EXA performance ( XCOMPOSITE and XRENDER ) performance regression from xorg 7.0 to 7.1 ( r200 )

James Blanford Xorguser at cox.net
Sat Jul 1 21:50:30 PDT 2006

On  2 Jul, Daniel Kasak wrote:
> Hi all.
> I've done some testing of xorg 7.0 and 7.1 on a Radeon 9250
> ( r200 ). I had been running 7.0 for quite a while, and using EXA to
> accelerate compositing. This was working pretty well, apart from the
> known problems when you open too many windows ( grinds to a halt ).

How many is too many?  15? 100?
> After updating to 7.1, compositing seems to have gotten considerably
> slower. I run an Enlightenment-0.17 desktop, and I manually run
> xcompmgr in a terminal, and then manually run transset from another
> terminal to set window transparency.
> The first thing I noticed was that there is a LONG period of high CPU
> usage immediately after running transset and clicking a window. This
> used to be instantaneous. But also the general performance seems to be
> noticably slower than under 7.0 ( still good, but slower than it was ).
> Switching desktops also used to be lightning fast. Now it can take 10
> seconds. EXA is working, though. Once things settle down, I can drag
> around transparent windows quite smoothly, but setting transparency
> and switching desktops is very slow.
I'm running a Radeon 8500, also an r200, known to be dog slow with XAA,
but seems to be fast with EXA.  It seemed to speed up if anything when I
switched to cvs (git?) xserver and drivers.  I tried 15 windows on one
desktop and 10 in another and didn't notice any slowdown or high cpu
usage.  I didn't use transset, though. I used fluxbox's built-in
transparency control.

> Switching Enlightenment-0.17 to use the XRENDER engine also shows that
> XRENDER performance has degraded since 7.0 - my CPU usage has
> increased by about 10% while rendering a number of animated
> backgrounds.
> I'm attaching my xorg log ( there's nothing out of the ordinary I can
> see ) and xorg.conf.
> Is this performance regression a known issue? Maybe something specific
> to my setup?

I've noticed huge differences in performance among the various
compositing and window managers.  Window moves are jerky and peg my cpu
with metacity and libcm.  Compiz is almost unbelievably fast and
responsive.  Unfortunately, I get no window decorations.  Fluxbox and
xcompmgr are great.  Maybe I'll give e a try.

     -  Jim

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