Asynchronous tree-based multicasting in wormhole-switched MINs

Multicast operation is an important operation in multicomputer communication systems and can be used to support several collective communication operations. A significant performance improvement can be achieved by supporting multicast operations at the hardware level. We propose an asynchronous tree-based multicasting (ATBM) technique for multistage interconnection networks (MINs). The deadlock issues in tree-based multicasting in MINs are analyzed first to examine the main causes of deadlocks. An ATBM framework is developed in which deadlocks are prevented by serializing the initiations of tree operations that have a potential to create deadlocks. These tree operations are identified through a grouping algorithm. The ATBM approach is not only simple to implement but also provides good communication performance using minimal overheads in terms of additional hardware requirements and synchronization delay. Using the ATBM framework, algorithms are developed for both unidirectional and bidirectional multistage interconnection networks. The performances of the proposed algorithms are evaluated through simulation experiments. The results indicate that the proposed hardware-based ATBM scheme reduces the communication latency when compared to the software multicasting approach proposed earlier.