Bug 8476

I found this conversation that explains the problem a bit better:
http://www.redhat.com/archives/fedora-devel-list/2006-September/msg00392.html

ons, 13 09 2006 kl. 15:49 -0400, skrev Kristian Høgsberg:
> David Nielsen wrote:
> ...
> >>> Did you solve the Firefox scrolling issue with compiz on an r300 based 
> >>> card? Firefox becomes unusably slow over here (Radeon 9500pro) when I 
> >>> switch to compiz but the effects themselves work smoothly.
> >>>
> >>> Regards,
> >>>    Dennis
> >>>
> >> I see the same thing with the R100. Firefox scrolling is unbearable and
> >> so is gnome-terminal scrolling, especially full screen.
> > 
> > Admittedly that one is rather bad but it only happens if you scroll
> > using the mouse wheel not if you grap the scrollbar - I'm thinking
> > pango?
> 
> I know everybody likes to kick pango, but this is not pango's fault.  The 
> problem is that when we run compiz on AIGLX, we kick out all pixmaps to host 
> memory.  This means that XCopyArea (which is what drives most scrolling) is no 
> longer accelerated and furthermore, for each line you scroll, we have to copy 
> the pixmap contents back out to the card.  This is the big bottleneck in the 
> compiz+AIGLX architecture, we're hoping to fix it post-fc6.
> 
> Kristian

Damn you Kristian for ruining a perfectly good pango bashing with things
like an informed opinion and the truth on your side.. :)

but I'm glad to see that the problem is being worked on.

- David

This is fixed for me with svn version of xorg/mesa.

Although my display randomly locks up  when running beryl a longer time and I
have to reboot.

*** Bug 9676 has been marked as a duplicate of this bug. ***

This bug happens not only when scrolling, but also when
-) using the scale plugin 
-) viewing animated things like flash or animated gifs (tested in firefox)
-) using vim in a maximized gnome-terminal
-) using the blur effect
-) using the animation plugin

I own a 9700 mobility

To tell the truth I've discovered that with normal metacity scrolling and
resizing are very cpu-intensive operations! So the problem might not be compiz.
Or if it is normal that those operations are cpu-intensive, compiz adds lots of
weight to the cpu, so everything becomes choppy!

Please try to use option --use-copy in beryl.

is it the same as rendering path -> copy?

if so I enabled it but it seems slower... (maybe) is there a way to absolutely test it?

this problem is quite fixed with xorg 7.2 mesa 6.5.2. the performance is now acceptable but still not metacity-like

Sorry about the phenomenal bug spam, guys.  Adding xorg-team@ to the QA contact so bugs don't get lost in future.

The patches I put up at http://people.freedesktop.org/~daenzer/aiglx-zero-copy-tfp/ fix this IME, I'm hoping to clean them up and push them soon. Porting to other 3D drivers than r300 welcome.

Pushed my patches to the GIT master branches of xserver, mesa (r300 and i915tex drivers), xf86-video-ati and xf86-video-intel.