ZEN kernels perform worse, give wrong results, compared to HASWELL kernels on Zen/Ryzen #1147
Description
My application extensively uses SGEMM kernels with sizes:
M=128, N=361, K=1152
M=32, N=361, K=288
(This is an im2col+SGEMM combo for DCNN computation)
Single-threaded (application itself is multithreaded) with OPENBLAS_CORETYPE=Haswell
1000 predictions in 37.00 seconds -> 27 p/s
1000 evaluations in 4.29 seconds -> 233 p/s
Static build for Zen (see previous issue, dynamic dispatch is broken):
1000 predictions in 40.23 seconds -> 24 p/s
1000 evaluations in 4.50 seconds -> 222 p/s
So performance tanks about 5% to 20%.
So, "Zen" support in OpenBLAS actually worsens performance on Zen.