Please take a look:
My performance of factorization: 130.29 GFlop/s if I have " set OPENBLAS_NUM_THREADS=1"
My performance of factorization: 19.61 GFlop/s if I have " set OPENBLAS_NUM_THREADS=8"
If you don’t have the “OPENBLAS_NUM_THREADS” at all, it takes the value from “OMP_NUM_THREADS”.