Dear Warren, It's an Intel i7 950, 4 cores, 8 with hyper-threading.
I used MKL 11.0.2.146, but I will read your link. It seems spot on. Best, Quyen On Sun, Mar 10, 2013 at 10:31 PM, Warren Weckesser < warren.weckes...@gmail.com> wrote: > 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 >
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