On Wed, Oct 17, 2012 at 3:23 PM, Berk Hess <span dir="ltr"><<a href="mailto:hess@kth.se" target="_blank">hess@kth.se</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br><br>ICC can actually sometimes be (a lot) faster than gcc on AMD.<br>The issue here seems to be that the configuration didn't add a compiler flag for fma4.<br></blockquote><div><br></div><div>That is only the case on pre-Bulldozer processors like Magny-Cours. On Bulldozer, with the current kernels gcc is as fast or faster than icc.</div>
<div><br></div><div>--<br>Szilárd<br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>Cheers,<br><br>Berk<div class="HOEnZb"><div class="h5"><br><br>
----- Reply message -----<br>From: "Alexey Shvetsov" <<a href="mailto:alexxy@omrb.pnpi.spb.ru" target="_blank">alexxy@omrb.pnpi.spb.ru</a>><br>To: <<a href="mailto:gmx-developers@gromacs.org" target="_blank">gmx-developers@gromacs.org</a>><br>
Subject: [gmx-developers] warning Emulating FMA instructions - this is probably not what you want!<br>Date: Wed, Oct 17, 2012 14:00<br><br><br>Hi all!<br><br>Well ICC isnt good with AMD CPUs especialy with new ones. Try to use <br>
recent gcc versions like gcc-4.7.<br><br><br>Jochen Hub писал 17-10-2012 13:14:<br>> Hi developers,<br>><br>> does anyone know how to interpret this icc warning:<br>><br>> [ 8%] /home/jhub/src/gromacs/include/gmx_x86_avx_128_fma.h(88):<br>
> warning #1224: #warning directive: Emulating FMA instructions - this<br>> is probably not what you want!<br>><br>> #warning Emulating FMA instructions - this is probably not what you <br>> want!<br>><br>
> I am compiling 46-release on a Interlagos 6378 with OpenMPI and icc<br>> 13.0.0 20120731. My cmake line is:<br>><br>> cmake $gmxsrc \<br>> -DFFTW_LIBRARY=$FFTW_LOCATION/lib/libfftw3f.a \<br>> -DFFTW3F_INCLUDE_DIR=$FFTW_LOCATION/include \<br>
> -DFFTW3F_LIBRARIES=$FFTW_LOCATION/lib/libfftw3f.a \<br>> -DCMAKE_INSTALL_PREFIX=$(pwd) \<br>> -DGMX_X11=OFF \<br>> -DCMAKE_CXX_COMPILER=$MPICXX \<br>> -DCMAKE_C_COMPILER=$MPICC \<br>> -DGMX_MPI=ON \<br>
> -DGMX_PREFER_STATIC_LIBS=ON \<br>> -DGMX_GPU=OFF<br>><br>> and cmake reported:<br>><br>> -- Performing Test GNU_AVX_CFLAG<br>> -- Performing Test GNU_AVX_CFLAG - Success<br>> -- Enabling 128-bit AVX Gromacs acceleration (with fused-multiply<br>
> add), and it will help compiler optimization.<br>><br>> Thanks a lot,<br>> Jochen<br>><br>><br>><br>> --<br>> ---------------------------------------------------<br>> Dr. Jochen Hub<br>> Computational Molecular Biophysics Group<br>
> Institute for Microbiology and Genetics<br>> Georg-August-University of Göttingen<br>> Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.<br>> Phone: <a href="tel:%2B49-551-39-14189" value="+495513914189" target="_blank">+49-551-39-14189</a><br>
> <a href="http://cmb.bio.uni-goettingen.de/" target="_blank">http://cmb.bio.uni-goettingen.de/</a><br>> ---------------------------------------------------<br><br>-- <br>Best Regards,<br>Alexey 'Alexxy' Shvetsov<br>
Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, <br>Gatchina, Russia<br>Department of Molecular and Radiation Biophysics<br>Gentoo Team Ru<br>Gentoo Linux Dev<br>mailto:<a href="mailto:alexxyum@gmail.com" target="_blank">alexxyum@gmail.com</a><br>
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