For reading the data from an isend buffer to cause problems, the underlying hardware would need to have very unusual characteristic that the MPI implementation is exploiting.  People have imagined hardware characteristics that could make reading an Isend buffer a problem but I have never heard of real hardware where it would be.  (Imagine hardware where posting an ISEND causes addressability of the underlying memory to be handed over to an adapter until the send is done. The processor loses addressability.  No such real hardware I ever heard of but if there were, the send buffer access rule would be relevant)

The Forum has decided the send buffer rule is to restrictive.



Dick Treumann  -  MPI Team          
IBM Systems & Technology Group
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