On Thu, Aug 12, 2010 at 8:46 AM, Ralf W. Grosse-Kunstleve <r...@yahoo.com> wrote: > Hi Vladimir, > > Thanks for the feedback! Very interesting. > > >> Intel optimization compiler team (besides researchers) is much bigger than >>whole GCC community. > > That's a surprise to me. I have to say that the GCC community has done amazing > work, as you came within factor 1.4 (gfortran) and 1.6 (g++ compiling > converted > code) > of ifort performance, which is close enough for our purposes, and I think > those > of many people.
Well, I think a ratio of gfortran/ifort=1.4 isn't so great, really. If you look at one of the popular Fortran benchmarks (Polyhedron, http://www.polyhedron.com/pb05-linux-f90bench_p40html), the ratio was less than 1.2 for gfortran 4.3 vs. ifort 11 on an Intel iCore7. Can you tell how you obtained the performance numbers you are using? There may be a few compiler flags you could add to reduce that ratio of 1.4 to something better. Ciao! Steven