Re: [OMPI users] SHARED Memory----------------

[Eugene Loh]

shan axida wrote: What I am asking is if I use MPI_Send and MPI_Recv between processes in  a node, does it mean using shared memory or not? It (typically) does.  (Some edge cases could occur.)  Your question is addressed by the FAQ I mentioned. if not, how to use  shared memory among processes which are runing in a node? ________________________________ From: Eugene Loh <eugene....@sun.com> To: Open MPI Users <us...@open-mpi.org> Sent: Thursday, April 23, 2009 1:20:05 PM Subject: Re: [OMPI users] SHARED Memory---------------- Just to clarify (since "send to self" strikes me as confusing)... If you're talking about using shared memory for point-to-point MPI message passing, OMPI typically uses it automatically between two processes on the same node.  It is *not* used for a process sending to itself.  There is a well-written FAQ (in my arrogant opinion!) at http://www.open-mpi.org/faq/?category=sm -- e.g., http://www.open-mpi.org/faq/?category=sm#sm-btl . If you're talking about some other use of shared memory, let us know what you had in mind. Elvedin Trnjanin wrote: Shared memory is used for send-to-self scenarios such as if you're making use of multiple slots on the same machine. shan axida wrote: Any body know how to make use of shared memory in OpenMPI implementation?