python doesn't have atomic rc. the gil prevents multithreading because experiments into removing the gil and replacing it with atomic reference counting had too

python doesn't have atomic rc. the gil prevents multithreading because experiments into removing the gil and replacing it with atomic reference counting had too high a performance overhead (roughly 2x for single threaded code). this is less of a problem for rust for 2 reasons: ARC is opt in and it's only used for a small fraction of objects, and compilers can do some fancy tricks and delete pairs of increments and decrements if it can prove that they don't cause corruption.