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Function to output which communication method is being used? RRS feed

  • Question

  • I understand MSMPI will automatically choose the optimum communication method to use (ie shared memory, TCP, infinband etc...).  I also understand a process can be launched and told to use a certain method.

    Is there an MPI function (that can be called from code) that can inform the user about which communication method has been auto-chosen?

    Thursday, July 5, 2012 3:36 AM

All replies

  • Hi,

    I checked with a developer on the team and here is the answer for you

    MPI process will communicate through the following channels (in this order, if more than one is available)

    1. Shared memory
    2. ND
    3. Sock

    The user can use the connectivity table option to see which channel the process are connected to

    The option is described here

    http://technet.microsoft.com/en-us/library/cc947675(v=ws.10).aspx

    Michael

    Wednesday, July 18, 2012 1:01 AM
  • There is no programmatic way of querying which communication method was chosen.  You can however disable certain communication channels using environment variables passed to the program via the -env option to mpiexec.

    As Michael pointed out above, you can have MS-MPI append to the job output a connectivity table that will show what communication channels were used during the job between all processes.

    -Fab

    Thursday, June 27, 2013 10:31 PM