Messages in this thread | | | Date | Wed, 28 Jan 2009 18:06:37 -0800 (PST) | From | Xiaoning Ding <> | Subject | Re: a question about p4_clockmod module on Xeon quad core processors |
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Thanks for the correction. My experiments need to reduce CPU speed. However, I can only reduce the speed by about 30% (from 2.67GHz to 2GHz) with ACPI. That is not enough for the experiments.
p4-clockmod has not been removed from 2.6.29. It is under the same directory as acpi-cpufreq (arch/x86/kernel/cpu/cpufreq). So I thought it was an alternative approach. But I could not get it loaded.
Xiaoning
--- On Wed, 1/28/09, Dave Jones <davej@redhat.com> wrote:
> From: Dave Jones <davej@redhat.com> > Subject: Re: a question about p4_clockmod module on Xeon quad core processors > To: "Xiaoning Ding" <dingxn@ymail.com> > Cc: linux-kernel@vger.kernel.org > Date: Wednesday, January 28, 2009, 9:02 PM > On Tue, Jan 27, 2009 at 12:17:25PM -0800, Xiaoning Ding > wrote: > > Hi list, > > > > I have tried the p4-clockmod module in Linux kernel > 2.6.29 on Xeon 5355 quad-core CPUs with no luck. It seems > current p4-clockmod driver still cannot support Intel Quad > core processors, right? > > > > I know I can also use acpi-cpufreq. It can only scale > down the frequence from 2.67GHz to 2GHz. But I need some > lower frequencies for some experiments. > > p4-clockmod doesn't change the processor frequency. > Because of common misconceptions like this, the user > interface has been removed. > > In 2.6.29, the clock modulation code is called directly > from ACPI > whenever thermal events indicate that throttling is > necessary. > > Dave > > -- > http://www.codemonkey.org.uk
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