[mpiwg-tools] [MPIWG Fortran] Proposal: MPI_SIZEOF not profiled

Mon May 19 15:49:47 CDT 2014

I'll be not at the June Meeting in Chicago. My apologies.

For me, the solution is now nearly clear:
Allow for all these special cases that they are non-interceptable,
and require that the PMPI Version is still available,
and to mention "macro in C" only as an "e.g.",
and the list includes the existing list plus MPI_SIZEOF
plus status conversion routines.
Du to the problems in the existing wording, and with MPI_SIZEOF,
I would propose it as an erratum, that is needed for MPI-3.1.

Best regards
Rolf

----- Original Message -----
> From: "Jeff Squyres (jsquyres)" <jsquyres at cisco.com>
> To: "MPI-WG Fortran working group" <mpiwg-fortran at lists.mpi-forum.org>
> Cc: mpiwg-tools at lists.mpi-forum.org
> Sent: Monday, May 19, 2014 8:19:58 PM
> Subject: Re: [mpiwg-tools] [MPIWG Fortran] Proposal: MPI_SIZEOF not profiled
> 
> Ok.  Will any other Fortran people be there?  (besides me)
> 
> 
> On May 19, 2014, at 2:03 PM, Martin Schulz <schulzm at llnl.gov> wrote:
> 
> > Yes, sounds like it - I¹ll take 428 off the list then. We should
> > take some
> > time on Monday afternoon as part of the tools WG time to talk about
> > this.
> > 
> > Martin
> > 
> > ________________________________________________________________________
> > Martin Schulz, schulzm at llnl.gov, http://scalability.llnl.gov/
> > CASC @ Lawrence Livermore National Laboratory, Livermore, USA
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > On 5/19/14, 8:35 AM, "Jeff Squyres (jsquyres)" <jsquyres at cisco.com>
> > wrote:
> > 
> >> I think we need to push this errata out to the Japan meeting.
> >>  There
> >> seems to be a bunch of subtlety here; trying to rush this through
> >> today
> >> does not seem like a good idea just to meet the T-2 week deadline
> >> for the
> >> Chicago meeting (which technically expires at 2pm US Central time
> >> today
> >> -- which is about 3.5 hours from now).
> >> 
> >> Let me try to summarize the salient points so far:
> >> 
> >> 1. The old text kinda sucks:
> >>  a. it says "macros" (including the section title) where it really
> >> means "not interceptable"
> >>  b. p19 implies that these function can only be macros in C (not
> >> inlined, and not in Fortran), which seems to contradict p555
> >> 
> >> 2. We need to add the Status conversion functions in there
> >> 
> >> 3. We want to add MPI_SIZEOF (which is Fortran-only, BTW) to the
> >> list
> >> 
> >> 4. The use of the word "inline" seems to be a bad idea because it
> >> can
> >> have many different meanings.  We should say that these functions
> >> are not
> >> interceptable, which is the real requirement.
> >> 
> >> 5. I think it would be better to change p555 to not say "macros"
> >> (i.e.,
> >> "non-interceptable"), but rather to say "the routines listed in
> >> 2.6.4"
> >> (i.e., who cares what the reason is -- just cite 2.6.4 and let
> >> 2.6.4
> >> explain everything).
> >> 
> >> Is that all?
> >> 
> >> 
> >> 
> >> 
> >> On May 19, 2014, at 11:08 AM, Rolf Rabenseifner
> >> <rabenseifner at hlrs.de>
> >> wrote:
> >> 
> >>> Yes, the "allowed as macros" on MPI-3.0 p555:32
> >>> would allow a different mechanism for these routines
> >>> that makes them non-interceptable.
> >>> 
> >>> If this "non-interceptable" is done by other means
> >>> than macro, then p555:35 "For routines implemented
> >>> as macros, it is still required that the PMPI_
> >>> version be supplied" would not apply!
> >>> 
> >>> It is bad to use different wording for having
> >>> better English quality ;-(
> >>> 
> >>> And your are right, my "#ifdef MPI_Wait" says
> >>> therefore nothing.
> >>> 
> >>> Do you all agree that wording in
> >>> p19:48 - p20:5 and p555:31-37 is at all inconsistent
> >>> and therefore new and useful wording is needed
> >>> in this erratum?
> >>> 
> >>> Rolf
> >>> 
> >>> ----- Original Message -----
> >>>> From: "N.M. Maclaren" <nmm1 at cam.ac.uk>
> >>>> To: "MPI-WG Fortran working group"
> >>>> <mpiwg-fortran at lists.mpi-forum.org>
> >>>> Sent: Monday, May 19, 2014 4:35:10 PM
