Re: [linux-audio-dev] user lowlatency kernel experience

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Subject: Re: [linux-audio-dev] user lowlatency kernel experience
From: Benno Senoner (sbenno_AT_gardena.net)
Date: Thu Jun 14 2001 - 13:29:09 EEST


On Thursday 14 June 2001 09:59, Joakim Verona wrote:
> Thanks,
>
> this was very informative. I will study this kernel and see if I'm able
> to use it.
>
> Your statement below is exactly how I viewed this problem initially and
> thought that it worked this way. 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.

Yes, this is why I'm advocating the in-process model, where there is a
single audio server and the apps are "pluigns" that run under the control of
ther audio server.
That way the audio server can detect CPU overload situations and act
accordingly.
Of course it can be done with with out of process model too.
(probably hiding this stuff in APIs like the one proposed by Paul Davis)

My feeling is that the single process model simplifies things in that area,
but I could be wrong.

PS: Paul Davis: once things settle down and you get LAAGA test code runnnig
(with at least audio out running and a few time consuming test plugins), let
me know so I will profile it graphically using the latency-graph library.

Benno.

>
> (thanks everybode else to, you are all very helpfull)
>
> John Regehr wrote:
> > On Wed, 13 Jun 2001, Paul Davis wrote:
> >
> >
> >
> >
> > The whole idea of using a priority-based scheduler (like Linux's) to
> > schedule real-time applications is based on the assumption that
> > applications can be trusted not to hog the CPU. When this assumption is
> > false (and in other cases when application authors do not cooperate) a
> > different kind of scheduler is required.
> >
> > John


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