Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Improving MPI Collective I/O Performance With Intra-node Request
  Aggregation   Two-phase I/O is a well-known strategy for implementing collective MPI-IO
functions. It redistributes I/O requests among the calling processes into a
form that minimizes the file access costs. As modern parallel computers
continue to grow into the exascale era, the communication cost of such request
redistribution can quickly overwhelm collective I/O performance. This effect
has been observed from parallel jobs that run on multiple compute nodes with a
high count of MPI processes on each node. To reduce the communication cost, we
present a new design for collective I/O by adding an extra communication layer
that performs request aggregation among processes within the same compute
nodes. This approach can significantly reduce inter-node communication
congestion when redistributing the I/O requests. We evaluate the performance
and compare with the original two-phase I/O on a Cray XC40 parallel computer
with Intel KNL processors. Using I/O patterns from two large-scale production
applications and an I/O benchmark, we show the performance improvement of up to
29 times when running 16384 MPI processes on 256 compute nodes.

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The categories of this paper are: astro-ph
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The categories of this paper are: nlin
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The categories of this paper are: nucl-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th