Modifying Guest OS to optimize I/O virtualization in KVM

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