Re: [RESEND PATCH V5 0/8] remove cpu_load idx

From: Peter Zijlstra
Date: Tue May 06 2014 - 07:43:24 EST


On Tue, May 06, 2014 at 04:33:38PM +0800, Alex Shi wrote:
>
> >
> > Maybe the predication is reasonable on per task history. but on a cpu
> > load history, with many tasks rebalance. No testing show current method
> > is helpful.
> >
> > For task load change, scheduler has no idea for its future except guess
> > from its history. but for cpu load change, scheduler know this from task
> > wakeup and balance, which both under control and its aim.
> >
> >
> > I think the first patch of this serial has the same effect of LB_LIAS
> > disable. and previous result show performance is good.
> >
> > Anyway, I just pushed the following patch to github, maybe fengguang's
> > testing system will care this.
>
> Fengguang,
>
> Are there any performance change on
> https://github.com/alexshi/power-scheduling.git noload repository?

You forgot to qualify that with the important bit; on _large_ systems.
Esp. non fully connected numa boxen. Also, I'm not sure Wu has workloads
that are typical of such systems -- even if he has such machines, which
I don't know either.

Enterprise distro testing has _some_ of that, but the very sad truth is
that most enterprise users lag behind at least a full release cycle. So
by the time people start using the kernel, its so old nobody really
cares anymore :-(


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