Henrik S (henrik.stahl@nospam.oracle.nothanks.com) on 4/12/09 wrote:
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>No difference between Windows 2003 and 2008. We get slightly higher scores (1%?)
>on Windows than Linux, something we believe can be partially attributed to a gcc
>compiler optimization we don't use on Linux (omit_frame_pointer), but we haven't
>analyzed it lately so it may be something else (if any Linux gurus here feel like
>figuring that one out, I'd be happy to help them get started).

I think that omit-frame-pointer pointer has been part of -O for GCC for a while, a lot of work was put in to make debugging possible on x86 without the frame pointer.

What version of GCC are you using? To be competitive with the MS compiler you'll need to be bang up to date with the 4.3 series.

The other thing it would be interesting to do is to compile your codebase with the Intel C++ compiler, you can get evaluation versions of this and if your code compiles with both GCC and MSVC++ then you ought to be able to get it past Intel C++ without much effort.

A 1% difference might not even be the compiler it could be some difference in CPU affinity, or slighly non optimal case in the VM or something.

Recent versions of VTune have a library you can link your code to which allows you to teach VTune about JIT compiled code, it could be instructive to try that as well.