Fast networking with socket-outsourcing in hosted virtual machine environments

This paper proposes a novel method of achieving fast networking in hosted virtual machine (VM) environments. This method, called socket-outsourcing, replaces the socket layer in a guest operating system (OS) with the socket layer of the host OS. Socket-outsourcing increases network performance by eliminating duplicate message copying in both the host OS and the guest OS. Furthermore, socket-outsourcing significantly enhances inter-VM communication within the same host OS since it enables network packets to bypass the protocol stack in guest OSes. Socket-outsourcing was implemented in two representative operating systems (Linux and NetBSD) and on two virtual machine monitors (Linux KVM and PansyVM). These virtual machine monitors provided support for socket-outsourcing through shard memory, event queues, and VM-specific Remote Procedure Call between a guest OS and a host OS. The experimental results revealed that a guest OS outsourcing the socket layer achieved the same network throughput as a native OS using up to four Gigabit Ethernet links. Moreover, the benchmark results obtained from an N-tier Web application that generated a significant amount of inter-VM communication indicated that socket-outsourcing improved performance by up to 45 percent compared with conventional hosted VM environments.