Subject: Re: [linux-audio-dev] ALSA API
From: Alexander Ehlert (alexander.ehlert_AT_uni-tuebingen.de)
Date: Mon Apr 30 2001 - 23:54:37 EEST
> I can't tell you anything about the Maestro, but I routinely use a
> period size of 64 frames (1.3ms) on my Hammerfall and Trident cards on
> a dual PII-400. no dropouts.
The question is, how can you actually the period time that low. I can't
get alsa to set the period time lower than 5ms. Is that driver dependend
or does alsa check for a low latency kernel?
> are you running a low-latency kernel? if not, forget going below 10ms.
> if you are, are your IDE drivers properly tuned? this is a well known
> problem area for low latency settings.
Hmm, I not running a low latency kernel.
> the usual qualifications about the application doing the right thing
> (no system calls, no blocking calls of any kind) within the audio
> thread all apply to. i would imagine that GLAME adheres to this, but
> i don't have any basis for that imagination.
Hmm, glame plugins communicate via sockets, each plugin in a thread.
So we have some function calls to get buffers to process. But I don't
see a way circumventing that :) And IMHO function calls take only
a couple of museconds, so do you really think that's a problem.
BTW: There are heaps of assert calls in the alsa lib, maybe that's
the problem. But I didn't see a way to compile alsa lib without asserts.
Do I have to set CFLAGS="-DNDEBUG" by hand?
Cheers, Alex
--Conscience doth make cowards of us all. -- Shakespeare
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