OSX, Linux - any difference?

[gib]

Hi,
Please excuse my ignorance. I am using IVF with OMP, and planning to create executables for Linux and Mac OSX in order to distribute my program. I haven't yet tried building on Linux or OSX, but I've spoken to a colleague with a Mac, and apparently he has found that while his code gets a good speedup with OMP on Linux, the Mac performance is much inferior.

Should there be a performance difference between Linux and OSX? I would have expected the two to behave in very similar ways (of course, he might be doing something wrong). Are there any particular issues I should be aware of when porting my code to the different OS versions of ifort?

Thanks
Gib

[Steven_L_Intel1]

I would not expect them to be similar - the codebases for the OS kernels are VERY different. The Intel compiler and libraries are very close.

[TimP]

Quoting - Steve Lionel (Intel)

I would not expect them to be similar - the codebases for the OS kernels are VERY different. The Intel compiler and libraries are very close.

Intel compilers provide their own OpenMP library, which also supports gcc/gfortran OpenMP. You may be comparing very different versions of gcc; there's a definite advantage to using up to date versions, or, even better, the Intel compilers.

[gib]

Quoting - tim18

Intel compilers provide their own OpenMP library, which also supports gcc/gfortran OpenMP. You may be comparing very different versions of gcc; there's a definite advantage to using up to date versions, or, even better, the Intel compilers.

This person is using Intel compilers, i.e. the comparison was between ifort on Linux and ifort on OSX.

[gib]

Quoting - Steve Lionel (Intel)

I would not expect them to be similar - the codebases for the OS kernels are VERY different. The Intel compiler and libraries are very close.

Rephrasing my question slightly: Is it known that OpenMP performance on Mac OS X is poor, as my colleague's limited experience suggests?