混合实时任务的两级调度策略

Two-Level Hierarchical Scheduling Scheme of Hybrid Real-Time Tasks

面向混合实时任务应用,提出一种两级结构调度策略:对周期性实时任务采用时间触发,非周期性实时任务则采用事件触发.先建立任务模型并定义相关概念,然后给出调度策略的架构,并对调度算法、可调度性、抖动、时标间隔及调度策略优化等进行研究.结合Windows CE.NET进行的调度策略实验验证结果表明,该方法能提高混合实时任务的确定性,减小抖动.文中最后讨论了时标间隔对处理器利用率和周期分辨率的影响.

In this paper, a two-level hierarchical scheduling scheme is presented for the application-oriented hybrid real-time tasks （HRTF）. In this scheme, the time-triggered and the event-triggered modes are adopted for periodic real-time and aperiodic tasks respectively, and a task model is established, with the related concepts being also defined. Then, the structure of the scheduling scheme is proposed, and some crucial technologies such as scheduling algorithm, schedulability, jitter, tick-interval and optimal scheduling scheme are investigated. Moreover, some experiments combined with Windows CE. NET are performed to validate the scheduling scheme. The results show that the proposed scheme improves the certainty of HRTT and reduces the jitter. The effects of tick-interval on CPU utilization and period resolution are finally discussed.