[Musix-users] Do I run a low-latency and realtime kernel?

[julien bodd]

Hi all,

I'm experiencing tons of xruns and sound saturation when I use
zynAddSubFx in combination with freewheeling (live looper).

I went through the linux-audio-users-request mailing list and I saw
that a low-latency kernel is not the same with a realtime kernel.

When I do : uname - a, I have :
... 2.6.16-beyond4.1 #1 PREEMPT Sun May 28 ...

So my kernel is low-latency? But, it doesn't seem it is realtime as I
have installed no patch (Ingo Molnar patch). It doesn't seem to be
PREEMPT_RT. Or is it included in Musix by default?

This might be the problem.

Another thing I see is that when I run QJackCtl, it doesn't seem to
run realtime!
Although it does not complain and I have activated the R (realtime)
switch. I can see it is not realtime because there is a RT indicator
that is not yellow.
I tried running as root, and it is the same.

I have libpam-modules installed (0.79-4) and I added :
/etc/security/limits.conf
@audio		 -	 rtprio		 99
@audio		 -	 nice		 -10
@audio		 -	 memlock	 250000

(I belong to the audio group of course)

(I also tried some optimizations with fluxbox, no 3D accel, disable
unnecessary services, increase  pci latency for soundcard..)

So, I is the problem the lack of realtime patch, or a bad version of QJackCtl?


Thank you very much, and sorry for this long post !

Julien