For anyone still reading this: I'm now confused by Eigen reportedly being basically on a par with optimized L3 BLAS, which I assume doesn't just mean punting t

For anyone still reading this: I'm now confused by Eigen reportedly being basically on a par with optimized L3 BLAS, which I assume doesn't just mean punting to optimized BLAS, which it seems it can do. I can't see any indication that you can do run-time dispatch on the micro-architecture, which I think is important; I saw very poor results until I examined CMakeLists.txt. Anyway, I cmade v3.4 with -DEIGEN_TEST_AVX512DQ=on, which seems most appropriate for my SKX system, and then did make blas. I ran my normal initial quick test using the OpenBLAS 0.3.15 dgemm benchmark, which reports a plateau of ~99000 MFlops. LD_PRELOADing libeigen_blas.so with the same binary under the same conditions (bound to a core, with the hpc-compute tuned profile) gave ~66000 MFlops. What did I do wrong?