A priority-based MLFQ scheduler for CPU power saving

The graving popularity of mobile computing devices has made energy management important for modern systems. With increasing clock speed and level of integration in today's processors, memories, and I/0-controllers, power dissipation is becoming a definitive concern of system design. The CPU is one of the major power consumers in a portable computer, and considerable power can be saved by turning off the CPU when it is not doing useful work. Significant amount of energy can be saved by dynamically varying CPU speed; numerous algorithms have been proposed with this goal. In this paper we have proposed a Priority-based Multilevel Feedback Queue Scheduler (PMLFQS) for mobile devices. PMLFQS is a work-conserving algorithm that uses different CPU speeds for different queues to minimize the energy consumed by the CPU. Our on paper verification results show that PMLFQS saves energy substantially with little impact on QoS. Compared to system without Dynamic Voltage Scaling (DVS), PMLFQS reduces the total energy of the CPU by more than 80% compared to scheduling at full CPU speed.