[CentOS] powernow-k8 in newer centosplus kernel

JohnS jses27 at gmail.com
Fri Apr 10 07:25:47 UTC 2009


On Thu, 2009-04-09 at 22:39 -0700, Mark Pryor wrote:
> Hello,
> 
> Using kernel:
> 2.6.18-92.1.13.el5.centos.plus
> 
> the cpu throttling works as desired (see 2 traces below)
> 
> ------------- trace snips --------------
> dmesg | grep -i pow
> ACPI: SSDT (v001 PTLTD  POWERNOW 0x00000001  LTP 0x00000001) @ 0x3fff9b40
> powernow-k8: Found 1 AMD Athlon(tm) 64 X2 Dual Core Processor 4600+ processors (                       2 cpu cores) (version 2.20.00)
> powernow-k8:    0 : fid 0x10 (2400 MHz), vid 0x8
> powernow-k8:    1 : fid 0xe (2200 MHz), vid 0xa
> powernow-k8:    2 : fid 0xc (2000 MHz), vid 0xc
> powernow-k8:    3 : fid 0xa (1800 MHz), vid 0xe
> powernow-k8:    4 : fid 0x2 (1000 MHz), vid 0x12
> ACPI: Power Button (FF) [PWRF]
> ACPI: Power Button (CM) [PWRB]
> 
> #cpufreq-info
> cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006
> Report errors and bugs to linux at brodo.de, please.
> analyzing CPU 0:
>   driver: powernow-k8
>   CPUs which need to switch frequency at the same time: 0 1
>   hardware limits: 1000 MHz - 2.40 GHz
>   available frequency steps: 2.40 GHz, 2.20 GHz, 2.00 GHz, 1.80 GHz, 1000 MHz
>   available cpufreq governors: ondemand, userspace, performance
>   current policy: frequency should be within 1000 MHz and 2.40 GHz.
>                   The governor "ondemand" may decide which speed to use
>                   within this range.
>   current CPU frequency is 1000 MHz (asserted by call to hardware).
> (ditto for cpu 1)
> 
> ------------- end snip ----------
> 
> When I update to the newer xx-128.1.6 centosplus kernel all the throttling stops and the box runs at highest speed.
> 
> I noticed that the 92* kernel has no separate powernow-k8.ko module, while the 128* kernel does. Does this module now need to be force loaded?
> 
> This box is used as a desktop.
> ---
Have a look at /etc/sysconf/apmd  CPUFREQ="performance" 
And /etc/sysconfig/cpuspeed  Self explanatory.
Also there is a Gnome Applet you can add to the Gnome Panel called
cpufreq scalling monitor. "The Easy Way"

To use the above you may have to load the correct driver for them and
restart the cpuspeed service.

JohnStanley



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