[Mpi3-tools] MPI_T session question

[Pavan Balaji]

Sure.  That was my first thought as well, but that doesn't reduce the 
number of variables being stored in most cases.  And will probably get 
messy in the THREAD_MULTIPLE case when we need to support reset of a 
variable on one session and read of the same value on another session.

  -- Pavan

On 08/17/2013 10:14 AM, William Gropp wrote:
> 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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>
>
>
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-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji