Bug#583653: xserver-xorg-video-radeon: 15x-slower performance regression in KMS mode for 2D operations
daenzer at debian.org
Sat May 29 07:21:46 PDT 2010
On Sam, 2010-05-29 at 15:02 +0200, Sylvain Beucler wrote:
> On Sat, May 29, 2010 at 01:05:36PM +0200, Michel Dänzer wrote:
> > On Sam, 2010-05-29 at 10:21 +0200, Sylvain Beucler wrote:
> > >
> > > The attached simple test runs at 17FPS in KMS mode on my computer,
> > > against 300FPS in non-KMS mode.
> > Forgot to mention: sysprof or oprofile profiles of slow and fast runs
> > might be interesting, at least if the CPU is pegged during the runs.
> Here are 2 sysprof runs:
> - UMS / fast:
> - kernel 11.25%
> - X 77.20%
> - KMS / slow:
> - kernel 90.28%
> - X 5.79%
Unfortunately, there's no information about where in the kernel the
cycles are burnt. This information should be available with sysprof
1.1.x and a kernel with the performance counter/event framework.
Anyway, this probably means it's an issue in the kernel, not the X
driver. May be solved already in newer kernels, there have been some AGP
performance improvements which I'm not sure have made it into Debian's
2.6.32 DRM backport.
> You'll have to guide me for oprofile, in particular I don't know what
> kind of kernel image I can feed it with.
I said 'sysprof or oprofile', the former is usually preferable.
Earthling Michel Dänzer | http://www.vmware.com
Libre software enthusiast | Debian, X and DRI developer
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