Re: Issues with Patch: "sched: Improve latencies and throughput"
From: Mike Galbraith
Date: Thu Apr 01 2010 - 15:36:09 EST
On Thu, 2010-04-01 at 10:43 +0200, Michael Grzeschik wrote:
> On Thu, Apr 01, 2010 at 07:49:46AM +0200, Mike Galbraith wrote:
> > On Thu, 2010-04-01 at 00:31 +0200, Michael Grzeschik wrote:
> > > We are using an arm mx31 embedded cpu with the v2.6.34 Kernelrelease and
> > > realized some issues with the scheduling behaviour the patch "sched:
> > > Improve latencies and throughput"  by Mike Galbraith introduced to
> > > the kernel.
> > >
> > > When we used the alsa utility aplay to pipe some audio through an
> > > usbaudio device and put some scheduling overhead on the device, the
> > > amount of underruns, due to the not fast enough refilled ring buffer,
> > > was noticable increased with that patch  applied. Until we reverse
> > > applied the patch the amount of underruns was appreciable lower.
> > Testcase?
> What we did was:
> # Copy some audiofile to /dev/shm
> $ cp audiofile.wav /dev/shm
> # Play that file with aplay in background
> $ aplay /dev/shm/auduifile.wav &
> # Put some scheduling load on the system
> $ hackbench 6
> We did use this on an MX31 from Freescale running with about 500 MHz and
> the generic usbaudio driver to play the audio throgh an C-Media USB
Hm. I don't _think_ you've demonstrated a clear problem yet.
Q: how much CPU is aplay routinely using on this platform?
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/