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

["Jack O'Quin" <joq@io.com>]

Con Kolivas <kernel@kolivas.org> 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