Combining hard periodic and soft aperiodic real-time task scheduling on heterogeneous compute resources

Effectively scheduling tasks on heterogeneous resources is critical to maximizing the overall benefit of those resources in system-on-a-chip architectures. In this paper we focus on scheduling soft aperiodic tasks alongside periodic tasks with hard deadline constraints on heterogeneous realtime systems. We introduce a method to improve aperiodic task responsiveness without breaking periodic task deadline guarantees, by first scheduling periodic tasks offline, then dynamically scheduling aperiodic tasks in the remaining resource slack time. Experimental results indicate that the quality of aperiodic task scheduling depends highly on the slack distribution within and across resources after periodic task scheduling, and on the flexibility of the aperiodic task scheduler to rearrange these compute slacks to accommodate incoming aperiodic tasks.