【摘要】 面向嵌入式实时系统中,任务非抢占式实时容错调度问题,得出了任务能够容忍一次故障的条件,以及能够容忍的故障间隔条件;其次,为了减少任务的等待时间,分别在EDF、RM算法中增加了任务可重复次数的判断条件,在相同等待时间或最终期限下,可重复次数少的任务具有较高的优先级。仿真结果显示,基于RM改进的容错算法NP-PBOR-FT性能较好,平均任务失效率比NP-EDF-FT算法降低了44.19%,比NP-RM-FT算法降低了45.87%,比NP-DBOR-FT算法降低了4.43%,任务等待时间比NP-EDF-FT算法降低了60.54%,比NP-RM-FT算法降低了48.09%,比NP-DBOR-FT算法降低了4.09%;最后,利用设计的NP-PBOR-FT算法,完成实际系统中非抢占式任务的容错调度,采用故障注入的方法,对系统进行了验证,结果表明系统满足实时性以及容错要求。更多还原

【Abstract】 This paper faces the non-preemptive task schedule problem in embedded real-time systems and derives the conditions for one tolerable fault of the task and the tolerable fault gap.In order to reduce the task wait-time,the decision criteria for the task worst-case execution number(WCEN) is introduced in EDF and RM scheduling,at the same wait period or deadline,the task with shorter WCEN has higher priority.Simulation results show that the NP-PBOR-FT algorithm with RM improvement has better performance then the others,the average invalidation rate of the task is 44.19 percent lower than that of NP-EDF-FT algorithm,45.87 percent lower than that of NP-RM-FT algorithm and 4.43 percent lower than that of NP-DBOR-FT algorithm;the average wait-time is 60.54 percent lower than that of NP-EDF-FT algorithm,48.09 percent lower than that of NP-RM-FT algorithm and 4.09 percent lower than that of NP-DBOR-FT algorithm.At last,based on the proposed NP-PBOR-FT algorithm,a non-preemptive real-time fault-tolerant system is designed and verified using the fault-inject method,and results prove that the system satisfies the requirements of real-time and fault-tolerance.更多还原