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.
出处
《东北大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
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)
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
weakly hard systern
scheduling algorithm
weakly hard real-time restrietion
preempt segment
yield segment