[Mpi3-rma] RMA chapter for quick review

Barrett, Brian W bwbarre at sandia.gov
Fri Mar 11 14:21:41 CST 2011

On 3/11/11 12:10 PM, "Torsten Hoefler" <htor at illinois.edu> wrote:

>> Page and line numbers are from the marked-up copy, not the clean copy.
>> Pg 1, ln 45/46 & pg 2, ln 1&2: The discussion of communication
>> being delayed for the separate model and immediate for the unified model
>> is a bit confusing.  When the implementation *starts* the communication
>> the same for both models, depending on the synchronization calls.  The
>> only difference between the two models is when the private and public
>> copies on the target must be synchronized.  As I read the standard, an
>> implantation is free to start a put immediately upon calling MPI_PUT in
>> the separate model and also free to start a put during MPI_UNLOCK in the
>> unified model.
>It's a very high-level view - we don't separate between completion and
>start at this point (in the intro). Both statements are "can" statements
>and not wrong. Do you have a concrete wording proposal that makes it
>less confusing?

No, I wasn't suggesting that we do.  My main concern was that we were
introducing the potential for someone to read a requirement where none
existed.    To be honest, I think the best route is to remove the two

  "; for efficiency, the implementation can delay communication operations
until the synchronization calls occur" and
  "In this model, communication can be independent of synchronization

Neither are strictly necessary for the point being made, and there's no
great way to describe the concept without more detail than makes sense for
an introduction.

Thoughts from others?


  Brian W. Barrett
  Dept. 1423: Scalable System Software
  Sandia National Laboratories

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