一种计算混合关键任务响应时间的方法

混合关键系统中不同关键等级的任务在同一个平台运行,任务的可调度性分析更加复杂.基于目前最有效的固定优先级混合关键的调度算法AMC(adaptive mixed criticality),提出了一种任务响应时间分析算法AMC-PM(AMC partition max).该算法将任务最长执行时间(worst case execution time,简称WCET)分成低关键等级态执行时间与高关键等级态执行时间,将这两部分对应的最长响应时间加起来得到总的响应时间上界.通过仿真实验,与已有的AMC响应式分析算法进行比较,结果表明,在任务高关键下最长执行时间较小时,与AMC-rtb相比,AMC-PM能够显著地提高系统的可调度性.同时与AMC-max相比,AMC-PM能够显著降低算法的运行时间.

Method of Response-Time Analysis for Mixed Criticality Systems

In mixed criticality systems, tasks with different criticality levels share a common platform, which makes the schedulability more complex. Considering AMC (adaptive mixed criticality) scheduling is currently the most effective fixed priority approach for scheduling mixed criticality systems, this work presents a response time analysis algorithm AMC-PM (AMC partition max) for AMC. In AMC-PM, the WCET (worst case execution time) of the task is partitioned into low critical execution time and high critical execution time. Then an upper bound of response time can be derived by adding the response times of the two parts together. For tasks with small WCET, evaluations illustrate that AMC-PM can significantly enhance the schedulability comparing with AMC-rtb and that AMC-PM can effectively decrease the run time comparing with AMC-max.