Dear support team,
I have a question about a performance difference between Windows 7 SP 1 and RHEL 6.5.
The situation is as follows:
The hardware is a DELL precision rack 7910, see link for exact specification (click on components):
http://www.dell.com/support/home/us/en/19/product-support/servicetag/3X8GG42/configuration
We installed Linux RHEL 6.5 on this machine and ran our product (compiled with Intel C/C++/Fortran 13.1.3 (gcc version 4.4.7 compatibility) and Intel MPI 5.0.2.044 on Linux).
After that, we installed Windows 7 SP 1 on this machine and ran our product (compiled with Intel C/C++/Fortran 13.1.3.198 and Intel MPI 5.0.2.044 on Windows) again.
What we observed is a big performance drop on 1 and 2 cpu on Windows in comparison to Linux. If we go up to 8, 16, 32 cpus we got nearly the same performance on Windows as on Linux, but we got heavy oscillation in computation time only on Windows (sometimes 16 cpus faster than 32 cpu). On Intel MPI 4.1.3.045 we didn't see this oscillation phenomenon.
The question is:
Is there a problem with Intel MPI 5.0.2.044 on Windows 7 SP 1 on the above described hardware?
This machine got two 18 core cpus, is there a problem with the cpu scheduler on Windows which does not respect the pinning or something else?
Many thanks in advance
Frank