Abstract: Virtualization technology is widely accepted due to its advantage of running multiple services on a single physical machine while preserving service isolation.However，traditional Virtual Machine Monitors（VMMs） tend to treat virtual machines as completely separated ones，and as a result，the interactions among virtual machines are neglected when VMM performs virtual machine scheduling，which reduces the parallelizability of virtual machines and the quality of service.Based on the study of the virtual machine co-scheduling and the analysis about how scheduling impacts on the cooperativity among virtual machines and the quality of service，a co-scheduling algorithm for virtual machines is proposed.Finally，the experiments show that co-scheduling reduces one third of the server response time and has few effects on the fairness of scheduling.

Key words: co-scheduling, virtualization technology, virtual machine, Xen

摘要： 由于虚拟化技术能对多个服务有效隔离避免其相互间干扰而得到广泛应用。对于需要多个服务协同工作的大型应用，传统虚拟机监控器调度时忽视了虚拟机间的协同性，降低了虚拟机间并行工作的可能性，从而影响了服务质量。对虚拟机的协同调度进行研究，分析了调度对虚拟机协同性及服务质量的影响，提出了一种虚拟机协同调度算法。实验表明，协同调度使虚拟化平台服务器响应时间降低了1/3，且没有对调度的公平性造成明显影响。

关键词: 协同调度, 虚拟化技术, 虚拟机, Xen