Evaluation of real-time fiber communications for parallel collective operations

Abstract

Real-Time Fiber Communications (RTFC) is a gigabit speed network that has been designed for damage tolerant local area networks. In addition to its damage tolerant characteristics, it has several features that make it attractive as a possible interconnection technology for parallel applications in a cluster of workstations. These characteristics include support for broadcast and multicast messaging, memory cache in the network interface card, and support for very fine grain writes to the network cache. Broadcast data is captured in network cache of all workstations in the network providing a distributed shared memory capability. In this paper, RTFC is introduced. The performance of standard MPI collective communications using TCP protocols over RTFC are evaluated and compared experimentally with that of Fast Ethernet. It is found that the MPI message passing libraries over traditional TCP protocols over RTFC perform well with respect to Fast Ethernet. Also, a new approach that uses direct network cache movement of buffers for collective operations is evaluated. It is found that execution time for parallel collective communications may be improved via effective use of network cache.

This work was supported in part by NSF Research Instrumentation Grant #9617384 and by equipment support from Belobox Systems, Inc., Irvine, California.