[Mpi3-tools] latest draft of mqs

Anh Vo Anh.Vo at microsoft.com
Tue May 21 21:15:25 CDT 2013

Thanks Kathryn for starting up the discussion.

I'll start with my existing definition of mqs_image in the document, which definitely is not adequate.

Existing definition:
An image is an executable file that was loaded into memory when
a process is started.  For SIMD-style programs, all MPI processes have
the same image. For MIMD-style programs, MPI processes might have
different images.

Dong's comments:
The definition of "Image" isn't all that rigorous here. I think this creates some confusion somewhere down this document. Is an image really an executable file? Which  typically means the base executable or does this refer to both the based executable and DSOs being loaded into the process address space? Though it sounds hair-splitting, even the SPMD remark, the statement is only true if the image is defined to be the base executable.

John's comments:
I think we should be more general with the term "image" to mean executable or shared library. The reason is that we do not want to require symbols to reside in the executable. We should allow symbols to reside in shared libraries.
Also, I think we need to define the "address space" of a process, and an "image list" as a collection of image files that have been loaded in the address space, and possibly relocated at runtime.

I think I agree with both comments. Image should not refer to a single executable image (a.out or a.exe), but rather the base executable and the shared libraries that were loaded into the process address space.

So how about this new definition:
An image represents the executable (e.g., a.out) and the collection of dynamically loaded libraries that were loaded into the process address space.

From: mpi3-tools-bounces at lists.mpi-forum.org [mailto:mpi3-tools-bounces at lists.mpi-forum.org] On Behalf Of Kathryn Mohror
Sent: Tuesday, May 21, 2013 6:27 PM
To: mpi3-tools at lists.mpi-forum.org
Subject: Re: [Mpi3-tools] latest draft of mqs

Hi John,

Thank you for the extensive feedback and help with the document! I'm sure you will get the 'nod' you referred to on page 1 :-)

For the definition of mqs_image, I agree that it needs work.  Dong Ahn also mentioned that it needed to be more rigorously defined. However if possible, I think it would be beneficial if we could at least start the conversation before next week so that we have a better chance of having it nailed down in advance of the next meeting.

So, that said -- does anyone want to take a first stab at a definition to get us started?


On May 21, 2013, at 2:18 PM, John DelSignore <John.DelSignore at roguewave.com<mailto:John.DelSignore at roguewave.com>> wrote:


Attached are my edits and comments on the MPI Message Queue document. Anh provided me with a Word document generated from the LaTex, so the formatting is funky in some places. I enabled change tracking in Word before making my edits, and I added many comments to the document in places where I think we have more work to do. Unfortunately, I think the changes might be somewhat extensive.

The volume of edits and comments aside, I think Anh did a great job! The first draft of the document closely reflects the 10+ year-old description of the interface pretty well. Unfortunately, the original interface has some problem that we need to resolve, most critically, we have to resolve how to describe the concept of "mqs_image". We can talk about this during the next concall.

Cheers, John D.

Anh Vo wrote:

Hi all,

As mentioned on the tool WG call today, I'm re-sending the latest draft.
Feedbacks are appreciated. We'll send this one out to the wider audience
on Tuesday 5/21 to meet the requirement for first reading in June

Mpi3-tools mailing list
Mpi3-tools at lists.mpi-forum.org<mailto:Mpi3-tools at lists.mpi-forum.org>

Kathryn Mohror, kathryn at llnl.gov<mailto:kathryn at llnl.gov>, http://people.llnl.gov/mohror1
CASC @ Lawrence Livermore National Laboratory, Livermore, CA, USA

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