Multicore-optimized wavefront diamond blocking for optimizing stencil updates

The importance of stencil-based algorithms in computational science has focused attention on optimized parallel implementations for multilevel cache-based processors. Temporal blocking schemes leverage the large bandwidth and low latency of caches to accelerate stencil updates and approach theoretic...

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Bibliographic Details
Published in:arXiv.org 2014-10
Main Authors: Malas, Tareq, Hager, Georg, Ltaief, Hatem, Stengel, Holger, Wellein, Gerhard, Keyes, David
Format: Article
Language:English
Subjects:
Algorithms
Central processing units
Concurrency
CPUs
Data paths
Diamonds
Microprocessors
Tiling
Online Access:Get full text
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Summary:The importance of stencil-based algorithms in computational science has focused attention on optimized parallel implementations for multilevel cache-based processors. Temporal blocking schemes leverage the large bandwidth and low latency of caches to accelerate stencil updates and approach theoretical peak performance. A key ingredient is the reduction of data traffic across slow data paths, especially the main memory interface. In this work we combine the ideas of multi-core wavefront temporal blocking and diamond tiling to arrive at stencil update schemes that show large reductions in memory pressure compared to existing approaches. The resulting schemes show performance advantages in bandwidth-starved situations, which are exacerbated by the high bytes per lattice update case of variable coefficients. Our thread groups concept provides a controllable trade-off between concurrency and memory usage, shifting the pressure between the memory interface and the CPU. We present performance results on a contemporary Intel processor.
ISSN:2331-8422
DOI:10.48550/arxiv.1410.3060