This was the motivation, more than avoiding declaring a variable that was never read in the user’s program.  There was evidence for this from Intel in the early ‘90s, though I don’t know if anyone has looked into it recently.

Bill

William Gropp
Director, Parallel Computing Institute
Thomas M. Siebel Chair in Computer Science
Chief Scientist, NCSA
University of Illinois Urbana-Champaign





On May 26, 2016, at 6:30 PM, Jeff Hammond <jeff.science@gmail.com> wrote:

Is it correct to assume that it is cheaper to check for MPI_STATUS_IGNORE and MPI_STATUSES_IGNORE than to fill in the status object, in the case where the user does not need the status?

Thanks,

Jeff

--
Jeff Hammond
jeff.science@gmail.com
http://jeffhammond.github.io/
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