That's what Ractor is for, if you want full parallelization without processes. And, yes, it's to do with a GIL/GVL. The lock is released during blocking IO, an

That's what Ractor is for, if you want full parallelization without processes. And, yes, it's to do with a GIL/GVL. The lock is released during blocking IO, and some C extensions etc., so in practice for a lot of uses it's fine.