via k8m890 very slow with vesa

Roland Scheidegger rscheidegger_lists at
Wed Nov 29 05:02:21 PST 2006

bob davis wrote:
> I am the original poster and I have ubuntu edgy 6.10.
> I ran the x11perf test with a few relevent tests
> I also booted with a ubuntu 6.06 live dapper disk.
> I attached both logs and you can see the tremendous slow down on scroll, 
> copy, and move window.

>    1200 reps @   6.1317 msec (   163.0/sec): Copy 500x500 from window to window
>      24 reps @ 241.7143 msec (     4.1/sec): Copy 500x500 from window to window
That's pretty drastic. I've just tried it with 7.2 and it's still very 
slow. Since only operations seems to be affected which have to read from 
fb, but not write (so copy from window to pixmap is slow, pixmap to 
window is not), it looks to me like something goes wrong wrt shadowfb, 
which afaik should prevent having to ever read from framebuffer (though 
I could be wrong).
Some quick oprofile run does not show anything from xorg or libfb 
promintently, the most prominent xorg function is WaitForSomething, but 
that's only 1.5%, most of the rest of the cpu time spent is inside the 
kernel with lock acquiring and releasing stuff...


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