KVM虚拟机CPU虚拟化的研究与调度策略的优化

发布时间：2019-02-09 17:49

【摘要】：由于能够有效地提高计算机资源的利用率，以及应用上的灵活性、安全性和可扩展性，虚拟化技术逐渐成为计算机技术研究和应用方面的热门领域。随着虚拟化技术的发展，主流的硬件厂商Intel和AMD公司提出了新的支持虚拟化技术的硬件架构，使虚拟化技术有了巨大的飞跃。在硬件支持下的虚拟化技术，进一步提高了虚拟化环境下虚拟机的整体性能，并且由于这项技术具有显著的优越性，因此在Linux操作系统中也得到了支持和应用。本文的研究对象是支持硬件辅助虚拟化技术的KVM虚拟化方案，从Linux2.6.20版本开始，该方案已经被集成到Linux内核中。 Intel VT技术是Intel平台上硬件辅助虚拟化技术的总称，该项技术提供了包含CPU、内存、I/O设备等各方面虚拟化支持的一整套虚拟化方案。本文在分析传统的CPU虚拟化技术的基础上，重点对Intel VT技术下的CPU虚拟化技术——VT-x的机制和原理进行了深入的研究。详细地分析了VT-x技术下VMX根操作模式和非根操作模式的特点，以及虚拟化技术在两种模式下的应用。在对VT-x技术研究的基础上，本文根据KVM虚拟化方案的两大特点—Linux模块化和QEMU设备化，深入研究和分析了KVM虚拟机的虚拟CPU的实现机制和运行流程，以及QEMU模拟器通过ioctl功能进入/退出虚拟机机制，设计并验证了一套异常捕捉方法的方案，为进一步提高虚拟机的整体性能提供了一条有效途径。根据KVM虚拟化方案特点，本文继续深入研究和分析了KVM虚拟机的进程模型，并设计和实现了一套KVM虚拟机处理器调度优化方案。该优化方案主要包括三个部分：调度策略、运行优先级和客户机操作系统的隔离。进而实现KVM虚拟机的个性化，即不同的虚拟机可以拥有不同的优先级和调度策略，以及运行在不同的CPU上，并在整个运行期间不发生迁移。通过使KVM虚拟机对CPU拥有更高的优先权，以及减少KVM虚拟机运行期间在CPU之间的切换开销，实现提高KVM虚拟机性能的目标。本文通过KVM虚拟机异常捕捉实验，实现了对KVM方案下客户机异常的分类处理，从而验证了KVM虚拟机异常捕捉方案的可行性。通过虚拟机调度策略实验，客户机绑定实验，以及UnixBench的综合测试，证实了本文研究的调度优化方案使虚拟机的性能有了一定的提高。因此，，该方案的实现不仅可以满足用户对虚拟机的功能需求，还能进一步提高虚拟机的整体性能，具有一定的实用价值。
[Abstract]:Because it can effectively improve the utilization of computer resources, as well as the flexibility, security and scalability of applications, virtualization technology has gradually become a hot area in the research and application of computer technology. With the development of virtualization technology, Intel and AMD, the mainstream hardware manufacturers, have proposed a new hardware architecture to support virtualization technology, which has made a great leap forward in virtualization technology. The virtualization technology supported by hardware further improves the overall performance of virtual machine in virtualized environment, and because this technology has obvious advantages, it is also supported and applied in Linux operating system. The research object of this paper is the KVM virtualization scheme which supports the hardware assisted virtualization technology. Since the Linux2.6.20 version, the scheme has been integrated into the Linux kernel. Intel VT technology is the general name of hardware aided virtualization technology on Intel platform. This technology provides a complete set of virtualization schemes including CPU, memory, I / O devices and other aspects of virtualization support. Based on the analysis of traditional CPU virtualization technology, this paper focuses on the mechanism and principle of CPU virtualization technology (VT-x) under Intel VT technology. The characteristics of VMX root operation mode and non-root operation mode under VT-x technology and the application of virtualization technology in these two modes are analyzed in detail. Based on the research of VT-x technology, according to the two characteristics of KVM virtualization scheme, Linux modularization and QEMU instrumentation, this paper deeply studies and analyzes the implementation mechanism and running flow of virtual CPU of KVM virtual machine. And the QEMU simulator designs and verifies a set of exception capture scheme through ioctl function entry / exit mechanism, which provides an effective way to further improve the overall performance of virtual machine. According to the characteristics of KVM virtualization scheme, this paper further studies and analyzes the process model of KVM virtual machine, and designs and implements a set of KVM virtual machine processor scheduling optimization scheme. The optimization scheme consists of three parts: scheduling policy, running priority and isolation of client operating system. Then the KVM virtual machine can be personalized, that is, different virtual machines can have different priorities and scheduling policies, run on different CPU, and do not migrate during the whole running period. By making the KVM virtual machine have higher priority to CPU and reducing the overhead of switching between CPU during the running of KVM virtual machine, we can achieve the goal of improving the performance of KVM virtual machine. In this paper, through the KVM virtual machine exception capture experiment, we realize the classification of the client exceptions under the KVM scheme, and verify the feasibility of the KVM virtual machine exception capture scheme. Through the experiment of virtual machine scheduling strategy, client binding experiment, and the comprehensive test of UnixBench, it is proved that the scheduling optimization scheme in this paper has improved the performance of virtual machine to a certain extent. Therefore, the implementation of the scheme can not only meet the functional needs of the virtual machine, but also further improve the overall performance of the virtual machine, which has a certain practical value.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP302

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