10-50% CPU used by xorg?

Daniel Kasak dkasak at nusconsulting.com.au
Thu Feb 21 16:49:40 PST 2008


On Thu, 2008-02-21 at 19:00 +0100, Simon Thum wrote:

> > Ahhhh ... the 'window-wanking' test. If you must do this as part of
> > everyday use, then run a compositing manager. If you don't want any
> > compiz special effects, then the best performance is with XAA,
> > XAANoOffscreenPixmaps set, and xcompmgr.
> 
> Since you seem to have played a bit with that, I've got a stupid 
> question bugging me:
> For my system (currently ati with XAANoOffScreen), the XAANoOffScreen 
> lets me toggle good console perf vs. good firefox/thunderbird perf, with 
> the other one darn slow. Isn't there someting like 
> XAASensibleOffscreenPixmaps that avoids the bad cases? (or is it hackable?)

*All* ATI users of r100, r200 & r300 cards should now be using EXA. The
latest stable releases of xserver and xf86-video-ati provide
zero-copy-texture-from-pixmap ( if you're using compiz or a
derivative ), which makes things *very* fast. Also r100 and r200 owners
get decent XRENDER acceleration. On my Apple Powerbook ( r280 video
card, basically an r200 ), I was getting about 2.5x the performance with
EXA than XAA ( tested with evas & enlightenment-0.17 ), and also getting
very fast compositing just with xcompmgr. This was in the early days
anyway. It actually slowed down a bit after that, but it was still
faster than XAA. r300 users don't get full XRENDER acceleration, but
these systems are usually fast enough not to need it anyway.

As for firefox, use a firefox-3-beta build. They've switched to using
cairo, which speeds up rendering ( and scrolling ) performance
considerably.

Lastly, as other people have noted, font anti-aliasing and stuff in
terminals slows things down ( in particular with XAA ). Turn it off if
you don't really need it. Or use EXA.

What card have you got anyway?

--
Daniel Kasak
IT Developer
NUS Consulting Group
Level 5, 77 Pacific Highway
North Sydney, NSW, Australia 2060
T: (+61) 2 9922-7676 / F: (+61) 2
9922 7989
email: dkasak at nusconsulting.com.au
website:
http://www.nusconsulting.com.au







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