The Virtual Interface (VI) Architecture provides protected userlevel communication with high delivered bandwidth and low permessage latency, particularly for small messages. The VI Architecture attempts to reduce latency by eliminating user/kernel transitions on routine data transfers and by allowing direct use of user memory for network buffering. This results in significantly lower latencies than those achieved by network protocols such as TCP/IP and UDP. In this paper we examine the low-level performance of two VI implementations, one implemented in hardware, the other implemented in device driver software. Using a set of low-level benchmarks, we measure bandwidth, latency, and processor utilization as a function of message size for the GigaNet cLAN and Tandem ServerNet VI implementations. We report that both VI implementations offer significant performance advantage relative to the corresponding UDP implementation on the same hardware. We also investigate the problems associated w...
Evan Speight, Hazim Abdel-Shafi, John K. Bennett