Le jeudi 18 septembre 2014 à 15:12 -0400, Andreas Noack a écrit : > You are not using a fast BLAS, but the slow reference BLAS which > unfortunately is the default on Linux. An option is to build Julia > from source. Usually it is just to download the source and write make. > Then you'll have Julia compiled with OpenBLAS which is much faster and > comparable in speed to Intel MKL which MATLAB uses. My Fedora RPM package uses OpenBLAS, or at least is supposed to. But indeed only one thread is used in my tests here too. The problem seems to be that LAPACK is not the OpenBLAS one: julia> versioninfo() Julia Version 0.3.0 Platform Info: System: Linux (x86_64-redhat-linux) CPU: Intel(R) Core(TM) i5 CPU M 450 @ 2.40GHz WORD_SIZE: 64 BLAS: libopenblas (DYNAMIC_ARCH NO_AFFINITY) LAPACK: liblapack LIBM: libopenlibm LLVM: libLLVM-3.3
And indeed I'm passing USE_SYSTEM_LAPACK=1. I didn't know it would incur such a slowdown. Is there a way to get Julia use the system's OpenBLAS version of LAPACK? Regards
