niedakh/pqdm

RuntimeError with example in multiprocessing.spawn

Closed this issue · 1 comments

eric-brunner commented

Hi! I wanted to use your library, but got quickly stuck by this error. The concept is very interesting. I hope there is a solution to this issue :)

  • Parallel TQDM version: 0.1.0
  • Python version: 3.7
  • Operating System: Windows 10

Description

Provided example raises RuntimeError in multiprocessing.spawn.

What I Did

from pqdm.processes import pqdm
# If you want threads instead:
# from pqdm.threads import pqdm

args = [
    {'a': 1, 'b': 2},
    {'a': 2, 'b': 3},
    {'a': 3, 'b': 4},
    {'a': 4, 'b': 5}
]
# args = range(1,6) would also work

def multiply(a, b):
    return a*b

result = pqdm(args, multiply, n_jobs=2, argument_type='kwargs')

What I got

SUBMITTING | : 100%|██████████| 4/4 [00:00<00:00, 400.22it/s]
SUBMITTING | :   0%|          | 0/4 [00:00<?, ?it/s]Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 105, in spawn_main
    exitcode = _main(fd)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 114, in _main
    prepare(preparation_data)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 225, in prepare
    _fixup_main_from_path(data['init_main_from_path'])
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 277, in _fixup_main_from_path
    run_name="__mp_main__")
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\runpy.py", line 263, in run_path
    pkg_name=pkg_name, script_name=fname)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\runpy.py", line 96, in _run_module_code
    mod_name, mod_spec, pkg_name, script_name)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Users\eric.brunner\Documents\Personnal\S1PR-E02-RDF-DPS\02_Development\Python\dps\test_parallel_loading.py", line 45, in <module>
    result = pqdm(args, multiply, n_jobs=2, argument_type='kwargs')
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\site-packages\pqdm\processes.py", line 24, in pqdm
    **kwargs
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\site-packages\pqdm\_base.py", line 47, in _parallel_process
    for a in TQDM(iterable, **submitting_opts)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\site-packages\pqdm\_base.py", line 47, in <listcomp>
    for a in TQDM(iterable, **submitting_opts)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\concurrent\futures\process.py", line 641, in submit
    self._start_queue_management_thread()
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\concurrent\futures\process.py", line 583, in _start_queue_management_thread
    self._adjust_process_count()
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\concurrent\futures\process.py", line 607, in _adjust_process_count
SUBMITTING | :   0%|          | 0/4 [00:00<?, ?it/s]    p.start()
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\process.py", line 112, in start
    self._popen = self._Popen(self)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\context.py", line 322, in _Popen
Traceback (most recent call last):
  File "<string>", line 1, in <module>
    return Popen(process_obj)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\popen_spawn_win32.py", line 46, in __init__
    prep_data = spawn.get_preparation_data(process_obj._name)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 143, in get_preparation_data
    _check_not_importing_main()
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 136, in _check_not_importing_main
    is not going to be frozen to produce an executable.''')
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.
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 105, in spawn_main
    exitcode = _main(fd)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 114, in _main
    prepare(preparation_data)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 225, in prepare
    _fixup_main_from_path(data['init_main_from_path'])
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 277, in _fixup_main_from_path
    run_name="__mp_main__")
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\runpy.py", line 263, in run_path
    pkg_name=pkg_name, script_name=fname)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\runpy.py", line 96, in _run_module_code
    mod_name, mod_spec, pkg_name, script_name)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Users\eric.brunner\Documents\Personnal\S1PR-E02-RDF-DPS\02_Development\Python\dps\test_parallel_loading.py", line 45, in <module>
    result = pqdm(args, multiply, n_jobs=2, argument_type='kwargs')
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\site-packages\pqdm\processes.py", line 24, in pqdm
    **kwargs
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\site-packages\pqdm\_base.py", line 47, in _parallel_process
    for a in TQDM(iterable, **submitting_opts)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\site-packages\pqdm\_base.py", line 47, in <listcomp>
    for a in TQDM(iterable, **submitting_opts)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\concurrent\futures\process.py", line 641, in submit
    self._start_queue_management_thread()
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\concurrent\futures\process.py", line 583, in _start_queue_management_thread
    self._adjust_process_count()
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\concurrent\futures\process.py", line 607, in _adjust_process_count
    p.start()
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\process.py", line 112, in start
    self._popen = self._Popen(self)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\context.py", line 322, in _Popen
    return Popen(process_obj)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\popen_spawn_win32.py", line 46, in __init__
    prep_data = spawn.get_preparation_data(process_obj._name)
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 143, in get_preparation_data
    _check_not_importing_main()
  File "C:\Users\eric.brunner\Anaconda3\envs\dps\lib\multiprocessing\spawn.py", line 136, in _check_not_importing_main
    is not going to be frozen to produce an executable.''')
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.
SUBMITTING | :   0%|          | 0/4 [00:00<?, ?it/s]
SUBMITTING | :   0%|          | 0/4 [00:00<?, ?it/s]
PROCESSING | : 100%|██████████| 4/4 [00:00<00:00,  6.16it/s]
COLLECTING | : 100%|██████████| 4/4 [00:00<?, ?it/s]