Re: [patch] CFS scheduler, -v19

[Bill Davidsen <davidsen@tmr.com>]

Ingo Molnar wrote:
> * Bill Davidsen <davidsen@tmr.com> wrote:
>
> > > I've taken mainline git tree (freshly integrated CFS!) out for a 
> > > multimedia spin.  I tested watching movies and listenign to music in 
> > > the presence of various sleep/burn loads, pure burn loads, and mixed 
> > > loads. All was peachy here.. I saw no frame drops or sound skips or 
> > > other artifacts under any load where the processor could possibly 
> > > meet demand.
> > I would agree with preliminary testing, save that if you get a lot of 
> > processes updating the screen at once, there seems to be a notable 
> > case of processes getting no CPU for 100-300ms, followed by a lot of 
> > CPU.
> >
> > I see this clearly with the "glitch1" test with four scrolling xterms 
> > and glxgears, but also watching videos with little busy processes on 
> > the screen. The only version where I never see this in test or with 
> > real use is cfs-v13.
>
> just as a test, does this go away if you:
>
> 	renice -20 pidof `Xorg`
>
> i.e. is this connected to the way X is scheduled?
Doing this slows down the display rates, but doesn't significantly help 
the smoothness of the gears.

> Another thing to check would be whether it goes away if you set the 
> granularity to some really finegrained value:
>
>     echo 0 > /proc/sys/kernel/sched_wakeup_granularity_ns
>     echo 500000 > /proc/sys/kernel/sched_granularity_ns
>
> this really pushes things - but it tests the theory whether this is 
> related to granularity.
I didn't test this with standard Xorg priority, I should go back and try 
that. But it didn't really make much difference. The gears and scrolling 
xterms ran slower with Xorg at -20 with any sched settings. I'll do that 
as soon as a build finishes and I can reboot.

I should really go back to 2.6.21.6, 2.6.22 has many bizarre behaviors 
with FC6. Automount starts taking 30% of CPU (unused at the moment), the 
sensors applet doesn't work, etc. I hope over the weekend I can get bug 
reports out on all this, but there are lots of non-critical oddities.
> 	Ingo


--
Bill Davidsen <davidsen@tmr.com>
  "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot
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