Investigating the Effects of Schedulability Conditions on the Power Efficiency of Task Scheduling in an Embedded System

Power consumption, performance and reliability are the most important parameters in modern safety-critical distributed real-time embedded systems. This paper evaluates and compares different schedulability conditions in fault-tolerant Rate-Monotonic (RM) and Earliest-Deadline-First (EDF) algorithms, with respect to their power efficiency. The primary-backup scheme is used to implement fault tolerance in the algorithms. To evaluate the algorithms, a software tool is developed that can simulate an embedded system consisting of n processors and m periodic tasks. The results show that depending on the different schedulability conditions, the EDF algorithm implemented with the Best-Fit policy is on average 9.6% more power efficient than other algorithms when n=1500 and m=1000. between the two selected schedulability conditions in the RM algorithm, the Utilization Oriented (UO) condition implemented with the Best-Fit policy is on average 5% more power efficient than the other schedulability condition.