Subject: Re: Linux emulation, binary software, cluster/grid and SMP
To: Bruce O'Neel <firstname.lastname@example.org>
From: George Georgalis <email@example.com>
Date: 01/19/2006 05:35:42
On Thu, Jan 19, 2006 at 09:45:13AM +0000, Bruce O'Neel wrote:
>On Wed, Jan 18, 2006 at 11:20:31AM -0500, George Georgalis wrote:
>> The intel site makes it look like you need Intel cpu, but thoes
>> quotes are from Intel Fortran requirements, and I think it will
>> work on AMD, plus Linux emul for NetBSD.
>We've run older versions on amd systems and they have worked fine. The
>resulting code (no processor specific switches set though) has also worked
>You might want to think hard about g95. The Intel compiler is likely
>to produce faster code, of course, but g95 has gotten really good
>recently. We also find that:
>- it requres less patches than the intel compiler to deal with
>odd corners of F90/F95.
>- it's way less of a pain to install.
>- you don't have a bizzaro website to navigate to get updates.
>- the executables are much smaller.
>oneel@isdclin6:~ > ls -hl /isdc/integration/osa_int/current_linux/bin/ii_skyimage
>-rwxr-xr-x 1 oneel obs_gen 7.9M Jan 11 16:02 /isdc/integration/osa_int/current_linux/bin/ii_skyimage
>oneel@isdclin6:~ > ls -hl $ISDC_ENV/bin/ii_skyimage
>-rwxr-xr-x 1 isdc_cms obs_gen 23M Nov 29 14:38 /isdc_sw/osa_sw/osa_sw-5.1/gcc/3.2.2/bin/ii_skyimage
>The bigger one is built with ifc. Plus the ifc one requires fortran specific
>shared libraries. Oh, and the ifc one is stripped and the g95 one isn't.
>We've not seen huge differences between the generated code. That said,
>we don't set cpu specific optimization flags, nor has it been carefully
>measured. Ie, we could have g95 be say 20% slower and we probably wouldn't
>notice it. We can't easily use CPU specific optimizations since our cluster
>ends up not completely homogeneous. Ie, we have some xenons, some amd systems,
>and now we're getting some amd dual core systems.
Thanks Bruce, that's just the kind of perspective I'm looking for.
We are concerned that clients or vendors will _require_ the intel
compiler, so we should be prepared for that.
George Georgalis, systems architect, administrator <IXOYE><
http://galis.org/ cell:646-331-2027 mailto:firstname.lastname@example.org