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[Author] Naoya NIWA(2hit)

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  • Boosting the Performance of Interconnection Networks by Selective Data Compression

    Naoya NIWA  Hideharu AMANO  Michihiro KOIBUCHI  

     
    PAPER

      Pubricized:
    2022/07/12
      Vol:
    E105-D No:12
      Page(s):
    2057-2065

    This study presents a selective data-compression interconnection network to boost its performance. Data compression virtually increases the effective network bandwidth. One drawback of data compression is a long latency to perform (de-)compression operation at a compute node. In terms of the communication latency, we explore the trade-off between the compression latency overhead and the reduced injection latency by shortening the packet length by compression algorithms. As a result, we present to selectively apply a compression technique to a packet. We perform a compression operation to long packets and it is also taken when network congestion is detected at a source compute node. Through a cycle-accurate network simulation, the selective compression method using the above compression algorithms improves by up to 39% the network throughput with a moderate increase in the communication latency of short packets.

  • A Compression Router for Low-Latency Network-on-Chip

    Naoya NIWA  Yoshiya SHIKAMA  Hideharu AMANO  Michihiro KOIBUCHI  

     
    PAPER-Computer System

      Pubricized:
    2022/11/08
      Vol:
    E106-D No:2
      Page(s):
    170-180

    Network-on-Chips (NoCs) are important components for scalable many-core processors. Because the performance of parallel applications is usually sensitive to the latency of NoCs, reducing it is a primary requirement. In this study, a compression router that hides the (de)compression-operation delay is proposed. The compression router (de)compresses the contents of the incoming packet before the switch arbitration is completed, thus shortening the packet length without latency penalty and reducing the network injection-and-ejection latency. Evaluation results show that the compression router improves up to 33% of the parallel application performance (conjugate gradients (CG), fast Fourier transform (FT), integer sort (IS), and traveling salesman problem (TSP)) and 63% of the effective network throughput by 1.8 compression ratio on NoC. The cost is an increase in router area and its energy consumption by 0.22mm2 and 1.6 times compared to the conventional virtual-channel router. Another finding is that off-loading the decompressor onto a network interface decreases the compression-router area by 57% at the expense of the moderate increase in communication latency.