A Layout-Oriented Routing Method for Low-Latency HPC Networks

Ryuta KAWANO  Hiroshi NAKAHARA  Ikki FUJIWARA  Hiroki MATSUTANI  Michihiro KOIBUCHI  Hideharu AMANO  

IEICE TRANSACTIONS on Information and Systems   Vol.E100-D   No.12   pp.2796-2807
Publication Date: 2017/12/01
Publicized: 2017/07/14
Online ISSN: 1745-1361
DOI: 10.1587/transinf.2017PAP0019
Type of Manuscript: Special Section PAPER (Special Section on Parallel and Distributed Computing and Networking)
Category: Interconnection networks
high performance computing,  network topology,  interconnection networks,  

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End-to-end network latency has become an important issue for parallel application on large-scale high performance computing (HPC) systems. It has been reported that randomly-connected inter-switch networks can lower the end-to-end network latency. This latency reduction is established in exchange for a large amount of routing information. That is, minimal routing on irregular networks is achieved by using routing tables for all destinations in the networks. In this work, a novel distributed routing method called LOREN (Layout-Oriented Routing with Entries for Neighbors) to achieve low-latency with a small routing table is proposed for irregular networks whose link length is limited. The routing tables contain both physically and topologically nearby neighbor nodes to ensure livelock-freedom and a small number of hops between nodes. Experimental results show that LOREN reduces the average latencies by 5.8% and improves the network throughput by up to 62% compared with a conventional compact routing method. Moreover, the number of required routing table entries is reduced by up to 91%, which improves scalability and flexibility for implementation.