I thought I would write a little howto on how to get cpu frequency
scaling to work directly with the kernel modules. These modules are
generally more efficient for performance computing and battery life.
Prerequisites
kernel >= 2.6.9
Step 1: Enable BIOS Support
Enter your BIOS at boot and make sure Cool'n'Quiet (AMD) or SpeedStep
(Intel) is enable for you CPU. Some BIOS may not have option at all. If
that is the case it is probably enabled by default. Other BIOS may have
the option but it is listed as another name altogether. If that is the
case check your BIOS manual for more info.
Step 2: Remove Userspace Scaling Software
powernowd
cpudyn
Step 3: Install CPU Module
Identify your cpu type by runnig the command
You can also Check the following links
AMD CPU Chart -
Intel CPU Chart -
AMD Sempron/Athlon/MP ( K7 )
Socket Types: A, Slot A
AMD Duron/Sempron/Athlon/Opteron 64 ( K8 )
Socket Types: 754, 939, 940, S1 ( 638 ), AM2 ( 940 ), F ( 1207 )
Intel Core Duo
Intel Pentium M
Others (Unknown)
I'm not entirely sure which cpus are supported using this module. If
your cpu doesn't work with one of the above methods try this one.
Step 4: Scaling Modules
Step 5: Testing/Configuration
Show Available Governors
You should see output similar to
conservative
Description: CPU frequency is scaled based on load in incremental steps up and down.
Advanced Configuration Options
ondemand
Description: CPU frequency is scaled based on load.
Advanced Configuration Options
performance
Description: CPU only runs at max frequency regardless of load.
Configuration Dir: N/A
powersave
Description: CPU only runs at min frequency regardless of load.
Configuration Dir: N/A
Step 6: Load Modules at Boot
Add the following lines to the end of /etc/modules
Step 7: Configure Modules at Boot
This step needs to be done in order for the modules to retain your settings.
Make sure you have sysfsutils installed
Then add the following lines to /etc/sysfs.conf
Where ondemand
can be changed to
another governor type (i.e. conservative, powersave, etc.). You can
also add other configuration options that are specific to the governor
selected.
Useful Links
