Re: [OMPI users] How to establish communication between two separate COM WORLD (fwd)

[Ralph Castain]

At the moment, this is still in "design" - all I've done for now is breadboard a connection that places them effectively in the same comm_world. Each process in both jobs is given the complete comm info for all the processes. Details of the MPI interface, however, remain to be determined by my MPI colleagues. The mode isn't documented yet since it isn't available in any of the current tarballs or releases. I'm working on the infrastructure to allow multiple applications to collaborate across multiple clusters on a separate development branch - this capability is buried in that work. I'm sure documentation will follow as soon as we get a little further towards completing implementation. Ralph Chris Gottbrath wrote: Ralph, Interesting. How would the two jobs be 'connected' in this scheme? Would they share a single MPI_COMM_WORLD or would they both be created with an intercommunicator to the other jobs MPI_WORLD? If so, how would that intercommmunicator be obtained in each program? Is this mode documented anywhere? Cheers, Chris -- Chris Gottbrath Partner Technologies Engineer Etnus, LLC chris.gottbr...@etnus.com http://www.etnus.com/ Voice: 508-652-7700 x7735 Fax: 508-652-7787 ---------- Forwarded message ---------- List-Post: users@lists.open-mpi.org Date: Mon, 27 Mar 2006 06:44:04 -0700 From: Ralph Castain <r...@lanl.gov> To: Open MPI Users <us...@open-mpi.org> Subject: Re: [OMPI users] How to establish communication between two separate COM WORLD Actually, in a not-too-distant future release, there will be an option to mpirun called "--connect" that will allow you to specify that this job is to be connected to a specified earlier job. The run-time environment will then spawn the new job and exchange all required communication information between the two jobs for you. You could therefore accomplish your desired operation by: nohup mpirun --np xx app1 (system returns job number to you) mpirun --np yy --connect job1 app2 (system starts app2 and connects it to job1) Should be a little more transparent. No specific coding for making the connection would be required in your application itself. Ralph Jean Latour wrote: Hello, It seems to me there is only one way to create a communication between two MPI_COMM_WORLD : use MPI_Open_Port with a specific IP + port address, and then MPI_comm_connect / MPI_comm_accept. In order to ease the port number communication, the use of MPI_publish-name / MPI_lookup_name is also possible with the constraint that the "publish" must be done before the "lookup", and this involves some synchronization between the processes anyway. Simple examples can be found in the handbook on MPI : "Using MPI-2" by William Gropp et al. Best Regards, Jean Ali Eghlima wrote: Hello, I have read MPI-2 documents as well as FAQ. I am confused as the best way to establish communication between two MPI_COMM_WORLD which has been created by two mpiexec calls on the same node. mpiexec -conf config1 This start 20 processes on 7 nodes mpiexec -conf config2 This start 18 processes on 5 nodes I do appreciate any comments or pointer to a document or example. Thanks Ali, ------------------------------------------------------------------------ _______________________________________________ users mailing list us...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/users ________________________________________________________________________________________________ _______________________________________________ users mailing list us...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/users _______________________________________________ users mailing list us...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/users