【作者】 杨夏妮；

【导师】 覃海生；

【作者基本信息】 广西大学 ， 计算机应用技术， 2008， 硕士

【摘要】 负载平衡技术是一种提高分布式系统整体性能和吞吐量的有效方法。本文针对目前负载平衡调度算法存在的不确定性、不完全性和不稳定性问题,负载平衡调度一般模型的单一层次问题以及被大规模系统忽略的集中式调度策略优点的问题,提出一个将集中式调度的易管理性、易实现性和分布式调度的可扩展性相结合的动态负载平衡双层调度模型。该模型将分布式系统分成若干个相对独立的任务调度组,每个任务调度组由一个调度服务器和三个工作站组成,任务调度组内部采用集中式调度,而任务调度组之间采用分布式调度,顶层子系统和底层子系统分别由每个任务调度组的调度服务器和工作站组成。在对动态负载平衡双层调度模型进行描述的过程中,主要根据负载平衡调度一般模型的分布式系统的网络环境、任务集、负载指标和负载平衡调度策略这四个组成部分描述了模型的实现原理、实现规则等,并应用Petri网理论对该模型进行建模。应用Petri网理论构建出来的模型与常用的模型仿真方法和基于数学分析的方法构建出来的模型相比,更能反映系统的动态行为特征,更具有灵活性。Petri网除了是建模工具之外,还被认为是迄今研究系统性能的最有力的工具。在完成动态负载平衡双层调度模型的建模之后,根据该模型的特点提出了系统的设计方案,并利用Petri网对该系统进行性能评价。将在动态负载平衡双层调度模型下采用的集中式调度和分布式调度相结合的策略与负载平衡调度的一般模型下常用的几种动态负载平衡调度策略的进行对比分析后,实验结果表明,该模型能够减少系统的平均响应时间,提高系统的吞吐量,从而有效地提高分布式系统的效率。更多还原

【Abstract】 Load balancing technology is the effective method of improving the performance and the throughput in distributed system. In this paper, considered the problem of uncertainty, incomplete and instability in the current load balancing algorithm, the problem of single level in the general model of load balancing scheduling, the problem of the advantage of the centralized scheduling strategy ignored by the large-scale system, proposed the dynamic load balancing double-decked model that integrated the easy managed and realization of the centralized scheduling and the expansibility of the distributed scheduling. The model divided distributed system into several relative independent task scheduling groups, each task scheduling group made up by a scheduling server and three workstations, within the group used centralized scheduling, among groups used distributed scheduling, the top subsystem and the bottom subsystem made up by scheduling server and workstations of each task scheduling group respectively.In the process of described the dynamic load balancing double-decked scheduling model, according to the four components of the general load balancing scheduling model, there are net condition of the distributed system, task collection, load indicator and load balancing scheduling strategy, made the description of principle, rule etc., and then modeled the model by the theory of Petri net. The model modeled by the theory of Petri net compared with the model modeled by the common method of model simulation and based on mathematical analysis, which was better reflect the dynamic behavior characteristics of the system, and have more flexibility.Petri net was deemed to be the most powerful tool of research the system performance until now, besides the modeling tool. After accomplished modeling the model, proposed the design program of the system based on the behavior of the model, and finally carry out the performance evaluation by Petri net. When carried out the analysis between the integrated strategies both the centralized scheduling and the distributed scheduling under the dynamic load balancing double-decked scheduling model and many common dynamic load balancing scheduling strategies under the general load balancing scheduling model, the experiment result is the model can decrease the average response time and increase the throughput of the system, thereby, it can improve the performance of the distributed system effectively.更多还原