[Beowulf] MPI build with different compilers

[Nifty niftyompi Mitch]

On Tue, Aug 19, 2008 at 11:01:19AM +0500, amjad ali wrote:
> 
> 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?
> 
> 
> 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?
> 

Not so much in OpenMPI but there could be very large differences
in the speed of the application code.

It does make sense to build OpenMPI with both compilers and benchmark those applications
you care about.   

Some vendor compilers have a GNU ABI some do not.  Building
libraries and the application with different compilers can prove
problematic (i.e. hard to debug problems).

Note that the helper scripts: mpicc, mpif77, mpi<language> are built at
the same time MPI is and will correctly match libraries with generated objects from your
build.   In the land of Fortran there are binary issues that can make
mixing problematic.  This is possibly an issue in C++ too.... 

Some work is being done on this check the release notes.



-- 
	T o m  M i t c h e l l 
	Got a great hat... now what.