ZCopy-Vhost: Replacing Data Copy With Page Remapping in Virtual Packet I/O

Abstract

Virtualization technology is the core technology of cloud computing. While virtualization technology offers flexibility in many ways, it also introduces additional performance overhead. For network systems, it needs to provide additional virtual switching, the virtual packet I/O, and other functions. Providing these features requires a lot of CPU resources. As cloud services grow, more and more CPU resources are being used to provide virtualization support, which means that fewer CPUs can be sold to tenants. Therefore, cloud service providers have been constantly seeking more efficient virtualization solutions for network systems. In this paper, we identify one of the main reasons for the large consumption of CPU resources in the virtual networking system - copy and propose to use memory page remapping technology to eliminate the copy. Moreover, to adapt to the zero-copy technology, we have integrated the technology with a mature virtual switch software in the host and a userspace protocol stack in the virtual machine. These components together build a more efficient network system in virtual environments. The evaluations with microbenchmarks and macrobenchmark show that our system performs much better than the state-of-the-art solutions.

Keywords

• Network I/O virtualization
• virtio/vhost
• zero-copy vhost
• virtual switch