Spawned tasks cannot use the sm nor vader btl so you need an other one (tcp, openib, ...) self btl is only to send/recvcount with oneself (e.g. it does not work for inter process and intra node communications.
I am pretty sure the lo interface is always discarded by openmpi, so I have no solution on top of my head that involves openmpi. maybe your bed bet is to use a "dummy" interface, for example tan or tun or even a bridge. Cheers, Gilles On Friday, March 11, 2016, Rémy Grünblatt <remy.grunbl...@ens-lyon.fr> wrote: > Hello, > I'm having communications problem between two processes (with one being > spawned by the other, on the *same* physical machine). Everything works > as expected when I have network interface such as eth0 or wlo1 up, but > as soon as they are down, I get errors (such as « At least one pair of > MPI processes are unable to reach each other for MPI communications […] »). > I tried to specify a set of mca parameters including the btl "self" > parameter and including the lo interface in btl_tcp_if_include list, as > advised by https://www.open-mpi.org/faq/?category=tcp but I didn't reach > any working state for this code with "external" network interface down. > > Got any idea about what I might do wrong ? > > Example code that triggers the problem: https://ptpb.pw/YOjr.tar.gz > Ompi_info: https://ptpb.pw/Vt_V.txt > Full log: https://ptpb.pw/JCXn.txt > > Rémy > > >
