基于M/M/1排队模型的网络服务尾延迟分析  

Network Service Tail Latency Analysis Based on M/M/1 Queuing Model

作　　者：郭子亭 张文力[1] 陈明宇[1,2,3] GUO Zi-ting;ZHANG Wen-li;CHEN Ming-yu(State Key Laboratory of Computer Architecture,Institute of Computing Technology,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;Peng Cheng Laboratory,Shenzhen,Guangdong 518055,China)

机构地区：[1]中国科学院计算技术研究所计算机体系结构国家重点实验室,北京100190 [2]中国科学院大学,北京100049 [3]鹏城实验室,广东深圳518055

出　　处：《计算机科学》2020年第11期286-293,共8页Computer Science

基　　金：国家重点研发计划项目(十三五)(2017YFB1001602)。

摘　　要：研究表明,在大规模的网络服务系统中,网络延迟往往表现出长尾效应,即存在一定比例的延迟远大于网络的平均延迟。延迟的长尾引起了广泛的关注,长尾效应会严重影响用户体验和内容供应商收益,尤其在对延迟敏感的大型交互式网络应用中。因此,网络服务系统研究的重点经历了从关注吞吐量和平均延迟到关注系统的尾延迟的变化。然而,现有的理论模型大多关注平均延迟,难以用来分析网络服务延迟的尾部特征,复杂网络服务中的尾延迟时间计算缺乏形式化的建模和计算方法。文中提出了一种将复杂的网络抽象为以M/M/1排队模型为基础的排队网络模型的方法,在该模型的基础上给出了串联、并行场景下逗留时间尾延迟分布的表达式,同时分析了当模型中个别子部件发生变化时对系统整体尾延迟的影响,并将模型预测结果和仿真网络的结果进行对比,误差不超过2%。Studies have shown that in large-scale network service systems,network latency often exhibits a long tail effect,i.e.,a certain percentage of latency are much larger than the average latency of the network service systems.The long tail of latency has caused widespread concern,and can seriously affect user experience and content provider revenue,especially in large interactive network applications that are sensitive to latency.Therefore,the focus of network service system research has experienced a change from focusing on throughput and average latency to the tail latency of the system of interest.However,most of the exi-sting theoretical models focus on average latency,and it is difficult to analyze the tail characteristics of the network service latency.Due to the complexity of existing research,stay time calculations in complex network services lack formal modeling and computational methods.This paper proposes a method of abstracting a complex network into a queuing model.Based on the model,the expressions of stay time distribution in series and parallel scenes are given,and at the same time,the influence of the tail latency on the change of individual sub-components in the model is analyzed.The predicted results of the model analysis are compared with the results of the simulation network,the error does not exceed 2%.

关 键 词：尾延迟 建模 M/M/1 串联 并行 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]