POWERNOWD will CONTROL OF THE CPU IN LINUX

Modern cpu linux are now all point to a very thorough energy savings. This is due to several factors, mainly for energy consumption (which if reduced leading to increased battery life of a laptop for example) and heating problems. For some years the cpu are equipped with the ability to exchange the fly's clock speed and voltage of the processor, so that it consumes less when heated and does not require a lot of computing power.

The Linux kernel supports this feature, present in such cpu Intel Centrino and Core Duo or AMD Athlon 64 and there are several daemons that deal specifically to manage this resource based on criteria set by the user.

One of these is called powernowd and will be the subject of our article. Powernowd has the advantage of being simple to use and simultaneously support the technologies from AMD and Intel cpu linux. This program is still created for AMD, but you can use it without problems on Intel. Powernow fact it is the name of AMD's technology (Power Now!, Which evolved later in Cool & Quiet), while below this is called Intel SpeedStep (now Enhanced SpeedStep Technology).

One of the advantages of powernowd is in its simplicity: a few similar projects, adopt the policy to change the clock speed based on events as a high temperature reached by the processor, or battery power supply or power grid.

Although it may seem useful to this type of approach, the developer of this project not considered useful for example to reduce the clock (with a relative decrease of benefits) resulting from the use of the battery: it may be that the user still needs power calculation, and if it were willing to have the utmost to save battery life at that time, however, may diminish the power of clock "manually" by running a command powernowd. This energy-saving technology operates on the CPU linux, and this is what should be the focus of attention.

It is important, before proceeding, ensure that some packages are present on our system. As the end is necessary only to powernowd, some of them, such as acpi and acpid are very useful for the management of the system and will most likely already on your system.

Acpid is the daemon that is responsible for managing the entire energy system, and ACPI is a software that allows the user to interact with this system: for example, you can know the temperature of the PC by running as root acpi-V.

With regard to the installation under Debian and Ubuntu just run as administrator (after the command "apt-get update" to update the package database) command: