Key Messaging on SOME-Bus clusters Ming Zhu a, * , Constantine Katsinis a , Wentong Cai b , Bu-Sung Lee b a Department of Electrical and Computer Engineering, Drexel University, Philadelphia, PA 19104/10104, United States b School of Computer Engineering, Nanyang Technological University, Singapore 639798, Singapore Received 11 August 2003; revised 28 May 2004; accepted 13 July 2004 Abstract One implementation of broadcast-based networks is the Simultaneous Optical Multiproces- sor Exchange Bus (SOME-Bus). It is a low-latency, high-bandwidth, fiber-optic network that directly connects each processing node to all other nodes without contention. To better utilize the communication network and reduce the completion time of a parallel application, this paper describes the Key Message (KM) approach on SOME-Bus clusters. The main mechanism of the KM approach is to prioritize messages using KM algorithm. After presenting KM algo- rithm with SOME-Bus structure which is modeled by a M/D/1 queue, an analytical method is adopted to evaluate its performance. The analysis results show better improvement on commu- nication of a parallel application over the system that does not use the KM approach. Ó 2004 Elsevier B.V. All rights reserved. Keywords: Cluster computing; Priority queue; SOME-Bus cluster; Critical path 1. Introduction Parallel applications usually require high performance communication systems in cluster computing environments and improving the performance of these systems is a 0167-8191/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.parco.2004.07.004 * Corresponding author. Tel.: +1 215 895 6173. E-mail address: zhuming@cbis.ece.drexel.edu (M. Zhu). www.elsevier.com/locate/parco Parallel Computing 30 (2004) 947–971