基于反馈控制的开放式实时系统自适应调度算法设计与实现  

Design and Implementation of Self-adaptation Scheduling Algorithm for Open Real-time System

作　　者：牛云[1] 戴冠中[1] 慕德俊[1] 梁亚琳[1] 

机构地区：[1]西北工业大学自动化学院,西安710072

出　　处：《计算机科学》2008年第9期59-61,118,共4页Computer Science

基　　金：国防基础科研项目(项目编号:C2720061361)

摘　　要：对于负载不可预测且资源受限的开放式实时系统,传统"开环"调度算法不能根据系统负载情况调整调度策略,影响系统实时性能或造成资源浪费。采用双闭环反馈控制方法,改进目前开放式实时系统常用的时限驱动总带宽利用率服务器。本方法根据负载情况,动态地为不同实时性能需求的任务分配资源,保证硬实时任务满足时限要求并且提高资源利用率。实验表明,系统负载存在突发的情况下,算法既很好地控制了任务的时限错过率,又得到了较高的资源利用率。The traditional ＂open loop＂ scheduling algorithms perform poorly in open real time systems whose workloads vary unpredictable dynamically because the ＂open loop＂ refers to the fact that once schedules are created they are not adjusted based on the system workloads. A dual close-loop feedback scheduling algorithm is proposed to improve total bandwidth server in EDF scheduling which is widely used in open real time systems. The algorithm adjusts the resource assignation for different kinds of tasks based on feedback workloads and guarantees the deadline miss ratio of hard real time tasks with adequate resource utilization. Experiments based on VxWorks/Goahead embedded Web server system demonstrate the effectiveness of the proposed scheduling algorithm when there are large bursts of total load in the systern.

关 键 词：开放式实时系统 总带宽利用率服务器 反馈控制调度 硬实时性能保证 资源利用率 

分 类 号：TP316.2[自动化与计算机技术—计算机软件与理论] TP277[自动化与计算机技术—计算机科学与技术]