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

From: Con Kolivas
Date: Thu Jan 20 2005 - 01:35:34 EST


Con Kolivas wrote:
Jack O'Quin wrote:
I was misreading the x-axis. They're actually every 20 sec. My
system isn't doing that.


Possibly reiserfs journal related. That has larger non-preemptible code sections.

You're really getting hammered with those periodic 6 msec delays,
though. The basic audio cycle is only 1.45 msec.


As you've already pointed out, though, they occur even with SCHED_FIFO so I'm certain it's an artefact unrelated to cpu scheduling.

Ok to try and answer my own possibility I remounted reiserfs with the nolog option and tested with SCHED_ISO

*********************************************
Timeout Count . . . . . . . . :( 0)
XRUN Count . . . . . . . . . : 0
Delay Count (>spare time) . . : 1
Delay Count (>1000 usecs) . . : 0
Delay Maximum . . . . . . . . : 6750 usecs
Cycle Maximum . . . . . . . . : 717 usecs
Average DSP Load. . . . . . . : 30.7 %
Average CPU System Load . . . : 5.7 %
Average CPU User Load . . . . : 23.2 %
Average CPU Nice Load . . . . : 0.0 %
Average CPU I/O Wait Load . . : 0.0 %
Average CPU IRQ Load . . . . : 0.6 %
Average CPU Soft-IRQ Load . . : 0.0 %
Average Interrupt Rate . . . : 1683.8 /sec
Average Context-Switch Rate . : 20015.8 /sec
*********************************************


You'll see on
http://ck.kolivas.org/patches/SCHED_ISO/iso2-benchmarks/jack_test3-iso2-40c-nolog.png

That the 20s periodic thing delay has all but gone. Just one towards the end (no idea what that was).

Cheers,
Con
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