Dear all,
I’m looking for guidance please. I would like to make sure, that I use all
eight of my CPU cores, when I run Python’s 3.9.9 NumPy on my macOS BigSur 12.1.
When I run my NumPy code, I see in ‘htop’, that only one ‘python’ process is
running and the core utilisation is 20–25%. I remember in the past, stock
MacPorts NumPy installation would use Apple’s Accelerate library including the
multithreaded BLAS and LAPACK
(https://developer.apple.com/documentation/accelerate). As I understand this is
no longer the case.
I run Python code using a virtual environment located under
/opt/venv/zipfstime/lib/python3.9/site-packages/numpy/core
When I change there and issue
otool -L _multiarray_umath.cpython-39-darwin.so
_multiarray_umath.cpython-39-darwin.so:
@loader_path/../.dylibs/libopenblas.0.dylib (compatibility version
0.0.0, current version 0.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current
version 1281.100.1)
In other words, NumPy relies on openBLAS. Command `port variants openblas`
returns
OpenBLAS has the variants:
g95: Build using the g95 Fortran compiler
* conflicts with gcc10 gcc11 gcc8 gcc9 gccdevel
gcc10: Build using the MacPorts gcc 10 compiler
* conflicts with g95 g95 gcc11 gcc8 gcc9 gccdevel
[+]gcc11: Build using the MacPorts gcc 11 compiler
* conflicts with g95 g95 gcc10 gcc8 gcc9 gccdevel
gcc8: Build using the MacPorts gcc 8 compiler
* conflicts with g95 g95 gcc10 gcc11 gcc9 gccdevel
gcc9: Build using the MacPorts gcc 9 compiler
* conflicts with g95 g95 gcc10 gcc11 gcc8 gccdevel
gccdevel: Build using the MacPorts gcc devel compiler
* conflicts with g95 g95 gcc10 gcc11 gcc8 gcc9
[+]lapack: Add Lapack/CLapack support to the library
native: Force compilation on machine to get fully optimized library
universal: Build for multiple architectures
I tried installing the “native” variant of OpenBLAS port with `sudo port
install openblas +native` and setting the environment variable
`OMP_NUM_THREADS=8`, but I didn’t see any improvement when running my Python
code. I would welcome your help and guidance on this subject.
—
Best wishes,
Maxim
