[Beowulf] MPI build with different compilers

[Joshua mora acosta]

Comments inline.

Joshua

------ Original Message ------
Received: Mon, 18 Aug 2008 11:29:22 PM PDT
From: "amjad ali" <amjad11 at gmail.com>
To: "Beowulf Mailing List" <beowulf at beowulf.org>
Subject: [Beowulf] MPI build with different compilers

> Hi,
> Please reply me about followings:
> 
> 
> 1) Is there any significant performance difference between OpenMPI
> built with GNU compilers and the one built with Intel compilers?
Not much. You can find though the case where SSE can make a difference. Use
-mtune/-march on gcc.
> 
> 
> 2) Once we have built mpi on our system and then we remove the C/C++
> and Fortran compilers from the system. Will the mpicc and mpif90 still
> work properly? or the mpi bulit always needs installed base compilers?
I don't think so. There are 2 stages: compiling and linking. For compilation
you need gcc,icc,pgcc,.. For linking you need ld plus the libraries that are
needed at runtime. The easy way to find out the last one is by building a
executable and then run ldd (dependency walker on Windows) over it. Then get
to know the dependencies. That is what you will need to run. Then get to know
the dependencies at linking time (eg. look at the makefile or add the flag -V
or -v[erbose] to the compiler and linker to see what tools uses and what
libraries it needs in order to build your executable. All that is what you
need to package and deploy on your production systems if you want to create
executables and run them. Makefiles, include after the build is done, another
target named "distribution" or something like that which allows you to create
a tarball that can be deployed somewhere else. That takes care of
bin,etc,lib,man,examples directories.
> 
> 
> Regards,
> AA.
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