Migration Aware Low Overhead ERfair Scheduler

Limiting overall scheduling overheads (primarily combining task migration overheads and task selection overheads) is of utmost importance in today's resource constrained multiprocessor real-time embedded systems because it provides premium spare processor bandwidth that may be useful in various situations. This paper presents Migration Aware Low Overhead ERfair Scheduler (MALOES), a hard real-time ERfair multiprocessor scheduler. MALOES employs a two level scheduling technique in which the outer level consists of a load balancer with an online partitioning / merging mechanism that maintains the work load mapped onto disjoint groups of processors. At the inner level, within each task-processor group a task-to processor affinity aware ERfair scheduler is used to execute tasks in ERfair manner while simultaneously attempting to minimize inter-processor task migrations. Experimental results show that MALOES incurs significantly lower overheads compared to all the known ERfair schedulers under most workload scenarios.