[linux-audio-dev] Linux kernel HZ, audio latency and how to measure?

Stephen Sinclair radarsat1 at gmail.com
Sat Aug 19 00:49:17 UTC 2006

> The user application code is woken up by the interrupt from the audio
> interface, not from a timer firing - in addition to getting data from
> the card and storing it in memory, the interrupt handler wakes up any
> processes that are waiting on the audio data.  So HZ is irrelevant.
> SCHED_FIFO is needed because otherwise, if there are multiple runnable
> processes when the audio interrupt fires, the kernel could decide to run
> a different process.  With SCHED_FIFO it must run the audio process.

Ah, interesting. Thanks.
I feel like I should have known that. I'm going to go read up on audio
drivers now..


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