Re: [PATCH] sched - Implement priority and fifo support forSCHED_ISO
From: Jack O'Quin
Date: Mon Jan 31 2005 - 17:52:57 EST
Con Kolivas <kernel@xxxxxxxxxxx> writes:
> Sure enough I found the bug in less than 5 mins, and it would
> definitely cause this terrible behaviour.
>
> A silly bracket transposition error on my part :P
The corrected version works noticeably better, but still nowhere near
as well as SCHED_FIFO. The first run had a cluster of really bad
xruns. The second and third were much better, but still with numerous
small xruns.
http://www.joq.us/jack/benchmarks/sched-iso-fix/
With a compile running in the background it was a complete failure.
Some kind of big xrun storm triggered a collapse on every attempt.
http://www.joq.us/jack/benchmarks/sched-iso-fix+compile/
The summary statistics are mixed. The delay_max is noticeably better
than before, but still much worse than SCHED_FIFO. But, the xruns are
really bad news...
http://www.joq.us/jack/benchmarks/.SUMMARY
# sched-iso-fix
Delay Maximum . . . . . . . . : 33894 usecs
Delay Maximum . . . . . . . . : 745 usecs
Delay Maximum . . . . . . . . : 341 usecs
# sched-iso
Delay Maximum . . . . . . . . : 21410 usecs
Delay Maximum . . . . . . . . : 36830 usecs
Delay Maximum . . . . . . . . : 4062 usecs
# sched-fifo
Delay Maximum . . . . . . . . : 347 usecs
Delay Maximum . . . . . . . . : 277 usecs
Delay Maximum . . . . . . . . : 246 usecs
Delay Maximum . . . . . . . . : 199 usecs
Delay Maximum . . . . . . . . : 261 usecs
Delay Maximum . . . . . . . . : 305 usecs
# sched-iso-fix+compile
Delay Maximum . . . . . . . . : 14549 usecs
Delay Maximum . . . . . . . . : 38961 usecs
Delay Maximum . . . . . . . . : 26904 usecs
# sched-iso+compile
Delay Maximum . . . . . . . . : 98909 usecs
Delay Maximum . . . . . . . . : 39414 usecs
Delay Maximum . . . . . . . . : 40294 usecs
Delay Maximum . . . . . . . . : 217192 usecs
Delay Maximum . . . . . . . . : 156989 usecs
# sched-fifo+compile
Delay Maximum . . . . . . . . : 285 usecs
Delay Maximum . . . . . . . . : 269 usecs
Delay Maximum . . . . . . . . : 277 usecs
Delay Maximum . . . . . . . . : 569 usecs
Delay Maximum . . . . . . . . : 461 usecs
Delay Maximum . . . . . . . . : 405 usecs
Delay Maximum . . . . . . . . : 286 usecs
Delay Maximum . . . . . . . . : 579 usecs
# sched-iso-fix
XRUN Count . . . . . . . . . : 26
XRUN Count . . . . . . . . . : 24
XRUN Count . . . . . . . . . : 17
# sched-iso
XRUN Count . . . . . . . . . : 15
XRUN Count . . . . . . . . . : 17
XRUN Count . . . . . . . . . : 5
# sched-fifo
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
# sched-iso-fix+compile
XRUN Count . . . . . . . . . : 22
XRUN Count . . . . . . . . . : 44
XRUN Count . . . . . . . . . : 39
# sched-iso+compile
XRUN Count . . . . . . . . . : 44
XRUN Count . . . . . . . . . : 46
XRUN Count . . . . . . . . . : 45
XRUN Count . . . . . . . . . : 27
XRUN Count . . . . . . . . . : 101
# sched-fifo+compile
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 4
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
XRUN Count . . . . . . . . . : 0
--
joq
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