多核环境下虚拟机VCPU调度研究：问题与挑战  

Virtual Machine VCPU Scheduling in the Multi-core Environment:Issues and Challenges

作　　者：金海[1,2] 钟阿林[1,2] 吴松[1,2] 石宣化[1,2] 

机构地区：[1]服务计算技术与系统教育部重点实验室华中科技大学武汉430074 [2]集群与网格计算湖北省重点实验室华中科技大学武汉430074

出　　处：《计算机研究与发展》2011年第7期1216-1224,共9页Journal of Computer Research and Development

基　　金：国家“九七三”重点基础研究发展计划基金项目(2007CB310900);国家自然科学基金项目(61073024,60973037);教育部新世纪优秀人才支持计划基金项目(NCET07-0334);武汉市晨光科技计划基金项目(201050231075)

摘　　要：虚拟机VCPU调度策略和机制是影响虚拟机系统性能的关键因素.由于虚拟机系统改变了传统的软件栈结构,简单地将传统操作系统中所采用的调度策略和算法移植到虚拟机监视器层用于虚拟机VCPU的调度,会导致虚拟机系统性能的偏离甚至严重下降,虚拟机系统下层的物理处理器采用多核结构更增加了虚拟机VCPU调度的复杂性.详细介绍并分析了虚拟机系统的架构及虚拟机系统两层调度框架的特点,指出了虚拟机客户操作系统与虚拟机监视器之间的语义缝隙、多处理器操作系统的同步机制、多核处理器的共享cache结构以及新出现的不对称多核结构是虚拟机VCPU调度所面临的主要问题和挑战,深入剖析了目前已提出的针对上述问题和挑战的各种解决方法和机制,指出了它们的特点及局限性,为未来进一步的研究工作提出了建议.The policies and mechanisms of VCPU （virtual CPU） scheduling in a virtual machine system are key factors to determine the system performance. Because the architecture of the software stack in the virtual machine system is different from the traditional computer systems, when scheduling the VCPUs in virtual machines, simply adopting scheduling strategies and algorithms of existing operating systems without any modifications can lead to drastic degradation of the system performance. Moreover, with the multi-core technology being employed for physical processors, the complexity of the VCPU scheduling is increased. Firstly, the architecture of the virtual machine system and its two-stage scheduling framework are depicted and analyzed in detail in this paper. Because the deterministic mapping relationship between application threads and physical cores is difficult to establish in the two-stage framework, and part functions of operating systems move down to virtual machine monitor, VCPU scheduling will confront many problems and challenges that mainly embody four aspects： the semantic gap between guest operating systems and a virtual machine monitor, the synchronization mechanisms in a multiprocessor operating system, the structure of shared cache in multi-core processors and emerging asymmetric multi-core structure. And then advantages and limitations of the existing solutions for these problems are discussed and analyzed deeply, and suggestions for further researches are presented.

关 键 词：VCPU调度 多核 语义缝隙 同步机制 cache共享 不对称多核 

分 类 号：TP316[自动化与计算机技术—计算机软件与理论]