Minimizing Energy Consumption of Real-Time Parallel Applications Using Downward and Upward Approaches on Heterogeneous Systems

The problem of minimizing the energy consumption of a real-time parallel application on a heterogeneous system has been studied recently, and slack time reclamation based on the dynamic voltage and frequency scaling (DVFS) energy-efficient design technique has been proposed as a solution. However, the state-of-the-art algorithms merely minimize energy consumption through an “upward” approach (i.e., from exit to entry tasks) and do not apply the “downward” approach (i.e., from entry to exit tasks) to energy consumption minimization. This study solves the same problem by employing “downward” and “upward” approaches. The concepts of deadline-slack and task level are introduced to transfer the deadline of the parallel application to each task, that is, “downward” energy consumption minimization is implemented. “Upward” energy consumption minimization by reclaiming the slack time is then included to implement “downward” and “upward” energy consumption minimization with low time complexity. Results of the experiments using real parallel applications show that the proposed algorithm can generate the minimum energy consumption compared with the state-of-the-art algorithms under different real-time and scale conditions.