Optimizing the performance of streaming numerical kernels on the IBM Blue Gene/P PowerPC 450 processor

T. Malas, A. J. Ahmadia, J. Brown, J. A. Gunnels, and D. E. Keyes
International Journal of High Performance Computing Applications, 27, pp. 193-209, (2013)

Optimizing the performance of streaming numerical kernels on the IBM Blue Gene/P PowerPC 450 processor

Keywords

High  Performance  Computing,  Performance  Optimization,  Code  Generation, SIMD, Blue Gene/P

Abstract

​Several emerging petascale architectures use energy-efficient processors with vectorized computational units and in-order thread processing. On these architectures the sustained performance of streaming numerical kernels, ubiquitous in the solution of partial differential equations, represents a challenge despite the regularity of memory access. Sophisticated optimization techniques are required to fully utilize the Central Processing Unit (CPU).

We propose a new method for constructing streaming numerical kernels using a high-level assembly synthesis and optimization framework. We describe an implementation of this method in Python targeting the IBM Blue Gene/P supercomputer's PowerPC 450 core. This paper details the high-level design, construction, simulation, verification, and analysis of these kernels utilizing a subset of the CPU's instruction set.

We demonstrate the effectiveness of our approach by implementing several three-dimensional stencil kernels over a variety of cached memory scenarios and analyzing the mechanically scheduled variants, including a 27-point stencil achieving a 1.7x speedup over the best previously published results.

Code

DOI: 10.1177/1094342012444795

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