A source-synchronous Htree-based network-on-chip Conference Paper uri icon

abstract

  • Most existing Network-on-Chip (NoC) designs operate at the same or lower clock speed as the processing elements (PEs). Recently, a new source-synchronous ring-based NoC architecture has been proposed, which runs significantly faster than the PEs and offers a significantly higher bandwidth and lower communication latency. However, the ring-based design assumes a separate clock distribution scheme for the NoC and the PEs, and uses a standard mesh topology for the NoC. In this work, we present a source synchronous ring-based NoC, laid out in an H-tree topology, with each data link being routed parallel to a clock ring. The clock is generated and distributed by multiple standing wave oscillator (SWO) rings, which are also laid out in an H-tree topology. Our design allows the PEs to extract a low jitter clock directly from the high speed ring-based SWO clock by division. Moreover, since the PEs are synchronous with the ring clock, they do not need synchronizers while communicating with the NoC. We also show that by recursively duplicating links in the H-tree based source synchronous NoC (Hnoc), we can obtain new hybrid NoC structures. In the limit, this recursive duplication causes the H-tree based NoC to morph into the meshbased source synchronous NoC (Mnoc). The performance of each such intermediate hybrid NoC structure is quantified in terms of area, link utilization and contention free latency. We also enhance the performance of the hybrid NoCs by widening congested links, and quantify the tradeoffs. Experimental results show that the hybrid NoC designs can provide significantly lower latency (upto 5x lower) and are able to sustain a higher injection rate (upto 6.8x higher) compared to a state of the art mesh. Moreover, these hybrid NoC designs use fewer buffers (upto 19.4% less) and lower wire length (upto 19.7% lower) compared to a mesh. Based on the performance and the area tradeoffs, an NoC designer can select any hybrid NoC structure among the presented. 2013 ACM.

name of conference

  • Proceedings of the 23rd ACM international conference on Great lakes symposium on VLSI - GLSVLSI '13

published proceedings

  • Proceedings of the 23rd ACM international conference on Great lakes symposium on VLSI - GLSVLSI '13

author list (cited authors)

  • Mandal, A., Khatri, S. P., & Mahapatra, R. N.

citation count

  • 1

complete list of authors

  • Mandal, Ayan||Khatri, Sunil P||Mahapatra, Rabi N

publication date

  • January 2013