Workload-Aware Dual-Speed Dynamic Voltage Scaling

Dynamic voltage scaling (DVS) is a frequently used technique in mobile and embedded systems, aimed at reducing the energy consumption of mobile processors. In systems with a discrete number of frequency levels, existing dual-speed DVS approaches compute an optimal theoretical CPU speed and approximate it by choosing the two neighboring discrete speed levels. By comparing experimentally the energy savings attained with different frequency combinations on a mobile platform, this work shows that choosing the two neighboring frequency levels does not necessarily yield the highest energy savings. As a result of the above observation, this work introduces an online approach to dual-speed DVS that a) formulates a model for speed selection based on the workload characteristics of the current task set, b) computes a frequency pair that yields the best possible energy savings for a given taskset and workload