Dear all,

Thank you for all of your replies and suggestions! I have written my own matrix 
multiplication script in order to test NumPy’s performance. Please find it 
attached. I’m using the MKL variant of NumPy. Strangely enough the `port 
variants py39-numpy` still returns:

port variants py39-numpy
py39-numpy has the variants:
   atlas: Use MacPorts ATLAS Libraries
     * conflicts with mkl openblas
   gcc10: Build using the MacPorts gcc 10 compiler
     * conflicts with gcc11 gcc8 gcc9 gccdevel gfortran gfortran
   gcc11: Build using the MacPorts gcc 11 compiler
     * conflicts with gcc10 gcc8 gcc9 gccdevel gfortran gfortran
   gcc8: Build using the MacPorts gcc 8 compiler
     * conflicts with gcc10 gcc11 gcc9 gccdevel gfortran gfortran
   gcc9: Build using the MacPorts gcc 9 compiler
     * conflicts with gcc10 gcc11 gcc8 gccdevel gfortran gfortran
   gccdevel: Build using the MacPorts gcc devel compiler
     * conflicts with gcc10 gcc11 gcc8 gcc9 gfortran gfortran
[+]gfortran: Build using the MacPorts gcc 11 Fortran compiler
     * conflicts with gcc10 gcc11 gcc8 gcc9 gccdevel
   mkl: Use MacPorts MKL Libraries
     * conflicts with atlas openblas
[+]openblas: Use MacPorts OpenBLAS Libraries
     * conflicts with atlas mkl
   universal: Build for multiple architectures

Either I don’t understand the expected behaviour or my `port variants` command 
returns something else. I would expect it to show [+]gfortran and [+]mkl, not 
the [+]openblas. On the other hand, command `port installed py39-numpy` shows:

port installed py39-numpy
The following ports are currently installed:
  py39-numpy @1.21.5_1+gfortran+mkl
  py39-numpy @1.22.0_0+gfortran+mkl (active)

Finally, I wasn’t able to specify 8 execution threads with `export 
MKL_NUM_THREADS=8`. NumPy was still using 4, but the `htop` reported 350–380% 
CPU load for the `/usr/bin/env python3 ./dgemm_numpy.py` process. I think this 
is good news!

The `otool` command executed under 
`/opt/local/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/numpy/core`
 shows that MKL backend is being used.

otool -L _multiarray_umath.cpy
_multiarray_umath.cpython-39-darwin.so:
        
/opt/local/Library/Frameworks/Python.framework/Versions/3.9/lib/libmkl_rt.2.dylib
 (compatibility version 0.0.0, current version 0.0.0)
        /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current 
version 1311.0.0)

I think I still need to experiment with OpenBLAS and compare the performance 
numbers. Thank you for your help!

—
Best wishes,
Maxim

#!/usr/bin/env python3

import numpy as np
import time

print(np.__version__)
print(np.show_config())

m = 20000
k = 20000
n = 20000

t0 = time.time()
alpha = np.random.rand()
beta  = np.random.rand()

A  = np.random.rand(m, k)
B  = np.random.rand(k, n)
C  = np.random.rand(m, n)
t1 = time.time()

t = t1-t0
print('Generation time: {0:f}'.format(t))
print('  alpha: {0:f},  beta: {1:f}'.format(alpha, beta))

t0 = time.time()
C  = alpha*np.matmul(A, B) + beta*C
t1 = time.time()
t  = t1-t0
print('Multiplication time: {0:f}'.format(t))

## @eof dgemm_numpy.py

> On 29 Dec 2021, at 13:33, Joshua Root <[email protected]> wrote:
> 
> Maxim Abalenkov wrote:
> 
> 
>> 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.
>> 
> I'm using py39-numpy with default variants:
> 
> % port installed py39-numpy openblas
> The following ports are currently installed:
>   OpenBLAS @0.3.19_0+gcc11+lapack (active)
>   py39-numpy @1.21.5_1+gfortran+openblas (active)
> 
> I see Python using around 600% CPU on my 6-core machine when running this 
> basic benchmark 
> script:<https://gist.github.com/markus-beuckelmann/8bc25531b11158431a5b09a45abd6276>
> 
> If you try that and see how many cores it uses, that will at least tell you 
> if there is something different about your code. If it doesn't use all the 
> cores for you, there are some other environment variables that OpenBLAS looks 
> at that you could check: 
> <https://github.com/xianyi/OpenBLAS#setting-the-number-of-threads-using-environment-variables>
> 
> - Josh
> 

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