Processor Shapes and Topologies for Dense On-Chip Networks

Zhibin Xiao
Bevan M. Baas
VLSI Computation Laboratory
Department of Electrical and Computer Engineering
University of California, Davis


Interconnection topologies greatly affect the performance, energy efficiency, and circuit area of many-core processor arrays. Simple topologies such as buses, rings and 2-dimensional (2D) meshes are commonly utilized due to their simplicity of physical implementation. This work proposes novel processor shapes and interconnection topologies for many-core processor arrays that include two 5-neighbor, three 6-neighbor and two 8-neighbor topologies three of which utilize house-shaped and hexagonal-shaped processor tiles. Two complete complex applications are mapped onto both the 2D mesh and the hexagonal array -- 25-processor 1080p H.264/AVC video residual encoder and a 24-processor 802.11a/11g wireless LAN baseband receiver. The hexagonal-shaped processor tiles and array are built with industry-standard CAD tools, an automatic place and route flow without full-custom layout, and regular Manhattan routing. Compared to the 2D mesh, both the 6-neighbor hexagonal and the 6-neighbor rectangular tile incur a 2.9% area penalty per tile, but their much more effective inter-processor interconnect yields an average total application area reduction of 21%, and a total application inter-processor communication distance reduction of 19%.


Brief Slide Overview


Zhibin Xiao and Bevan Baas, "Processor Shapes and Topologies for Dense On-chip Networks," presented in the IEEE International Solid-Sate Circuit Conference (ISSCC 2012) Student Forum, San Francisco, CA, Feb. 2012.

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Last update: Feb 2, 2012