Towards Energy-Aware Multi-Core Scheduling

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.There are two major current trends that can easily be identified in computer industry: (i) the shift towards massively parallelization fostered by multi-core technology resulting in growing numbers of cores per processor and (ii) the increasing importance of energy-awareness in computing due to rising energy costs and environmental awareness. In current operating systems, these two issues are often addressed independently: one component, the scheduler, assigns processes to cores and a second component manages the power states of individual cores in time. In this paper, we explain why this orthogonal treatment can lead to problems such as a considerably degraded system performance in case of on-demand processor power state management. Furthermore, we present an approach to energy-aware multi-core scheduling at the operating system level avoiding the performance penalty while still saving energy. To corroborate our argumentation and to illustrate the applicability of the presented approach, we give numbers from experiments based on Linux and current multi-core processors