Hi Shuwei, Were you able to run over multiple hosts directly, e.g.: ``` $ mpiexec -n 2 -hosts “hostname_1,hostname_2” ./cpi ``` ? — Hui Zhou On Nov 28, 2018, at 3:33 PM, Shuwei Zhao <[email protected]<mailto:[email protected]>> wrote: Hi hui I tried your suggestion but looks like the newly spawned jobs are using ssh to distribute on the new hosts. Howver In my machine farm, ssh & rsh connections are disabled. have to submit through qsub network interface. Is using qsub possible in mpi_comm_spawn? Thanks a lot Shuwei On Mon, Nov 19, 2018 at 09:21 Zhou, Hui <[email protected]<mailto:[email protected]>> wrote: On Sun, Nov 18, 2018 at 10:33:48PM -0600, Shuwei Zhao wrote:

2. About the MPI_Info object, I tried to use mpi_comm_spawn on the same machine, it can work. But I don't know how to spawn processes cross machines. For example, if I have 4 processes on machine 1, and I want to spawn 4 more processes on other machines (resource managed by qsub), how do I need to declare in the MPI_Info object?

Did you try setting the host parameter in the info object? For example: MPI_Info info; MPI_Info_create(&info, "host", "A,B,C"); MPI_Comm_spawn("worker", MPI_ARGV_NULL, n_hosts, info, 0, MPI_COMM_SELF, &comm_workers, MPI_ERRCODES_IGNORE)? MPI_Info_free(&info); Replace "A,B,C" with host name list that you want to spawn process on. -- Hui Zhou