Network of workstation (NOW) is a cost-effective alternative to massively parallel supercomputers. As commercially available off-the-shelf processors become cheaper and faster, it is now possible to build a PC or workstation cluster that provides high computing power within a limited budget. However, a cluster may consist of different types of processors and this heterogeneity within a cluster complicates the design of efficient collective communication protocols. This paper shows that a simple heuristic called fastest-node-first (FNF) [2] is very effective in reducing broadcast time for heterogeneous cluster systems. Despite the fact that FNF heuristic does not guarantee an optimal broadcast time for general heterogeneous network of workstation, we prove that FNF always gives near optimal broadcast time in a special case of cluster, and this finding helps us show that FNF delivers guaranteed performance for general clusters. In a previous paper we showed a similar bound on the competitive ratio in a send-only communication model. This paper extends the result to a more realistic sender-receiver model. We show that FNF gives a total broadcast of 2T + β, where T is the optimum time and β is a constant. This improves over the previous bound on 2αT + β [17], where is a theoretically unbounded ratio of the processor performance in the cluster.
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