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Design and Use of Loop-Transformation Pragmas

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OpenMP: Conquering the Full Hardware Spectrum (IWOMP 2019)

Part of the book series: Lecture Notes in Computer Science ((LNPSE,volume 11718))

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Abstract

Adding a pragma directive into the source code is undoubtedly easier than rewriting it, for instance for loop unrolling. Moreover, if the application is maintained for multiple platforms, their difference in performance characteristics may require different code transformations. Code transformation directives allow replacing the directives depending on the platform, i.e. separation of code semantics and its performance optimization.

In this paper, we explore the design space (syntax and semantics) of adding such directive into a future OpenMP specification. Using a prototype implementation in Clang, we demonstrate the usefulness of such directives on a few benchmarks.

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Notes

  1. 1.

    Our previous paper [5] suggested to use safe semantics as the default, in conflict to the normal OpenMP behavior.

  2. 2.

    https://github.com/SOLLVE/clang/tree/pragma and

    https://github.com/SOLLVE/polly/tree/pragma.

References

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  6. Kruse, M., Finkel, H.: User-directed loop-transformations in Clang. In: 2018 IEEE/ACM 5th Workshop on the LLVM Compiler Infrastructure in HPC (LLVM-HPC), pp. 49–58, November 2018. https://doi.org/10.1109/LLVM-HPC.2018.8639402

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Acknowledgments

This research was supported by the Exascale Computing Project (17-SC-20-SC), a collaborative effort of two U.S. Department of Energy organizations (Office of Science and the National Nuclear Security Administration) responsible for the planning and preparation of a capable exascale ecosystem, including software, applications, hardware, advanced system engineering, and early testbed platforms, in support of the nation’s exascale computing imperative.

This research used resources of the Argonne Leadership Computing Facility, which is a DOE Office of Science User Facility supported under Contract DE-AC02-06CH11357.

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Authors and Affiliations

  1. Argonne Leadership Computing Facility, Argonne National Laboratory, Lemont, IL, 60439, USA

    Michael Kruse & Hal Finkel

Authors
  1. Michael Kruse
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  2. Hal Finkel
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Corresponding authors

Correspondence to Michael Kruse or Hal Finkel .

Editor information

Editors and Affiliations

  1. University of Auckland, Auckland, New Zealand

    Xing Fan

  2. Lawrence Livermore National Laboratory, Livermore, CA, USA

    Bronis R. de Supinski

  3. University of Auckland, Auckland, New Zealand

    Oliver Sinnen

  4. University of Auckland, Auckland, New Zealand

    Nasser Giacaman

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Kruse, M., Finkel, H. (2019). Design and Use of Loop-Transformation Pragmas. In: Fan, X., de Supinski, B., Sinnen, O., Giacaman, N. (eds) OpenMP: Conquering the Full Hardware Spectrum. IWOMP 2019. Lecture Notes in Computer Science(), vol 11718. Springer, Cham. https://doi.org/10.1007/978-3-030-28596-8_9

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  • DOI: https://doi.org/10.1007/978-3-030-28596-8_9

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  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-030-28595-1

  • Online ISBN: 978-3-030-28596-8

  • eBook Packages: Computer ScienceComputer Science (R0)

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