https://build.opensuse.org/request/show/835366 switched numpy to plain
BLAS/LAPACK, which causes a significant performance regression:

---
import numpy as np
import time

n = 4000

start_time = time.time()
A = np.random.randn(n,n).astype('float64')
B = np.random.randn(n,n).astype('float64')
print(" init took {} seconds ".format(time.time() - start_time))

start_time = time.time()
m = A@B
print(" mmult took {} seconds ".format(time.time() - start_time))

print(np.__config__.show())
---
python3-numpy-1.19.1 with openblas:    mmult took 2.4579274654388428 seconds
python3-numpy-1.19.2 with blas/lapack: mmult took 877.8246397972107 seconds
python3-numpy-1.19.2 with openblas:    mmult took 2.6917877197265625 seconds

MMult 4000x4000 is 64e9 multiplications and additions, thats ~150kOps/s for
BLAS/LAPACK.