Smashing: Folding Space to Tile through Time

Authors:
Nissa Osheim;Michelle Mills Strout;Dave Rostron;Sanjay Rajopadhye
Affiliations:
Colorado State University, Fort Collins, USA CO 80523;Colorado State University, Fort Collins, USA CO 80523;Colorado State University, Fort Collins, USA CO 80523;Colorado State University, Fort Collins, USA CO 80523
Venue:
Languages and Compilers for Parallel Computing
Year:
2008

Citing 16
Cited 0

Supernode partitioning

POPL '88 Proceedings of the 15th ACM SIGPLAN-SIGACT symposium on Principles of programming languages
A data locality optimizing algorithm

PLDI '91 Proceedings of the ACM SIGPLAN 1991 conference on Programming language design and implementation
New tiling techniques to improve cache temporal locality

Proceedings of the ACM SIGPLAN 1999 conference on Programming language design and implementation
Synthesizing transformations for locality enhancement of imperfectly-nested loop nests

Proceedings of the 14th international conference on Supercomputing
High Performance Compilers for Parallel Computing

High Performance Compilers for Parallel Computing
Increasing temporal locality with skewing and recursive blocking

Proceedings of the 2001 ACM/IEEE conference on Supercomputing
Achieving Scalable Locality with Time Skewing

International Journal of Parallel Programming
Climate Modeling with Spherical Geodesic Grids

Computing in Science and Engineering
Cache-Efficient Multigrid Algorithms

ICCS '01 Proceedings of the International Conference on Computational Sciences-Part I
Iteration Space Tiling for Memory Hierarchies

Proceedings of the Third SIAM Conference on Parallel Processing for Scientific Computing
Optimizing Transformations of Stencil Operations for Parallel Object-Oriented Scientific Frameworks on Cache-Based Architectures

ISCOPE '98 Proceedings of the Second International Symposium on Computing in Object-Oriented Parallel Environments
Automatic Blocking of Nested Loops

Automatic Blocking of Nested Loops
Cache oblivious stencil computations

Proceedings of the 19th annual international conference on Supercomputing
Impact of modern memory subsystems on cache optimizations for stencil computations

Proceedings of the 2005 workshop on Memory system performance
Implicit and explicit optimizations for stencil computations

Proceedings of the 2006 workshop on Memory system performance and correctness
Effective automatic parallelization of stencil computations

Proceedings of the 2007 ACM SIGPLAN conference on Programming language design and implementation

Quantified Score

Hi-index	0.00

Visualization

Abstract

Partial differential equation solvers spend most of their computation time performing nearest neighbor (stencil) computations on grids that model spatial domains. Tiling is an effective performance optimization for improving the data locality and enabling course-grain parallelization for such computations. However, when the domains are periodic, tiling through time is not directly applicable due to wrap-around dependencies. It is possible to tile within the spatial domain, but tiling across time (i.e. time skewing) is not legal since no constant skewing can render all loops fully permutable. We introduce a technique called smashing that maps a periodic domain to computer memory without creating any wrap-around dependencies. For a periodic cylinder domain where time skewing improves performance, the performance of smashing is comparable to another method, circular skewing, which also handles the periodicity of a cylinder. Unlike circular skewing, smashing can remove wrap-around dependencies for an icosahedron model of earth's atmosphere.