Regional Congestion Awareness for Load Balance in Networks-on-Chip Conference Paper uri icon


  • Interconnection networks-on-chip (NOCs) are rapidly replacing other forms of interconnect in chip multiprocessors and system-on-chip designs. Existing interconnection networks use either oblivious or adaptive routing algorithms to determine the route taken by a packet to its destination. Despite somewhat higher implementation complexity, adaptive routing enjoys better fault tolerance characteristics, increases network throughput, and decreases latency compared to oblivious policies when faced with non-uniform or bursty traffic. However, adaptive routing can hurt performance by disturbing any inherent global load balance through greedy local decisions. To improve load balance in adapting routing, we propose Regional Congestion Awareness (RCA), a lightweight technique to improve global network balance. Instead of relying solely on local congestion information, RCA informs the routing policy of congestion in parts of the network beyond adjacent routers. Our experiments show that RCA matches or exceeds the performance of conventional adaptive routing across all workloads examined, with a 16% average and 71% maximum latency reduction on SPLASH-2 benchmarks running on a 49-core CMP. Compared to a baseline adaptive router, RCA incurs a negligible logic and modest wiring overhead. ©2008 IEEE.

name of conference

  • 2008 IEEE 14th International Symposium on High Performance Computer Architecture (HPCA)

published proceedings

  • 2008 IEEE 14th International Symposium on High Performance Computer Architecture

author list (cited authors)

  • Gratz, P., Grot, B., & Keckler, S. W

citation count

  • 280

complete list of authors

  • Gratz, Paul||Grot, Boris||Keckler, Stephen W

publication date

  • February 2008