Re: [PATCH] Performance regression in 2.6.7-rc3

Con Kolivas
2004-06-15T13:12:48Z

On Tue, 15 Jun 2004 14:56, Ingo Molnar wrote:
> * Con Kolivas <kernel@kolivas.org> wrote:
> > with a little bit of detective work and help from Wli we tracked down
> > that this patch caused it:
> > [PATCH] sched: improve wakeup-affinity
> >
> > A massive increase in idle time was observed and the throughput
> > dropped by 40% Reversing this patch gave these results:
> >
> > backsched1: http://khack.osdl.org/stp/293865/
> > Composite Query Processing Power Throughput Numerical Quantity
> > 193.93 145.95 257.67
> >
> > It may be best to reverse this patch until the regression is better
> > understood.
>
> agreed. It is weird because Nick said that pgsql was tested with the
> patch - and we applied the patch based on those good results. Nick?
>
> Anyway, does the patch below fix the pgsql problem? It reverts to the
> more agressive idle-balancing variant (which isnt strictly necessary for
> the bw_pipe problem).

Better than the patch backed out but still worse than it was before:
http://khack.osdl.org/stp/293958/
Composite Query Processing Power Throughput Numerical Quantity
161.42 152.90 170.41

Con