A Pipelined Algorithm for Large, Irregular All-Gather Problems

We describe and evaluate a new, pipelined algorithm for large, irregular all-gather problems. In the irregular all-gather problem each process in a set of processes contributes individual data of possibly different size, and all processes have to collect all data from all processes. The pipelined algorithm is useful for the implementation of the MPI Allgatherv collective operation of MPI (the Message-Passing Interface) for large problems. By conception the new algorithm is well suited to implementation on clustered multiprocessors, like for instance SMP clusters. The new algorithm has been implemented within different MPI libraries. Benchmark results on NEC SX-8, Linux clusters with InfiniBand and Gigabit Ethernet, IBM Blue Gene/P, and SiCortex systems show huge performance gains in accordance with the expected behavior. ∗ This paper is a revised version of the conference presentation “A Simple, Pipelined Algorithm for Large, Irregular All-gather Problems” that appeared in Re...

• Type: Journal
• Year: 2010
• Where: IJHPCA
• Authors: Jesper Larsson Träff, Andreas Ripke, Christian Siebert, Pavan Balaji, Rajeev Thakur, William Gropp
• Keywords: Algorithm, IJHPCA 2010, Instance Smp Clusters, Irregular All-gather Problems