Re: [LAU] unable to set scheduling priority with rt kernel

On Mon, 2007-10-29 at 23:54 +0200, Chuckk Hubbard wrote:
> On 10/29/07, Florian Schmidt <mista.tapas@email-addr-hidden> wrote:
> On Monday 29 October 2007, Chuckk Hubbard wrote:
> > On 10/25/07, Florian Schmidt <mista.tapas@email-addr-hidden> wrote:
> > > Well, if chrt works now without sudo, try running
> > >
> > > jackd -R -P 70 -d alsa ...
> > >
> > > again. It should work now, too..
> >
> > Update: I just discovered that running jackd -R -P 70 -dalsa
> -P -p256 -n2
> > -r44100 as ROOT doesn't even set priority 70. jackd then
> runs as a root
> > process with priority 20, according to both chrt and top.
> > Apparently my system is not able to run anything higher than
> 20 priority;
> > does this mean my kernel is misconfigured, or might it be
> something else?
> > -Chuckk
>
> install htop
>
> run it
>
> press f2 [setup]
> -> Display Options
> -> uncheck "Hide userland threads"
> -> uncheck "Hide kernel threads"
>
> Do you see all 4 jack threads now?
>
> Woop, there it is. Thanks. I see 5 actually, one -71, one -81
> (watchdog?), and the rest 20. Running Csound with its --sched=N flag,
> I also see two csound processes, one of which is -70 and the other 20,
> no matter what value I put... time to take that up with the Csound
> list I guess.

With JACK output?

From the Csound manual:

"DO NOT use "--sched" if you are using JACK for audio output. JACK
controls scheduling for the audio applications connected to it, and also
tries to run at the highest possible priority. If the "--sched" flag is
used, Csound and JACK will be competing rather than cooperating,
resulting in extremely poor performance."

--ll

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