O(1) scheduler gives big boost to tbench 192

From: rwhron@earthlink.net
Date: Thu May 02 2002 - 16:36:56 EST

On an OSDL 4 way x86 box the O(1) scheduler effect
becomes obvious as the run queue gets large.

2.4.19-pre7-ac2 and 2.4.19-pre7-jam6 have the O(1) scheduler.

At 192 processes, O(1) shows about 340% improvement in throughput.
The dyn-sched in -aa appears to be somewhat improved over the
standard scheduler.

Numbers are in MB/second.

tbench 192 processes
2.4.16 29.39
2.4.17 29.70
2.4.19-pre5 29.01
2.4.19-pre5-aa1 29.22
2.4.19-pre5-aa1-2g-hio 29.94
2.4.19-pre5-aa1-3g-hio 28.66
2.4.19-pre7 29.93
2.4.19-pre7-aa1 32.75
2.4.19-pre7-ac2 103.98
2.4.19-pre7-rmap13 29.46
2.4.19-pre7-jam6 104.98
2.4.19-pre7-rl 29.74

At 64 processes, O(1) helps a little. ac2 and jam6 have
the highest numbers here too.

tbench 64 processes
2.4.16 101.99
2.4.17 103.49
2.4.19-pre5-aa1 102.43
2.4.19-pre5-aa1-2g-hio 104.30
2.4.19-pre5-aa1-3g-hio 104.60
2.4.19-pre7 100.86
2.4.19-pre7-aa1 101.76
2.4.19-pre7-ac2 105.89
2.4.19-pre7-rmap13 100.94
2.4.19-pre7-rl 99.65
2.4.19-pre7-jam6 108.23

I've seen some benefit on a uniprocessor box running tbench 32
for kernels with O(1). Hmm, have to try tbench 192 on uniproc
and see if the difference is all scheduler overhead.

I'm putting together a page with more results on this machine.
It will be growing at:

Randy Hron

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