半虚拟化框架Virtio下的实时网络I/O请求门控机制  

Gating Mechanism for Real-time Network I/O Requests Based on Para-virtualization Virtio Framework

作　　者：申浩希 牛保宁 SHEN Hao-xi;NIU Bao-ning(School of Information and Computer Science,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学信息与计算机学院,太原030024

出　　处：《计算机科学》2022年第2期368-376,共9页Computer Science

基　　金：国家自然科学基金(62072326);山西省重点研发计划项目(201903D421007)。

摘　　要：响应时间是服务等级目标(Service Level Objective,SLO)的一个重要性能指标,与资源的使用量有关。资源充足可以保证请求的正常执行,响应时间短;资源不足,请求需要等待资源,响应时间长。在云计算虚拟化环境下,控制资源的访问既有对整体资源的控制,也有对CPU、网络带宽等单个资源的控制,但是目前很少有通过对网络I/O请求的直接控制来保证响应时间。为了获得更好的性能,虚拟化技术大多采用半虚拟化框架Virtio。网络I/O请求通过Virtio共享通道进行传输,使得在Virtio设立网络I/O请求的门控机制成为可能。文中利用双端聚合方法(Two-end Aggregation Method,TAM),提出实时网络I/O请求门控机制(Gating Mechanism for Real-time Network I/O Requests,GMRNR),通过控制网络I/O请求经过Virtio的时刻,保证各类请求的响应时间。GMRNR设立在Virtio前端virtio-net模块中,将请求按照其响应时间指标分级,采用计时器和聚合队列长度来控制不同级别请求经过Virtio的时刻和聚合频率,保证请求的响应时间。实验测试表明:GMRNR能够区分网络I/O请求优先级,在资源充足时,使得不同等级的网络I/O请求在各自要求的时间内完成;在资源不充足时,能优先保证高优先级的网络I/O请求的响应时间。同时,GMRNR具有较高的资源利用效率。Response time is an important performance indicator of the service level objective(SLO),which is related to the usage of resources.If resources are sufficient to ensure the normal execution of the request,the response time is short.If resources are insufficient,the request needs to wait for resources,and the response time is long.In the cloud computing virtualization environment,the control of resource access includes both the control of the overall resource and the control of individual resources such as CPU and network bandwidth.However,there are currently few direct control of network I/O requests to ensure response time.In order to achieve better performance,virtualization technology mostly uses the para-virtualization framework Virtio.Network I/O requests are transmitted through the Virtio shared channel,making it possible to set up a gating mechanism for network I/O requests in Virtio.Therefore,the study uses the two-end aggregation method(TAM)to propose gating mechanism for real-time network I/O requests(GMRNR),which controls the time when the network I/O request passes Virtio to ensure the response time of various requests.GMRNR is set up in the virtio-net module of Virtio front-end and classifies requests according to their response time indicators.It uses timers and aggregation queue length to control the time and aggregation frequency of diffe-rent levels of requests through Virtio to ensure the response time of the request.Experimental tests show that GMRNR can distinguish the priority of network I/O requests,and when resources are sufficient,network I/O requests of different levels can be completed within their respective required time.When resources are insufficient,the response time of high-priority network I/O requests is given priority.Meanwhile,GMRNR has high resource utilization efficiency.

关 键 词：响应时间 服务等级目标 网络I/O请求 门控机制 Virtio 优先级 

分 类 号：TP393.09[自动化与计算机技术—计算机应用技术]