Batched packet processing for high-speed software data plane functions

In the last decade, a number of frameworks started to appear that implement, directly in user-space with kernel-bypass mode, high-speed software data plane functionalities on commodity hardware. Vector Packet Processor (VPP) is one of such frameworks, representing an interesting point in the design space in that it offers: (i) in user-space networking, (ii) the flexibility of a modular router (Click and variants) with (iii) the benefits brought by techniques such as batch processing that have become commonplace in lower-level building blocks of high-speed networking stacks (such as netmap or DPDK). Similarly to Click, VPP lets users arrange functions as a processing graph, providing a full-blown stack of network functions. However, unlike Click where the whole tree is traversed for each packet, in VPP each traversed node processes all packets in the batch before moving to the next node. This design choice enables several code optimizations that greatly improve the achievable processing throughput: the purpose of this demonstration is to introduce the main VPP concepts and architecture, as well as experimentally showing the impact of design choices- and especially of batch packet processing-, on the achievable packet forwarding performance.