> a per-thread GIL with an explicit mode to share particular objects This is like Ruby's Ractors and I haven't really seen that be super successful so far. The

> a per-thread GIL with an explicit mode to share particular objects This is like Ruby's Ractors and I haven't really seen that be super successful so far. The "Objects" that need to be shared are things like class definitions, etc.... there are a ton of subtle issues with objects that are being marked as sharable when they should really not be or vice versa.