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Subject: [OMPI users] on-the-fly nodes liberation
From: Marcia Cristina Cera (marcia.cristina.cera_at_[hidden])
Date: 2009-03-09 08:28:18


May I sign one orted daemon to finish its execution on-the-fly?

Context: I intend to use OpenMPI in a dynamic resource environment as I did
with LAM/MPI helped by lamgrow and lamshrink commands.

To perform grow operations (increase the amount of nodes/resources
on-the-fly) OpenMPI enable an incremental resource utilization. All nodes
that can be used are listed in the hostifile file (inform as mpirun
parameter) and according to they are firstly used through MPI_Comm_spawn one
orded daemon is created in each node. According to some first tests, this
feature is enough to satisfy our goals.

In the other hand, performing shrink operations, we need to liberate nodes
to be eventually used by other application/jobs. In other words, we must
terminate all applications processes and also the orted daemon. In the
application side, the solution is easy once we can notify the processes (by
a message or signal) to safety finish its execution and perform
MPI_Finalize. In the orted side, we must finish its execution in the target
node and also update its status to 'INVALID'.
How may I do it? Is there a specific signal or procedure to this?

Thank you in advance!