Debian HOW-TO : CPU power management
Jul. 1st, 2013 04:16 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
oio11к постам ---
Last revision : February 5th, 2007
In this tutorial, I use sudo to get root privileges.
Debian Etch (and Sid) should automatically configure CPU frequency management on most processors that supports it, so it might very well be already enabled. You can verify if that is the case using this command :
and analyze the output regarding the current policy.
If CPU frequency management is off (or the command is not found), then you can go on with this tutorial.
In order to make this work, you need to install the required packages:
Next, verify your exact CPU model :
Which should output something like that :
Once you know your exact CPU type, the next step is to load the proper modules :
the CPU frequency driver and the CPU frequency policy governor.
As you may guess the CPU frequency driver will differ depending on your type of CPU. For example, my laptop is equipped with a Pentium M, so I type :
to load the proper driver.
Some of the other common drivers (or modules) are :
AMD K6 processors : powernow_k6
AMD K7 processors (Athlon, Duron, Sempron 32 bits) : powernow_k7
AMD K8 processors (Athlon 64, Turion 64, Sempron 64, Opteron 64) : powernow_k8
Pentium 4, Celeron D, Pentium D, Celeron M : p4_clockmod
Pentium M, Core Duo, Core 2 Duo : speedstep_centrino
There are of course other CPU frequency drivers. In doubt, you can use the generic driver : acpi_cpufreq
Once the proper driver is loaded, you need to choose the desired CPU policy governor.
This policy governor will manage the actual behavior of your CPU. Here is some policy governors and their module names :
performance, which sets the CPU statically to the highest possible frequency : cpufreq_performance
powersave, which is the opposite, clocks the CPU statically to the lowest frequency : cpufreq_powersave
ondemand, which sets the CPU speed dynamically depending on the work load (ideal for desktops) : cpufreq_ondemand
conservative, which also sets the CPU dynamically, but less aggressively then the ondemand governor (ideal for laptops) :
cpufreq_conservative
For example, my machine has a Pentium M processor, so I type :
to load both the CPU frequency driver and the CPU policy governor.
Once the modules are loaded, you need to configure the policy governor. For example, I use the ondemand governor, so :
will enable it.
You can verify that everything went well with this command :
It should output your actual frequency, as well as the governor presently in use.
If everything is good, then you can make this configuration permanent.
First make sure the proper modules are loaded at startup (in /etc/modules).
So in my case :
Finally, ensure that the CPU uses your policy governor of choice by default. Simply edit the file /etc/sysfs.conf
with a line like this one :
http://technowizah.com/2007/01/debian-how-to-cpu-frequency-management.html
Тестирование компьютера
Jul. 1st, 2011 04:43 amLast revision : February 5th, 2007
CPU frequency management is one of the keys to power preservation.
The Linux kernel now provides all the necessary tools to properly manage CPU frequency : no need to use a daemon (like cpufreqd or powernowd) to take care of your CPU.
Of course the benefits of such power management are obvious for a laptop, but most desktop users should also consider this.
In this tutorial, I use sudo to get root privileges.
- Prerequisites
Debian Etch (and Sid) should automatically configure CPU frequency management on most processors that supports it, so it might very well be already enabled. You can verify if that is the case using this command :
cpufreq-info
and analyze the output regarding the current policy.
If CPU frequency management is off (or the command is not found), then you can go on with this tutorial.
In order to make this work, you need to install the required packages:
sudo apt-get install cpufrequtils sysfsutils
Next, verify your exact CPU model :
cat /proc/cpuinfo | grep "model name"
Which should output something like that :
model name : Intel(R) Pentium(R) M processor 1.73GHz
Once you know your exact CPU type, the next step is to load the proper modules :
the CPU frequency driver and the CPU frequency policy governor.
- CPU frequency driver
As you may guess the CPU frequency driver will differ depending on your type of CPU. For example, my laptop is equipped with a Pentium M, so I type :
sudo modprobe speedstep_centrino
to load the proper driver.
Some of the other common drivers (or modules) are :
AMD K6 processors : powernow_k6
AMD K7 processors (Athlon, Duron, Sempron 32 bits) : powernow_k7
AMD K8 processors (Athlon 64, Turion 64, Sempron 64, Opteron 64) : powernow_k8
Pentium 4, Celeron D, Pentium D, Celeron M : p4_clockmod
Pentium M, Core Duo, Core 2 Duo : speedstep_centrino
There are of course other CPU frequency drivers. In doubt, you can use the generic driver : acpi_cpufreq
- CPU policy governor
Once the proper driver is loaded, you need to choose the desired CPU policy governor.
This policy governor will manage the actual behavior of your CPU. Here is some policy governors and their module names :
performance, which sets the CPU statically to the highest possible frequency : cpufreq_performance
powersave, which is the opposite, clocks the CPU statically to the lowest frequency : cpufreq_powersave
ondemand, which sets the CPU speed dynamically depending on the work load (ideal for desktops) : cpufreq_ondemand
conservative, which also sets the CPU dynamically, but less aggressively then the ondemand governor (ideal for laptops) :
cpufreq_conservative
For example, my machine has a Pentium M processor, so I type :
sudo modprobe speedstep_centrino sudo modprobe cpufreq_ondemand
to load both the CPU frequency driver and the CPU policy governor.
- CPU configuration
Once the modules are loaded, you need to configure the policy governor. For example, I use the ondemand governor, so :
echo ondemand | sudo tee /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
will enable it.
You can verify that everything went well with this command :
cpufreq-info
It should output your actual frequency, as well as the governor presently in use.
- System configuration
If everything is good, then you can make this configuration permanent.
First make sure the proper modules are loaded at startup (in /etc/modules).
So in my case :
echo speedstep_centrino | sudo tee -a /etc/modules echo cpufreq_ondemand | sudo tee -a /etc/modules
Finally, ensure that the CPU uses your policy governor of choice by default. Simply edit the file /etc/sysfs.conf
with a line like this one :
devices/system/cpu/cpu0/cpufreq/scaling_governor = ondemand
http://technowizah.com/2007/01/debian-how-to-cpu-frequency-management.html
-
To problem ;
/etc/sysfs.conf
or
/etc/default/cpufrequtils
my lenny;
uname -a
Linux XXX 2.6.26-2-486 #1 Tue Mar 9 17:10:34 UTC 2010 i686 GNU/Linux
cat /etc/init.d/cpufrequtils
or
cat /etc/init.d/cpufrequtils | grep GOVERNOR
See GOVERNOR="ondemand" or whatelse..
Change it to what you want.
/etc/init.d/cpufrequtils restart
