Joseph Cessna

Honeycomb-structured computational interconnects and their scalable extension to spherical domains

The present paper is part of a larger effort to redesign, from the ground up, the best possible interconnect topologies for switchless multiprocessor computer systems. We focus here specifically on honeycomb graphs and their extension to problems on the sphere, as motivated by the design of special-purpose computational clusters for global weather forecasting. Eight families of efficient tiled layouts have been discovered which make such interconnects trivial to scale to large cluster sizes while incorporating no long wires. In the resulting switchless interconnect designs, the physical proximity of the cells created (in the PDE discretization of the physical domain) and the logical proximity of the nodes to which these cells are assigned (in the computational cluster) coincide perfectly, so all communication between physically adjacent cells during the PDE simulation require communication over just a single hop in the computational cluster.