Python is experimenting with a novel approach where objects have two reference counts, one exclusively for the owning thread and another for all other threads,

Python is experimenting with a novel approach where objects have two reference counts, one exclusively for the owning thread and another for all other threads, improving performance when most of the increments/decrements are done by the owning thread. https://lwn.net/Articles/872869/ https://lwn.net/Articles/872869/