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A Consideration of TCP/IP Congestion Control Mechanisms for the GridMPI
Takano Ryousei,†,†† Kudoh Tomohiro ,† Matsuda Motohiko ,†Kodama Yuetsu ,† Tezuka Hiroshi† and Ishikawa Yutaka†,†††
We are developing the GridMPI, which is an MPI implementation for Grid environment,in which clusters are distributed in a wide area and connected by an IP network. When MPIcollective communication is performed on such environment, communication performance issometimes signiﬁcantly low. In this report, we precisely analyze all-to-all collective communi-cation, and make clear that the performance degradation is caused by Retransmission TimeOut (RTO). We also discuss some ideas to avoid such performance degradation.
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