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Message-ID: <1326120367.2442.84.camel@twins>
Subject: Re: [PATCH] x86,sched: Fix sched_smt_power_savings totally broken
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Youquan Song <youquan.song@intel.com>, linux-kernel@vger.kernel.org,
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        Youquan Song <youquan.song@linux.intel.com>,
        Paul Turner <pjt@google.com>
Date: Mon, 09 Jan 2012 15:46:07 +0100
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On Mon, 2012-01-09 at 15:29 +0100, Vincent Guittot wrote:

> I'm also using sched_mc level for doing powersaving load balance on
> ARM platform and we have real benefits.

Right, I've never said that power aware balancing was without merit, I
know it matters (quite a lot for some).

> We might modify the way we choose between power or performance mode
> because it's not always a matter of gathering or spreading tasks on
> cpus but until we found a best interface it's the way to enable
> powersaving mode

Sure, it was the only interface available.

But I really want to get rid of the topology based knobs we have now,
preferably I even want to get rid of the multi-value thing.

pjt still needs to post his linsched rework *poke* *poke*, that should
give a good basis to rework most of this without regressing the world
and then some.

But even without that I think we can do better than we do currently.