Date: Mon, 27 Apr 2009 11:24:51 +0530
From: Dipankar Sarma <dipankar@in.ibm.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
       Linux Kernel <linux-kernel@vger.kernel.org>,
       Suresh B Siddha <suresh.b.siddha@intel.com>,
       Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Arjan van de Ven <arjan@infradead.org>,
       Balbir Singh <balbir@linux.vnet.ibm.com>,
       Vatsa <vatsa@linux.vnet.ibm.com>, Gautham R Shenoy <ego@in.ibm.com>,
       Andi Kleen <andi@firstfloor.org>,
       Gregory Haskins <gregory.haskins@gmail.com>,
       Mike Galbraith <efault@gmx.de>, Thomas Gleixner <tglx@linutronix.de>,
       Arun Bharadwaj <arun@linux.vnet.ibm.com>
Subject: Re: [RFC PATCH v1 0/3] Saving power by cpu evacuation using
	sched_mc=n
Message-ID: <20090427055451.GF13342@in.ibm.com>
Reply-To: dipankar@in.ibm.com
References: <20090426204029.17495.46609.stgit@drishya.in.ibm.com> <20090427035216.GD10087@elte.hu>
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On Mon, Apr 27, 2009 at 05:52:16AM +0200, Ingo Molnar wrote:
> 
> Regarding the values for 2...5 - is the AvgPower column time 
> normalized or workload normalized?
> 
> If it's time normalized then it appears there's no power win here at 
> all: we'd be better off by throttling the workload directly (by 
> injecting sleeps or something like that), right?

Energy savings with this will depend on the workload running. We have 
seen transactional workloads where taking off a few cores has almost 
no impact on throughput or response time.

Thanks
Dipankar
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