From: Ingo Molnar <mingo@elte.hu>
To: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: 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>,
Dipankar Sarma <dipankar@in.ibm.com>,
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
Date: Mon, 27 Apr 2009 05:52:16 +0200 [thread overview]
Message-ID: <20090427035216.GD10087@elte.hu> (raw)
In-Reply-To: <20090426204029.17495.46609.stgit@drishya.in.ibm.com>
* Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote:
> Test results for ebizzy 8 threads at various sched_mc settings has
> been summarised with relative values below. The test platform is
> dual socket quad core x86 system (pre-Nehalem).
>
> --------------------------------------------------------
> sched_mc No Cores Performance AvgPower
> used Records/sec (Watts)
> --------------------------------------------------------
> 0 8 1.00x 1.00y
> 1 8 1.02x 1.01y
> 2 8 0.83x 1.01y
> 3 7 0.86x 0.97y
> 4 6 0.76x 0.92y
> 5 4 0.72x 0.82y
> --------------------------------------------------------
Looks like we want the kernel default to be sched_mc=1 ?
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?
Ingo
next prev parent reply other threads:[~2009-04-27 3:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-26 20:46 [RFC PATCH v1 0/3] Saving power by cpu evacuation using sched_mc=n Vaidyanathan Srinivasan
2009-04-26 20:46 ` [RFC PATCH v1 1/3] sched: add more levels of sched_mc Vaidyanathan Srinivasan
2009-04-26 20:46 ` [RFC PATCH v1 2/3] sched: threshold helper functions Vaidyanathan Srinivasan
2009-04-26 20:47 ` [RFC PATCH v1 3/3] sched: loadbalancer hacks for forced packing of tasks Vaidyanathan Srinivasan
2009-04-27 3:52 ` Ingo Molnar [this message]
2009-04-27 5:43 ` [RFC PATCH v1 0/3] Saving power by cpu evacuation using sched_mc=n Vaidyanathan Srinivasan
2009-04-27 5:53 ` Ingo Molnar
2009-04-27 6:39 ` Vaidyanathan Srinivasan
2009-04-27 7:01 ` Balbir Singh
2009-04-27 5:54 ` Dipankar Sarma
2009-04-27 10:09 ` Peter Zijlstra
2009-04-27 14:20 ` Vaidyanathan Srinivasan
2009-04-28 8:33 ` Peter Zijlstra
2009-04-28 8:52 ` Ingo Molnar
2009-04-28 16:15 ` Vaidyanathan Srinivasan
2009-04-28 16:11 ` Vaidyanathan Srinivasan
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