[Mpi3-rma] [EXTERNAL] Re: Ticket for WG discussion

Thu Mar 14 12:18:50 CDT 2013

Ok,

this was one of the questions which was open to me.
If you want to create an address  (better displacement to MPI_BOTTOM) for another process
you have to include the id (i.e. win, rank) of this process into
MPI_Aint_index(). MPI_BOTTOM may be different in each process in Fortran
and the local value of MPI_BOTTOM cannot be used.

Hubert
________________________________________
From: mpi3-rma-bounces at lists.mpi-forum.org [mpi3-rma-bounces at lists.mpi-forum.org] on behalf of Barrett, Brian W [bwbarre at sandia.gov]
Sent: Thursday, March 14, 2013 6:04 PM
To: MPI 3.0 Remote Memory Access working group
Subject: Re: [Mpi3-rma] [EXTERNAL] Re:  Ticket for WG discussion

Hubert -

The issue with MPI_Get_address() in your usage model is one of heterogeneity.  If process A is 32 bit and trying to create an address to talk to process B (which is 64 bit), there's now a difference (this, of course, assumes that MPI_Aint is an int64_t in that MPI).

Brian

--
  Brian W. Barrett
  Scalable System Software Group
  Sandia National Laboratories
________________________________________
From: mpi3-rma-bounces at lists.mpi-forum.org [mpi3-rma-bounces at lists.mpi-forum.org] on behalf of Hubert Ritzdorf [Hubert.Ritzdorf at emea.nec.com]
Sent: Thursday, March 14, 2013 10:56 AM
To: MPI 3.0 Remote Memory Access working group
Subject: [EXTERNAL] Re: [Mpi3-rma] Ticket for WG discussion

Hi Jim,

this sounds to me that

   addr2 = MPI_Aint_index (base, disp)

is equivalent to

   MPI_Get_Address ((char *) base + disp, &addr2)

Is this correct or where is the difference ?

Or is "base" also a displacement relative to MPI_BOTTOM
(in which case it might be signed in Fortran) and

   addr2 = MPI_Aint_index (base, disp)

is equivalent to

    MPI_Get_address ((char *) MPI_BOTTOM + base + disp, &addr2)

Hubert
________________________________________
From: mpi3-rma-bounces at lists.mpi-forum.org [mpi3-rma-bounces at lists.mpi-forum.org] on behalf of Jim Dinan [dinan at mcs.anl.gov]
Sent: Thursday, March 14, 2013 4:05 PM
To: mpi3-rma at lists.mpi-forum.org
Subject: Re: [Mpi3-rma] Ticket for WG discussion

A little clearer:

The value returned is the address, relative to MPI_BOTTOM, resulting
from the sum of base and disp.

  ~Jim.

On 3/14/13 9:42 AM, Jim Dinan wrote:
> Hi Hubert,
>
> My apologies, the ticket is light on details.  The proposed function is:
>
> MPI_Aint MPI_Aint_index(MPI_Aint base, MPI_Aint disp);
>
> This function interprets the base argument as an address relative to
> MPI_BOTTOM and the disp argument as a signed integer displacement.  The
> value returned is the sum of these two values.
>
>   ~Jim.
>
> On 3/13/13 7:12 AM, Hubert Ritzdorf wrote:
>> Hi Jim,
>>
>> Sorry, I have some problems with the interpretation of function
>> MPI_Aint_index().
>>
>> (*) What does MPI_Aint_index() return ?
>>        A target displacement which can be used in RMA functions such
>> as MPI Put/Get or
>>        does it return an address such as MPI_Get_address () ?
>>
>> (*) What is argument "base" ?
>>         An address returned by MPI_Get_address() of any address or
>>         a window base returned by
>>         MPI_Win_get_attr(win, MPI_WIN_BASE, &base, &flag) ?
>>         May "base" (as MPI_Aint) be transferred from a different
>> process ?
>>
>> Hubert
>> ________________________________________
>> From: mpi3-rma-bounces at lists.mpi-forum.org
>> [mpi3-rma-bounces at lists.mpi-forum.org] on behalf of Jim Dinan
>> [dinan at mcs.anl.gov]
>> Sent: Tuesday, March 12, 2013 9:08 PM
>> To: mpi3-rma at lists.mpi-forum.org
>> Subject: Re: [Mpi3-rma] Ticket for WG discussion
>>
>> Hubert,
>>
>> We have added a solution #3 to the ticket based on discussion in the
>> working group today.  That's our current proposal.  Could you take a
>> look and see if that will be Fortran compatible?
>>
>> Thanks,
>>    ~Jim.
>>
>> On 3/12/13 2:28 PM, Hubert Ritzdorf wrote:
>>> Hi,
>>>
>>> concerning Ticket 349.
>>> (*) In Fortran, the displacement for dynamic windows may be signed
>>>         since MPI_BOTTOM of Fortran is not (void *) NULL..
>>> (*) Fortran doesn't have unsigned integers, thus you cannot use
>>>         a Fortran version of MPI_Disp for arithmetics (such as disp++).
>>> (*) MPI Displacements in general may be signed.
>>>         They might be relative to any address.
>>>
>>>
>>> Therefore, I can't see that the Proposed Solution 2 solves the problem.
>>>
>>> Hubert
>>>
>>> ________________________________________
>>> From: mpi3-rma-bounces at lists.mpi-forum.org
>>> [mpi3-rma-bounces at lists.mpi-forum.org] on behalf of Jim Dinan
>>> [dinan at mcs.anl.gov]
>>> Sent: Tuesday, March 12, 2013 5:12 PM
>>> To: MPI 3.0 Remote Memory Access working group
>>> Subject: [Mpi3-rma] Ticket for WG discussion
>>>
>>> Hi All,
>>>
>>> I would like to propose the following two tickets for discussion in
>>> today's WG meeting:
>>>
>>> https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/349
>>> https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/344
>>>
>>> #349 is a bugfix that definitely needs to be addressed.  #344 is an
>>> "elegance of the interface" ticket where I would like to poll the WG to
>>> determine the level of support and determine if this should be pursued.
>>>
>>> I unfortunately need to duck out at 4pm today, so if possible, I propose
>>> that we discuss these at the beginning of the meeting.
>>>
>>> Thanks!
>>>     ~Jim.
>>> _______________________________________________
>>> mpi3-rma mailing list
>>> mpi3-rma at lists.mpi-forum.org
>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma
>>>
>>>
>>>    Click
>>> https://www.mailcontrol.com/sr/kHf7UuVmhqHGX2PQPOmvUu5zZAYN1MosNz2OH0bOQrlt5gIrfPQ8MyK+!tr+rBycX!uZHqHqrIVkxH4nYzTQYQ==
>>> to report this email as spam.
>>>
>>> _______________________________________________
>>> mpi3-rma mailing list
>>> mpi3-rma at lists.mpi-forum.org
>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma
>>>
>> _______________________________________________
>> mpi3-rma mailing list
>> mpi3-rma at lists.mpi-forum.org
>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma
>>
>> _______________________________________________
>> mpi3-rma mailing list
>> mpi3-rma at lists.mpi-forum.org
>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma
>>
> _______________________________________________
> mpi3-rma mailing list
> mpi3-rma at lists.mpi-forum.org
> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma
_______________________________________________
mpi3-rma mailing list
mpi3-rma at lists.mpi-forum.org
http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma

_______________________________________________
mpi3-rma mailing list
mpi3-rma at lists.mpi-forum.org
http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma

_______________________________________________
mpi3-rma mailing list
mpi3-rma at lists.mpi-forum.org
http://lists.mpi-forum.org/mailman/listinfo.cgi/mpi3-rma