Before, using the MPI_Isend I just read the page describing Isend at
www-unix.mcs.anl.gov/mpi/www/www3/MPI_Isend.html. At the page it is not
stated that to complete the Isend some has to do some freeing steps, like
Request_free, or Test, or Wait. Even if the message has been delivered to
the destination there are somethings (that comsume time) to be freed. I
later check the page for MPI_Wait and it does not state the
"side-effects" of the function (freeing stuff). Then later I checked it
in our system by typing man MPI_Isend and see the crucial note there("The
communication started with this function is not guaranteed to progress or
complete until req has been given to one of the test or wait functions
MPI_Test, MPI_Testall,...").
By the way, is it more efficient (in terms of communication computation
overlap) to use MPI_Isend(buf..) and immediately after use
MPI_Request_free (like Mr. Lebeau) assuming that programmer has guarenteed
that the "buf" is reusable.
Anyway, thanks for all the correspondence.
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