Parameterized diamond tiling for stencil computations with Chapel parallel iterators

Ian J. Bertolacci, Catherine Olschanowsky, Ben Harshbarger, Bradford L. Chamberlain, David G. Wonnacott, Michelle Mills Strout

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

26 Scopus citations


Stencil computations figure prominently in the core kernels of many scientific computations, such as partial differential equation solvers. Parallel scaling of stencil computations can be significantly improved on multicore processors using advanced tiling techniques that include the time dimension, such as diamond tiling. Such techniques are difficult to include in general purpose optimizing compilers because of the need for inter-procedural pointer and array data-ow analysis, plus the need to tune scheduling strategies and tile size parameters for each pairing of stencil computation and machine. Since a fully automatic solution is problematic, we propose to provide parameterized space and time tiling iterators through libraries. Ideally, the execution schedule or tiling code will be expressed orthogonally to the computation. This supports code reuse, easier tuning, and improved programmer productivity. Chapel iterators provide this capability implicitly. We present an advanced, parameterized tiling approach that we have implemented using Chapel parallel iterators. We show how such iterators can be used by programmers in stencil computations with multiple spatial dimensions. We also demonstrate that these new iterators provide better scaling than a traditional data parallel schedule.

Original languageEnglish (US)
Title of host publicationICS 2015 - Proceedings of the 29th ACM International Conference on Supercomputing
PublisherAssociation for Computing Machinery
Number of pages10
ISBN (Electronic)9781450335591
StatePublished - Jun 8 2015
Externally publishedYes
Event29th ACM International Conference on Supercomputing, ICS 2015 - Newport Beach, United States
Duration: Jun 8 2015Jun 11 2015

Publication series

NameProceedings of the International Conference on Supercomputing


Conference29th ACM International Conference on Supercomputing, ICS 2015
Country/TerritoryUnited States
CityNewport Beach


  • Chapel
  • Diamond tiling
  • Parallel iterators
  • Separation of concerns
  • Stencil computations

ASJC Scopus subject areas

  • Computer Science(all)


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