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Re: Polyhedron benchmark on Opteron


François-Xavier Coudert wrote:

I wanted to report some results for the Polyhedron benchmark** on
Opteron (hardware details at the bottom of this mail). Unfortunately, there are also tests for which Intel is a clear winner:
-- aermod, by 44%
-- air, by 30%

-- nf, by 29%

The differences aren't so large on the Core 2 Duo.
gprof profiling doesn't capture the deficits in gfortran performance. In aermod, with either ifort or gfortran, less than 50% of the time is spent in the code covered by gprof profiling. Most of the time spent by the ifort version of air is captured in gprof profile, but the gfortran version spends significant unaccounted time. The profile for the gfortran version of nf allocates by far the largest time segment to a mysterious frame_dummy symbol.


Some day, I'll check aermod and air with VTune, to look for the mysterious extra time.


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