Compatibility between OpenMP in Intel Fortran and an 8-core workstation

[roine_vestman]

Dear all,

I am using Intel Fortran for some computational tasks in Economics. I am just about to learn OpenMP and I got a grant to buy a workstation. I'll either buy a Dell Precision or Mac Pro with two quad core Intel Xeon processors (two Quad Core Intel Xeon X5355) so that I'll have an 8-core machine.

What I am wondering is, first,if I'll be able to fully utilize core number 5 to 8 with Intel Fortran if I use OpenMP.Second, from that point of view, does it matter if I'll buy a Dell Precision, with either operating system WinXP or Vista, or a Mac Pro with operating system Leopard. Does one OS or the other provide better support for up to 8 cores and is there a difference how well Intel Fortran works under either OS?

Third, what about IMSL that is available with the Intel Fortran Pro edition - can it utilize a second Xeon processor (in my case core number 5 to 8)?

Best regards,

Roine

[jimdempseyatthecove]

Roine,

You may get a lot of flame here regarding which is better Windows or Mac system. Most of this flame, probably all of the flame, has nothing to do with regards to which is a better platform for software development. The flame usualy revolves around user interface and utilities. (or why you would ever need more than 1 button ona mouse)

If you intend to do program development I would suggest you consider Windows XP Pro 64-bit edition or Windows Server 2003 64-bit edition and purchase Visual Studio 2005 Professional version. For now, stay away from Vista. The reason for using Windows is the Integrated Development Environment of Microsoft Visual Studio is much better to work with than the procedures you typically do on a Mac. From my perspective the Edit, Build, Debug, Edit, Build, Debug, Edit, Build, Debug, etc... works better using MS Visual Studio. The debugger integration in Visual Studio is real nice. If you do program development, you will do a lot of debugging.

The usage of the 2nd processor (second set of 4 cores) is dependent on the operating system rather than on OpenMP.

I would also suggest adding a dual head video card, two largish LCD monitors and disable the on-board video if your motherboard has integrated video.

Jim Dempsey

(I use Windows Server 2003 x64, vs 2005 Pro, Intel Visual Fortran, MSVC++)

[roine_vestman]

Thanks for that response.

I didn't quite understand if Leopard (the new Mac OS) vs. Win XP vs. Vista makes a difference in terms of being able to write an IntelFortran program that uses all 8 cores. Please clarify, if possible.

Best,

Roine

[TimP]

In principle, there's little difference among Windows, linux, or Mac 64-bit OS, in use of Intel Fortran on the same hardware. Windows is somewhat more dependent than linux on the use of KMP_AFFINITY environment variable; Leopard is more of an unknown to most of use, but this is a minor issue compared to personal preferences.

[jimdempseyatthecove]

Microsoft considers a Processor as a chip carrier that plugs into a processor socket on a motherboard regardless of the number of processing cores. Your system will have two processor sockets each with 4 cores. "Windows XP Professional" and "Windows XP Professional x64 Edition" provide a license for up to 2 processor sockets.

Windows XP Home version provides licensing for 1 processor socket (1, 2, 4 cores today, maybe 8, 16,... cores later in on package).

The Windows XP Professional x64 Edition will not constrict you on physical RAM until you reach 128GB. The 32-bit versions of XP will provide an application between 2GB and 3GB depending on options. 2GB today is tight on memory.

Also, the motherboard you will be getting may exhibit best performance when memory is installed in groups of 4 sticks.

For MS licensing (older docs) See:

http://support.microsoft.com/kb/888732

and

http://www.microsoft.com/licensing/highlights/multicore.mspx

There may be revised documents on their site.

Jim Dempsey