[Mpi3-tools] latest draft of mqs

Anh Vo Anh.Vo at microsoft.com
Wed May 22 15:37:18 CDT 2013


Continue from where I left off
Page 15 (Word page 22)
I believe the typedef for function mqs_put_image_info should mark image as OUT (which is what I have in the existing document now), but one of John's edit changed it to IN

This callback should be provided by the debugger so I'm not 100% clear, but based on the example tvtest.c, I see put_image_info being defined as follows:

static void dbgrI_put_image_info( mqs_image *image, mqs_image_info *info )
{
    image->i_info = info;
}

This means image needs to be marked as OUT because we're modifying image. Even though we're only modifying a field of "image", we're still modifying it. Now, it could also be INOUT, if we happen to read the image, but without a debugger's source code, I cannot tell for sure.

--Anh
-----Original Message-----
From: mpi3-tools-bounces at lists.mpi-forum.org [mailto:mpi3-tools-bounces at lists.mpi-forum.org] On Behalf Of Anh Vo
Sent: Wednesday, May 22, 2013 12:31 PM
To: mpi3-tools at lists.mpi-forum.org
Subject: Re: [Mpi3-tools] latest draft of mqs

Hi all,
I've addressed almost all of John's edits and comments (Many thanks to John!). There are a few items that I would like to get some feedbacks and consensus:

Page number refers to the PDF document (although I try to include the Word page number and comment number for easy reference)

Page 1, Comment JD3
Existing text: "the MPI Forum published a document which formally standardized  the MPIR Process Acquisition Interface"
John's comments that we should not use the word standardized, but rather should say that "the MPI Forum published a document which formally described..."
My impression was that the MPIR was standardized (i.e., it went through the voting process), but the quality of the document was not on-par with the rest of the standard so it was not included in the official document. But I wasn't there when that happened so I would like more background and context here.

Page 2, Comment JD4
John's comments about lots of hyphenated identifiers at end of line. Some of it are artifacts of converting PDF -> Word, but I think this is a common (and widely accepted) problems of latex documents. So we will probably have to live with it unless there're some magic way to make it nicer. 

Page 9 (Page 14 in Word), Comment JD18
John recommended the formatted table similar to what the MPIR document had. For example:

Char MPIR_dll_name[]
Definition is required
Definition is contained within the address space of the MPI process Variable is written by the MPI process, and read by the tool

I thought I did ask about this in the conf call at some point (or maybe it was an email, I can't remember the exact time and place) and we agreed that we would not be using that format because many people in the forum thought it was weird looking.

 Page 9 (Page 14 in Word), Comment JD19:
I think we agreed that we would not include the mpimsgq_dll_locations in this version and leave all extensions/improvements to document V1.1 or V2.0

Page 15 (Page 21 in Word),Comment JD26
Should we include semicolon at the end of the typedef definition? When I first created the document, I also debated a bit between this. I ended up following the style of the MPI standard where it lists the C declaration without any ; I'm fine either way, but would like to hear others' opinions on this.

I'm leaving for lunch now. More comments after I'm back. In the meantime, if folks can comments on what I've sent so far, that'd be great!!

Thanks
Anh

-----Original Message-----
From: mpi3-tools-bounces at lists.mpi-forum.org [mailto:mpi3-tools-bounces at lists.mpi-forum.org] On Behalf Of Anh Vo
Sent: Wednesday, May 22, 2013 8:10 AM
To: mpi3-tools at lists.mpi-forum.org
Subject: Re: [Mpi3-tools] latest draft of mqs

The definitions John provide look great for me. Unless there are other opinions, I will use those.

--Anh 

-----Original Message-----
From: mpi3-tools-bounces at lists.mpi-forum.org [mailto:mpi3-tools-bounces at lists.mpi-forum.org] On Behalf Of Ahn, Dong H.
Sent: Wednesday, May 22, 2013 7:54 AM
To: mpi3-tools at lists.mpi-forum.org
Subject: Re: [Mpi3-tools] latest draft of mqs

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>_______________________________________________
> >     Mpi3-tools mailing list
> >     Mpi3-tools at lists.mpi-forum.org <mailto:Mpi3-tools at lists.mpi-forum.org>
> >     http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-tools
> >
> >
> >
> > ______________________________________________________________
> > Kathryn Mohror, kathryn at llnl.gov
> > <mailto:kathryn at llnl.gov>, http://people.llnl.gov/mohror1 CASC @ 
> > Lawrence Livermore National Laboratory, Livermore, CA, USA
> >
> >
> >
> >
> >
> >
> >
> _______________________________________________
> Mpi3-tools mailing list
> Mpi3-tools at lists.mpi-forum.org
> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-tools

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