# [Mpi-forum] Feedback needed / Suggested Change to Chapter 8 (related to RMA)

Jim Dinan dinan at mcs.anl.gov
Thu Jul 19 12:44:59 CDT 2012

Same here.

~Jim.

On 7/19/12 11:17 AM, William Gropp wrote:
> This sounds good to me - deferring the discussion of the semantics to the RMA chapter makes the most sense.
>
> Bill
>
> William Gropp
> Director, Parallel Computing Institute
> Deputy Director for Research
> Institute for Advanced Computing Applications and Technologies
> Paul and Cynthia Saylor Professor of Computer Science
> University of Illinois Urbana-Champaign
>
>
>
> On Jul 19, 2012, at 11:05 AM, Schulz, Martin wrote:
>
>> Hi all,
>>
>> during the final chapter reads, the following issue came up in the section "Memory Allocation" in Chapter 8, MPI Environmental Management. Here is the context
>>
>>> \section{Memory Allocation}
>>> \label{sec:misc-memalloc}
>>>
>>> In some systems, message-passing and remote-memory-access (\RMA/) operations
>>> run faster when accessing specially allocated memory (e.g., memory that is
>>> shared by the other processes in the communicating group on an SMP).  \MPI/
>>> provides a mechanism for allocating and freeing such special memory.  The use
>>> of such memory for message-passing or \RMA/ is not mandatory, and this memory
>>> can be used without restrictions as any other dynamically allocated memory.
>>
>> This is followed by the following sentence:
>>
>>> However, implementations may restrict the use of the \mpifunc{MPI\_WIN\_LOCK}
>>> and \mpifunc{MPI\_WIN\_UNLOCK} functions to windows allocated in such memory
>>> (see Section~\ref{sec:1sided-lock}.)
>>
>> This covers the restrictions for 2.2, but not for the new RMA chapter. Therefore, the RMA group (or a subset thereof) suggested to change that sentence to:
>>
>>> However, implementations may restrict the use of some RMA functionality as defined
>>> in Section~\ref{sec:1sided-lock}.
>>
>> and leave the definition of the semantics to the RMA chapter.
>>
>> Please reply to the group if there are any objections or concerns.
>>
>> Thanks,
>>
>> Martin
>>
>>
>> ________________________________________________________________________
>> Martin Schulz, schulzm at llnl.gov, http://people.llnl.gov/schulzm
>> CASC @ Lawrence Livermore National Laboratory, Livermore, USA
>>
>>
>>
>>
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>
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