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DTSTAMP:20260422T000712Z
LOCATION:605
DTSTART;TZID=America/Denver:20231113T155000
DTEND;TZID=America/Denver:20231113T161000
UID:submissions.supercomputing.org_SC23_sess453_ws_exampi101@linklings.com
SUMMARY:Using Mixed-Radix Decomposition to Enumerate Computational Resourc
 es of Deeply Hierarchical Architectures
DESCRIPTION:Philippe Swartvagher, Sascha Hunold, Jesper Larsson Träff, and
  Ioannis Vardas (Technical University Wien (Vienna University of Technolog
 y))\n\nCurrent HPC architectures are deeply hierarchical (racks, nodes, so
 ckets, NUMA domains, caches, ...), and the mapping of MPI processes to cor
 es can significantly influence application performance. To study hierarchy
  effects on MPI application performance, we propose a procedure for expres
 sing mappings by enumerating cores in the hierarchy in different orders. W
 e explore two use cases: MPI rank reordering for applications using subcom
 municators, and core selection for applications not using all cores on a n
 ode.\n\nResults of micro-benchmarks executing collective operations in sub
 communicators show a performance difference up to a factor 4 between the b
 est and the worst rank orderings. By changing the rank orders, we observe 
 a performance impact for the Splatt application. The evaluation of the str
 ong scalability of a conjugate gradient benchmark shows that considering a
 ll hierarchy levels in the core selection policy can give better performan
 ce than using only options available with common MPI application launchers
 .\n\nTag: Exascale, Message Passing, Programming Frameworks and System Sof
 tware\n\nRegistration Category: Workshop Reg Pass\n\nSession Chairs: Purus
 hotham Bangalore (The University of Alabama); Amanda J. Bienz (University 
 of New Mexico); Matthew G. F. Dosanjh (Sandia National Laboratories); Ryan
  Grant (Queen's University, Canada; Power API); William Schonbein (Sandia 
 National Laboratories); and Anthony Skjellum (Tennessee Technological Univ
 ersity, ASCEND-TNTECH)\n\n
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