[Mpi-forum] MPI One-Sided Communication

[Scott Atchley]

On Apr 24, 2009, at 8:38 AM, Jeff Hammond wrote:

> Active messages are very appealing to me but I'm not aware of a
> library implementation (F77 and C compatible) that runs on BlueGene/P,
> Cray XT, Infiniband and Myrinet.  Can you point me to one?

MX does support a limited active message model. The application can  
register an unexpected handler that is called whenever MX receives a  
message for which the application has not pre-posted a receive. The  
handler has access to the match tag, the sender info, the length of  
the message, and the actual data if the length is 1 KB or less (small  
but useable).

It is useful in filesystems where there are a lot of unexpected  
messages. It avoids having to pre-post a lot of generic receives.

I believe Open-MX supports it as well.

Scott