Windows MKL 10.2 vs 10.1 - defaulting to single core/single threaded

[AndrewC]

I am running various regression cases on MKL 10.1 vs 10.2 update 2 and 10.2 seems to resolutely insist on only using one core on my machine -( Intel Pentium D 3.Ghz running Windows XP64 ( 64 bit MKL). Of course, OMP_NUM_THREADS=2
I am linking against the OpenMP compatibility libraries

To run 10.1 vs 10.2 I just drop the new DLLs into my app folder, and re-run the regression cases so repeating various tests s quite easy. It is very,very obvious that 10.2 only uses one core to detriment of solution times.

Any ideas why this would happen?

More...
If I reboot my machine, then run a test case then the first run will use both cores. Subsequent runs will only use one core - until I reboot , that is.....

[AndrewC]

Quoting - vasci_intel

I am running various regression cases on MKL 10.1 vs 10.2 update 2 and 10.2 seems to resolutely insist on only using one core on my machine -( Intel Pentium D 3.Ghz running Windows XP64 ( 64 bit MKL). Of course, OMP_NUM_THREADS=2
I am linking against the OpenMP compatibility libraries

To run 10.1 vs 10.2 I just drop the new DLLs into my app folder, and re-run the regression cases so repeating various tests s quite easy. It is very,very obvious that 10.2 only uses one core to detriment of solution times.

Any ideas why this would happen?

More...
If I reboot my machine, then run a test case then the first run will use both cores. Subsequent runs will only use one core - until I reboot , that is.....

I have answered my own question. I was not setting MKL_DYNAMIC so MKL, in its infinite wisdom, was setting the number of threads to 1. Setting MKL_DYNAMIC=FALSE forces MKL to use the number of threads set by , say, OMP_NUM_THREADS