一个基于RM的弱硬实时调度算法  

A Weakly Hard Real-Time Scheduling Algorithm Based on RM

作　　者：赵明[1] 赵海[1] 张文波[1] 孙佩刚[2] 

机构地区：[1]东北大学信息科学与工程学院,辽宁沈阳110004 [2]沈阳炮兵学院计算机系,辽宁沈阳110162

出　　处：《东北大学学报（自然科学版）》2006年第7期743-746,共4页Journal of Northeastern University(Natural Science)

基　　金：国家火炬计划项目(2002EB010154);国家高新技术研究发展计划项目(2001AA415320)

摘　　要：在定义弱硬实时系统周期任务模型的基础上,提出基于RM调度策略的弱硬实时调度算法PV-RM.PV-RM调度算法在对任务的未来行为进行预测的基础上,通过将任务在抢占段和让步段之间切换,动态调整任务的优先级以反映紧迫程度.在系统过载时,PV-RM调度算法按照任务的初始优先级,为重要的任务提供满足其弱硬实时约束的服务,为其他任务提供尽力而为的服务.给出了PV-RM调度算法的可调度性分析及可调度判定不等式,并通过示例分析说明了该算法的有效性.Defining the periodic task model for weakly hard system, the PV-RM scheduling algorithm is presented on the basis of RM scheduling policy. By virtue of predicting the future tasks, PV-RM can adjust dynamically the priority of task by switching over its running state between P segment and Y segment in accordance to urgency. Once the tasks overload the system, PV-RM will provide the more important tasks having higher initial priority with the service to satisfy their weakly hard real-time restriction, and provide best-effort service to other tasks having lower initial priority. Schedulability analysis and schedulable iudging inequation of the PV-RM are also presented, and thevalidity of the algorithm is illuminated by analyzing examples.

关 键 词：弱硬实时系统 调度算法 弱硬实时约束 抢占段 让步段 

分 类 号：TP316.2[自动化与计算机技术—计算机软件与理论]