Multiprocessor Priority Scheduling Algorithm in Real-time Systems

Abstract

In recent years, multiprocessor systems are used widespread. However, in real-time systems many scheduling algorithms are developed based on single processor systems, such as rate-monotonic (RM) scheduling algorithm and earliest deadline first (EDF) scheduling algorithm. There are some different properties between single processor systems and multiprocessor systems. Those scheduling algorithms designed for single processor systems are not suitable for applying to multiprocessor systems. For the hard real-time system, it is most important to keep all tasks to meet their deadlines. If the system’s utilization is high, it is hard to approach this goal. In this paper, we propose a scheduling algorithm, Multiprocessor Priority (MPP) scheduling algorithm, for multiprocessor real-time systems. The scheduler assigns all tasks and processors different priorities to prevent the processor time’s fragmentation. Moreover, it reserves longer available processor time for the task that requires longer execution time. This kind of scheduling strategy could increase system’s schedulable rate when the processor’s load is heavy. The simulation results show that the proposed algorithm is efficient even when the system load is heavy.