[Mpi3-tools] latest draft of mqs

Ahn, Dong H. ahn1 at llnl.gov
Wed May 22 09:54:29 CDT 2013


Hi John,

This works for me and should clarify a few things in the current draft. 

Best,
Dong

> -----Original Message-----
> From: mpi3-tools-bounces at lists.mpi-forum.org [mailto:mpi3-tools-bounces at lists.mpi-forum.org] On Behalf Of John DelSignore
> Sent: Wednesday, May 22, 2013 9:55 AM
> To: mpi3-tools at lists.mpi-forum.org
> Subject: Re: [Mpi3-tools] latest draft of mqs
> 
> I prefer to not muddy up the "standard definitions" (or maybe "common-sense definitions") of commonly used term, such as "image
> file", to make them conform to the MQD interface. Instead, I like to define the MQD typedefs in terms of the standard definitions. So,
> WRT to the document, I think we should include the following definitions:
> 
> * An "image file" is an executable or shared library file, that may contain symbol definitions needed by the MQD interface.
> 
> * An "MPI process" consists of an "address space" and a collection of execution contexts (threads or lightweight processes).
> 
> * An "address space" is a region of memory that consists of executable code and data, and is partially composed of a collection of image
> files. The collection of image files may change at any point during the execution of the MPI process, and image files may be relocated at
> runtime within the address space at the point they are loaded into memory.
> 
> Then we can say:
> 
> * An "mqs_image" is an abstract concept that represents the collection of image files loaded into the address space of the MPI process
> at any given time, and is debugger implementation defined. In static execution environments, where shared libraries are not supported,
> an mqs_image can represent an executable image file. However, in dynamic execution environments, where shared libraries,
> dynamically loaded shared libraries, and runtime relocation of shared libraries are supported, an mqs_image should represent the
> collection of image files loaded into the address space of the MPI process at any given point in time; in this situation, mqs_image may in
> fact represent the MPI process itself.
> 
> Cheers, John D.
> 
> 
> Anh Vo wrote:
> > 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.
> >
> >
> >
> > --Anh
> >
> > *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?
> >
> >
> >
> > Kathryn
> >
> >
> >
> > On May 21, 2013, at 2:18 PM, John DelSignore
> > <John.DelSignore at roguewave.com <mailto:John.DelSignore at roguewave.com>>
> > wrote:
> >
> >
> >
> >     Hi,
> >
> >     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
> >
> >
> >
> >         --Anh
> >
> >     <MPI-MQD-JVD-2013-05-17.doc>_______________________________________________
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> >
> >
> >
> > ______________________________________________________________
> > 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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