Energy Minimizing for Parallel Real-Time Tasks Based on Level-Packing

While much work has addressed energy minimizing problem of real-time sequential tasks, little has been done for the parallel real-time task case. In this paper, based on level-packing, we study energy minimization problem for parallel task systems with discrete operation modes and under timing constraints. For tasks with fixed (variable) parallel degrees, we first formulate the problem as a 0-1 Integer Linear Program (0-1 ILP), and then propose a polynomial-time complexity two-step (three-step) heuristic to determine task schedule and frequency assignment (and the task parallel degree). Our simulation result shows that the heuristics consume nearly the same energy as do 0-1 ILPs.