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Publications of SPCL
|S. Di Girolamo, F. Vella and T. Hoefler:|
|Transparent Caching for RMA Systems |
(In Proceedings of the 31st IEEE International Parallel & Distributed Processing Symposium (IPDPS'17), presented in Orlando, FL, USA, pages , IEEE, ISBN: , May 2017, )
AbstractThe constantly increasing gap between communication and computation performance emphasizes the importance of communication-avoidance techniques. Caching is a well-known concept used to reduce accesses to slow local memories. In this work, we extend the caching idea to MPI-3 Remote Memory Access (RMA) operations. Here, caching can avoid inter-node communications and achieve similar benefits for irregular applications as communication-avoiding algorithms for structured applications. We propose CLaMPI, a caching library layered on top of MPI-3 RMA, to auto- matically optimize code with minimum user intervention. We demonstrate how cached RMA improves the performance of a Barnes Hut simulation and a Local Clustering Coefficient computation up to a factor of 1.8x and 5x, respectively. Due to the low overheads in the cache miss case and the potential benefits, we expect that our ideas around transparent RMA caching will soon be an integral part of many MPI libraries.