High performance Fortran for highly irregular problems

Hu, Y. Charlie; Johnsson, S. Lennart; Teng, Shang‐Hua

doi:10.1145/263764.263769

Cited by 26 publications

(2 citation statements)

References 22 publications

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“…Researchers have demonstrated that the performance of irregular parallel code can be improved by applying a combination of computation and data layout transformations. Some researches focus on providing primitives and libraries for runtime support [2,12,3,9], some provide language support such as add irregular facilities to HPF or Fortran 90 [16,11,18], and some works attempt to utilize caches and locality efficiently [4].…”

Section: Fig 1 a Typical Irregular Loopmentioning

confidence: 99%

Reducing Communication Cost for Parallelizing Irregular Scientific Codes

Guo

Liu

et al. 2002

Lecture Notes in Computer Science

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In most cases of distributed memory computations, node programs are executed on processors according to the owner computes rule. However, owner computes rule is not best suited for irregular application codes. In irregular application codes, use of indirection in accessing left hand side array makes it difficult to partition the loop iterations, and because of use of indirection in accessing right hand side elements, we may reduce total communication by using heuristics other than owner computes rule. In this paper, we propose a communication cost reduction computes rule for irregular loop partitioning, called least communication computes rule. We partition a loop iteration to a processor on which the minimal communication cost is ensured when executing that iteration. The experimental results show that, in most cases, our approaches achieved better performance than other loop partitioning rules.

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Section: Fig 1 a Typical Irregular Loopmentioning

confidence: 99%

Reducing Communication Cost for Parallelizing Irregular Scientific Codes

Guo

Liu

et al. 2002

Lecture Notes in Computer Science

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“…Space-filling curves also use geometric coordinate information to attempt to ensure proximity in memory. Data are laid out in memory according to space-filling curves (e.g., Hilbert, Morton), which are continuous, non-smooth curves that pass through every point in a finite k-dimensional space [24,38,46]. Figure 2 shows an example of using the Hilbert space-filling curve.…”

Section: Recursive Coordinate Bisection (Rcb)mentioning

confidence: 99%

Improving Locality for Adaptive Irregular Scientific Codes

Han

Tseng

2001

Languages and Compilers for Parallel Computing

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An important class of scientific codes access memory in an irregular manner. Because irregular access patterns reduce temporal and spatial locality, they tend to underutilize caches, resulting in poor performance. Researchers have shown that consecutively packing data relative to traversal order can significantly reduce cache miss rates by increasing spatial locality. In this paper, we investigate techniques for using partitioning algorithms to improve locality in adaptive irregular codes. We develop parameters to guide both geometric (RCB) and graph partitioning (METIS) algorithms, and develop a new graph partitioning algorithm based on hierarchical clustering (GPART) which achieves good locality with low overhead. We also examine the effectiveness of locality optimizations for adaptive codes, where connection patterns dynamically change at intervals during program execution. We use a simple cost model to guide locality optimizations when access patterns change. Experiments on irregular scientific codes for a variety of meshes show our partitioning algorithms are effective for static and adaptive codes on both sequential and parallel machines. Improved locality also enhances the effectiveness of LOCALWRITE, a parallelization technique for irregular reductions based on the owner computes rule.

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Code generator for the HPF Library and Fortran 95 transformational functions

Waveren

Addison

Harrison

et al. 2002

Concurrency and Computation

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SUMMARYOne of the language features of the core language of HPF 2.0 (High Performance Fortran) is the HPF Library. The HPF Library consists of 55 generic functions. The implementation of this library presents the challenge that all data types, data kinds, array ranks and input distributions need to be supported. For instance, more than 2 billion separate functions are required to support COPY SCATTER fully. The efficient support of these billions of specific functions is one of the outstanding problems of HPF. We have solved this problem by developing a library generator which utilizes the mechanism of parameterized templates. This mechanism allows the procedures to be instantiated at compile time for arguments with a specific type, kind, rank and distribution over a specific processor array. We describe the algorithms used in the different library functions. The implementation gives the ease of generating a large number of library routines from a single template. The templates can be extended with special code for specific combinations of the input arguments. We describe in detail the implementation and performance of the matrix multiplication template for the Fujitsu VPP5000 platform.

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High performance Fortran for highly irregular problems

Abstract: We present a general data parallel formulation for highly irregular problems in High Performance Fortran (HPF). Our formulation consists of (1)

Cited by 26 publications

References 22 publications

Reducing Communication Cost for Parallelizing Irregular Scientific Codes

Reducing Communication Cost for Parallelizing Irregular Scientific Codes

Improving Locality for Adaptive Irregular Scientific Codes

Code generator for the HPF Library and Fortran 95 transformational functions

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