I'm using a SMP Mainboard Tyan Tomcat II with 2 P100 w/ 256kByte L2 Cache,
64MB RAM and the systems overall performance is not very good with the
2.1.96 kernel.
For example mpg123 (Version 0.59m+ (1997/10/07)) used to eat about 26% cpu
time on one processor for decoding a MPEG 1 Layer III file in realtime. With
the new kernel it's over 80%(!) with almost all other processes sleeping.
An example top output:
CPU0 states: 45.1% user, 7.1% system, 0.0% nice, 48.0% idle
CPU1 states: 51.6% user, 7.7% system, 0.0% nice, 41.1% idle
[..]
PID USER PRI NI SIZE RSS SHARE STAT LIB %CPU CPU %MEM TIME COMMAND
607 carsten 14 0 496 496 300 R 0 83.5 1 0.7 0:08 mpg123
[..]
I think it is not a soundcard IRQ/DMA conflict, as an ordinary wavplay works
and uses only a few percent CPU time (3-4%) and no error gets logged.
I'm wondering about CPU 1 running at the same load as CPU 0. CPU0 _and_ CPU1
are forced (by the scheduler) to execeute 'mpg123'? This means every CPU has
to reload it's L1 cache very often. Perhaps this is the problem?
Regards
Carsten
-- Carsten Gross Internet: carsten@sol.wohnheim.uni-ulm.de Wohnheim Heilmeyersteige: Sebastian Kneipp Weg 6, 89075 Ulm
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