[Mpi3-rma] Unified model discussion

[William Gropp]

Would that call also complete/order local memory operations (e.g., we  
could use the same routine)?

Bill

On Apr 2, 2011, at 11:50 AM, Underwood, Keith D wrote:

> That is an important point.  What if we allow unified to work for  
> this use case without additional calls, but add a call to force  
> synchronization when the local and remote accesses would conflict?
>
> Keith
>
>> -----Original Message-----
>> From: mpi3-rma-bounces at lists.mpi-forum.org [mailto:mpi3-rma-
>> bounces at lists.mpi-forum.org] On Behalf Of Pavan Balaji
>> Sent: Thursday, March 31, 2011 3:52 PM
>> To: mpi3-rma at lists.mpi-forum.org
>> Subject: [Mpi3-rma] Unified model discussion
>>
>>
>> When we were having the discussion on the unified model during the  
>> last
>> working group meeting, I forgot to point out one important use case:
>>
>> Process 0
>> ----------
>> Win_lock(shared, P0)
>> load(A)
>> store(B)
>> Win_unlock
>>
>> Process 1
>> ---------
>> Win_lock(shared, P0)
>> Put(C)
>> Get(D)
>> Win_unlock
>>
>> That is, two processes are reading/writing to different parts of the
>> window. This is an important model and can only be supported in
>> unified,
>> not separate (because of potential cache-line false sharing).
>>
>> So, basically, no we cannot remove the unified model in spite of all
>> its
>> nonsense with load/store ordering.
>>
>>  -- Pavan
>>
>> --
>> Pavan Balaji
>> http://www.mcs.anl.gov/~balaji
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>> mpi3-rma at lists.mpi-forum.org
>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma
>
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William Gropp
Deputy Director for Research
Institute for Advanced Computing Applications and Technologies
Paul and Cynthia Saylor Professor of Computer Science
University of Illinois Urbana-Champaign