Hi, hast du das Problem nur mit OpenMPI oder auch mit anderen MPI Bibliotheken (z.B. MPICH2)
Ansonsten kannst du auch mal probieren, ob du das All-to-all mit Collectives hin bekommst, z.B. Scatter oder Gatter. Viele Grüße Sebastian > Hi, > > I have encountered really bad performance when all the nodes send data > to all the other nodes. I use Isend and Irecv with multiple > outstanding sends per node. I debugged the behavior and came to the > following conclusion: It seems that one sender locks out all other > senders for one receiver. This sender releases the receiver only when > there are no more sends posted or a node with lower rank, wants to > send to this node (deadlock prevention). As a consequence, node 0 > sends all its data to all nodes, while all others are waiting, then > node 1 sends all the data, … > > What is the rationale behind this behaviour and can I change it by > some MCA parameter? > > Thanks > > Stephan > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
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