Manually manage the GIL with Cython

[alxmrs]

I suspect that the performance of the ThreadPoolExecutor would substantially increase if we strategically placed cython with nogil calls.

• https://cython.readthedocs.io/en/latest/src/userguide/parallelism.html
• https://stackoverflow.com/questions/49047255/cython-nogil-with-threadpoolexecutor-not-giving-speedups
• https://stackoverflow.com/questions/56537989/usage-of-threadpoolexecutor-in-conjunction-with-cythons-nogil

There are drawbacks to process based parallelism; namely, there is a high overhead and IPC latency compared to multithreading.

[alxmrs]

Memory views for shared memory: https://docs.cython.org/en/latest/src/userguide/memoryviews.html

[tomwhite]

Another approach is free-threaded Python, which is just ramping up (but is going to take some time):

• Free-threaded CPython is ready to experiment with!
• py-free-threading.github.io

[alxmrs]

TIL! I didn’t realize threaded Python was coming so soon! Thanks for the pointers.

The Cython tricks may be useful in the near-term for younger versions of Python.