From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arjan van de Ven <arjan@linux.intel.com>
Subject: Re: [PATCH 3/3] PM: Introduce Intel PowerClamp Driver
Date: Tue, 13 Nov 2012 13:56:45 -0800
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References: <1352757831-5202-1-git-send-email-jacob.jun.pan@linux.intel.com> <1352757831-5202-4-git-send-email-jacob.jun.pan@linux.intel.com> <20121113211602.GA30150@linux.vnet.ibm.com>
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Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>, Linux PM <linux-pm@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, Rafael Wysocki <rafael.j.wysocki@intel.com>, Len Brown <len.brown@intel.com>, Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@elte.hu>, Zhang Rui <rui.zhang@intel.com>, Rob Landley <rob@landley.net>

On 11/13/2012 1:16 PM, Paul E. McKenney wrote:
> On Mon, Nov 12, 2012 at 02:03:51PM -0800, Jacob Pan wrote:
>> Intel PowerClamp driver performs synchronized idle injection across
>> all online CPUs. The goal is to maintain a given package level C-state
>> ratio.
>>
>> Compared to other throttling methods already exist in the kernel,
>> such as ACPI PAD (taking CPUs offline) and clock modulation, this is often
>> more efficient in terms of performance per watt.
>>
>> Please refer to Documentation/thermal/intel_powerclamp.txt for more details.
> 
> If I read this correctly, this forces a group of CPUs into idle for
> about 600 milliseconds at a time.  This would indeed delay grace periods,

6ms not 600