[Mpiwg-large-counts] Large Count - the principles for counts, sizes, and byte and nonbyte displacements

[Rolf Rabenseifner]

> I think that changes the conversation entirely, right?

Not the first part, the state-of-current-MPI.

It may change something for the future, or a new interface may be needed.

Please, can you describe how MPI_Get_address can work with the 
different variables from different memory segments.

Or whether a completely new function or a set of functions is needed.

If we can still express variables from all memory segments as 
input to MPI_Get_address, there may be still a way to flatten
the result of some internal address-iquiry into a flattened
signed integer with the same behavior as MPI_Aint today.

If this is impossible, then new way of thinking and solution 
may be needed.

I really want to see examples for all current stuff as you
mentioned in your last email.

Best regards
Rolf

----- Original Message -----
> From: "Jeff Squyres" <jsquyres at cisco.com>
> To: "Rolf Rabenseifner" <rabenseifner at hlrs.de>
> Cc: "mpiwg-large-counts" <mpiwg-large-counts at lists.mpi-forum.org>
> Sent: Thursday, October 24, 2019 5:27:31 PM
> Subject: Re: [Mpiwg-large-counts] Large Count - the principles for counts, sizes, and byte and nonbyte displacements

> On Oct 24, 2019, at 11:15 AM, Rolf Rabenseifner
> <rabenseifner at hlrs.de<mailto:rabenseifner at hlrs.de>> wrote:
> 
> For me, it looked like that there was some misunderstanding
> of the concept that absolute and relative addresses
> and number of bytes that can be stored in MPI_Aint.
> 
> ...with the caveat that MPI_Aint -- as it is right now -- does not support
> modern segmented memory systems (i.e., where you need more than a small number
> of bits to indicate the segment where the memory lives).
> 
> I think that changes the conversation entirely, right?
> 
> --
> Jeff Squyres
> jsquyres at cisco.com<mailto:jsquyres at cisco.com>

-- 
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 .
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