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

[Stephen Sinclair]

I've certainly seen setitimer()-driven sleeping get much better
response time on a kernel compiled to 1000 Hz (with preemption) over
one compiled to 100 Hz (without preemption).

>From this, I think it should be possible to say that one could read
the audio card with smaller buffers more quickly, reducing latency.
But I haven't made tests using audio, specifically, so I won't say
more.  I suspect the kernel driver and userspace API (ALSA or
whatever) might need to be made to take advantage of it, but I know
little about ALSA internals.


Steve


On 8/18/06, Paul Davis <paul at linuxaudiosystems.com> wrote:
> On Fri, 2006-08-18 at 23:10 +0700, Mulyadi Santosa wrote:
> > Is there any relationship between kernel HZ and audio timing? I imagine
>
> no. or almost none.
>
> recording audio doesn't involve using the system timer at all. the only
> clock involved is the sample clock that drives the audio interface.
>
> having HZ set too high could conceivably make the system more likely to
> xrun, but this is not likely with a fully RT kernel.
>
>
>