实时调度中的最好响应时间精确分析

Best-case exact analysis in real-time scheduling

计算了抖动分析依赖的最好响应时间和最坏响应时间,计算最好响应时间时假定了任务的截止期小于或等于其周期.在实时调度研究中,引入i级繁忙周期,精确分析任意相位固定优先级抢占调度的最好响应时间,分析中证明存在一个任务的最佳完成时刻.通过构造i级繁忙周期中的扩展作业,推导扩展作业的最佳完成时刻,得到截止期大于其周期的实时任务最好响应时间算法,并在推导过程中证明了算法的正确性.

The best and worst response times on which jitter analysis was relied were calculated. An assumption was made that a task＇ s deadline had to be smaller than or equal to its period when the best response time was calculated. The exact analysis derived with level-i busy period could be used to compute the best-case response times of periodic tasks under fixed-priority preemptive scheduling and arbitrary phasing with deadlines longer than the periods. The exact analysis proved that there was an optimal completion instant for an execution of the task. By constructing the expansion job in the level-i busy period, the algorithm of computing best-case response time of tasks with deadline greater than its period was obtained by the analysis of the optimal completion instant of the expansion job. The correctness of the algorithm was proved.