IOVTee: A Fast and Pragmatic Software-based Zero-copy/Pass-through Mechanism for NFV-nodes

Virtualization of various network equipment has been already seen in modern telco and cloud networks. Their mission-critical virtualized devices commonly run on ASIC-powered white-box switches instead of Commercial Off-The-Shelf (COTS) x86 servers for performance reasons. In fact, many studies have revealed insufficient throughput/latency of virtual machine/container-based virtual network functions (VNFs) on x86 servers, and virtual network I/O implementations have been thought to be major performance bottlenecks. Zero-copy and pass-through are well-known techniques to reduce the I/O overhead between a host and a guest; however, existing implementations incur pragmatic issues including security, compatibility, management, and inexplicable performance characteristics. In this paper, we propose a fully software-based SR-IOV-like zero-copy/pass-through technique, Tee-type I/O Virtualization (IOVTee), to resolve the problems. IOVTee takes advantage of SR-IOV and NetVM under the framework of de-facto standard DPDK/vhost-user. Inbound packet "data" are directly stored into VM's memory space like SR-IOV, but the hypervisor's virtual switch can handle the packets before the VNF's processing like NetVM. We evaluated the performance of IOVTee in 100 GbE environment, and the results showed that an IOVTee-accelerated single core VNF achieved about 19 Mpps (64 bytes) and 90 Gbps (1518 bytes) throughputs.