On Fri, 25 Nov 2005, Salman Pervez wrote:
> From what i understand, lam daemons/modules are booted up once on
> each machine for each mpi program.
The LAM daemons are indeed booted once per machine. They are used
mostly for starting up the processes that will form the MPI job and
monitoring them (so that they can signal a rank that has died, for
example); they may also be used for communication (UDP-based "lamd"
mode).
There are modules for all kinds of things in LAM/MPI, including
booting.
> In particular, there is a single tcp-rpi module running on each
> machine for point to point communication.
The TCP RPI module is not part of the LAM daemon. This module is used
by the communication part of the library and is part of the MPI
application binary in case you linked statically liblam.a.
> The tcp rpi module accesses certain global variables
... which is fine as they are global per process and there is no
interference with other accesses.
--
Bogdan Costescu
IWR - Interdisziplinaeres Zentrum fuer Wissenschaftliches Rechnen
Universitaet Heidelberg, INF 368, D-69120 Heidelberg, GERMANY
Telephone: +49 6221 54 8869, Telefax: +49 6221 54 8868
E-mail: Bogdan.Costescu_at_[hidden]
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