PGI User Forum

[Michal Kvasnicka]

OK, well ... After a year I again checked the current status regarding benchmark comparisons PGI vs Intel vs GFortran.

I do not understand why the PGI guys are still in theirs "nirvana", because the binaries produced by PGI are just now systematically slower than binaries by Gfortran!!! And, as always, far more slower then binaries by Intel compiler!!!

See: http://polyhedron.com/pb05-lin64-f90bench_SBhtml and
http://www.nersc.gov/users/computational-systems/hopper/performance-and-optimization/compiler-comparisons/.

During the last year there was more or less zero progress on PGI binaries execution speed!!! On the other hand the Intel and GFortran compilers are doing faster and faster binaries.

So my final question is:
As a regular commercial user of PGI products I need to know if the PGI developers understand this situation and what we can expect in the near future?

[mkcolg]

Hi Michal,

First, I do appreciate you pushing on Polyhedron performance. We do have analysis and action plans for the discrepancies. However, when prioritizing our compiler performance team's time, it's necessary to put Polyhedron lower on the list. Not that Polyhedron isn't important, but rather we focus first on the performance of HPC community applications, followed by wider used HPC industry standard benchmarks such as SPEC OMP2012, SPEC MPI2007, SPEC CPU2006, NPB, etc. Note in today's performance meeting, I did bring up your concerns.

The question to you is how are we performance wise on your codes? If we are not performing well on those, please send us reproducing examples. We would be interested in investigating them.

Note for a comparison of OpenMP application performance, please see http://www.pgroup.com/benchmark/specomp/pgi.htm

As for the NERSC results, I'm currently in direct contact with the person who ran these comparisons. My internal testing on our cluster (128 core Intel Sandybridge) shows PGI on-par or exceeding Intel and given Hopper is an AMD system, the NERSC results should be even better. We are currently working with them to understand where the discrepancy occurs. Last week they promised to rerun NPB LU-Class E at 128 cores and send me the results so I can compare them to mine. I'll ping Mike again today to see where he's at on this.

While it's too early to conclude, at this point it is my contention that there's a problem with how the benchmarks are being run at NERSC rather than a problem with the PGI compilers. If I'm correct, we will work to get these results updated. Granted, if it does turn out to be problem with the PGI compilers, this would be a high priority item for us.

Bet Regards,
Mat