LongRun and LongRun2 are

power management Power management is a feature of some electrical appliances, especially copiers, computers, computer CPUs, computer GPUs and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low-power ...

technologies introduced by

Transmeta Transmeta Corporation was an American fabless semiconductor company based in Santa Clara, California. It developed low power x86 compatible microprocessors based on a VLIW core and a software layer called Code Morphing Software. Code Morphing ...

. LongRun was introduced with the Crusoe processor, while LongRun2 was introduced with the Efficeon processor. LongRun2 has since been licensed to Fujitsu,

NEC is a Japanese multinational information technology and electronics corporation, headquartered at the NEC Supertower in Minato, Tokyo, Japan. It provides IT and network solutions, including cloud computing, artificial intelligence (AI), Inte ...

Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...

Toshiba is a Japanese multinational electronics company headquartered in Minato, Tokyo. Its diversified products and services include power, industrial and social infrastructure systems, elevators and escalators, electronic components, semiconductors ...

, and

NVIDIA Nvidia Corporation ( ) is an American multinational corporation and technology company headquartered in Santa Clara, California, and incorporated in Delaware. Founded in 1993 by Jensen Huang (president and CEO), Chris Malachowsky, and Curti ...

. LongRun automatically adjusted the processor, moving between higher performance but higher power, and lower power but lower performance. The goals of the automation could be adjusted. One control offered processor frequency levels, and the ability to set a minimum and maximum "window", where the automatic controls would not adjust the speed outside of the window. A second control offered a target of either "economy" or "performance". Some versions offered a third control that adjusted the processor based on power rather than speed. LongRun was based primarily on reducing the clock frequency and voltage supplied to the processor, now commonly called DVFS. Lower frequency reduces performance but also allows voltage reduction, and can yield both power savings and improved efficiency. LongRun2 built further on this by incorporating process technology aimed at reducing variations in the manufacturing process and thereby improving yields.

References

External links

Official description of LongRun2
recovered from the Internet Archive as of 2009. Embedded microprocessors Computer hardware tuning Clock signal {{Compu-hardware-stub