Re: [GIT PULL] sched/core for v2.6.32

From: Mike Galbraith
Date: Sun Sep 13 2009 - 02:42:27 EST


On Sun, 2009-09-13 at 00:07 +0200, Jesper Juhl wrote:
> On Sat, 12 Sep 2009, Ingo Molnar wrote:
>

> > It was a statistical property based on performance considerations -
> > and now we flipped it around based on latency and for kbuild
> > performance/throughput reasons: Serge Belyshev reported a 7%
> > increase on a quad due to this change and i measured a 1.5%
> > peak-kbuild performance increase.
> >
> Impressive. I wouldn't have expected that much gain by running the parent
> first. Actually I personally would have expected child-first to perform
> better since (in my experience) it's usually the child that's just forked
> that matters the most.

How can waiting for child1 to run a bit before forking off child2 _not_
hurt? The parent is the worker bee creator, the queen bee if you will.
Seems to me that making the queen wait until one egg hatches and ages a
bit before laying another egg is a very bad plan if the goal is to have
a hive full of short lived worker bees.

-Mike

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