A Simple Model for Understanding Optimal Hard Real-Time Multiprocessor Scheduling

We consider the problem of optimal real-time scheduling of periodic tasks for multiprocessors. A number of recent papers have used the notion of fluid scheduling to guarantee optimality and improve performance. In this paper, we examine exactly how fluid scheduling techniques overcome inherent problems faced by greedy scheduling algorithms such as EDF. Based on these foundations, we describe a simple and clear optimal scheduling algorithm which serves as a least common ancestor to other recent algorithms. We provide a survey of the various fluid scheduling algorithms in this novel context.