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parameter affect large message transfers?

April 26, 2017affect large message parameter transfers

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parameter affect large message transfers?

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NOTE: The mpi_leave_pinned parameter was broken in Open MPI v1.3 and v1.3.1 (see this announcement). mpi_leave_pinned functionality was fixed in v1.3.2. When mpi_leave_pinned is set to 1, Open MPI aggressively tries to pre-register user message buffers so that the RDMA Direct protocol can be used. Additionally, user buffers are left registered so that the de-registration and re-registration costs are not incurred if the same buffer is used in a future message passing operation. NOTE: Starting with Open MPI v1.3, mpi_leave_pinned is automatically set to 1 by default when applicable. It is therefore usually unnecessary to set this value manually. NOTE: The mpi_leave_pinned MCA parameter has some restrictions on how it can be set starting with Open MPI v1.3.2. See this FAQ entry for details. Leaving user memory registered when sends complete can be extremely beneficial for applications that repeatedly re-use the same send buffers (such as ping-pong benchmarks). Additionally, the fact that