(ffado) jack xruns

[sh0099]

Hallo

i setup ubuntu on my "contemporary" mac mini.
i use ubuntu 10.04 with the rt kernel (2.6.33-23-realtime) from KXStudio

long time i thought that i get iruns with jack-ffado because of irq sharing
but now i run the computer without X
and ffado-diag shows no irq sharing for the firewire stuff
but still i get every 5 to 10 minutes a big xrun

so now i have a few questions:
how can i know who is controling the cpu speed?
(for example on my laptop eee-control-deamon has more control than than
the cpufrequtils)
and where can i set up the defaults?

is there another place to tweek the performance beside cpu speed and the
irq prioritys
as described here?
http://subversion.ffado.org/wiki/IrqPriorities

best
olaf