[Mpi3-rma] RMA communication with single network messages

Oliver Mangold mangold at hlrs.de
Thu Jul 14 05:55:08 CDT 2011

On 13.07.2011 23:00, Rajeev Thakur wrote:
> There isn't a way to do exactly what you want, but you could do either of the following.
> 1. Call MPI_Win_post immediately after MPI_Win_create and immediately after every call to MPI_Win_complete.
This would necessarily result in an extra message for each MPI_Win_post 
or buffering on the receiver side, right? I do not see a way around as 
the framework has no way to know, that post will always happen after 

Is there a reason why the new MPI will not allow for this? From the 
viewpoint of performance it's so obviously desirable. I assume I'm not 
the first one thinking about it.

I guess it would be possible for implementations to define a key for the 
info of MPI_Win_Create to specify that the windows should be always open 
and MPI_Win_post and MPI_Win_start do exactly nothing for this window. 
Would be implementation-specific, of course.

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