[Mpi3-rma] Unified model discussion

[Pavan Balaji]

In the case of SEPARATE, Win_sync will be required to do two things: (1) 
order load/stores, and (2) synchronize public/private windows.

We can as well use Win_sync for unified too, and just get it to do the 
first part.

  -- Pavan

On 04/02/2011 12:35 PM, William Gropp wrote:
> 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
>>> _______________________________________________
>>> mpi3-rma mailing list
>>> 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
>
>
>
>
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-- 
Pavan Balaji
http://www.mcs.anl.gov/~balaji