I have the "isochronous" scheduling patch working now. Any task trying to start as real time that doesn't have authority to do so will be set to SCHED_ISO. This is a non-expiring scheduler policy designed to guarantee a timeslice within a reasonable latency while preventing starvation. Good for gaming, video at the limits of hardware, video capture etc. It is best set using the schedtool by a normal user trying to start something as SCHED_RR.
I think I'll leave these patches in the experimental directory till Jens gets out the latest CFQ and I/O priority patches. I'll get those playing nicely with normal "nice" settings, merge supermount and consider releasing a -ck patch.