Coordinated and adaptive power gating and dynamic voltage scaling for energy minimization

Customization and adaptation have emerged as the most effective paradigms for energy minimization. We employ these paradigms to address coordinated power gating and dynamic voltage scaling for energy minimization of real-time tasks in both application-specific and programmable systems. For a given hardware platform, the first task in adaptation is to determine which hardware allocations and supply voltages should be used to execute a given set of tasks. In the case where tasks induce constant capacitance and are of sufficient length to render power gating and voltage scaling overheads negligible, we obtain the provably optimal solution using a combination of convex enclosure and convex optimization. Our next goal is to relax these two assumptions to consider overheads and non-uniformity in capacitance by subdividing each task into multiple subtasks at a fine granularity. In this case, we use another dynamic programming formulation to find a solution which is optimal in most practical cases. We have also developed a dynamic programming-based approach to minimize overheads of configuration switching.