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集群动态负载平衡系统的性能评价 总被引:18,自引:0,他引:18
该文使用随机Petri网对集群动态负载平衡系统建立了一个抽象模型.通过细化模型中的节点本地处理部分对5种动态负载平衡算法的性能进行了分析,并讨论了集群负载特性对动态负载平衡系统性能的影响,最后得出的主要结论有:(1)动态负载平衡算法可以取得比静态负载平衡算法更好的性能;(2)与传统的只考虑CPU就绪队列的负载平衡算法相比,考虑了各种I/O请求队列的负载平衡算法可以取得更好的性能;(3)即使在极端的集群负载特性中。集群动态负载平衡算法仍然能取得比较理想的性能,因此实现即使是十分简单的集群动态负载平衡系统也是很有必要的。 相似文献
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实时集群中一种基于任务分配表的动态负载平衡算法 总被引:7,自引:2,他引:7
动态负载平衡问题是影响实时集群性能的重要因素。文章在分析实时集群负载平衡特点的基础上,提出了一种基于任务分配表的动态负载平衡算法,并对算法的设计思想和具体实现进行了详细阐述。算法在某指控实时集群系统中的应用证明了它的可行性。 相似文献
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负载平衡是影响并行绘制效率的关键问题。提出了动态负载平衡算法两阶段映射的模型,给出了负载平衡性能的一种度量方法;还提出了一种最佳的任务调度算法,对该算法的性能进行了分析,得出绘制时间的理论上限值,同时给出了多任务划分的方法。 相似文献
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在分布式系统中采用动态负载平衡算法分配系统中的工作负载,能够提高系统的性能。在简述目前常用的几种动态负栽平衡策略的基础上,提出了一种基于实时负载的动态负载平衡策略,并给出了其调度算法。 相似文献
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针对电路并行仿真,基于求解对角分块结构非线性系统的并行方法,提出并实现了"NOW"(Network Of Workstations) 环境下的一个并行计算模型.主要分析了该算法的并行特性、同步条件及"NOW"环境并行性能关键影响因素.文中提出了一种启发式的静态、动态负载平衡算法,并在Linux平台下采用MPI消息库实现该并行模型.仿真结果表明该算法在"NOW"环境下能获得比串行算法较为可观的加速比.同时文中提出的负载平衡算法也比一些经典算法能更有效得平衡系统负载. 相似文献
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分布式系统中一种负载平衡的动态反馈调整自适应算法 总被引:2,自引:0,他引:2
重点研究了分布式系统中的进程迁移和定位、负荷分担中的负载平衡等问题;提出并讨论了基于动态阈值和阈长的进程定位模型和系统负载平衡的动态反馈调整自适应算法,还通过具体的实验分析论证了算法的性能.实验结果说明该算法能在一定的范围内很好地解决进程定位和负载平衡问题,具有较大的实用价值. 相似文献
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集群的负载平衡问题是评价集群系统性能的重要指标.目前,各种负载平衡算法层出不穷,但由于这些算法往往基于特定的集群结构,因此非但不具备通用性,尤其是对于异构集群,造成了软件资源的极大浪费.本文提出了一种通用的负载平衡模型,旨在充分合理利用已有负载平衡算法的基础上,更进一步提高算法的可重用性和可扩展性. 相似文献
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负载均衡是提高分布式系统性能的重要技术,同时也是系统高可用性、可扩展性、冗余性的必然要求.针对分布式系统任务调度不均衡问题,在分析和建立系统仿真和任务调度模型的基础上,提出了一种基于公平指标的任务调度负载均衡算法,推导出在多节点条件下的任务分配方法,并在此模型下改进了基于公平指标的负载均衡算法.最后,在Linux平台下,进行了仿真实验和性能比较.实验结果表明,该算法是有效的,它可以有效地提高分布式系统的性能和效率. 相似文献
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We give a general model of partially asynchronous, distributed load-balancing algorithms for the discrete load model in parallel
computers, where the processor loads are treated as non-negative integers. We prove that all load-balancing algorithms in
this model are finite. This means that all load-balancing algorithms based on this model are guaranteed to reach a stable
situation at a certain time (which depends on the particular algorithm) at which no load will be sent from one processor to
another. With an additional assumption, we prove that the largest load difference between any two processors, in the final
stable situation of the load-balancing algorithms in this model, is upper-bounded by the diameter of the topology. 相似文献
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并行交换是新兴的交换技术,基于该技术能够利用小型交换模块来构建大容量的交换系统,例如太比特或更高容量的交换机.把带输入队列的并行交换称为带缓存并行交换(buffered parallel switch,简称BPS),重点研究其中并行且独立工作的交换模块之间的负载平衡问题.从不同角度出发,提出两种负载平衡的定义.基于两种定义,分别分析了BPS负载平衡的条件并提出分布式调度算法族.最后,提出一种简单而有效的调度算法,该算法能在无加速比BPS中同时满足两种定义,仿真实验结果表明了该算法的有效性和良好性能.另外,就算法的工程实现进行了讨论. 相似文献
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Saeed Sharifian Seyed A. Motamedi Mohammad K. Akbari 《The Journal of supercomputing》2010,53(3):440-463
The growth of web-based applications in business and e-commerce is building up demands for high performance web servers for
better throughputs and lower user-perceived latency. These demands are leading to a widespread substitution of powerful single
servers by robust newcomers, cluster web servers, in many enterprise companies. In this respect the load-balancing algorithms
play an important role in boosting the performance of cluster servers. The previous load-balancing algorithms which were designed
for the handling of static contents in web services suffer from significant performance degradation under dynamic and database-driven
workloads. Regarding this, we propose an approximation-based load-balancing algorithm with admission control for cluster-based
web servers in this study. Since it is difficult to accurately determine the loads of web servers through feedbacks from distributed
agents in web servers, we propose an analytical model of a web server to estimate the web servers’ loads. To achieve this,
the algorithm classifies requests based on their service times and track numbers of outstanding requests for each class of
each web server node and also based on their resource demands to dynamically estimate the loads of each node. For the error
handling of the model a proportional integral (PI) controller from control theory is used. Then the estimated available capacity
of each web server is used for load balancing and admission control decisions. The implementation results with a standard
benchmark confirm the effectiveness of the proposed scheme, which improves both the mean response time and the throughput
of the cluster compared to rival load-balancing algorithms, and also avoids situations in which the cluster is overloaded,
even when the request rates are beyond the cluster capacity. 相似文献
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This paper deals with the organization of a distributed load-balancing policy for a multicomputer system which consists of a cluster of independent computers that are interconnected by a local area communication network. We introduce three algorithms necessary to maintain load balancing in this system: the local load algorithm, used by each processor to monitor its own load; the exchange algorithm, for exchanging load information between the processors, and the process migration algorithm that uses this information to dynamically migrate processes from overloaded to underloaded processors. The policy that we present is distributed, i.e. each processor uses the same policy. It is both dynamic, responding to load changes without using an a priori knowledge of the resources that each process requires; and stable, unnecessary overloading of a processor is minimized. We give the essential details of the implementation of the policy and initial results on its performance. Our results confirm the feasibility of building distributed systems that are based on network communication for uniform access, resource sharing and improved reliability, as well as the use of workstations without a secondary storage device. 相似文献