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Maximizing loop parallelism and improving data locality via loop fusion and distribution

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Languages and Compilers for Parallel Computing (LCPC 1993)

Part of the book series: Lecture Notes in Computer Science ((LNCS,volume 768))

Abstract

Loop fusion is a program transformation that merges multiple loops into one. It is effective for reducing the synchronization overhead of parallel loops and for improving data locality. This paper presents three results for fusion: (1) a new algorithm for fusing a collection of parallel and sequential loops, minimizing parallel loop synchronization while maximizing parallelism; (2) a proof that performing fusion to maximize data locality is NP-hard; and (3) two polynomial-time algorithms for improving data locality. These techniques also apply to loop distribution, which is shown to be essentially equivalent to loop fusion. Our approach is general enough to support other fusion heuristics. Preliminary experimental results validate our approach for improving performance by exploiting data locality and increasing the granularity of parallelism.

This research was supported by the Center for Research on Parallel Computation, a NSF Science and Technology Center. Use of the Sequent Symmetry S81 was provided under NSF Cooperative Agreement No. CDA-8619393.

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Author information

Authors and Affiliations

  1. Rice University, 77251-1892, Houston, TX

    Ken Kennedy

  2. University of Massachusetts, 01003-4610, Amherst, MA

    Kathryn S. McKinley

Authors
  1. Ken Kennedy
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  2. Kathryn S. McKinley
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Editor information

Utpal Banerjee David Gelernter Alex Nicolau David Padua

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© 1994 Springer-Verlag Berlin Heidelberg

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Kennedy, K., McKinley, K.S. (1994). Maximizing loop parallelism and improving data locality via loop fusion and distribution. In: Banerjee, U., Gelernter, D., Nicolau, A., Padua, D. (eds) Languages and Compilers for Parallel Computing. LCPC 1993. Lecture Notes in Computer Science, vol 768. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-57659-2_18

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  • DOI: https://doi.org/10.1007/3-540-57659-2_18

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  • Publisher Name: Springer, Berlin, Heidelberg

  • Print ISBN: 978-3-540-57659-4

  • Online ISBN: 978-3-540-48308-3

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