> >>>> Subject: Re: [MPIWG Fortran] [mpiwg-tools] Proposal: MPI_SIZEOF
> >>>> not
> >>>> profiled
> >>>> 
> >>>> On May 19 2014, Rolf Rabenseifner wrote:
> >>>>> 
> >>>>> Bill,
> >>>>> 
> >>>>> your text goes beyond the errata goal.
> >>>>> 
> >>>>> The errata goal was:
> >>>>> - adding the missing Status conversion
> >>>>> - adding MPI_SIZEOF
> >>>>> 
> >>>>> And this works as errata.
> >>>>> 
> >>>>> Your goal is to allow also
> >>>>> - Fortran non-interceptable for these routines.
> >>>>> 
> >>>>> Your additional Change is to allow other methods
> >>>>> than C macros for C.
> >>>>> This would prevent "#ifdef MPI_Wtime".
> >>>>> 
> >>>>> All this would be MPI-4.0 and not MPI-3.0 errata.
> >>>> 
> >>>> Would it?  I don't know what useful effect you would expect
> >>>> "#ifdef MPI_Wtime" to achieve, but it assuredly would NOT tell
> >>>> you (reliably) whether or not it can be accessed through the
> >>>> profiling interface.  14.2 says:
> >>>> 
> >>>>   1. provide a mechanism through which all of the MPI defined
> >>>>   functions, except those allowed as macros (See Section 2.6.4),
> >>>>   may be accessed with a name shift.
> >>>> 
> >>>> Because it says "ALLOWED as macros", MPI_Wtime may not be
> >>>> accessed
> >>>> through the profiling interface, whether or not it is
> >>>> implemented
> >>>> as a macro.  Doing so is a user error, leading to undefined
> >>>> behaviour.
> >>>> Therefore, an implementation may implement them as C inline
> >>>> functions,
> >>>> and would meet all of the requirements of MPI.
> >>>> 
> >>>> The error is more pervasive than just for Fortran.  Because it
> >>>> did
> >>>> not say what it meant, but something that was equivalent under
> >>>> K&R C
> >>>> (sic), it wasn't strictly true in C90 and was rendered
> >>>> significantly
> >>>> misleading (arguably erroneous) by C99.  And that's the reason
> >>>> that
> >>>> some people get very unhappy about the proposed partial fix.
> >>>> 
> >>>> It's also why the best solution is to regard ALL of the wording
> >>>> as
> >>>> an error - which would probably mean starting a new ticket.  But
> >>>> it's
> >>>> definitely an error in the wording, not a change.
> >>>> 
> >>>> 
> >>>> Regards,
> >>>> Nick Maclaren.
> >>>> 
> >>>> _______________________________________________
> >>>> mpiwg-fortran mailing list
> >>>> mpiwg-fortran at lists.mpi-forum.org
> >>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> >>>> 
> >>> 
> >>> --
> >>> Dr. Rolf Rabenseifner . . . . . . . . . .. email
> >>> rabenseifner at hlrs.de
> >>> High Performance Computing Center (HLRS) . phone
> >>> ++49(0)711/685-65530
> >>> University of Stuttgart . . . . . . . . .. fax ++49(0)711 /
> >>> 685-65832
> >>> Head of Dpmt Parallel Computing . . .
> >>> www.hlrs.de/people/rabenseifner
> >>> Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room
> >>> 1.307)
> >>> _______________________________________________
> >>> mpiwg-fortran mailing list
> >>> mpiwg-fortran at lists.mpi-forum.org
> >>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> >> 
> >> 
> >> --
> >> Jeff Squyres
> >> jsquyres at cisco.com
> >> For corporate legal information go to:
> >> http://www.cisco.com/web/about/doing_business/legal/cri/
> >> 
> >> _______________________________________________
> >> mpiwg-tools mailing list
> >> mpiwg-tools at lists.mpi-forum.org
> >> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-tools
> > 
> > 
> > _______________________________________________
> > mpiwg-fortran mailing list
> > mpiwg-fortran at lists.mpi-forum.org
> > http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-fortran
> 
> 
> --
> Jeff Squyres
> jsquyres at cisco.com
> For corporate legal information go to:
> http://www.cisco.com/web/about/doing_business/legal/cri/
> 
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> 

-- 
Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseifner at hlrs.de
High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530
University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832
Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner
Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307)