My impression was that that was exactly what they were going to do: replace the GIL with fine-grained locking on the objects themselves. I can't imagine they'd

My impression was that that was exactly what they were going to do: replace the GIL with fine-grained locking on the objects themselves. I can't imagine they'd let multiple python threads manipulate python data-structures concurrently, the interpreter would segfault immediately. > (but then how do you get a non-synchronized [] if you want one?) You don't. This is one of the reasons why using the GIL is higher performance for single-threaded use-cases: stuff like lists and dicts can be non-synchronized