I'm having a problem where VS Code returns an error when I run my multiprocessing code. I'm pretty new to multiprocessing and VS Code, so I am completely in the dark on what to do to fix this error. I've looked up numerous tutorials on how to implement multiprocessing and even straight up copied the majority of the below code from a tutorial in an attempt to see if I made a mistake in my code, but every time I run the code, it sends the error message in the terminal. The code:
import multiprocessing
#12 cpu's
import time
def sleepy_man():
print('Starting to sleep')
time.sleep(1)
print('Done sleeping')
if __name__ == '__main__':
multiprocessing.freeze_support()
...
tic = time.time()
p1 = multiprocessing.Process(target= sleepy_man)
p2 = multiprocessing.Process(target= sleepy_man)
p1.start()
p2.start()
p1.join()
p2.join()
toc = time.time()
print('Done in {:.4f} seconds'.format(toc-tic))
The error:
PS C:\Users\me\.py> & C:/Users/me/AppData/Local/Microsoft/WindowsApps/python3.11.exe c:/Users/me/.py/multiprocessinglearn.py
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 120, in spawn_main
exitcode = _main(fd, parent_sentinel)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 129, in _main
prepare(preparation_data)
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 240, in prepare
_fixup_main_from_path(data['init_main_from_path'])
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 291, in _fixup_main_from_path
main_content = runpy.run_path(main_path,
^^^^^^^^^^^^^^^^^^^^^^^^^
File "<frozen runpy>", line 291, in run_path
File "<frozen runpy>", line 98, in _run_module_code
File "<frozen runpy>", line 88, in _run_code
File "c:\Users\100146766\.py\multiprocessinglearn.py", line 17, in <module>
p1.start()
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\process.py", line 121, in start
self._popen = self._Popen(self)
^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\context.py", line 224, in _Popen
return _default_context.get_context().Process._Popen(process_obj)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\context.py", line 336, in _Popen
return Popen(process_obj)
^^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\popen_spawn_win32.py", line 45, in __init__
prep_data = spawn.get_preparation_data(process_obj._name)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 158, in get_preparation_data
_check_not_importing_main()
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 138, in _check_not_importing_main
raise RuntimeError('''
RuntimeError:
An attempt has been made to start a new process before the
current process has finished its bootstrapping phase.
This probably means that you are not using fork to start your
child processes and you have forgotten to use the proper idiom
in the main module:
if __name__ == '__main__':
freeze_support()
...
The "freeze_support()" line can be omitted if the program
is not going to be frozen to produce an executable.
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 120, in spawn_main
exitcode = _main(fd, parent_sentinel)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 129, in _main
prepare(preparation_data)
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 240, in prepare
_fixup_main_from_path(data['init_main_from_path'])
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 291, in _fixup_main_from_path
main_content = runpy.run_path(main_path,
^^^^^^^^^^^^^^^^^^^^^^^^^
File "<frozen runpy>", line 291, in run_path
File "<frozen runpy>", line 98, in _run_module_code
File "<frozen runpy>", line 88, in _run_code
File "c:\Users\100146766\.py\multiprocessinglearn.py", line 17, in <module>
p1.start()
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\process.py", line 121, in start
self._popen = self._Popen(self)
^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\context.py", line 224, in _Popen
return _default_context.get_context().Process._Popen(process_obj)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\context.py", line 336, in _Popen
return Popen(process_obj)
^^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\popen_spawn_win32.py", line 45, in __init__
prep_data = spawn.get_preparation_data(process_obj._name)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 158, in get_preparation_data
_check_not_importing_main()
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.11_3.11.752.0_x64__qbz5n2kfra8p0\Lib\multiprocessing\spawn.py", line 138, in _check_not_importing_main
raise RuntimeError('''
RuntimeError:
An attempt has been made to start a new process before the
current process has finished its bootstrapping phase.
This probably means that you are not using fork to start your
child processes and you have forgotten to use the proper idiom
in the main module:
if __name__ == '__main__':
freeze_support()
...
The "freeze_support()" line can be omitted if the program
is not going to be frozen to produce an executable.
I have no clue what VS Code is asking for and how to fix this.
I've tried a number of different fixes:
Adding the freeze_support() line that VS Code was recommending.
Copying tutorial code.
I've imported just Process, and just freeze_support, those almost worked, but brought up some errors in the code that when I fixed the errors, brought back the same error message in the terminal.
I feel like I am missing something vital to getting multiprocessing to work, do I have to place the p1.start() and p1.join() into the if statement?
You are not quite using the idiom correctly...
Try:
import multiprocessing
import time
def sleepy_man():
print('Starting to sleep')
time.sleep(1)
print('Done sleeping')
if __name__ == '__main__':
tic = time.time()
p1 = multiprocessing.Process(target= sleepy_man)
p2 = multiprocessing.Process(target= sleepy_man)
p1.start()
p2.start()
p1.join()
p2.join()
toc = time.time()
print('Done in {:.4f} seconds'.format(toc-tic))