Memory-aware dynamic voltage scaling for multimedia applications

As the computing environments are continuously moving towards battery-operated mobile and handheld systems, the development of energy-saving mechanisms for such devices has recently become a technical challenge. Dynamic voltage scaling (DVS) has historically been considered an effective method to reduce the processor power consumption. Conventional DVS techniques typically consider only processor utilisation issues in a policy-making process. However, as memory-bound multimedia applications are becoming popular in handheld devices, the DVS policies should consider the so-called 'memory wall' problem to maximise energy gain. Recent DVS techniques suffer from the inefficiency of their policies caused by the memory-wall problem while executing multimedia applications, and no previous research on DVS considers the problem explicitly. The existence of the memory wall problem in a real system is revealed and a metric that can be used to detect the problem in advance is found. A memory-aware DVS (M-DVS) technique that takes the memory wall problem fully into consideration is proposed. The experimental results on a PDA show that M-DVS can reduce similar to 8% of additional power consumption, compared with conventional DVS, without any QoS degradation for handling multimedia clips.