Implementing and optimizing ROM table for broadcast message used in MPI unit

In this paper, we propose to implement and optimize a ROM table which contains a set of point-to-point communications for broadcast communication in message passing interface (MPI) systems in multi-processors that use distributed memory. MPI broadcast communication is one of the most frequently used collective functions. The contents of the ROM table are part of message packets about a set of point-to-point communications for broadcast communication determined by considering the states of every processing node. Thus, it can prevent the sending node from communicating the data to another node in a busy state. This minimizes the performance degradation caused by conflict. Also, the broadcast communication is based on a binary tree algorithm. Since each processing node owns the same ROM table, we need to optimize the size of the ROM table. The states of all the processing nodes and their own identification number are required to index the ROM table correctly. Consequently, by optimizing the ROM table, the bit size is reduced about 25% with four nodes, about 75% with eight nodes, and about 81% with 16 nodes.