[mpich-devel] find out what processes are on the same node

[Tatiana V. Martsinkevich]

Hello,

I have a couple of questions:

1) is there a way to find out what other processes reside in the same
node as my_rank from within MPICH?

I found this function: MPIR_Comm_is_node_aware(comm_ptr) and if it's
true I can get access (although not always?) to comm_ptr->node_comm. I
wonder what are the situations when I won't be able to know what
processes are on the same node ( i.e. comm_ptr->node_comm is null) and
is there any other way to get the info then?

2) MPIR_Comm_is_node_aware() returns true if comm->hierarchy_kind ==
MPID_HIERARCHY_PARENT and apparently there are the following
hierarchies: /* flat, parent, node, or node_roots */  Could someone
please explain what are each of the hierarchy?

regards,

-- 
Tatiana V. Martsinkevich
PhD student
INRIA Saclay, University of Paris Sud XI