Need help solving Xorg slowness.

Michel Dänzer michel at
Thu Nov 1 00:31:22 PDT 2007

On Wed, 2007-10-31 at 19:32 -0700, Ray Van Dolson wrote:
> On Thu, Nov 01, 2007 at 02:12:26AM +0000, Omari Stephens wrote:
> >  You may want to try explicitly disabling Composite in your xorg.conf.  I 
> >  recently experienced what sounds like similar behavior and composite was 
> >  related.  See [1].  Clearly, the bug report is specific to xfce, but I 
> >  believe other apps were affected in my case as well.  For the record, I'm 
> >  running an nVidia card with the non-binary driver.
> > 
> >  --xsdg
> > 
> >  [1]
> Thanks for the reply.  I've switched back to the OSS radeon driver and
> do have Compositing disabled.  Still the slowness persists.  I find
> that the problem is made even worse when I am in EXA mode.
> I am going to get some additional oprofile dumps on this.  Initial ones
> show _very_ heavey calls to memcpy() when resizing Windows, changing
> tabs in Firefox, etc.

The problem is that RENDER acceleration hasn't been implemented for R300
class cards (or in the nv driver).

> Another question... what's a good test for this sort of thing using
> x11perf?  

The anti-aliased text tests, or -comp{win,pix}win* with x11perf from

> Should I use one of their pixmap tests?  I see x11perf
> -shmput500 listed quite a bit here -- is this a pretty accurate
> depiction of how my X environment is performing?

No, that should be fast with your setup but doesn't usually determine
performance of a modern desktop.

Earthling Michel Dänzer           |
Libre software enthusiast         |          Debian, X and DRI developer

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