Hardware for fast global operations on workstation cluster multicomputers

The results presented show that the addition of a secondary network with a wide-tree topology and one or more coordination processors (COPs) to a workstation cluster multicomputer can speed up synchronization, broadcasting, reduction, and several other important global operations by two or three orders of magnitude. The wide tree topology contributes to this by allowing a large number of nodes to simultaneously send commands to a COP and allowing a COP to broadcast a computed value to a large number of nodes simultaneously. Hardware based protection mechanisms in the COP system permit direct user access to the COP network and thus eliminate the overhead of software protocol layers for these global operations. Although the COP system provides a large performance gain for global operations, it increases overall system cost by only 2-3%