Energy Aware EDF Scheduling with Task Synchronization for Embedded Real Time Systems

Slowdown factors determine the extent of slowdown a computing system can experience based on functional and performance requirements. Dynamic Voltage Scaling (DVS) of a processor based on slowdown factors can lead to considerable energy savings. For the Earliest Deadline First (EDF) scheduling, the problem of DVS in the presence of task synchronization has not yet been addressed. We compute slowdown factors for tasks which synchronize for access to shared resources. Tasks synchronize to enforce mutually exclusive access to these resources and can be blocked by lower priority tasks. We compute static slowdown factors for the tasks which guarantee meeting all the task deadlines. Our simulation experiments show on an average 30% energy gains over the known slowdown techniques.