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

On Wed, 2007-10-24 at 15:59 +0300, Chuckk Hubbard wrote:
> Hi doc, thanks for the guess. sudo chrt does work, though. I'm
> supposed to not need it with the rt-patched kernel, which allows
> non-root users to set high priorities.

Not exactly right. The rt-patched kernel (Ingo's patches) only optimizes
the max latency paths in the kernel. Other software is what allows
non-root users to use SCHED_FIFO scheduling. There are several options,
the current one is /etc/security/limits.conf through PAM, there are
others.

-- Fernando

> On 10/24/07, Dragan Noveski <perodog@email-addr-hidden> wrote:
> chuckk, i can only try to guess.
> perhaps sudo on your system is not allowed to do chrt?
> on my system i have the file /etc/sudoers containing this two
> important
> lines:
>
> root ALL=(ALL) ALL
> nowhiskey ALL=NOPASSWD: ALL
>
> don't know if it could be the root of the problem, because if
> so, i
> would expect something like 'operation not permitted' error,
> but who knows.
>
>
> cheers,
> doc
> >
> > My kernel has:
> > # CONFIG_PREEMPT_NONE is not set
> > # CONFIG_PREEMPT_VOLUNTARY is not set
> > # CONFIG_PREEMPT_DESKTOP is not set
> > CONFIG_PREEMPT_RT=y
> > CONFIG_PREEMPT=y
> > CONFIG_PREEMPT_SOFTIRQS=y
> > CONFIG_PREEMPT_HARDIRQS=y
> > CONFIG_PREEMPT_BKL=y
> > # CONFIG_CLASSIC_RCU is not set
> > CONFIG_PREEMPT_RCU=y
> >
> > /etc/security/limits.conf has:
> > @audio - nice -10
> > @audio - rtprio 99
> > @audio - memlock 4000000 (someone on the
> jack list
> > suggested that my previous value "unlimited" was not
> recognized, so I
> > stuck this in but no change)
> >
> > and user "chuckk" is in group "audio".
> >
> > Lastly, the output from my script when the second sudo chrt
> line is
> > commented out:
> > ------------------------------
> > pid 684's current scheduling policy: SCHED_FIFO
> > pid 684's current scheduling priority: 82
> > jackd 0.103.0
> > Copyright 2001-2005 Paul Davis and others.
> > jackd comes with ABSOLUTELY NO WARRANTY
> > This is free software, and you are welcome to redistribute
> it
> > under certain conditions; see the file COPYING for details
> >
> > JACK compiled with System V SHM support.
> > pid 5132's current scheduling policy: SCHED_OTHER
> > pid 5132's current scheduling priority: 0
> > loading driver ..
> > Enhanced3DNow! detected
> > SSE2 detected
> > apparent rate = 44100
> > creating alsa driver ... hw:0|-|256|2|44100|0|0|nomon
> > |swmeter|-|32bit
> > control device hw:0
> > configuring for 44100Hz, period = 256 frames, buffer = 2
> periods
> > ALSA: final selected sample format for playback: 32bit
> little-endian
> > ALSA: use 2 periods for playback
> >
> > --------------------------------------
> >
> > Any ideas what I may have missed or misconfigured?
> >
> > Thanks!
> > -Chuckk
> >
> >
> > --
> > http://www.badmuthahubbard.com
> >
> ------------------------------------------------------------------------
> >
> > _______________________________________________
> > Linux-audio-user mailing list
> > Linux-audio-user@email-addr-hidden
> >
> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
> >
>
> _______________________________________________
> Linux-audio-user mailing list
> Linux-audio-user@email-addr-hidden
> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
>
>
>
> --
> http://www.badmuthahubbard.com
> _______________________________________________
> Linux-audio-user mailing list
> Linux-audio-user@email-addr-hidden
> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user

_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
Received on Wed Oct 24 20:15:04 2007