[linux-audio-user] jackd and realtime priority

[Florian Schmidt]

On Sat, 25 Feb 2006 02:44:54 -0500
Hector Centeno-Garcia <h.centeno at sympatico.ca> wrote:

> Hi,
> 
> I've been playing around a little with the priority thing. I would like 
> to understand better the way it works. Looking at the priority of jackd 
> (running realtime, as user, and with a RT kernel, full-preemption) I 
> can't figure out why if I start jackd with -P 60 (or any other number > 
> 0) the output of chrt is always:
> 
> $ chrt -p (jackd's pid)
> pid 8115's current scheduling policy: SCHED_OTHER
> pid 8115's current scheduling priority: 0

the relevant excerpt of "man jackd":

       -P, --realtime-priority int
              When running --realtime, set the scheduler priority to int.

The important part is "When running --realtime".. Usually you call jackd
like this to get a high rt prio:

jackd -R -P 70 ...

BTW: shortcut:

chrt -p `pidof jackd`

or 

chrt -p `pidof "IRQ 8"`

etc..

Flo

P.S.: See my site in the signature for some more in depth info.

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