一种无抖动的分布式多媒体任务调度算法

在分布式多媒体系统中，资源的管理和分配算法是保证应用的服务质量（ＱｏＳ）的关键问题，而资源管理中，ＱｏＳ协商和确认都和多媒体任务调芳算法有关，任务调度算法是资源管理的重要内容。现有的调度算法ＥＤＦ，ＲＭ，ＤＳｒ适用在分布式多媒体系统中，有局限性。本文基于风车调度模型，提出了一种无抖动调度的逐步消除候选项的并行算法ＤＭＳｒ，能达到分布系统中多媒体任务周期调度的无抖动特点，并讨论了算法的计算复杂度，证

A JITTERLESS TASKS SCHEDULING ALGORITHM FOR DISTRIBUTED MULTIMEDIA SYSTEMS

The algorithm of resource management and allocation is very important to guarantee the application's quality of service (QoS) in distributed multimedia systems. In resource management, the QoS negotiation and admission depend on scheduling algorithm. Thus it is the kernel of resource management. Early deadline first (EDF) and rate monotonic (RM) in real time systems have been used in distributed multimedia systems today. But they can result to schedule with much jitter. Recently, a new pinwheel scheduling DSr that is little jitter scheduling is presented. But it is only suitable for uniprocessor systems. Although DSr is a distributed scheduling algorithm, its assumption is not very suitable for distributed systems so that it can not be adopted. This paper presents a jitterless integrated task scheduling algorithm DMSr that removes candidates step by step based on the pinwheel model of distance constraints. It discusses the time complexity and proves the schedulability condition. It can guarantee the QoS of multimedia tasks. Specially it can schedule with jitterless. Two examples illustrate scheduling algorithm procession and tight schedulability condition in this paper. Finally, the authors do experiments with client/server model in 100M switching Ethernet and make the compression about results in delay, jitter and CPU utilization among EDF, RM and DMSr.