SessionMaterials and Chemistry
Event Type
Paper
Applications
Effective Application of HPC
Scientific Computing
TimeWednesday, November 15th3:30pm -
4pm
Location402-403-404
DescriptionQMCPACK has enabled cutting-edge materials research on
supercomputers for over a decade. It scales nearly
ideally but has low single-node efficiency due to the
physics-based abstractions using array-of-structures
objects, causing inefficient vectorization. We present a
systematic approach to transform QMCPACK to better
exploit the new hardware features of modern CPUs in
portable and maintainable ways. We develop miniapps for
fast prototyping and optimizations. We implement new
containers in structure-of-arrays data layout to
facilitate vectorizations by the compilers. Further
speedup and smaller memory-footprints are obtained by
computing data on the fly with the vectorized routines
and expanding single-precision use. All these are
seamlessly incorporated in production QMCPACK. We
demonstrate up-to 4.5x speedups on recent Intel®
processors and IBM Blue Gene/Q for representative
workloads. Energy consumption is reduced significantly
commensurate to the speedup factor. Memory-footprints
are reduced by up-to 3.8x, opening the possibility to
solve much larger problems of future.
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