Cooperative Software–Hardware Power Management for Main Memory

Energy is becoming a critical resource to not only small battery-powered devices but also large server systems, where high energy consumption translates to excessive heat dissipation, which, in turn, increases cooling costs and causes servers to become more prone to failure. Main memory is one of the most energy-consuming components in many systems. In this paper, we propose and evaluate a novel power management technique, in which the system software provides the memory controller with a small amount of information about the current state of the system, which is used by the memory controller to significantly reduce power. Our technique enables the memory controller to more intelligently react to the changing state in the system, and therefore, be able to make more accurate and more aggressive power management decisions. The proposed technique is evaluated against previously-implemented power management techniques running synthetic, SPECjbb2000 [35] and various SPECcpu2000 [36] benchmarks. Using SPEC benchmarks, we are able to show that the cooperative technique consumes 14.2–17.3% less energy than the previously-proposed hardware-only technique, 16.0–25.8% less than the software-only technique, and 71.6– 75.8% less than no power management.