Research Of CPU Virtualization And Optimization Of Scheduling Policy Under KVM

Since it is effective to improve the utilization of computer resources, and thefeatures of applications, such as flexibility, security and scalability, virtualizationtechnology is becoming one of hot fields in research and application of computertechnology. Along with the development of virtualization technology, the mainstreamof hardware manufacturers Intel and AMD put forward the new hardware architecturewhich can support virtualization technology very well, it makes a big leap in this filed.In the hardware-assisted virtualization technology, the overall performance of virtualmachines in virtualized environment has been further improved, and because of itsremarkable superiority, it has also been supported and applied under the Linuxoperating system. The research of this thesis is KVM virtualization scheme, which isa hardware-assisted virtualization technology and has been integrated into the Linuxkernel since Linux2.6.20.Intel VT technology is a generic terms of hardware-assisted virtualizaion whichis implemented on Intel platform, it is a complete set of virtualization scheme andprovides many capture resource virtualization, such as CPU, memory, I/O devices. Onthe basis of analysis of the traditional CPU virtualization, this thesis focuses on themechanisms and principles of the VT-x CPU virtualization under Intel VT andconducts a deep research. What is more, the characteristics of VMX root/non-rootoperation mode have been detailed analyzed under the VT-x technology, and theapplication of the virtualization technology under the two modes.On the basis of the studying of the Intel VT-x technology, and combine with thetwo main characteristics of the KVM virtualization scheme: Linux modularization andQEMU’s device emulation, this thesis has deep and mainly studied and analyzed theimplementation mechanism and running process of virtual CPU under KVM virtualmachine, and the entry/exit virtual machine mechanism refers to ioctl function ofQEMU emulator. What is more, an exception capture scheme have been designed andverified, it could be an effective way to further improve the overall performance of thevirtual machine under KVM virtualization solutions. According to the features of the KVM virtualization scheme, this thesisresearches and analyzes further the process model of KVM virtual machine, and ascheduling policy optimization scheme is designed and implemented. Theoptimization scheme mainly includes three parts: The scheduling policy, Priority ofthe running level and the isolation of Guest OS. It can achieve the personalization ofthe KVM virtual machine by means of these three part, it means that the differentvirtual machine can have various priority and scheduling policy and runs on differentCPU. Furthermore, it would not migrate to other CPUs during the entire running time.So, it achieves to improve the performance of the KVM virtual machine by higherCPU priority of KVM virtual machine and reducing the switching overhead which isoccurring during running time.In KVM virtual machine exception captured experiments, the feasibility of thescheme is tested and verified by the classification processing of the KVM Guest OS’sexception. The experiments refer to scheduling policy of KVM virtual machine, GuestOS pinning, as well as the comprehensive test of the UnixBench have proved that theperformance of the KVM virtual machine in this scheme has certain improvement.Therefore, it has some practical value, because the implementation of the scheme notonly can meet the user’s demand for the function of the virtual machine, but also canfurther improve the overall performance of the virtual machine.