[Python] What causes extra subprocesses to be created by Python multiprocessing? [closed]

I've built a command-line app using the Python multiprocessing module, specifically a small suite of long-lived processes explicitly created via Process (with the spawn context, on Linux) communicating with multiple multiprocessing.Queue and multiprocessing.Event instances.

When I watch it run, I see the expected persistent subprocesses that correspond to the Process instances I created. But I also see many more subprocesses that I didn't explicitly create, and at least sometimes they seem to come and go frequently (though it might be that something unrelated to this question is killing them; I'm running under a cgroups configuration I don't fully control).

My understanding is that implicit helper subprocesses might be created by multiprocessing.Manager, but I'm not using that. Is there something else in multiprocessing that could be creating those processes? And is it expected for them to come and go, if I'm not destroying or creating any multiprocessing objects?

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