Re: Multithreading on Multicore Processors

Richard Maine wrote:
Grogley <grogley@!nospam!yahoo.com> wrote:

I guess it has always been my
impression that Unix/Linux systems were not particularly efficient at
floating point calculations.

That makes very little sense, insomuch as floating point calculation
generally has very little to do with the operating system.

My general experience with scientific codes is almost the opposite -
that they often run like a dog (if at all) in Windows.

The 16 codes of the Polyhedron Fortran benchmark run on both Windows
and Linux, and comparing the results at
http://www.polyhedron.com/pb05/win32/f90bench_p4.html and
http://www.polyhedron.com/pb05/linux/f90bench_p4.html , there are some
compilers available for both platforms where the Windows version was
slower -- the geometric means for Lahey on Windows and Linux are 38.0
and
29.0 seconds, but for Intel, generally the fastest compiler
benchmarked, the times were essentially the same, 24.0 and 23.7
seconds.

The Polyhedron results do not confirm the criticisms made of Windows.

But I wouldn't
say it had anything to do with floating point in particular. Poor memory
management and process priority management has more to do with it. Those
things are strongly operating system related. But this veers to far from
Fortran and too near to flame-bait, so I'll not argue the point.

.

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