一种独立式I/O虚拟化方法研究

Research on a Stand-alone I/O Virtualization Method

当前虚拟化系统中的设备仿真过程与I/O指令串行执行,无法发挥真实体系结构中直接存储器访问、异步I/O等加速I/O访问技术的性能优势,致使虚拟平台I/O性能与真实I/O性能存在一定差距。针对该问题,提出一种独立式I/O虚拟化方法,通过将I/O仿真活动(如磁盘读写)分离成一个独立的进程,虚拟机监控器(VMM)只保留相应的接口,达到将VMM与I/O设备分离实现仿真与指令并行化执行的目的,并基于QEMU平台实现该方法。实验结果表明,采用该方法后的QEMU I/O读写性能优于原有I/O子系统。由于I/O指令不必再等待I/O仿真的结束,因此在提高CPU指令执行速度的同时,能够有效提高4.9%的磁盘读取速度及9.2%的VGA测试基准软件Viewpref得分。

Because current virtualized devices in the system simulation process and I/O instructions execute serially, which can not play performance advantages of accelerated I/O access technical such as Direct Memory Access（ DMA） , asynchronous I/O in the real architecture,there is a certain gap between virtual platform I/O performance and the real I/O performance. To solve this problem,this paper presents a stand-alone I/O virtualization method,which separates the I/O simulation activities such as disk access from the Virtual Machine Monitor （ VMM ） only retained the appropriate interfaces by putting the activities in a stand-alone process to achieve I/O simulation and parallel instruction execution, and based on QEMU platform implements the method. Experimental results show that the I/O performance is better than the original QEMU I/O subsystem by this method. Because I/O instructions do not have to wait for I/O simulation ends, this method not only improves the speed of the CPU instruction execution, but also can effectively improve disk read speed by 4. 9% and increase software Viewpref VGA benchmark score by 9. 2%.