On 3/10/13, Warren Weckesser <warren.weckes...@gmail.com> wrote: > On 3/10/13, QT <rdirect...@gmail.com> wrote: >> Dear all, >> >> I'm at my wits end. I've followed Intel's own >> instructions<http://software.intel.com/en-us/articles/numpyscipy-with-intel-mkl>on >> how to compile Numpy with Intel MKL. Everything compiled and linked >> fine and I've installed it locally in my user folder...There is one nasty >> problem. When one calls the numpy library to do some computation, it >> does >> not use all of the available threads. I have 8 "cores" on my machine and >> it only uses 4 of them. The MKL_NUM_THREADS environmental variable can >> be >> set to tune the number of threads but setting it to 8 does not change >> anything. Indeed, setting it to 3 does limit the threads to 3....What is >> going on? > > > Does your computer have 8 physical cores, or 4 cores that look like 8 > because of hyperthreading? >
Here's why I ask this: http://software.intel.com/en-us/forums/topic/294954 > Warren > > >> >> As a comparison, the numpy (version 1.4.1, installed from yum, which uses >> BLAS+ATLAS) uses all 8 threads. I do not get this. >> >> You can run this test program >> >> python -mtimeit -s'import numpy as np; a = np.random.randn(1e3,1e3)' >> 'np.dot(a, a)' >> >> There is one saving grace, the local numpy built with MKL is much faster >> than the system's numpy. >> >> I hope someone can help me. Searching the internet has been fruitless. >> >> Best, >> Quyen >> >> My site.cfg for numpy (1.7.0) >> [mkl] >> library_dirs = /opt/intel/mkl/lib/intel64 >> include_dirs = /opt/intel/mkl/include >> mkl_libs = mkl_rt >> lapack_libs = >> >> I've edited line 37 of numpy/distutils/intelcompiler.py >> self.cc_exe = 'icc -O3 -fPIC -fp-model strict -fomit-frame-pointer >> -openmp >> -parallel -DMKL_ILP64' >> >> Also line 54 of numpy/distutils/fcompiler/intel.py >> return ['-i8 -xhost -openmp -fp-model strict'] >> >> My .bash_profile also contains the lines: >> source /opt/intel/bin/compilervars.sh intel64 >> source /opt/intel/mkl/bin/mklvars.sh intel64 >> >> The above is needed to set the LD_LIBRARY_PATH so that Python can source >> the intel dynamic library when numpy is called. >> > _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
