Hi Toni, We figured out the reason (the spawned processes hang because when the "hosts" info keys for two commands have the same value (e.g., localhost) two processes get the same rank.), but it seems it will take some time to fix this. Pavan will rewrite the problematic part in hydra. I’ve created a ticket (https://trac.mpich.org/projects/mpich/ticket/2308) for this issue and cc’ed you in the ticket. Regards, Sangmin On Oct 8, 2015, at 10:17 AM, Antonio J. Peña <[email protected]<mailto:[email protected]>> wrote: Thanks a lot Sangmin! On 10/08/2015 03:43 PM, Seo, Sangmin wrote: Hi Toni, I confirmed the problem and am looking into it. I will get back to you after I resolve it. Regards, Sangmin On Oct 6, 2015, at 7:23 AM, Antonio J. Peña <[email protected]<mailto:[email protected]>> wrote: Right, but I do need to use the hosts key to get control of where the processes are spawned. Any clue? On 10/02/2015 07:32 PM, Thakur, Rajeev wrote: Looks like it is related to the hosts key. Works without that. Rajeev On Oct 2, 2015, at 10:34 AM, Antonio J. Peña <[email protected]<mailto:[email protected]>> wrote: Hi folks! I've been facing an issue with MPI_Comm_spawn_multiple when all the following conditions are met: 1. 'count' is > 1 2. Any value of 'array_of_maxprocs' is > 1 3. Setting the "hosts" info key What I'm finding is that the spawned processes hang at MPI_Init. Find attached a test case. You can reproduce my issue with -np 1. Is there anything I'm doing wrong? I'm using MPICH master at 1e6c4d8. I haven't found a pending ticket, xfail test, or test case covering this situation. All the best, Toni [P.S.: It still feels weird to be on the other side of [email protected]<mailto:[email protected]>] -- Antonio J. Peña Senior Researcher Barcelona Supercomputing Center WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer<spawn_multiple.c>_______________________________________________ discuss mailing list [email protected]<mailto:[email protected]> To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss _______________________________________________ discuss mailing list [email protected]<mailto:[email protected]> To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss -- Antonio J. Peña Senior Researcher Barcelona Supercomputing Center WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss _______________________________________________ discuss mailing list [email protected]<mailto:[email protected]> To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss -- Antonio J. Peña Senior Researcher Barcelona Supercomputing Center WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss