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MPI buffer size for Send/Recv

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Old   April 14, 2005, 08:36
Default MPI buffer size for Send/Recv
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I am using Scali MPI in my code. I use the MPI_Send() and MPI_Recv() routines for sending information between the nodes. I increase the amount of data that is sent between nodes and everything works fine, until a certain amount of data when the communications just become idle and the program gets stucked, as if the different processors do not receive the information they are waiting for and just keep on waiting for ever.

I have read something about the size of the buffer that is assign for MPI communiations. Could that be the problem? That I am sending more information than the maximum buffer size?

In this case, if I change to the nonblocking routines MPI_Isend() and MPI_Irecv(), do I solve the problem? Or is there any way of increasing the available buffer size?

Thanks in adavance.

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Old   April 15, 2005, 10:03
Default Re: MPI buffer size for Send/Recv
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I had a similar problem with my code. The fix for me was to use Isend and Irecv. Make sure you use a MPI_Waitall at an appropriate place to insure all the messages are complete.
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Old   April 15, 2005, 11:21
Default Re: MPI buffer size for Send/Recv
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Thanks very much! I will try that.
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