[Mpi3-tools] MPI_T session question

[William Gropp]

I believe that the answer is yes, but note that in many/most/all cases, the session can record the value of the underlying MPI implementation variable at start time and then compute the difference.  It does mean that the access in a session may not be as simple as a memory reference, though a high-quality implementation could optimize for a single session.

Bill

William Gropp
Director, Parallel Computing Institute
Deputy Director for Research
Institute for Advanced Computing Applications and Technologies
Thomas M. Siebel Chair in Computer Science
University of Illinois Urbana-Champaign




On Aug 17, 2013, at 10:08 AM, Pavan Balaji wrote:

> Folks,
> 
> If an application has multiple sessions and does a PVAR_START on all sessions, is the intention that the MPI implementation will keep track of each pvar on each of the sessions?  Since when the pvar_start is called for each session is different, the values of these variables can be different.  So is the MPI implementation expected to replicate these variables per session?  Is this true for the read-only ones as well, since the start time can be different for each session?
> 
> -- Pavan
> 
> -- 
> Pavan Balaji
> http://www.mcs.anl.gov/~balaji
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