Messages in this thread | | | Date | Wed, 29 Aug 2007 09:11:10 -0400 | From | Bill Davidsen <> | Subject | Re: CFS review |
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Ingo Molnar wrote: > * Bill Davidsen <davidsen@tmr.com> wrote: > > >>> There is another way to show the problem visually under X >>> (vesa-driver), by starting 3 gears simultaneously, which after >>> laying them out side-by-side need some settling time before >>> smoothing out. Without __update_curr it's absolutely smooth from >>> the start. >>> >> I posted a LOT of stuff using the glitch1 script, and finally found a >> set of tuning values which make the test script run smooth. See back >> posts, I don't have them here. >> > > but you have real 3D hw and DRI enabled, correct? In that case X uses up > almost no CPU time and glxgears makes most of the processing. That is > quite different from the above software-rendering case, where X spends > most of the CPU time. >
No, my test machine for that is a compile server, and uses the built-in motherboard graphics which are very limited. This is not in any sense a graphics powerhouse, it is used to build custom kernels and applications, and for testing of kvm and xen, and I grabbed it because it had the only Core2 CPU I could reboot to try new kernel versions and "from cold boot" testing, discovered the graphics smoothness issue by having several windows open on compiles, and developed the glitch1 script as a way to reproduce it.
The settings I used, features=14, granularity=500000, work to improve smoothness on other machines for other uses, but they do seem to impact performance for compiles, video processing, etc, so they are not optimal for general use. I regard the existence of these tuning knobs as one of the real strengths of CFS, when you change the tuning it has a visible effect.
-- bill davidsen <davidsen@tmr.com> CTO TMR Associates, Inc Doing interesting things with small computers since 1979
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