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SubjectRe: [BENCHMARK] 2.5.47{-mm1} with contest
Quoting Andrew Morton <akpm@digeo.com>:

> Con Kolivas wrote:
> >
> > io_load:
> > Kernel [runs] Time CPU% Loads LCPU% Ratio
> > 2.4.18 [3] 474.1 15 36 10 6.64
> > 2.4.19 [3] 492.6 14 38 10 6.90
> > 2.5.46 [1] 600.5 13 48 12 8.41
> > 2.5.46-mm1 [5] 134.3 58 6 8 1.88
> > 2.5.47 [3] 165.9 46 9 9 2.32
> > 2.5.47-mm1 [5] 126.3 61 5 8 1.77
> >
> > Very nice. Further improvement in 2.5.47-mm1 (note the big change in
> 2.5.46-47
> > is consistent with the preempt addition as mentioned in a previous thread)
> >
>
> Actually, 2.5.47 changed fifo_batch from 32 to 16. That's what caused
> this big shift.

There I go again, inappropriately commenting on the kernel ;-P Anyway preempt
does help here too (I never said that).

> We've increased the kernel build speed by 3.6x while decreasing the
> speed at which writes are retired by 5.3x.
>
> It could be argued that this is a net decrease in throughput. Although
> there's clearly a big increase in total CPU utilisation.
>
> It's a tradeoff. I think this is a better tradeoff than the old one
> though.

I agree. Fortunately I don't think it's as bad a tradeoff as these numbers make
out. The load accounting in contest (johntest?) is still relatively bogus. Apart
from saying it's more or less loads I dont think the scale of the numbers are
accurate.

Con
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