Hello,
to benchmark our new Skylake cluster consisting of two and four socket machines together with a Broadwell system, I want to be able to run LINPACK with a different amount of MPI ranks per node. My problem is that there are too many processes spawned on the four socket nodes where I launch two MPI ranks.
I tried to limit the number of threads via OMP_NUM_THREADS and MKL_NUM_THREADS, but without effect. TBB seams to be the cause here, because some MKL functions (which will probably be used in LINPACK) are using this:
https://software.intel.com/en-us/mkl-macos-developer-guide-functions-thr...
As far as I know, there is no possibility to influence the number of threads with environment variables created with TBB.
So my question is, how to run LINPACK with two MPI ranks on one node (and get the full performance)?
Best regards,
Holger