PowerTOP is a software utility

Utility software

Utility software is system software designed to help analyze, configure, optimize or maintain a computer. A single piece of utility software is usually called a utility or tool....

 designed to measure, explain and minimise a computer's electrical power

Electric power

Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...

 consumption. It was released by Intel in 2007 under the GPL

GNU General Public License

The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....

v2 license. It works for Intel, AMD

Advanced Micro Devices

Advanced Micro Devices, Inc. or AMD is an American multinational semiconductor company based in Sunnyvale, California, that develops computer processors and related technologies for commercial and consumer markets...

, ARM

ARM architecture

ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...

 and UltraSPARC

UltraSPARC

The UltraSPARC is a microprocessor developed by Sun Microsystems who is now a part of Oracle Corporation and fabricated by Texas Instruments that implements the SPARC V9 instruction set architecture . It was introduced in mid-1995. It was the first microprocessor from Sun Microsystems to implement...

 processors.

PowerTOP analyzes the programs, device driver

Device driver

In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....

s, and kernel options running on a computer based on the Linux

Linux

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 and Solaris operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s, and estimates the power consumption resulting from their use. This information may be used to pinpoint software that results in excessive power use. This is particularly useful for laptop computer users who wish to prolong battery life

Battery life

Battery life can refer to*How long a mobile device can work on a single charge of a rechargeable battery.*Battery lifetime degrading of battery quality over time....

, and data center

Data center

A data center is a facility used to house computer systems and associated components, such as telecommunications and storage systems...

 operators, for whom electrical and cooling costs are a major expenditure.

Usage

The original focus was on CPU sleep states, and showing the programs or drivers responsible for "wakeups" which prevent CPUs entering sleep states. A database of known problems automatically provides more user friendly "tips" for specific sources of wakeups. However, it also shows information on CPU frequency scaling. Over time the database has been expanded to include tips on a wide range of power consumption issues.

Software

Many open source and free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

 programs, such as Mozilla Firefox

Mozilla Firefox

Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers...

 , have been patch

Patch (computing)

A patch is a piece of software designed to fix problems with, or update a computer program or its supporting data. This includes fixing security vulnerabilities and other bugs, and improving the usability or performance...

ed to reduce their power consumption since the release of PowerTOP.

Hardware

It is most effective on laptop computers. Laptops are specifically designed to allow power use to be both monitored and controlled. In particular, many laptop computers can measure the rate of battery use (when not connected to mains power). PowerTOP uses this feature to estimate power usage in Watts and battery life. This provides immediate feedback on changes made e.g. disabling wireless networking when not used.

See also

• Power management
  Power management
  Power management is a feature of some electrical appliances, especially copiers, computers and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low-power state when inactive. In computing this is known as PC power management and is built...
  
  
• Green computing
  Green computing
  Green computing or green IT, refers to environmentally sustainable computing or IT. In the article Harnessing Green IT: Principles and Practices, San Murugesan defines the field of green computing as "the study and practice of designing, manufacturing, using, and disposing of computers, servers,...
  
  
• LatencyTOP
  LatencyTOP
  LatencyTOP is a Linux application for identifying operating system latency within the kernel and find out the operations/actions which cause the latency. LatencyTOP is a tool for software developers to visualize system latencies. Based on these observations, the source code of the application or...
  
  
• top (Unix)
  Top (Unix)
  top is a program found in many Unix-like operating systems. It produces an ordered list of running processes selected by user-specified criteria, and updates it periodically. Default ordering by CPU usage, and only the top CPU consumers shown top shows how much processing power and memory are...
  
  

External links

• PowerTOP: Official website
• Intel and PowerTOP extend Linux laptop battery life
• lesswatts.org Computer Power saving projects on Linux
• Powertop for OpenSolaris, Part of Project Tesla