[mpiwg-rma] [EXTERNAL] Re: MPI_WIN_CREATE for intercommunicators

[Thomas Jahns]

Hello,

On Jan 22, 2014, at 19:56 , Jeff Hammond wrote:

> On Wed, Jan 22, 2014 at 12:16 PM, Barrett, Brian W  
> <bwbarre at sandia.gov> wrote:
>> On 1/22/14 11:09 AM, "Jeff Hammond" <jeff.science at gmail.com> wrote:
>>
>>> On Wed, Jan 22, 2014 at 11:53 AM, Barrett, Brian W <bwbarre at sandia.gov 
>>> >
>>> wrote:
>>>> On 1/22/14 3:41 AM, "Thomas Jahns" <jahns at dkrz.de> wrote:
>>>>
>>>>> Hello Maik,
>>>>>
>>>>> On 01/22/14 10:14, maik peterson wrote:
>>>>>> thomas, today you should start thinking about other possibilities
>>>>>> to solve your problem. this mpi rma stuff is crappy.
>>>>>
>>>>> I guess that very much depends on your kind of machine. We've  
>>>>> found it
>>>>> to
>>>>> work
>>>>> very nice with MVAPICH, not so great with PE and OpenMPI.

perhaps I should qualify my very brief original statement before it  
becomes more flammable: MVAPICH gave the best out-of-the-box  
performance on that particular system (IBM xSeries with FDR IB) and  
while OpenMPI (on the same machine) did give the desired performance  
improvements with RMA, base-line performance was lower for some yet  
undiscovered reason, but system adminstration will look into it. I  
have no doubt this could have been different. For PE we asked IBM what  
to do differently but have no final answer so far.

Regards, Thomas
-- 
Thomas Jahns
DKRZ GmbH, Department: Application software

Deutsches Klimarechenzentrum
Bundesstraße 45a
D-20146 Hamburg

Phone: +49-40-460094-151
Fax: +49-40-460094-270
Email: Thomas Jahns <jahns at dkrz.de>



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