Hi, I've built a fortran 90 code that uses lapack's getrf and getri for inverting complex matrices. I used Intel Fortran compiler 11.1 update 5 (069) to compile the code, linking with the MKL library that came with that compiler (from what I gathered here
http://software.intel.com/en-us/articles/which-version-of-ipp--mkl--tbb-is-installed-with-intel-compiler-professional-edition/ it corresponds to the latest update to MKL. When I try to run the code with 4 threads (I have a Xeon X5570) I see the program takes 400% of the CPU, but the wall time, compared with only one thread running, is the same, or even larger! I also tried changing the size of the matrices I am inverting (from 18x18 to 100x100), but there was no change in the pattern. Am I doing something stupid here?! I can't figure it out. I searched all over Intel, and also the rest of the internet using google, and I didn't find any reference to this kind of problem. Any suggestion will be much appreciated. Cheers, Antonio
