Subject: Re: [PATCH] sched: Wholesale removal of sd_idle logic
From: Peter Zijlstra <peterz@infradead.org>
To: Venkatesh Pallipadi <venki@google.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>, Ingo Molnar <mingo@elte.hu>,
        linux-kernel@vger.kernel.org, Paul Turner <pjt@google.com>,
        Mike Galbraith <efault@gmx.de>, Nick Piggin <npiggin@gmail.com>,
        Tim Chen <tim.c.chen@intel.com>, Alex Shi <alex.shi@intel.com>,
        Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
In-Reply-To: <1297723130-693-1-git-send-email-venki@google.com>
References: <1297473616.2806.16.camel@sbsiddha-MOBL3.sc.intel.com>
	 <1297723130-693-1-git-send-email-venki@google.com>
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Date: Wed, 16 Feb 2011 12:43:55 +0100
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On Mon, 2011-02-14 at 14:38 -0800, Venkatesh Pallipadi wrote:
> 
> The initial patch here - https://patchwork.kernel.org/patch/532501/
> applies cleanly over the below change and provides a micro-optimization
> for a specific case, where an idle core can pull tasks instead of a
> core with one thread being idle and other thread being busy.
> It will be good to get some data on whether this micro-optimization
> matters or not. 

I would much rather see a solution that solves that problem for the more
generic situation where we lower capacity to 1.

The whole double-balance thing is fairly inherent in the whole design,
and making an exception for just one special case doesn't look right.
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