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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