Re: High X server CPU usage when drawing - more info

On Thu, 12 Dec 2002, Rafael E. Herrera wrote:

> Dr Andrew C Aitchison wrote:
> > Sometimes pixmaps are stored in offscreen video memory, sometimes
> > in system memory. Maybe you are resizing your window such that the pixmaps
> > don't fit in video memory so the server puts some in system memory.
> > Under ideal conditions copying from video -> video requires no CPU
> > overhead, but system -> video copies can require CPU effort.
> > 
> > The X server logfile often gives clues about how much video memory
> > is available for pixmaps.
> 
> The server log only reports 'Offscreen Pixmaps' in the accelerated 
> features of our G450 Matrox cards, although I'm not sure what it means. 
> Your explanation for the slow down makes sense, however, i've reproduced 
> this problem even with a card with 32 MB of memory.

Last time I looked at the mga code, DRI tried to steal as much video 
memory as possible - I think it left at most a screen-full of memory
for pixmaps. Are you using DRI ?


-- 
Dr. Andrew C. Aitchison		Computer Officer, DPMMS, Cambridge
[email protected]	http://www.dpmms.cam.ac.uk/~werdna