Transparently Achieving Superior Socket Performance Using Zero Copy Socket Direct Protocol over 20Gb/s InfiniBand Links

Sockets Direct Protocol (SDP) is a byte stream protocol that utilizes the capabilities of the InfiniBand fabric to transparently achieve performance gains for existing socket-based networked applications. In this paper we discuss an implementation of Zero Copy support for synchronous send()/recv() socket calls, that uses the remote DMA capability of InfiniBand for SDP data transfers. We added this support to the open-source implementation of SDP over InfiniBand. We evaluate this implementation over a 20 Gb/s InfiniBand link. We demonstrate scalability of Zero Copy and show its benefits for systems that utilize multiple socket connections in parallel. For example, enabling Zero Copy with 8 active connections yields a bandwidth growth from 630MB/s to 1360MB/s, at the same time reducing the CPU utilization by a factor often