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From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Len Brown <lenb@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Shaohua Li <shaohua.li@intel.com>,
	"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
	"svaidy@linux.vnet.ibm.com" <svaidy@linux.vnet.ibm.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
	"andi@firstfloor.org" <andi@firstfloor.org>,
	Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH]new ACPI processor driver to force CPUs idle
Date: Fri, 26 Jun 2009 20:49:08 +0100	[thread overview]
Message-ID: <20090626194908.GA11492@srcf.ucam.org> (raw)
In-Reply-To: <alpine.LFD.2.00.0906261209370.4148@localhost.localdomain>

On Fri, Jun 26, 2009 at 12:46:53PM -0400, Len Brown wrote:

> Low Frequency Mode (LFM), aka Pn - the deepest P-state,
> is the lowest energy/instruction because it is this highest
> frequency available at the lowest voltage that can still
> retire instructions.
> 
> That is why it is the first method used -- it returns the
> highest power_savings/performance_impact.

For a straightforward workload on a dual package system, do you get more 
performance from two packages running at their lowest P state or from 
one package at its highest P state and a forced-idle package? Which 
consumes more power?

-- 
Matthew Garrett | mjg59@srcf.ucam.org

  parent reply	other threads:[~2009-06-26 19:49 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-24  4:13 [PATCH]new ACPI processor driver to force CPUs idle Shaohua Li
2009-06-24  6:39 ` Peter Zijlstra
2009-06-24  7:47   ` Shaohua Li
2009-06-24  8:03     ` Peter Zijlstra
2009-06-24  8:21       ` Shaohua Li
2009-06-26 18:16         ` Vaidyanathan Srinivasan
2009-06-29  2:54           ` Shaohua Li
2009-07-06 18:03             ` Vaidyanathan Srinivasan
2009-07-06 23:43               ` Andi Kleen
2009-07-07  0:50                 ` Pallipadi, Venkatesh
2009-07-10 19:31               ` Len Brown
2009-06-24 17:20       ` Len Brown
2009-06-26  7:46         ` Peter Zijlstra
2009-06-26 16:46           ` Len Brown
2009-06-26 18:42             ` Vaidyanathan Srinivasan
2009-07-10 19:47               ` Len Brown
2009-06-26 19:49             ` Matthew Garrett [this message]
2009-07-10 20:29               ` Len Brown
2009-06-30  8:02             ` Shaohua Li
2009-07-07  8:26               ` Peter Zijlstra
2009-07-07  8:24             ` Peter Zijlstra
2009-07-10 20:41               ` Len Brown

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