On Thu, 2006-05-25 at 01:55 +0200, Wolfgang Woehl wrote: > Damn, it doesn't make sense to me. If I can configure the kernel to be > or not to be preemptible then what is the separation good for? Isn't > overhead because of preemption the only price tag? You are confusing preemption (which improves the performance of realtime processes) with the permission to run realtime processes at all (addressed by the realtime LSM, pam, or set_rtlimits). It is also confusing that if JACK is told to start in realtime mode and it does not have permission, it falls back to non-realtime rather than failing to start. This is fixed in the latest development versions. Lee