cp2k bulk water benchmarks, intel xeon quadcode w infiniband

[cavallo]

Dear Axel,

thank you for the very interesting post. I just have one question.
According to my little HW knowledge, the bottleneck using all the
cores is RAM access. I knew that amd outperforms intel on this. At
least,  this is what some posts in other lists claim. In the case,
could it be that cp2k on the opterons scales better than on the intel,
which means that all the 8 cores could be used ?  Any experience/
comments on this ?

Thanks,
Luigi

Axel wrote:
> hi everybody,
>
> since there were several discussions on the performance and
> scaling of cp2k, i just done a series of benchmark runs on our
> new cluster and uploaded a graph with the resulting data to.
>
> http://groups.google.com/group/cp2k/web/cp2k-water-bench-cmm.png
>
> scaling is quite ok for the larger systems. the main result is that
> with quad-core nodes it is almost always better to use only half
> the cores (this was expected, but at the time of purchase the
> quad-cores were cheaper than the available dual-core cpus).
>
> a few notes on hard and software:
> each node has 8GB RAM and two 2.66GHz intel xeon E5430 quad-core cpus
> (45nm)
> the nodes were manufactured by dell
> OS: Scientific Linux 5.1
> infiniband is (from /sbin/lspci): Mellanox Technologies MT25204
> [InfiniHost III Lx HCA]
> infiniband speed is 4x DDR (20 Gb/sec).
> infiniband software: ofed-1.3.1
> MPI: OpenMPI 1.2.7, using --mca btl_openib_use_srq 1 and --mca
> mpi_paffinity_alone = 1
> compiler: intel 10.1.015, optimization is set to: -O2 -unroll -
> march=pentiumpro -pc64
> scalapack/blacs/lapack/blas: intel mkl 10.0.1.014
> cp2k version: cvs as of 2008-08-29
> linker flags: LDFLAGS  = $(FCFLAGS) -i-static
> LIBS     = -L/cmm/pkg/intel/mkl/default/lib/em64t/ -Wl,-rpath,/cmm/pkg/
> intel/mkl/default/lib/em64t/ \
>            -lmkl_scalapack_lp64 -lmkl_blacs_openmpi_lp64 -
> lmkl_intel_lp64 -lmkl_sequential -lmkl_core \
>            /cmm/pkg/lib/libfftw3.a
>
> cheers,
>    axel.