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Optimizing Irregular Communication with Neighborhood Collectives and Locality-Aware Parallelism
DescriptionIrregular communication limits both performance and scalability of parallel applications. Typically, it is implemented as point-to-point, and optimizations are integrated into the application, lacking portability. Optimization of point-to-point messages within MPI is difficult, as the interface only provides information on a piece of overall communication. However, persistent neighbor collectives expose a suitable interface for such optimizations.
This paper presents methods for implementing existing optimizations for irregular communication within neighborhood collectives, analyzes the impact of neighborhood collectives in Hypre BoomerAMG, and shows up to a 1.38x speedup on sparse matrix-vector multiplication using optimized neighbor collectives. The authors analyze three implementations of neighborhood collectives for Alltoallv: an unoptimized wrapper of standard point-to-point communication, and two locality-aware aggregating methods. The second exposes a non-standard interface to perform additional optimization for an additional 0.07x speedup.
Optimizations are available open-source in MPI Advance which wraps MPI, allowing use with any MPI installation.
This paper presents methods for implementing existing optimizations for irregular communication within neighborhood collectives, analyzes the impact of neighborhood collectives in Hypre BoomerAMG, and shows up to a 1.38x speedup on sparse matrix-vector multiplication using optimized neighbor collectives. The authors analyze three implementations of neighborhood collectives for Alltoallv: an unoptimized wrapper of standard point-to-point communication, and two locality-aware aggregating methods. The second exposes a non-standard interface to perform additional optimization for an additional 0.07x speedup.
Optimizations are available open-source in MPI Advance which wraps MPI, allowing use with any MPI installation.
Event Type
Workshop
TimeMonday, 13 November 20233:30pm - 3:50pm MST
Location605
Exascale
Message Passing
Programming Frameworks and System Software
W