Subject: Re: [linux-audio-dev] user lowlatency kernel experience
From: John S. Rhoades (jsr_AT_clearspeed.com)
Date: Thu Jun 14 2001 - 19:54:58 EEST
An example:
I've got a (unix) pipeline of filters followed by a sound player,
mostly written by myself, with no consideration of scheduling
fairness. When I run it with real-time priority, it consistently has
underruns about every 1/4 sec. The problem is that the filters are
working with fairly large (8k sample) chunks, and naturally the player
underruns while the filters are working.
One of these days, I'll fix the filters to have some concept of
fairness. Meantime, I just run at nice level -20, and get no dropouts
at all, even with 10 copies of emacs open and a kernel compilation
running. This using a kernel with low latency patches applied, of
course.
Hopefully someone will bite the bullet and write a linux scheduler
that supports a hybrid of realtime and fairness and that has adjustable
parameters.
/s jsr
On Thu, 14 Jun 2001, Joakim Verona wrote:
> ... In my opinion, different applications
> can never be assumed to be well-behaved and cooperative. Then we will
> wind up with systems behaving like windows 3.11 and the old Macintoshes.
>
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