[Mpi-22] Another MPI-2.2 attribute ambiguity?

[Jeff Squyres]

Ok, I'll file an MPI-3 ticket for this.

(for everyone else on the 2.2 list wondering why you just got  
blitzkrieged with a whole pile of emails on this topic: the listserver  
sent all these mails to moderation because of the lengthy CC list.  IU  
just approved all the mails to go through this morning)

On Apr 17, 2009, at 9:40 AM, William Gropp wrote:

> Yes, this is worth an ATI - the fact that we traded this much mail on
> it is proof of that :)
>
> Thanks, Jeff.
>
> Bill
>
> On Apr 17, 2009, at 8:14 AM, Jeff Squyres wrote:
>
> > Someone pointed out to me this morning that there's no restriction  
> on
> > the value of EXTRA_STATE when CREATE_KEYVAL is invoked -- it may  
> be an
> > expression, for example.  I think that pretty much seals the deal  
> that
> > #2 is the correct way.
> >
> > I think that this is worth an ATI in the text; does anyone disagree?
> > I volunteer to write it up/make a 3.0 ticket (hey, first ticket for
> > the Misc WG! :-) ) if no one disagrees.
> >
> >
> > On Apr 17, 2009, at 8:59 AM, Supalov, Alexander wrote:
> >
> >> Hi,
> >>
> >> Intel MPI (and most likely other MPICH2 derivatives) appears to use
> >> method #2.
> >>
> >> Best regards.
> >>
> >> Alexander
> >>
> >> -----Original Message-----
> >> From: Jeff Squyres [mailto:jsquyres_at_[hidden]]
> >> Sent: Thursday, April 16, 2009 4:19 PM
> >> To: MPI 2.2; Rajeev Thakur; William Gropp; Rolf Rabenseifner;  
> Hubert
> >> Ritzdorf; Terry Dontje; Dave Goodell; Darius Buntinas; Pavan  
> Balaji;
> >> Supalov, Alexander; Bronis de Supinski; David Solt; Hans Westgaard
> >> Ry; Håkon Bugge
> >> Subject: Another MPI-2.2 attribute ambiguity?
> >>
> >> This is related to -- but different from -- MPI 2.2 ticket #55
> >> ("MPI-2.1 Cross-language attribute example is wrong").  Explicitly
> >> adding all the #55 CC members to this mail, plus a few others.
> >>
> >> I cannot find any text in MPI-2.1 (e.g., p223-225) describing
> >> specific
> >> behavior regarding the EXTRA_STATE arguments passed to the Fortran
> >> keyval copy and delete functions (both the ADDRESS_KIND and
> >> deprecated
> >> flavors).  I see two choices:
> >>
> >> 1. pass the user's original EXTRA_STATE argument by reference to  
> the
> >> callbacks, or
> >> 2. copy the user's original EXTRA_STATE into internal MPI storage  
> and
> >> pass *that* value by reference to the callbacks
> >>
> >> ==> Open MPI currently does #1.  What do other implementations do?
> >>
> >> I raise this issue because the text does not indicate which way is
> >> right.  And I just ran across an old Sun test that assumed #2.  But
> >> our internal copy of the Intel MPI tests assume #1 (to be fair: I
> >> have
> >> no idea if the Intel tests originally assumed #2 and we changed  
> them
> >> to #1 over time).  Indeed, #2 is actually in-line with the  
> philosophy
> >> of storing attribute values in internal MPI storage.  E.g.:
> >>
> >>   INTEGER foo = 4
> >>   INTEGER bar
> >>   CALL MPI_COMM_SET_ATTR(comm, keyval, foo, ierr)
> >>   foo = 5
> >>   CALL MPI_COMM_GET_ATTR(comm, keyval, bar, flag, ierr)
> >>
> >> bar should equal 4, not 5 (right?).
> >>
> >> So what does that mean (or imply) about the EXTRA_STATE value  
> passed
> >> to the Fortran callbacks?
> >>
> >> --
> >> Jeff Squyres
> >> Cisco Systems
> >>
> >>  
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> >>
> >
> >
> > --
> > Jeff Squyres
> > Cisco Systems
> >
>
> William Gropp
> Deputy Director for Research
> Institute for Advanced Computing Applications and Technologies
> Paul and Cynthia Saylor Professor of Computer Science
> University of Illinois Urbana-Champaign
>
>
>
>


-- 
Jeff Squyres
Cisco Systems