| The cloud computing technology has been flourishing in recent years and how to increase the efficiency of network virtual I/O is a much researched filed.I/O virtualization is to abstract the hardware I/O device into multiple virtual I/O devices that can be assigned to VM,which required software simulation or hardware assistance.For “Software simulation”,software is qualified for network virtualization,but this approach suffers from drawbacks includeing low I/O efficiency and high CPU resources occupancy.“Hardware assistance” is to provide multiple functional interfaces through specialized hardware to improve network I/O performance.Based on hardware-assisted I/O virtualization,this paper presents a new designed a PCIe Gigabit NIC that supports virtualization.Compared with the traditional NIC structure,the following innovations and improvements are proposed.1.When two-layer filtered,the frames are classified initially by the queue number,and the final queue number(VMDq?Pool)is generated according to priority.Improve the memory management unit,use a two-level linked list to manage memory.Each descriptor corresponds to a frame and the descriptors are classified according to VMDq?Pool to realize the pre-classification of frames in RAM.The frame classification is implemented by hardware,which was originally performed by software.2.According to the pool concept of VMDq technology,a ram module composed of eight FIFO pairs is added.Each pair corresponds to a VM.Pre-classified data frames and descriptors are stored in the corresponding Pool.And the data frame is written to the corresponding VM memory through DMA.The experimental results show that the frames on a single lane are written into the corresponding VM memory according to the Ethernet type,and the I/O rate reaches1000 Mbps.Compared with software simulation,this design not only realizes Passthrough between multiple VM and single NIC through VMDq and function offload,but also improves virtual I/O performance and reduces CPU burden. |
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