Re: [patch] CFS scheduler, -v6

From: Thomas Gleixner
Date: Fri Apr 27 2007 - 09:37:51 EST


On Fri, 2007-04-27 at 13:55 +0200, Ingo Molnar wrote:
> * Ingo Molnar <mingo@xxxxxxx> wrote:
>
> > update for lkml readers: this is some really 'catastrophic' condition
> > triggering on your box. Here ogg123 just never skips on an older 750
> > MHz box, which is 4-5 times slower than your 2GHz box - while i have
> > _fourty nice-0 infinite loops_ running. I.e. at this clearly
> > ridiculous load, at just 2.5% of CPU time ogg123 is just chugging
> > along nicely and never leaves out a beat.
>
> Kasper, just to exclude the possibility that this is somehow related to
> IO scheduling, could you copy the OGG file over to /dev/shm and play it
> from there? Do you still get the bad skips?

That's what I can observe here:

ogg123 local harddisk skips
ogg123 nfs works
ogg123 /dev/shm works

The skips when running from the local harddisk are definitely caused by
the I/O scheduler or some other bottleneck in the block/disk/scsi/sata
jungle. I try to find out more details.

tglx


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