Modified Hierarchical 3D-Torus Network

Abstract

SUMMARY Three-dimensional (3D) wafer stacked implementation (WSI) has been proposed as a promising technology for massively parallel computers. A hierarchical 3D-torus (H3DT) network, which is a 3D-torus network of multiple basic modules in which the basic modules are 3D-mesh networks, has been proposed for efficient 3D-WSI. However, the restricted use of physical links between basic modules in the higher level networks reduces the dynamic communication performance of this network. A torus network has better dynamic communication performance than a mesh network. Therefore, we have modified the H3DT network by replacing the 3D-mesh modules by 3D-tori, calling it a Modified H3DT (MH3DT) network. This paper addresses the architectural details of the MH3DT network and explores aspects such as degree, diameter, cost, average distance, arc connectivity, bisection width, and wiring complexity. We also present a deadlock-free routing algorithm for the MH3DT network using two virtual channels and evaluate the network's dynamic communication performance under the uniform traffic pattern, using the proposed routing algorithm. It is shown that the MH3DT network possesses several attractive features including small diameter, small cost, small average distance, better bisection width, and better dynamic communication performance. key words: MH3DT network, static network performance, wormhole routing, deadlock-free routing, dynamic communication performance

Dynamic Communication Performance of a Modified Hierarchical 3D-Torus Network under Non-uniform Traffic Patterns

“…In this section, we review the routing algorithm proposed in our previous study [9] for the convenience of readers. Since dimension-order routing is used in the MH3DT network, messages in the network are routed first in the zdirection then in y-direction, and finally in the x-direction.…”

“…With this key motivation, the H3DT network [5] was modified by replacing the 3D-mesh of its BM by a 3D-torus network. This Modified Hierarchical 3D-Torus (MH3DT) network [9] also consists of BMs which are themselves 3D-tori (m × m × m), hierarchically interconnected in 3D-torus (n × n × n) networks.…”

“…With small buffer, it is not as good as mesh and torus networks [9]. However, the dynamic communication performance of the MH3DT under various non-uniform traffic patterns had not yet been evaluated.…”

“…In Section II, we briefly describe the basic structure of the MH3DT network. We review the routing algorithm in Section III, and its freedom from deadlock is also proved using 2 VCs [9]. The dynamic communication performance of the MH3DT under non-uniform traffic patterns is discussed in Section IV.…”

Research on Next-Generation Scalable Routers Implemented with H-Torus Topology

“…Although 3-D torus topology shows good scalability, its implementation in TSR has limited the number of line cards to 560 [10] . The Hierarchical 3D-Torus network and its modified version have also been put forward for large-scale 3D multicomputers [11,12] . Another new interconnection network topology, called Cellular Router architecture [13,14] , is introduced as well.…”