Re: [Lse-tech] [patch] sched-domain cleanups, sched-2.6.5-rc2-mm2-A3

From: John Hawkes
Date: Thu Mar 25 2004 - 11:26:28 EST

From: "Nakajima, Jun" <jun.nakajima@xxxxxxxxx>
> We have found some performance regressions (e.g. SPECjbb) with the
> scheduler on a large IA-64 NUMA machine, and we are debugging it. On SMP
> machines, we haven't seen performance regressions.

I've run a flavor of AIM7 and kernbench on a variety of ia64-NUMA CPU counts,
ranging up to 128p (and my 2.6.4 + Piggin-scheduler kernel hangs during boot
at >=192p, vs. 2.6.4 + vanilla-scheduler booting and running at 512p), and the
Piggin scheduler is 10-15% slower at 64p, and even worse at 128p. I did,
however, produce superior performance (superior to the vanilla scheduler) with
AIM7 by increasing the sched_domain->busy_factor by 4x. I tried a few other
things, but nothing improved performance on these big systems better than a
simple increase of busy_factor.

John Hawkes

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