28. Powersaving Governor Configuration 

If you don’t have a cpu that supports power throttling you may omit this step. Cpus that support this feature are only AMD Athlon64(X2) (as well as the same Opteron and Sempron) and Intel Pentium-4 και Core (2) Solo/Duo (as well as Xeon the same and Celeron). 

pacman -S cpufrequtils

Now we have to find what is the name of the kernel’s module that does this job for our processor. The name will be diffirent depending on our processor and its architecture.

Open Midnight Commander: 

mc

And go to directory /lib/modules.

In there you should find different directories for each one of the kernels you have installed in your system. Go to the one you are using.

In there go to kernel/arch and then depending on our architecture:

for amd64

x86_64

for x86

i386

and then at kernel/cpufreq.

In here you will see files with the suffix ".ko".

One of them is needed for our processor.
For example the name for AMD K8 is:

powernow-k8.ko

while for Core2 it is:

acpi-cpufreq.ko

Take a note of it somewhere without its suffix (powernow-k8).

Next go to /sys/devices/system/cpu/cpu0 directory.

In there you should find a directory with the name cpufreq. Enter in there.

Now we will check the content of some files without changing them by using F3:

scaling_driver

In there, there should the module’s name we enabled previously:

powernow-k8

scaling_max_freq
scaling_min_freq

In those two files there should be a number. We also take a note of those two numbers, exactly as they are shown.
For example:

2200000

1000000

scaling_available_governors

In there we will see something like this: 

ondemand performance

We are interested on ondemand.

Let’s correct this file:

etc/conf.d/cpufreq

2-3 lines are of our interest:

governor="ondemand"

And:

min_freq="1GHz"
max_freq="2.2GHz"

Be carefull here to define the minimum and maximum frequencies of our processor.
These are the numbers we previously noted down. Previously they were in Hz, now they are in GHz.
Press F2 for Save and F10 for Exit.

ow let’s correct again the file:
 /etc/rc.conf

In the line:

MODULES=(powernow-k8 forcedeth r8169)

 
If there is no throttling module we add it first.
We should also add some ACPI modules. They should be placed at the end and with the given order:

MODULES=(powernow-k8 forcedeth r8169 ac battery button fan thermal)

Finaly go to the daemons line:

DAEMONS=(

And remove the exclamation mark from cpufreq:

DAEMONS=(syslog-ng network portmap netfs @crond nfslock @nfsd @samba acpid sensors @fam dbus @hal @alsa cpufreq @cups @smartd @openntpd @sshd @gdm)

If you have only KDE in your system instead of @gdm use @kdm

Press F2 for Save and F10 for Exit.

You may now close the Midnight Commander.