Long-release-interval-first real-time scheduling algorithm and its schedulability test  

长释放时间间隔优先调度算法及其可调度性分析(英文)

作　　者：沈卓炜[1] 汪芸[1] 

机构地区：[1]东南大学计算机网络和信息集成教育部重点实验室,南京210096

出　　处：《Journal of Southeast University(English Edition)》2006年第4期484-489,共6页东南大学学报（英文版）

基　　金：The Natural Science Foundation of Jiangsu Province(NoBK2005408)

摘　　要：To fulfill the requirements for hybrid real-time system scheduling, a long-release-interval-first （LRIF） real-time scheduling algorithm is proposed. The algorithm adopts both the fixed priority and the dynamic priority to assign priorities for tasks. By assigning higher priorities to the aperiodic soft real-time jobs with longer release intervals, it guarantees the executions for periodic hard real-time tasks and further probabilistically guarantees the executions for aperiodic soft real-time tasks. The schedulability test approach for the LRIF algorithm is presented. The implementation issues of the LRIF algorithm are also discussed. Simulation result shows that LRIF obtains better schedulable performance than the maximum urgency first （MUF） algorithm, the earliest deadline first （EDF） algorithm and EDF for hybrid tasks. LRIF has great capability to schedule both periodic hard real-time and aperiodic soft real-time tasks.针对混合任务实时调度的需求和现有混合任务实时调度算法的局限性,提出了一种长释放时间间隔优先的混合任务实时调度算法LRIF,该算法采用固定优先级和动态优先级相结合的调度策略,根据非周期性软实时任务作业到达流分布,将一定比例的软实时任务作业当作硬实时作业调度,除了可对周期性硬实时任务提供调度保证外,同时还可确保非周期性软实时任务的可调度率.还提出了LRIF调度算法的可调度性分析方法,并讨论了LRIF调度算法的实现方法.测试结果表明:LRIF调度算法具有更好的调度性能,可有效调度由周期性硬实时任务和非周期性软实时任务构成的混合实时系统.

关 键 词：real-time scheduling schedulability test earliest deadline first maximum urgency first long release interval first 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]