What is the right way to compile a fortran 77 file using the amd64 bits technology? If I write f77 -m64 -march=opteron file.f and then run a.out, the time of execution is so slow as if it I had´nt called to 64bits option. what is happening?
Pavel Ritto wrote:
What is the right way to compile a fortran 77 file using the amd64 bits technology? If I write f77 -m64 -march=opteron file.f and then run a.out, the time of execution is so slow as if it I had´nt called to 64bits option. what is happening?
I thought the Gnu Fortran compiler was called g77 ? ... oh, I see, f77 is a link to g77. yes, -m64 should generate x86_64 code... I dunno what -march=opteron does.
otherwise, insufficient information to diagnose your problem. was this fortran program written for GCC F77 ? is it slow because its CPU bound or is it slow because its swapping?
(note, btw, I haven't actually touched fortran since the 1970s)
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John R Pierce -
Pavel Ritto