一种基于多处理机的容错实时任务调度算法

容错是实时系统的重要要求，在实时系统中，若一个实时任务没在规定的时间期限内完成，则认为系统出现错误，针对多处理机实时系统提出了一种容错调度算法．算法采用了任务的主从备份技术和Ｆｉｒｓｔ－ｆｉｔ启发式方法，通过为可能因处理机故障而执行失败的实时任务预留重新运行的时间来实现容错功能；并通过对预留时间段的重叠利用和无错时预留时间的回收分配，来提高处理机的利用率和系统对任务的接收率．模拟结果表明算法是有效

A MULTIPROCESSOR-BASED FAULT-TOLERANT REAL-TIME TASK SCHEDULING ALGORITHM

Fault tolerance is the important requirement of real time systems. In real time systems, if there is a real time task that does not finish before its deadline, then system will appear abnormal. In this paper, a fault tolerant scheduling algorithm applied for multiprocessor real time system is proposed. Primary backup technique and first fit heuristic method are adopted in this algorithm. The algorithm provides fault tolerance through reserving the re execute time for the failed tasks caused by processor failure, and improves the processor utilization and the task accepted ratio through reclaiming and re assigning the reserved time to other tasks if there is no task failure, as well as through overlapping the reserved time. Simulation results show that the algorithm is efficient.