Re: [PATCH] sched - Implement priority and fifo support for SCHED_ISO

From: Con Kolivas
Date: Mon Jan 31 2005 - 15:16:51 EST


Jack O'Quin wrote:
Con Kolivas <kernel@xxxxxxxxxxx> writes:


While it is not clear what form the final soft real time
implementation is, we should complete the partial implementation of
SCHED_ISO that is in 2.6.11-rc2-mm1.


I finally had a chance to try this today. I applied a slightly
different patch (2.6.11-rc2-iso3.diff) on top of patch-2.6.11-rc2. I
tried to use 2.6.11-rc2-mm2, but could not due to conflicts with other
scheduler updates.

It is not clear whether the realtime threads are running in the new
scheduler class. Checking with schedtool yields odd results.
(Before, my old schedtool always said "POLICY I: SCHED_ISO".)

[joq@sulphur] jack_test/ $ pst jackd
2173 2173 TS - 0 19 0 0.0 SLs rt_sigsuspend jackd
2174 2174 ? 21 0 60 0 0.0 SL - jackd
2175 2175 TS - 0 23 0 0.0 SL rt_sigsuspend jackd
2176 2176 TS - 0 23 0 0.0 SL - jackd
2177 2177 ? 20 0 59 0 0.0 SL syscall_call jackd
2178 2178 ? 10 0 49 0 1.7 SL - jackd
[joq@sulphur] jack_test/ $ schedtool 2174 2176 2177 2178
PID 2174: PRIO 21, POLICY (null) , NICE 0
PID 2176: PRIO 0, POLICY N: SCHED_NORMAL, NICE 0
PID 2177: PRIO 20, POLICY (null) , NICE 0
PID 2178: PRIO 10, POLICY (null) , NICE 0

They're SCHED_ISO_FIFO which schedtool doesn't know about.

The results of the first run indicate something is badly wrong. It is
quite possible that I got confused and messed up the build somehow.

http://www.joq.us/jack/benchmarks/sched-iso3/jack_test3-2.6.11-rc2-q1-200501311225.log
http://www.joq.us/jack/benchmarks/sched-iso3/jack_test3-2.6.11-rc2-q1-200501311225.png

Loading the realtime-lsm and then running with SCHED_FIFO *does* work
as expected on this kernel. I should retry the test with *exactly*
the expected patch sequence. What would that be?

Shouldn't matter. There must still be something wrong with my code... sigh. I'll look into it at some stage, but there doesn't seem much point.

Cheers,
Con

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