env:

gcc version 4.8.5 20150623 (Red Hat 4.8.5-16)

mkl 2018.1.1

compile:

icc erf.c -lmkl_rt -qopenmp -o erf

run:

./erf

result (28 physical cores x 2 sockets):

$ export OMP_NUM_THREADS=1

$ ./erf

std time: 3278.84 ms

mkl time: 1141.68 ms

org time: 5398.45 ms

simd time: 1155.34 ms

$ export OMP_NUM_THREADS=28

$ ./erf

std time: 173.57 ms

mkl time: 124.99 ms

org time: 289.07 ms

simd time: 125.32 ms

$ export OMP_NUM_THREADS=56

$ ./erf

std time: 208.19 ms

mkl time: 158.96 ms

org time: 154.67 ms

simd time: 158.58 ms