RM算法的运行时开销研究与算法改进

RM算法是经典的固定优先级实时调度算法.而在嵌入式实时系统中,系统的工作负荷往往是由很多频率快、执行时间较短的任务组成.因此,直接使用RM算法进行任务调度会由于实时操作系统中任务的上下文切换开销而导致嵌入式系统资源利用率的降低.分析了基于RM算法调度的任务之间的抢占关系,并建立了以任务属性为参数的上下文切换开销模型.在该模型的基础上,通过优化任务的释放时间来降低RM算法导致的系统运行时任务切换开销.最后的实验结果验证了该策略的有效性.

Research on run-time overhead of RM and improvement

RM algorithm is a classic fixed priority real-time scheduling algorithm, but in most embedded real-time systems, where the workload is composed of many tasks of high frequency and short execution time. the overheads from context-switches of real-time operating system will lead to a low resource utilization rate if RM algorithm is directly used. By studying the preemption relationship of the tasks scheduled by RM algorithm, a model of context-switches overheads is established with task attributes, based on which the run-time context-switches overheads of RM algorithm are reduced by optimizing the release time of the tasks in embedded real-time systems. Finally, the experimental results show the validity of the proposed strategy.