Optimal number and placement of Through Silicon Vias in 3D Network-on-Chip

In this paper, we analyze the performance impact of different number of Through Silicon Vias (TSVs) in 3D Network-on-Chip (NoC). The adoption of a 3D NoC design depends on the performance and manufacturing cost of the chip. Therefore, a study of the placement of the TSV, that connects different layers of a 3D chip, is crucial. A 64-core 3D NoC is modeled based on state-of-the-art 2D chips. We discuss the number of TSVs required for a 3D NoC. Different placements of layer-layer connections are explored. We present benchmark results using a cycle accurate full system simulator based on realistic workloads. Experiments show that under different workloads, the average network latencies in two configurations (full and quarter connection) are reduced by 14.78% and 7.38% respectively, compared with the one-eighth connection design. The improvement of performance is a trade-off of manufacturing cost. Our analysis and experiment results provide a guideline for selecting optimal number of TSVs in 3D NoCs.