System-Wide Leakage-Aware Energy Minimization Using Dynamic Voltage Scaling and Cache Reconfiguration in Multitasking Systems

System optimization techniques are widely used to improve energy efficiency as well as overall performance. Dynamic voltage scaling (DVS) is well studied and known to be successful in reducing processor energy consumption. Due to the increasing significance of the memory subsystem´s energy consumption, dynamic cache reconfiguration (DCR) techniques are recently proposed at the aim of improving cache subsystem´s energy efficiency. As the manufacturing technology scales into the order of nanometers, leakage current, which leads to static power consumption, becomes a significant contributor in the overall power dissipation. In this paper, we consider various system components and study their impact on system-wide energy consumption under different processor voltage levels as well as cache configurations. Based on the observation, we efficiently integrate DVS and DCR techniques together to make decisions judiciously so that the total energy consumption is minimized. Our studies show that considering only DVS or DCR and ignoring the impact from other system components may lead to incorrect conclusions in overall energy savings. Experimental results demonstrate that our approach outperforms existing leakage-aware DVS techniques by 47.6% and leakage-oblivious DVS + DCR technique by up to 23.5%.