[LAU] Linuxsampler says: " Thread: WARNING, can't assign realtime scheduling to thread!"

From: Guru Prasad B. R. <prasadbrg@email-addr-hidden>
Date: Sun Jan 10 2010 - 19:37:26 EET

Hello everyone,
  I'm running Ubuntu Jaunty 9.04 (on a different laptop, not the one
running AVLinux). Till recently, my linuxsampler setup on this
particular system was working without (major, noticable) glitches, i.e
very few xruns and not many dropped notes. Since the past few days,
however, I'm seeing a host of xruns and buzzes and drop notes. I tried
switching to the RT kernel (kernel 2.6.28-3-rt, via synaptic). The
result - a *huge*, unmanageable latency. I also noticed this warning
which I'd not seen before:

Thread: WARNING, can't assign realtime scheduling to thread!

I'm using jackdmp 1.9.4, compiled from source:

/usr/local/bin/jackd -S -R -dalsa -dhw:0 -r44100 -p256 -n2

I'm sure there are better realtime kernels out there, but before I
switch the kernel, I'd like to understand why exactly linuxsampler is
not being allocated realtime priority. I don't know much about this.
Incidentally, here's what 'top' reveals: (Note: these are with the
vanilla kernel).

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+
COMMAND
29516 guru 20 0 35872 13m 10m R 10.3 1.4 0:28.17
qsampler
29503 guru 20 0 437m 436m 76m S 2.7 46.5 0:11.57
linuxsampler
29493 guru 20 0 88632 74m 72m S 2.3 8.0 0:11.20
jackd

No user-owned entries have RT priority, but down the list some
root-owned processes do, for e.g:
3 root RT -5 0 0 0 S 0.0 0.0 0:00.00 migration/0
All user-oned processes have the same priority: 20
My /etc/security/limits.conf file ends with this:
@audio - rtprio 19
@audio - memlock unlimited
@audio - nice -19
 And I'm a member of the group 'audio'.

Can someone help me out with this?
Thanks in advance!
Cheers,

Guru

-- 
Guru Prasad B.R.
Centre for Ecological Sciences 
Indian Institute of Science
Bangalore - 560 012
India
Ph:+91-80-22933103
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-user
Received on Sun Jan 10 20:15:01 2010

This archive was generated by hypermail 2.1.8 : Sun Jan 10 2010 - 20:15:02 EET