[gmx-users] problems with building & performance on a Itanium2 system

[Malcolm Tobias]

I'm trying to build gromacs 3.1.4 on an Itanium2 based system (specifically
a SGI Altix system).  I've succeeded in building the code using gcc +
Intel's Fortran compiler, but the performance seems way off when I run
the gmxbench benchmarks (although the performance is much better
than if I use g77).  Any hints to get better performance?  Currently I just:
setenv F77 efc
./configure --enable-fortran

I did try building using both the Intel Fortran and C compilers, but found the
code died right away with the message:
reading file topol.tpr, VERSION 3.1.4 (single precision)
Illegal instruction

Also, I'm having trouble building with MPI when I use the Intel Fortran 
compilers:
setenv LIBS '-lmpi'
setenv FLIBS '-lmpi -L/opt/intel/compiler70/ia64/lib -L/usr/lib -lintrins 
-lIEPCF90 -lF90 -limf -lm -lirc -lcxa -lunwind'
(the above was needed to fix the configuration error:
checking for dummy main to link with Fortran 77 libraries... unknown
configure: error: Linking to Fortran libraries from C fails.
I came across a suggested fix at:
http://www.lam-mpi.org/MailArchives/lam/msg06266.php)

./configure --enable-fortran --enable-mpi
...
checking for xdr_float in -lnsl... (cached) no
configure: error: Couldn't find XDR headers and/or libraries

If I don't include mpi support, this goes through fine:
./configure --enable-fortran
...
checking for xdr_float in -lnsl... (cached) yes
checking for working memcmp... yes

I saw this error was reported before:
http://www.gromacs.org/pipermail/gmx-users/2001-December/027029.html
I don't think it's a problem with the 'mpi-enabled compiler' because I'm using
the same compilers (gcc + Intel Fortran) for both the mpi and non-mpi builds.

Any ideas?

Thanks in advance.

Malcolm

-- 
Malcolm Tobias
314.935.5289