Multiple message broadcasting in the postal model

Broadcasting is an important operation in many message-passing systems that has been widely investigated. Most existing broadcasting algorithms, however, do not address several emerging trends in distributed-memory parallel computers and high-speed communication networks. These trends include ( i ) treating the system as being fully connected with all processors equally distant, ( ii ) packetizing large amounts of data into sequences of messages, and ( iii ) tolerating communication latencies. In this paper, we explore the broadcasting problem in the postal model that addresses these issues. We provide two efficient algorithms for broadcasting m messages in a fully connected message-passing system with n processors and communication latency l. A lower bound on the time required for this problem is (m0 1)/ fl (n ) , where fl (n ) is the optimal time for broadcasting one message. We present two algorithms: The first is Algorithm PARTITION , the running time of which is at most m / n / 2l when m ¢ n and 3m / fl (n ) / 2l when m ° n . The second is Algorithm D-D-TREES , the running time of which is at most m / 2 fl (n ) / O (l ) for any value of m . q 1997 John Wiley & Sons, Inc.