When MPI_Bcast and MPI_Reduce are called for the first time, they are very slow. But after that, they run at normal and stable speed. Is there anybody out there who have encountered such problem? If you need any other information, please let me know and I'll provide. Thanks in advance.
This is expected, and I think you can dig though the message archive to find the answer. OMPI does not wireup all the communication at startup, thus the first time you communicate with a host the connection is made, but after that it is fast because it is already open. This behavior is expected, and is needed for very large systems where you could run out of sockets for some types of communication with so many hosts.
Brock Palen www.umich.edu/~brockp Center for Advanced Computing bro...@umich.edu (734)936-1985
_______________________________________________ users mailing list us...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/users
