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Scheduling for Reduced CPU Energy

  • Mark Weiser
  • Brent Welch
  • Alan Demers
  • Scott Shenker
Part of the The Kluwer International Series in Engineering and Computer Science book series (SECS, volume 353)

Abstract

The energy usage of computer systems is becoming more important, especially for battery operated systems. Displays, disks, and cpus, in that order, use the most energy. Reducing the energy used by displays and disks has been studied elsewhere; this paper considers a new method for reducing the energy used by the cpu. We introduce a new metric for cpu energy performance, millions-of-instructions-per-joule (MIPJ). We examine a class of methods to reduce MIPJ that are characterized by dynamic control of system clock speed by the operating system scheduler. Reducing clock speed alone does not reduce MIPJ, since to do the same work the system must run longer. However, a number of methods are available for reducing energy with reduced clock-speed, such as reducing the voltage [2] [5] or using reversible [7] or adiabatic logic [1]. What are the right scheduling algorithms for taking advantage of reduced clock-speed, especially in the presence of applications demanding ever more instructions-per-second? We consider several methods for varying the clock speed dynamically under control of the operating system, and examine the performance of these methods against workstation traces. The primary result is that by adjusting the clock speed at a fine grain, substantial CPU energy can be saved with a limited impact on performance.

Keywords

Energy Saving Schedule Algorithm Idle Time Power Saving Clock Rate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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Copyright information

© USENIX Association 1994

Authors and Affiliations

  • Mark Weiser
    • 1
  • Brent Welch
    • 2
  • Alan Demers
    • 1
  • Scott Shenker
    • 1
  1. 1.Xerox Palo Alto Research CenterPalo Alto
  2. 2.Sun Microsystems LaboratoryMountain View

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