Quantitative Evaluation of Single and Multicore Real-Time DVFS Schedulers in Linux

We report on our experience in implementing and evaluating nine, state-of-the-art single and multicore real-time dynamic voltage and frequency scaling (DVFS) schedulers on an embedded Linux platform. The algorithms include CC-EDF, LA-EDF, DRA, AGR, CVFS, and DR, among others, and the platform is a dual-core ARM Cortex-A9 MPCore processor/PandaBoard, running a real-time Linux kernel. Our evaluations reveal the effectiveness of the algorithms’ power savings. However, due to non-negligible scheduling and voltage/frequency transition overheads, non ideal time accounting, and our integrated Linux scheduling environment, their timeliness behaviors deviate from the theoretical. We propose solutions and identify reduced, schedulable total task utilization bounds.