Re: [Jack-Devel] Trying to understand jackd's threads

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DateFri, 15 Feb 2013 21:00:59 +0100
From Joakim Hernberg <[hidden] at alchemy dot lu>
To[hidden] at lists dot jackaudio dot org
In-Reply-ToPaul Davis Re: [Jack-Devel] Trying to understand jackd's threads
On Fri, 15 Feb 2013 14:40:05 -0500
Paul Davis <[hidden]> wrote:

> On Fri, Feb 15, 2013 at 12:59 PM, aCOSwt <[hidden]> wrote:
> 
> >
> > Now that the irqs are threaded SCHED_FIFO, aren't we in the
> > situation where SCHED_RR would sound more appropriate ?
> >
> 
> not in my opinion. jack2 did this for a while.
> 
> it is helpful to think of jack (sometimes) not as an audio-related
> tool but as
> 
>   "A cooperative user-space realtime scheduling system"
> 
> it is not interested in sharing cores with any/all SCHED_RR tasks, but
> instead with taking very "tight" control over tasks that are a part
> of its "scheduling domain". SCHED_FIFO is more appropriate for this
> purpose, in my opinion.

If I'm not mistaken the time quantum that a RR thread runs before
possibly being preempted is determined by the ticker frequency and thus
between 10 and 100ms long.  Seems like that for our purposes (low
latency), they will act the same anyways?

-- 

   Joakim
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