firefox slowness with xorg 6.9.0

Roland Scheidegger rscheidegger_lists at
Tue Mar 7 11:24:54 PST 2006

Michel Dänzer wrote:
> On Tue, 2006-03-07 at 17:39 +0100, Roland Scheidegger wrote:
>> Tommi Sakari Uimonen wrote:
>>> I'm using debian unstable (also tried kanotix), both have xorg 6.9.0 and 
>>> kde 3.5. Video card is ATI 7500. Firefox is 1.5
>>> For reference, I have also oldish gentoo install with xorg 6.8.x and 
>>> it's fast. top shows that X takes only about 30% and firefox 50% cpu 
>>> while scrolling about:config page with mouse wheel while some other 
>>> window is on top of firefox. Gentoo has firefox 1.0.4 and kde 3.4
>>> I'm just compiling firefox 1.5 to gentoo to bring the two systems 
>>> configurations closer to each other. Hopefully I accomplish a situation 
>>> where only xorg version differs, and then I really can blame xorg for 
>>> the slowness. It could be GTK slowness, because konqueror works fast 
>>> with the same setup (same website and another window on top of konqueror)
>> FWIW, I noticed some massive slowdowns when using firefox too recently, 
>> but after some digging it seems firefox 1.5 is fully to blame. The 
>> slowdowns only happen with firefox 1.5 or seamonkey 1.0, but firefox 1.0 
>> is fast. Maybe it simply has to do how it's compiled (using gtk2 and 
>> such), I don't know.
>> Some quick profiling showed this however (scrolling on a VERY slow page 
>> since it updated its layout,
>> 8608     43.2107                 fbBlt
>> 5168     25.9425  vmlinux                  default_idle
>> 830       4.1665           (no symbols)
>> 436       2.1886  Xorg                     (no symbols)
>> 344       1.7268         (no symbols)
>> 255       1.2801                 fbBltOne
>> 188       0.9437              (no symbols)
>> 157       0.7881            (no symbols)
>> 153       0.7680                 fbSolid
>> So, firefox 1.5 causes some massive use of which firefox 1.0 
>> probably didn't (I did not profile firefox 1.0). As to why and how to 
>> fix it, no idea... My setup used radeons too if it matters (7200, 9000 
>> with xorg 6.9, and a x550 with xorg 6.8.2)
> Have you guys tried with EXA? This sounds like the good old 'Cairo and
> XAA don't mix well'. Cairo actually contains a bunch of workarounds for
> XAA, but I think they're disabled with X.Org 6.9 or newer, as it was
> assumed that XAA would get fixed. Also note that GTK+ 2.8.12+ has some
> XAA workarounds again, so if you have an older version, you may want to
> upgrade.
Right on, EXA fixes this. If cairo has workarounds for XAA (do you have 
a link handy what the problem actually is?), they don't work for xorg 
6.8.2 however neither, at least not with the version suse 10.0 (and a 
firefox 1.5 pulled from their site) ships.


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