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 S ...

. LongRun was introduced with the Crusoe processor, while LongRun2 was introduced with the

Efficeon The Efficeon processor is Transmeta's second-generation 256-bit VLIW design released in 2004 which employs a software engine Code Morphing Software (CMS) to convert code written for x86 processors to the native instruction set of the chip. Like i ...

processor. LongRun2 has since been licensed to

Fujitsu is a Japanese multinational information and communications technology equipment and services corporation, established in 1935 and headquartered in Tokyo. Fujitsu is the world's sixth-largest IT services provider by annual revenue, and the la ...

, NEC,

Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professional ...

Toshiba , commonly known as Toshiba and stylized as TOSHIBA, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. Its diversified products and services include power, industrial and social infrastructure systems ...

, and

NVIDIA Nvidia CorporationOfficially written as NVIDIA and stylized in its logo as VIDIA with the lowercase "n" the same height as the uppercase "VIDIA"; formerly stylized as VIDIA with a large italicized lowercase "n" on products from the mid 1990s to ...

. 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