Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 29 Jan 2009 17:12:06 -0800 (PST) | From | Xiaoning Ding <> | Subject | Re: a question about p4_clockmod module on Xeon quad core processors |
| |
It works on my machine. Thanks for the help!
Xiaoning
--- On Thu, 1/29/09, 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: Thursday, January 29, 2009, 8:47 PM > This will give you an effective speed of 250 MHz: > > for cpu in 0 1 2 3; do > cpufreq-set -c $cpu -g userspace > cpufreq-set -c $cpu -u 2.0GHz > wrmsr -p $cpu 0x19A 0x12 > done > > 0x19A is the IA32_CLOCK_MODULATION MSR and 0x12 is > calculated from the Intel 64 and IA-32 Architectures > Software Developer’s Manual section 13.5.3. Legal MSR > values are 0x12 (12.5% duty cycle) - 0x1E (87.5%) or 0x00 > for 100%. I tested it on a quad-core Xeon and it works. > > This is somewhat reckless, so use it with caution. > > Wes Felter - wesley@felter.org
-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| ![\](/images/icornerr.gif) |