Slack computation for DVS algorithms in fixed-priority real-time systems using fluid slack analysis

摘要

This work presents a scheduling algorithm to reduce the energy of hard real-time tasks with fixed priorities assigned in a rate-monotonic policy. Sets of independent tasks running periodically on a processor with dynamic voltage scaling (DVS) are considered as well. The proposed online approach can cooperate with many slack-time analysis methods based on low-power work demand analysis (lpWDA) without increasing the computational complexity of DVS algorithms. The proposed approach introduces a novel technique called low-power fluid slack analysis (lpFSA) that extends the analysis interval produced by its cooperative methods and computes the available slack in the extended interval. The lpFSA regards the additional slack as fluid and computes its length, such that it can be moved to the current job. Therefore, the proposed approach provides the cooperative methods with additional slack. Experimental results show that the proposed approach combined with lpWDA-based algorithms achieves more energy reductions than do the initial algorithms alone.