Abstract
Title:
Power Management and Dynamic Voltage Scaling: Myths and FactsAuthors:
David C. Snowdon, Sergio Ruocco and Gernot Heiser School of Computer Science and Engineering
University of New South Wales
Sydney 2052 Australia
National ICT Australia, Sydney,
Australia
Abstract:
This paper investigates the validity of common approaches to power management based on dynamic voltage scaling (DVS). Using instrumented hardware and appropriate operating-system support, we account separately for energy consumed by the processor and the memory system.
We find that memory often contributes significantly to overall power consumption, which leads to a much more complex relationship between energy consumption and core voltage and frequency than is frequently assumed. As a consequence, we find that the voltage and frequency setting that minimises energy consumption is dependent on system characteristics, and, more importantly, on the application-specific balance of memory and CPU activity. The optimal setting of core voltage and frequency therefore requires either a-priori analysis of the application or, where this is not feasible, power monitoring at run time.