PGI vs GCC/GFortran

Dear PGI users:
I am currently running some global climate models on a 64-CPU opteron x64 linux system and am compiling with GFORTRAN+OpenMPI+Netcdf3.6.3. I wonder if someone here would please suggest which PGI product I should download (i.e., trial mode) to compare running times of the code generated by GCC/GFortran vs. the PGI equivalents. I see PGI Accelerator, PGI Workstation, both with and without PGI/C/C++ - not being a great programmer, I’m not exactly sure what to compile here. I do note that the codebase includes OpenMP code.

Thank You Very Much,
Patricia

Hi Patricia,

The download package is the same for all of the 64-bit Linux installs, so any one of them will work for you. The difference is with the license which enables the various features. A trial license will enable all features for the trial period.

Hope this helps,
Mat

Thank You, Mat! I am trying to compare GFORTRAN compile of GISS ModelE to a PGIFortran compile. Is there an easy way to do this (i.e., install and temporarily switch to PGI) without borking my GFORTRAN after the trial period expires? I’m pretty sure I’m going to have to custom compile netcdf363 and also OpenMPI with PGI before I even try to compile ModelE, correct?

Thanks Again!!!

Hi Patricia,

Is there an easy way to do this (i.e., install and temporarily switch to PGI) without borking my GFORTRAN after the trial period expires?

I would recommend starting from a clean build tree separate from your Gfortran build tree. Though even if you need to re-build in the same tree the worse case is that you’d need to rebuild your gfortran version from scratch. While I’ve never build GISS ModelE myself so do don’t know for sure, my assumption is that building isn’t too difficult. According to the NASA web pages for ModelE, PGI is a supported compiler (http://www.giss.nasa.gov/tools/modelE/HOWTO.html#part0_3) so they should have a PGI configuration available.

I’m pretty sure I’m going to have to custom compile netcdf363 and also OpenMPI with PGI before I even try to compile ModelE, correct?

Yes. You’ll need to build a PGI version of OpenMP and NetCDF.

Note that a temp license will time bomb any object you build so if you do decided later to obtain a permanent license, you need to make sure an re-build all your objects.

Let me know if you run into issues or recommendations on optimizations to use.

  • Mat

Thank you very much!!! OpenMPI also, correct? Lastly, what’s the time limit on this trial (I still haven’t installed and downloaded a week ago…)

Patricia

OpenMPI also, correct?

Yes.

Lastly, what’s the time limit on this trial (I still haven’t installed and downloaded a week ago…)

The date you downloaded doesn’t matter, rather it’s 15 days from when you generate the license file.

  • Mat