Re: [linux-audio-dev] Re: minimum tick time

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Subject: Re: [linux-audio-dev] Re: minimum tick time
From: Maarten de Boer (mdeboer_AT_iua.upf.es)
Date: Wed Nov 07 2001 - 18:25:30 EET


> what do you want the timer for? if you use a PCM device, it *is* a
> timer, much more accurate than the system timer. you can simply keep
> count of how many frames you have moved since time N, and you have the
> time accurate to 1/SR seconds (as accurately as the PCM sample clock,
> anyway).
>
> however, it sounds as if you have some other goal in mind ...

I don't think so, but I am probably completely missing the point.
Let's start all over. I have a patched kernel, and I want to have
low latency. I use latest alsa (cvs), and I run the latency test.
(As you might have noticed, I submitted an filtersweep effect for
the latency test, which Jaroslav added to the CVS. Try it with -e)

- if I run in nonblock mode, it eats all CPU. Latency is excellent,
  but it would be nice if I could do something else in the meantime,
  for example run a GUI.
  $ latency -m 128 -M 128
- if I run in block mode, i get XRUNs, even with larger bufsize
  $ latency -e -b -m 256 -M 256
- if I run in poll mode, idem
  $ latency -e -b -m 256 -M 256 -p

Is this expected behaviour?

Maarten
  


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