<s>[INST] Python thread pool similar to the multiprocessing Pool? Is there a Pool class for worker threads, similar to the multiprocessing module's Pool class?
I like for example the easy way to parallelize a map function
def long_running_func(p):
    c_func_no_gil(p)

p = multiprocessing.Pool(4)
xs = p.map(long_running_func, range(100))

however I would like to do it without the overhead of creating new processes.
I know about the GIL. However, in my usecase, the function will be an IO-bound C function for which the python wrapper will release the GIL before the actual function call.
Do I have to write my own threading pool?
 [/INST] I just found out that there actually  is a thread-based Pool interface in the multiprocessing module, however it is hidden somewhat and not properly documented.
It can be imported via
from multiprocessing.pool import ThreadPool

It is implemented using a dummy Process class wrapping a python thread.  This thread-based Process class can be found in multiprocessing.dummy which is mentioned briefly in the docs.  This dummy module supposedly provides the whole multiprocessing interface based on threads.
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