of new features these releases bring, and the upgrade pain for plug-ins that the major version release causes.

Anyway, after the FireFox updater bugged me long enough I finally gave in last week and updated to FireFox 6. Immediately after install I noticed terrible performance. Everything was running at a snail's pace with Web pages loading slowly and most content actually slowly 'painting' the page. A typical sign of content downloading slowly. However these are pages that should be mostly cached on my system and even repeated accesses ran just as slow. Just for a reality check I ran the same sites in Chrome (blazing fast) and IE (fast enough :-)) but FireFox - dog on a stick.

Why so slow Boss?

While complaining lots of people recommended to ditch FireFox - use Chrome, yada yada yada. Yeah, Chrome is fast and getting better but I have a number of plug-ins that I use in FF that I can't easily give up. So I suffered and started looking around more closely at what was happening.

The first thing I noticed when accessing pages was that I continually saw accesses to the Google CDN downloading jQuery and jQuery UI. UI especially is pretty heavy in size and currently I'm in a location with a fairly slow IP connection where large files are a bit of an issue. However, seeing the CDN urls pop up repeatedly raised a flag with me. That stuff should be caching and it looked like each and every hit was reloading these scripts and various images over and over again.

Fired up FireBug and sure enough I saw something like this on a repeated hit to my blog:

SlowLoads

Those two highlights are jquery and the main CSS file for the site and both are being loaded fully and taking a while to load. However, since this page had been loaded before, these items should be cached and show 304 requests instead of the full HTTP requests returning 200 result codes.

In short it looked like FireFox was not caching ANY content at all and constantly reloading all page resources. No wonder things were running dog slow.

Once I realized what the problem was I took a look in the about:config settings and lo and behold a bunch of the cache settings were set to not cache:

aboutconfigCache

In my case ALL the main cache flags were set to false for some reason that I can't figure out. 

It appears that after the FireFox 6 update these flags somehow mysteriously changed and performance took a nose dive. Switching the .enable flags back to true and resetting all the cache settings tote default reverted performance back to the way it's supposed to be: reasonably fast and snappy as soon as content is cached and accessed again  from cache.

I try not to muck with the about:config settings much (other than turning off the IPV6 option) but when there are problems access to these features can be really nice. However, I treat this as a last resort so it took me quite some time before I started looking through ALL the settings. This takes a while, not knowing what I was looking for exactly.

If Web load performance is slow it's a good idea to check the cache settings. I have no idea what hosed these settings for me - I certainly didn't explicitly set them in about:config and while in FireFox's Options dialog I didn't see any option that would affect global caching like this, so this remains a mystery to me.

Anyway, I hope that this is helpful to some, in case some of you end up running into a similar issue.

Posted in FireFox  

The Voices of Reason


 

Ramon Smits
August 25, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Checked the setting just in case :-) but mine were all good.

Jon
August 25, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Checked my settings. All were 'true' enabled on mine (not user set status). fyi

mknopf
August 25, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Thanks Rick, I have yet to upgrade to 6 and have also been puzzled by the major version number releases coming out so fast (since it took 8 years to move through 4 versions and now only 3 months to move another up another 2).

Ncage
August 25, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Hmm i don't know. I just upgraded to firefox 6 and all those settings you highlighted above are true and everything seems to be working perfectly.

Rick Strahl
August 25, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Thanks all. FWIW, I wasn't trying to imply that every upgrade would end up with mangled settings. It's also possible that upgrade of one of my plug-ins might have caused these FUBAR'd settings.

The point more so was that when FF gets really slow to check those cache settings since that's the most likely cause for dog slow performance.

Mark
August 26, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Mine were all enabled too, but thanks for the info, I didn't know those 3 settings were so easily switched!

Jim Kuiper
August 26, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Same thing happened to me - cache settings were all set and performance was very slow. Changed the settings as you mention and now it works fast again.

muskrat
August 27, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

FF6 was unbelievably slow, my pages hung & refreshed forever. Did the cache thing & no difference.

I reverted back to FF5 & it worked a great. Then I re downloaded FF6 & now no problems for some reason. Who knows.

Mike Gale
August 28, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

I too am perlexed by whatever Mozilla is up to. Their shenanigans are annoying me and a lot of others.

I succumbed to FF 6 a day or so ago and regret it already.

It's not your problems, the caching hasn't been messed.

It seems to be something called FF plugin container. (I run Sysinternals process monitor and it's gobbling up one of two reported processors on my test system.)

It might be triggered by some sites and not others. I'm not going to bother to check it out. Now I need to figure how to best revert to FF 5.

(If these guys carry on like this they're going to die.)

Mike Gale
August 28, 2011

# Reinstall FF 5, better

Relating to my last post.

I could reproduce the CPU hogging on FF6. (It was a newspaper web page (SMH), so there's a good chance it contains some unfriendly components (past experience).)

I installed FF5 on top of it. From a quick look I can't see anything lost.

The good news is that although that container is still running it now only takes between 6 and 15% of total CPU (12 to 30% of a single CPU). An improvement worth having. At least I'll allow FF to run on that machine!

From a software testing view = Big Fail. (Bad sign for the future!)

alan
September 03, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Rick you are genius! Thank you for the sanity check and resolution.

I came to this realization after tailing server logs and discovering Chrome/Opera were not asking for half as many resources as FireFox was. Sure enough, two of those settings were flipped to 'false' in some bizarre twist of fate.

The only plugins i have installed on FF6 are FireBug + GoogleReader. One wonders if it was one of those chaps that was the culprit.

How much extra load has FF6 put on todays servers?

silverlight
September 07, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

I have yet to upgrade to 6 and have also been puzzled by the major version number releases coming out so fast.

Rick Strahl
September 07, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Ok so it looks like FireFox 6.0.2 has fixed a number of the more drastic performance problems. As of this version it appears that FF is running reasonably fast again. No comparison though against Chrome which still blazes way faster in page browsing at much lower memory usage than FF.

I'm running Chrome now and only going back to FF when I need a specific plug-in feature... I really do hope Mozilla gets back on track and gets off this whacky development track that creates major versions for minor feature improvements. I really do wonder what the heck they are thinking that justifies this? Anybody have a clue of their reasoning?

Mike Gale
September 08, 2011

# re: FireFox 6 Super Slow? Cache Settings Corruption

Thanks for that update on FF 6 latest version.

Maybe a clue to some of the thinking at FF central. They've abandoned development of jssh (JavaScriptShell). This has been used by some web-test/automation frameworks to drive the browser. Result is that you can't use the latest versions of FF in some automated tests.

On top of that many add-ins no longer work. (Though there is a way to avoid that.)

In other words these guys are happy to abandon professional developers. Both those who want to test against their browser and those who develop for it. (I've seen a post where somebody calls providing programmatic access to the engine, jssh, a mistake!)

My guess is that they've decided to go exclusively for the consumer and consciously abandoned other user groups.

(Shades of the new Ubuntu UI.)

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