Topology-aware task mapping for reducing communication contention on large parallel machines

Tarun Agarwal, Amit Sharma, Laxmikant V. Kalé

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Communication latencies constitute a significant factor in the performance of parallel applications. With techniques such as wormhole routing, the variation in no-load latencies became insignificant, i.e., the no-load latencies for far-away processors were not significantly higher (and too small to matter) than those for nearby processors. Contention in the network is then left as the major factor affecting latencies. With networks such as Fat-Trees of hypercubes, with number of wires growing as P log P, even this is not a very significant factor. However, for torus and grid networks now being used in large machines such as BlueGene/L and the Cray XT3, such contention becomes an issue. We quantify the effect of this contention with benchmarks that vary the number of hops traveled by each communicated byte. We then demonstrate a process mapping strategy that minimizes the impact of topology by heuristically minimizing the total number of hop-bytes communicated. This strategy, and its variants, are implemented in an adaptive runtime system in Charm++ and Adaptive MPI, so it is available for a broad class of applications.

Original languageEnglish (US)
Title of host publication20th International Parallel and Distributed Processing Symposium, IPDPS 2006
PublisherIEEE Computer Society
ISBN (Print)1424400546, 9781424400546
DOIs
StatePublished - 2006
Event20th IEEE International Parallel and Distributed Processing Symposium, IPDPS 2006 - Rhodes Island, Greece
Duration: Apr 25 2006Apr 29 2006

Publication series

Name20th International Parallel and Distributed Processing Symposium, IPDPS 2006
Volume2006

Other

Other20th IEEE International Parallel and Distributed Processing Symposium, IPDPS 2006
Country/TerritoryGreece
CityRhodes Island
Period4/25/064/29/06

ASJC Scopus subject areas

  • Engineering(all)

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