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

William Gropp wgropp at illinois.edu
Thu Jul 19 11:17:31 CDT 2012


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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