[PlanetCCRMA] added: ALPHA version of Planet Core components for FC2

Steve Harris S.W.Harris@ecs.soton.ac.uk
Fri Jun 25 09:43:02 2004

On Fri, Jun 25, 2004 at 08:30:06 -0700, Fernando Pablo Lopez-Lezcano wrote:
> Well, probably not _the_ problem. But at least that is what seems to be
> causing the xrun explosions in my tests. Could it be that the handling
> of denormals has changed in newer kernels? That is done in the kernel,
> right? (I have no idea). 

Its possible the kernel's handling has changed, I think it has a little
> > I haven't been able to get anything like that kind of stability. If I run
> > AMS, then try to run jamin within a minute I will get a storm of messages,
> > then jackd will deteriorate to the point where apps will no longer be able
> > to connect. I had to reboot a couple of times. This is running at 2x256.
> I have not been able to run jamin, the latest official release does not
> even start. Jack (O'Quinn) posted a patch when I mentioned it but I did
> not get a chance to try it out. 

I can send you tarball if you want, but I don't think theres anything
special about jamin.
> > That does sound exactly like denormals. Are you running a P4 by any
> > chance?
> Yes, P4 1.7G on my laptop. 

The denomral handing on P4's seems to be much more expensive, and it
appears to react badly to small numbers that are not quite denormals.
> > I've only tried AMS and jamin (debugging) with the RT kernel, with the
> > stock fedora one I've run a variety of stuff, it xruns occasioanlly,
> > as you would expect, but no storms.
> That is interesting and something I should try. I have not actually
> tried to run things in the stock kernel as I would have to run them as
> root, and it is not possible to build the realcap kernel module :-( How
> long are the xruns you see? Should I assume that the tests in the stock
> kernel were done as root with SCHED_FIFO? (jackd -R).

I've done a bit of testing as root, but mostly running jackd as me.
I've just run 2x1024 AMS feeding meterberidge and jamin and I was able to
use them all nomrally for a quite a while without xruns (other than when I
started jack apps).

After sitting there for a bit, I got a 78ms xrun, possibly when I switched
virtual desktops.

At 2x512 I get xruns of about 2-8ms every few seconds.

At 2x4096, running as a user it is good enough for deugging, no xruns so
far (phew!), though not exatly low latency :)

I tried running it as root (2x1024) this time I got the
delay of 18841.000 usecs exceeds estimated spare time of 6248.000; restart ...
storm, as soon as I run jamin and AMS, as I was seeing with the CCRMA
kernel, but I dont remeber seeing that before.

> When you say stock kernel you mean the one originally shipped with FC2,
> right?

Right now I'm running 2.6.6-1.435, from FC2.

- Steve