[PlanetCCRMA] kernel-rt in new core components

Fernando Lopez-Lezcano nando@ccrma.Stanford.EDU
Tue Mar 6 17:52:01 2007

On Tue, 2007-03-06 at 20:37 -0500, Craig Bourne wrote:
> Trashing in the traditional sense of hitting swap constantly?
> Yes, evidently, thrashing randomly, between my two discs, spending
> most of its time on the one that holds swap, and interspersed with
> shorter stretches when the discs are untouched and the system amuses
> itself in memory. The fact that one of these sessions gave an out of
> memory error lends the aroma of truth to the message my intuition gets
> from watching Das Blinkenlights on the drives. But this is all
> completely anecdotal.
> ... /var/log/messages ...
> attached

Ok, definitely the machine is running out of memory. When that happens
all bets are off, a process will be randomly killed until enough memory
is freed... 

How much memory does the system have?

You may try running jackd _without_ memory locking active, and/or unlock
the gui toolkits (there's an option for that as well). 

If you have a realtime jack program that wants to use a lot of memory it
will be locked down and will never swap to disk (for example a sampler
player that keeps samples in memory can eat up anything you throw at it
- qsynth is an example). All other processes will be chasing after the
few free bytes left and thus the hard disk activity. Eventually there is
no more memory left and the kernel OOM killer (Out of Memory Killer)
will pick a process that is using a lot of memory and kill it in an
attempt to free memory so that the whole thing does not shut down...

> We will stay with Fedora FC6 for this work.

Wow, sounds impressive......

-- Fernando