RE: [patch 0/2] fix perf. bug in wake-up load balancing for aim7 and db workload

From: Chen, Kenneth W
Date: Tue Feb 14 2006 - 01:11:18 EST


Nick Piggin wrote on Monday, February 13, 2006 7:44 PM
> Andrew Morton wrote:
> > Well I don't see any benchmark numbers in the original patch. Just an
> > assertion that it "should" help something.
> >
> The regression was in a Ken's commercial database benchmark. I couldn't
> reproduce it but presumably it did fix it otherwise Ken would would have
> piped up?

I wasn't entirely happy though ;-)


> > I'm more inclined to revert it and not add the sysctl (ugh) until we have a
> > good reason to do so.
> >
>
> If you revert this then Ken's database benchmark gets worse. Hence the
> sysctl.

Yes, Nick is correct. For db workload, the wake-ups type are mixed.
Some of them are random, some of them are not because we do interrupt
binding. The break down between random/fixed is about 30/70. Thus,
Nick's patch helps 30% of time. With sysctl, we can regain the entire
up side for db workload while retain workload on the other end of
spectrum.

- Ken

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