https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/483
On Mon, Aug 24, 2015 at 8:03 AM, Jim Dinan <james.dinan(a)gmail.com> wrote:
> IIRC, per-window ordering was the intent of the working group and it also
> seems like the only sensible reading of the chapter, given that we allow
> each window to provide a different value for the ordering info key. This
> might just be an erratum, but it would be helpful to create a ticket for it.
>
> On Mon, Aug 10, 2015 at 10:04 AM, Jeff Hammond <jeff.science(a)gmail.com>
> wrote:
>
>> "11.7.2 Ordering" says:
>>
>> "MPI specifies ordering between accumulate operations from one process
>> to the same (or overlapping) memory locations at another process on a
>> per-datatype granularity."
>> This seems to say that ordering is required between overlapping windows,
>> which is a horrible semantic. We need to add a "per-window" caveat here.
>>
>> Later, we talk about overlapping memory regions, rather than locations,
>> which is confusing:
>>
>> "MPI does not provide any guarantees for accesses or updates from
>> different origin processes to overlapping target memory regions."
>> What is a memory region anyways? Is it a window? Is it a set of memory
>> locations?
>>
>> And to be clear, I think I know what we mean in the RMA chapter, but
>> others may not.
>>
>> Jeff
>>
>> --
>> Jeff Hammond
>> jeff.science(a)gmail.com
>> http://jeffhammond.github.io/
>>
>> _______________________________________________
>> mpiwg-rma mailing list
>> mpiwg-rma(a)lists.mpi-forum.org
>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-rma
>>
>
>
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--
Jeff Hammond
jeff.science(a)gmail.com
http://jeffhammond.github.io/
IIRC, per-window ordering was the intent of the working group and it also
seems like the only sensible reading of the chapter, given that we allow
each window to provide a different value for the ordering info key. This
might just be an erratum, but it would be helpful to create a ticket for it.
On Mon, Aug 10, 2015 at 10:04 AM, Jeff Hammond <jeff.science(a)gmail.com>
wrote:
> "11.7.2 Ordering" says:
>
> "MPI specifies ordering between accumulate operations from one process to
> the same (or overlapping) memory locations at another process on a
> per-datatype granularity."
> This seems to say that ordering is required between overlapping windows,
> which is a horrible semantic. We need to add a "per-window" caveat here.
>
> Later, we talk about overlapping memory regions, rather than locations,
> which is confusing:
>
> "MPI does not provide any guarantees for accesses or updates from
> different origin processes to overlapping target memory regions."
> What is a memory region anyways? Is it a window? Is it a set of memory
> locations?
>
> And to be clear, I think I know what we mean in the RMA chapter, but
> others may not.
>
> Jeff
>
> --
> Jeff Hammond
> jeff.science(a)gmail.com
> http://jeffhammond.github.io/
>
> _______________________________________________
> mpiwg-rma mailing list
> mpiwg-rma(a)lists.mpi-forum.org
> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-rma
>
"11.7.2 Ordering" says:
"MPI specifies ordering between accumulate operations from one process to
the same (or overlapping) memory locations at another process on a
per-datatype granularity."
This seems to say that ordering is required between overlapping windows,
which is a horrible semantic. We need to add a "per-window" caveat here.
Later, we talk about overlapping memory regions, rather than locations,
which is confusing:
"MPI does not provide any guarantees for accesses or updates from different
origin processes to overlapping target memory regions."
What is a memory region anyways? Is it a window? Is it a set of memory
locations?
And to be clear, I think I know what we mean in the RMA chapter, but others
may not.
Jeff
--
Jeff Hammond
jeff.science(a)gmail.com
http://jeffhammond.github.io/
