[mpich-discuss] mpi_comm_spawn - process not destroyed

Stanislav Simko s.simko at uu.nl
Fri Aug 11 07:31:30 CDT 2017

Dear all,

I'm just trying some very basic stuff with MPI_COMM_SPAWN in python
(i.e. I use mpi4py package), but I see behaviour that I do not
understand - the child process gets spawned, does its stuff and then
"should" finish. I see though, that the process created for the child
stays alive. I see this only with the MPICH, OPENMPI does what I would
(naively) expect. In this way I can end up with N "ghost" process,
after calling SPAWN N-times. My minimal working example is following:


from __future__ import print_function

from mpi4py import MPI
spawned =
print("parent process is waiting for child")



from __future__ import print_function
from mpi4py import MPI
parent = MPI.Comm.Get_parent()
# just do some stupid stuff that takes a bit of time
for i in range(5000000):
    a = i*i+1-(i*10) + math.sin(math.pow(i,i%8))


I run with e.g.:
mpirun -n 1 python mpi.py

Do I miss something with SPAWN method?
(I tested on two independent systems, our local cluster with mpich
v3.0.4, and my laptop - fedora 26, mpich v3.2.8 from repositories)

thank you very much for suggestions.


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mpich.org/pipermail/discuss/attachments/20170811/dec99756/attachment.html>
-------------- next part --------------
discuss mailing list     discuss at mpich.org
To manage subscription options or unsubscribe:

More information about the discuss mailing list