On Monday 12 March 2007 18:22, Mike Galbraith wrote:
quoted text
> On Sun, 2007-03-11 at 13:10 +0100, Ingo Molnar wrote:
> > * Mike Galbraith <efault@gmx.de> wrote:
> > > > Full patch for 2.6.21-rc3-mm2:
> > > > http://ck.kolivas.org/patches/staircase-deadline/2.6.21-rc3-mm2-rsdl-
> > > >0.29.patch
> > >
> > > I'm seeing a cpu distribution problem running this on my P4 box.
> > >
> > > With 2.6.21-rc3, X/Gforce maintain their ~50% cpu (remain smooth), and
> > > the encoders (100%cpu bound) get whats left when Amarok isn't eating
> > > it.
> > >
> > > I plunked the above patch into plain 2.6.21-rc3 and retested to
> > > eliminate other mm tree differences, and it's repeatable.  The nice 5
> > > cpu hogs always receive considerably more that the nice 0 sleepers.
> >
> > hm. Do you get the same same problem on UP too? (i.e. lets eliminate any
> > SMP/HT artifacts)
>
> Behavior is slightly different with a UP kernel.  Neither encoder
> receives more cpu than X, but they each still receive more than gforce.
> The distribution of X/Gforce vs lame/lame averages per eyeball to
> roughly ~50:50.
>
> I noticed Con posted an accounting fix, and applied it.  No change.

So the lames are nice 5 which means they should receive 75% of the cpu that 
nice 0 tasks receive so they should get 43% of the cpu...

Just a couple of questions;

The X/Gforce case; do they alternate cpu between them? By that I mean when 
they're the only thing running does the cpu load summate to 1 or does it 
summate to 2?

Gforce presumably is a 3d visualisation? Do you use one of the graphics card 
drivers listed that uses yield?

,----[grep -r sched_yield mesa]
| mesa/mesa/src/mesa/drivers/dri/r300/radeon_ioctl.c:       sched_yield();
| mesa/mesa/src/mesa/drivers/dri/i915tex/intel_batchpool.c:      
sched_yield();
| mesa/mesa/src/mesa/drivers/dri/i915tex/intel_batchbuffer.c:         
sched_yield();
| mesa/mesa/src/mesa/drivers/dri/common/vblank.h:#include <sched.h>   /* for 
sched_yield() */
| mesa/mesa/src/mesa/drivers/dri/common/vblank.h:#include <sched.h>   /* for 
sched_yield() */
| mesa/mesa/src/mesa/drivers/dri/common/vblank.h:      sched_yield();                                                   
\
| mesa/mesa/src/mesa/drivers/dri/unichrome/via_ioctl.c:      sched_yield();
| mesa/mesa/src/mesa/drivers/dri/i915/intel_ioctl.c:     sched_yield();
| mesa/mesa/src/mesa/drivers/dri/r200/r200_ioctl.c:       sched_yield();
`----

Thanks

-- 
-ck
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