基于资源回收的容错单调比率调度

【摘要】基于时间冗余的容错实时调度算法，其可调度条件是以任务的最坏执行时间和为任务预留容错操作的时间为分析基础，且任务拒绝率高，系统资源利用率低。该文提出的基于资源回收的容错单调比率调度，以容错实时调度算法FT-RM为基础，利用任务的实际执行时间低于最坏执行时间的特性，收集已完成任务释放的资源供等待任务使用，在保证系统容错要求的同时，提高了任务吞吐量和系统资源利用率，并通过模拟实验分析算法性能，研究了影响算法调度性能的若干因素。
关 键 词 容错; 实时系统; 容错单调比率调度; 资源回收

Fault-tolerant real-time scheduling algorithm through time redundancy, whose schedulability bound is based on the worst execution time of tasks and the time reserved for tasks’ fault-tolerant operation, has high rejection rate and low resource utilization. This paper presents fault-tolerant rate-monotonic scheduling with resource reclaim, based on FT-RM, to improve resource utilization and tasks throughoutput. This algorithm makes use of the attribute that the actual execution time of task is shorter than the worst execution time, to reclaim and reuse the resource released by the ended task. At last, the performance simulation and analysis of the scheduling algorithm are presented and factors that affect performance are investigated.