Messages in this thread | | | Date | Wed, 28 Jan 2009 18:11:40 -0800 (PST) | From | Xiaoning Ding <> | Subject | Re: a question about p4_clockmod module on Xeon quad core processors |
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I installed msr-tools, but could not find detailed information on how to change cpu speed with the tools. Can you point me to detailed documentations? Or, can you share your code?
Thanks!
Xiaoning
--- On Wed, 1/28/09, Wes Felter <wesley@felter.org> wrote:
> From: Wes Felter <wesley@felter.org> > Subject: Re: a question about p4_clockmod module on Xeon quad core processors > To: dingxn@ymail.com > Cc: linux-kernel@vger.kernel.org > Date: Wednesday, January 28, 2009, 9:05 PM > 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. > > Clock modulation is quite simple; in the past I've done > it from userspace with /dev/cpu/*/msr or written my own > module to do it. I don't know if I've ever tried it > on quad-cores, but it worked on dual-core Woodcrest. (Note: > I was not trying to save energy.) > > Wes Felter - wesley@felter.org
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