Contrasting topologies for regular interconnection networks under the constraints of nanoscale silicon technology

Abstract

Nowadays, system designers have adopted Networks-on-Chip as communication infrastructure of general-purpose tile-based Multi-Processor System-on-Chip (MPSoC). Such decision implies that a certain topology has to be selected to efficiently interconnect many cores on the chip. To ease such a choice, the networking literature offers a plethora of works about topology analysis and characterization for the off-chip domain. However, theoretical parameters and many intuitive assumptions of such off-chip networks do not necessarily hold when a topology is laid out on a 2D silicon surface. This is due to the distinctive features of silicon technology design pitfalls. This work is a first milestone to bridge this gap, in fact, we propose a comprehensive analysis framework to assess k-ary n-mesh and C-mesh topologies at different level of abstractions, from system to layout level, while capturing implications of system and layout parameters across design hierarchy. When a certain topology proves to be slow due to long links crossing the chip, pipeline stages have been inserted to cope with such slow-down. Furthermore, costs of such speed-up technique have been evaluated to draw a comprehensive performance/area figure.