I understand the first paragraph about the different lam universes.
If LAM_MPI_SESSION_SUFFIX is set, then I can follow how lamhalt can use
that to decide which lam daemon to kill. However, suppose one used the
-sessionsuffix argument to lamboot instead of the
LAM_MPI_SESSION_SUFFIX. Since the environment variable is not set when
lamhalt is issued, how then does lamhalt decide which is the correct
sessionsuffix to chose to halt the particular lam universe.
-----Original Message-----
From: Brian Barrett [mailto:brbarret_at_[hidden]]
Sent: Tuesday, July 17, 2007 9:59 PM
To: General LAM/MPI mailing list
Subject: Re: LAM: Does lamhalt use LAM_MPI_SESSION_SUFFIX
A given LAM daemon only knows the contact information for other
daemons in it's "universe", which is the group of daemons started
with the 'lamboot' command. Other daemons started with other calls
to 'lamboot' are in a different universe and are not in communication
with the first universe.
Lamhalt just sends a message to its local LAM daemon to get all the
daemons in the universe, then sends all of them a die message. The
universe to get the information from is determined by the session
directory (so usually the SESSION_SUFFIX).
So as long as the same value for LAM_MPI_SESSION_SUFFIX that was
there when lamboot was run is there when lamhalt is run, only those
daemons started by the given lamboot will be killed. All others will
continue on without disruption.
Brian
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