I installed mkl_2020.1 on centos7 and linked my cpp file with libmkl_rt.so. The application runs as well.
My question is that does my application use avx2 to speed up? It seems that libmkl_avx2.so was not called because it runs as well even I delete file libmkl_avx2.so. I confirmed my cpu is support avx2 instruction.
Yes, linking with lmkl_rt would be enough to run your code on avx2 based system w/o explicit linking with lmkl_avx2. You may easier to check which code path has been called by setting MKL_VERBOSE env. variable and if your code calls BLAS, LAPACK, or FFT routines. All another part of MKL still doesn't support the verbose mode so far.