Re: [PATCH]sched: Isochronous class v2 for unprivileged soft rt scheduling

[Con Kolivas]

Jack O'Quin wrote:
> Looked at this way, there really is no question.  The new scheduler
> prototypes are falling short significantly.  Could this be due to
> their lack of priority distinctions between realtime threads?  Maybe.
> I can't say for sure.  I'll be interested to see what happens when Con
> is ready for me to try his new priority-based SCHED_ISO prototype.

There are two things that the SCHED_ISO you tried is not that SCHED_FIFO 
is - As you mentioned there is no priority support, and it is RR, not 
FIFO. I am not sure whether it is one and or the other responsible. Both 
can be added to SCHED_ISO. I haven't looked at jackd code but it should 
be trivial to change SCHED_FIFO to SCHED_RR to see if RR with priority 
support is enough or not. Second the patch I sent you is fine for 
testing; I was hoping you would try it. What you can't do with it is 
spawn lots of userspace apps safely SCHED_ISO with it - it will crash, 
but it not take down your hard disk. I've had significantly better 
results with that patch so far. Then we cn take it from there.

Cheers,
Con

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