Abstract

Traditional multiprocessor real-time scheduling partitions a task set and applies uniprocessor scheduling on each processor. For architectures where the penalty of migration is low, such as uniform-memory access shared-memory multiprocessors, the non-partitioned method becomes a viable alternative. By allowing a task to resume on another processor than the task was preempted on, some task sets can be scheduled where the partitioned method fails. We address fixed-priority scheduling of periodically arriving tasks on Ñ equally powerful processors having a non-partitioned ready queue. We propose a new priorityassignment scheme for the non-partitioned method. Using an extensive simulation study, we show that the priorityassignment scheme has equivalent performance to the best existing partitioning algorithms, and outperforms existing fixed-priority assignment schemes for the non-partitioned method. We also propose a dispatcher for the nonpartitioned method which reduces the number of preemptions to levels below the best partitioning schemes.

Citations