Re: [ck] [PATCH][RFC] sched: Isochronous class for unprivilegedsoft rt scheduling

From: Jack O'Quin
Date: Tue Jan 18 2005 - 11:23:23 EST


Con Kolivas <kernel@xxxxxxxxxxx> writes:

> Cal wrote:
>
> SCHED_ISO
> /proc/sys/kernel/iso_cpu . . .: 70
> /proc/sys/kernel/iso_period . : 5
> XRUN Count . . . . . . . . . : 110
>
> vs
>
> SCHED_FIFO
> XRUN Count . . . . . . . . . : 114
> XRUN Count . . . . . . . . . : 187
>
> vs
>
> SCHED_RR
> XRUN Count . . . . . . . . . : 0
> XRUN Count . . . . . . . . . : 0
>
> Something funny going on here... You had more xruns with SCHED_FIFO
> than the default SCHED_ISO settings, and had none with SCHED_RR. Even
> in the absence of the SCHED_ISO results, the other results dont make a
> lot of sense.

Actually it makes perfect sense. Running non-realtime JACK threads
SCHED_FIFO will do the most harm. The others less.

I predict that using normal jackd -R (without schedtool) will produce
the same results running SCHED_FIFO and SCHED_ISO (within the normal
variance).

I think schedtool is too blunt and instrument for making these
measurements.
--
joq
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