Modifying Guest OS to Optimize I/O Virtualization in KVM

Abstract

There are some operations in Guest OS causing the I/O performance degradation.For it is the general OS,which is oriented physical machines,directly running on the virtual machine as the Guest OS.This paper evaluates KVM I/O performance,find that the Guest OS should be adapted to the virtual environment for better performance,and proposes some optimizations.First,reduce VM Exits by merging successive I/O instructions and decreasing the frequency of timer interrupt;Second,removes some redundant operations from Guest OS,including the operations useless in virtual environment,the I/O scheduler whose results will be rescheduled in the Host OS,and the NAPI support in virtual NIC driver.