Messages in this thread | | | Subject | Re: Issues with Patch: "sched: Improve latencies and throughput" | From | Mike Galbraith <> | Date | Thu, 01 Apr 2010 21:35:50 +0200 |
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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" [1] 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 [1] 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 > audiodongle.
Hm. I don't _think_ you've demonstrated a clear problem yet.
Q: how much CPU is aplay routinely using on this platform?
-Mike
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