[LAD] 2.6.20 scheduler and buffer underruns

[Darren Gibbs]

Thanks, cool... that solves the glitching that scales with CPU load,  
I still have more rare glitches (every few seconds) that look like  
buffer underruns.  I'm suspect this is because some other kernel  
entity has interrupts turned off when the DMA interrupt needs to be  
serviced to switch buffers.  Are there any clever tools for figuring  
out who might be doing this?


On Jul 11, 2007, at 12:33 PM, Lee Revell wrote:

> On 7/11/07, Darren Gibbs <tsquank at yahoo.com> wrote:
>> We're doing an ARM-based embedded device, which right now is running
>> vanilla 2.6.20.  For the sake of simplicity we wrote an OSS driver
>> that's simply double-buffering and writing to the DAC via I2S.  We
>> have a buffer underrun problem that is directly proportional to CPU
>> load... no glitches when simply cat-ing a file to /dev/dsp, but lots
>> of glitches when other things are happening on the system.  Can
>> anyone suggest tools/techniques/patches for improving the situation?
>
> Run the audio playback app with SCHED_FIFO priority.
>
> Lee
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