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 processing nodes concurrently request access to one data structure with resulting severe performance degradation. This paper presents one broadcast architecture, called the SOME-BUS interconnection network. To minimize the effect of hot-spots in the Some-Bus architecture, messages are combined to form a new message containing the payloads of all original messages. We examine the effect of message combining on the performance of SOME-Bus, in the presence of hot-spots, using simulation and analytical models, under the mssage-passing and distributed-shared-memory paradigms, and we compare it to similar performance measures on multiprocessor systems based on the crossbar and the torus.
