Analyzing the impact of communication imbalance in high‐speed networks

Abstract

SummaryIn this work we analyze the communication load imbalance generated by irregular‐data applications running in a multi‐node cluster. Experimental approaches to diminish communication load imbalance are evaluated using a hybrid programming model MPI + OpenMP including certain optimizations such as computation‐communication overlap, issuing communications in parallel, and a new proposal based on message fragmentation to take advantage of the eager‐protocol. Performance results show that overlapped versions can obtain a great benefit of this optimization because it avoids switching to rendezvous protocols. However, non‐overlapped versions showed a better performance than overlapped ones. To evaluate also the impact due to network latency, the work has been tested on two high‐speed interconnection networks: Infiniband and 10 Gigabit Ethernet. In this case, the optimizations in the non‐overlapped miniFE benchmark reached and improved up to 7% on Infiniband and 11% on 10 Gigabit.