What really gave clear performance improvements was generating Java bytecode. In the first attempt I got a 25% speedup, and I'm sure I could have gotten more out of it if I'd spent more time on it.
Oh yeah, absolutely. The trade off with byte code is that it can feel like threading your language through the class file format’s very particular needle, and you have to pay a larger initial cost generating and loading that class, and you have ongoing costs in terms of the meta space classes consume.