Hot-Spots and Message Combining in An Interconnection Network for Broadcast Communication

Due to advances in fiber-optics and VLSI technology, interconnection networks which allow multiple simultaneous broadcasts are becoming feasible. In such large systems hot-spot contention can occur when several processors concurrently request access to one data structure with resulting severe performance degradation. To minimize the effect of hot-spots in the broadcast architecture, messages are combined to form a new message containing the payloads of all original messages. In this paper, we examine the effect of message combining on the performance of a multiprocessor system based on a broadcast interconnection network using simulation and analytical models under the message-passing paradigm and the presence of hot-spots, and we compare it to similar performance measures on multiprocessor systems based on the crossbar and the torus.