Application-specific Topology-aware Mapping for Three Dimensional Topologies
Workshop on Large Scale Parallel Processing at IPDPS (LSPP) 2008
Publication Type: Paper
Repository URL: 200711_TopoLSPP
Abstract
The fastest supercomputers today such as Blue Gene/L and XT3 are
connected by a 3-dimensional torus/mesh interconnect. Applications
running on these machines can benefit from topology-awareness while
mapping tasks to processors at runtime. By co-locating
communicating tasks on nearby processors, the distance traveled by
messages and hence the communication traffic can be minimized,
thereby reducing communication latency and contention on the
network. This paper describes this technique and performance
improvements resulting from it in the context of a n-dimensional
k-point stencil program. Automated topology-aware mapping by the
runtime using similar ideas can relieve the application writer from
this burden and result in better performance. Preliminary work
towards achieving this for a molecular dynamics application, NAMD,
is also presented. Results on up to 32,768 processors of IBM's Blue
Gene/L and 2,048 processors of Cray's XT3 support the ideas
discussed in the paper.
TextRef
Abhinav Bhatele, Laxmikant V. Kale, Application-specific Topology-aware Mapping for Three Dimensional Topologies, Proceedings of Workshop on Large-Scale Parallel Processing (IPDPS), 2008
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