[Mpi3-rma] Disp_unit in allocate_shared should be returned by win_shared_query?

[Torsten Hoefler]

On Wed, Jul 18, 2012 at 01:18:53PM -0500, James Dinan wrote:
> On 7/18/12 1:06 PM, Torsten Hoefler wrote:
>> On Wed, Jul 18, 2012 at 01:08:43PM -0500, Pavan Balaji wrote:
>>>
>>> On 07/18/2012 01:02 PM, Torsten Hoefler wrote:
>>>> Jim,
>>>>> Is one process' disp_unit meaningful at another process?  I thought that
>>>>> this is not the case.  MPI provides no other routines to query another
>>>>> process' disp_unit.
>>>> It is something that the user is passing in. I don't know of a
>>>> particular use-case but we can query all other arguments that each
>>>> process passed. One more integer seemed safe to me.
>>>>
>>>>> Also, what meaning does a disp_unit have in the context of load/store
>>>>> operations that will result from win_shared_query?
>>>> Nothing.
>>>>
>>>>> Maybe I'm missing something, but this doesn't seem necessary.
>>>> Well, it's better to have it than to introduce it with a different name
>>>> later. That was my main motivation. One could also use it in a library
>>>> context to query. But that's weak, I know.
>>>
>>> This doesn't seem critical, and can always be added in MPI-3.1 if we
>>> find it necessary.  No reason to rush it.
> >
>> It cannot be added without a new function name. That was the concern
>> here. Adding it seems less risk than not adding it. In addition, it is
>> already added ;-).
>
> I am concerned that this is a harmful change.  The disp_unit from one  
> process has no meaningful use at another process.  If the user wants to  
> know it for some reason, they can use a separate communication operation.
I believe the potential damage is very limited. But we can have a vote.

So far it's still yes: 5, no: 1

I'm just mediating, not making decisions.

Torsten

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Torsten Hoefler         | Performance Modeling and Simulation Lead
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