模糊数据流实时任务调度算法

针对数据流系统中实时查询任务的特点,提出了基于模糊综合评判的动态优先级调度算法。用语言模糊集描述任务的不确定性因素和不同的优先等级,利用最大隶属度原理确定任务的优先等级。算法充分考虑了任务的持续周期性、任务之间存在依赖关系与共享滑动窗口的特点对任务优先级的影响。从累积实现价值率、差分截止期保证率和CPU切换频率3个方面测试了算法的性能,实验表明所提出算法相对于HVF算法、LSF算法、模糊动态抢占调度算法都有很大的改进。

Fuzzy data stream real-time task scheduling algorithms

Aiming at the real-time task characteristics of the data stream system,a dynamic priority scheduling algorithm based on fuzzy comprehensive evaluation is presented.Making use of linguistic fuzzy sets for describing uncertain factors and different priority levels,the principle of maximum membership function for determining the task priority level.Most of the task of data stream is continuous and period.There are depending relations and shared sliding windows among the tasks.The influence of these characteristics is sufficiently considered.Based on hit value ratio,differentiated guarantee ratio and CPU switching frequency,an experiment which testes the LSV performance is completed.The experimental results show that the algorithm can improve the performance compared to the classical HVF,LSF and fuzzy dynamic pre-emptive scheduling algorithms.