一种虚拟机监控器的时间片动态调整机制

A Dynamic Time Slice Adjusting Mechanism of Virtual Machine Monitor

在同一物理主机甚至同一CPU/core上,虚拟化技术使得多个虚拟机能够以公平共享物理资源的方式运行。然而,随着共享同一CPU/core的虚拟机数量的增多,每个虚拟机所经历的物理CPU/core访问延迟也在显著增加,造成异构型应用(运行过程中既有网络I/O需求,也有计算需求)在性能方面的负面影响。为解决上述问题,引入一种应用类型感知的虚拟机管理器时间片动态调整机制。该机制可以根据虚拟机中应用的类型动态调整虚拟机的时间片长度。实验结果表明,与Xen Credit调度机制相比,时间片动态调整机制可使异构型应用(Nginx Web服务器)具有更好的响应能力和吞吐能力。

Multiple Virtual Machines（ VMs） can be hosted in the same CPU core with virtualization technologies,in a fair share manner of the physical resources among the VMs. However,as the number of VMs sharing the same core/CPU increase, the CPU access latency perceived by each VM also increases, which translates into longer network I/O processing latency experienced by heterogeneous application including both network I/O and computation. To mitigate such impact, an application type driven dynamic time slice adjusting mechanism is presented. The evaluation of a prototype in Xen shows that,compared with Credit scheduler of Xen,this mechanism improves the connection rate and response time of Nginx Web server.