Re: O(1) scheduler gives big boost to tbench 192

Date: Fri May 03 2002 - 08:38:56 EST

> > > Rumor is that on some workloads MQ it outperforms O(1), but it
> > > may be that the latest (post K3?) O(1) is catching up?

Is MQ based on the Davide Libenzi scheduler?
(a version of Davide's scheduler is in the -aa tree).

> > I'd be interested to know what workloads ?

> AIM on large CPU count machines was the most significant I had heard
> about. Haven't measured recently on database load - we made a cut to
> O(1) some time back for simplicity. Supposedly volanomark was doing
> better for a while but again we haven't cut back to MQ in quite a while;
> trying instead to refine O(1). Volanomark is something of a scheduling
> anomaly though - sender/receiver timing on loopback affects scheduling
> decisions and overall throughput in ways that may or may not be consistent
> with real workloads. AIM is probably a better workload for "real life"
> random scheduling testing.

tbench 192 is an anomaly test too. AIM looks like a nice
"mixed" bench. Do you have any scripts for it? I'd like
to use AIM too.

A side effect of O(1) in ac2 and jam6 on the 4 way box is a decrease
in pipe bandwidth and an increase in pipe latency measured by lmbench:

kernel Pipe bandwidth in MB/s - bigger is better
----------------------- ------
2.4.16 383.93
2.4.19-pre3aa2 316.88
2.4.19-pre5 385.56
2.4.19-pre5-aa1 345.93
2.4.19-pre5-aa1-2g-hio 371.87
2.4.19-pre5-aa1-3g-hio 355.97
2.4.19-pre7 462.80
2.4.19-pre7-aa1 382.90
2.4.19-pre7-ac2 85.66
2.4.19-pre7-jam6 66.41
2.4.19-pre7-rl 464.60
2.4.19-pre7-rmap13 453.24

kernel Pipe latency in microseconds - smaller is better
----------------------- -----
2.4.16 12.73
2.4.19-pre3aa2 13.58
2.4.19-pre5 12.98
2.4.19-pre5-aa1 13.46
2.4.19-pre5-aa1-2g-hio 12.83
2.4.19-pre5-aa1-3g-hio 13.08
2.4.19-pre7 10.71
2.4.19-pre7-aa1 13.32
2.4.19-pre7-ac2 31.95
2.4.19-pre7-jam6 29.51
2.4.19-pre7-rl 10.71
2.4.19-pre7-rmap13 10.75

More at:

Randy Hron

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