Micro-architectures of High Performance, Multi-user System Area Network Interface Cards

This paper examines two Network Interface Card microarchitectures that support low latency, high bandwidth userlevel message passing in multi-user environments. The two are at different ends of a design spectrum – the Resident queues design relies completely on hardware, while the Non-resident queues design is heavily firmware driven. Through actual implementation of these designs and simulation-based micro-benchmark studies, we identify issues critical to the performance and functionality of the firmware-based approach. The firmware-based approach offers much flexibility at a moderate performance penalty, while the Resident design has superior performance for the functions it implements. This leads us to conclude that a hybrid design combining complete hardware support for common operations and a firmware implementation of less common functions achieves both high performance and flexibility.