> Yes: I used arenas a lot when I was shipping C code; they're a very easy way to get big speed boosts out of code that does a lot of malloc

This is something I look forwards to exploring later in my current pet project, right now it has possibly the stupidest GC (just tracks C++ 'new' allocated objects) but is set up for drop in arena allocation with placement new so, we'll see how much that matters later on. There are two allocation patterns, statements and whatnot get compiled to static continuation graphs which push and pop secondary continuations and Value objects to do the deed so, I believe, the second part with the rapid temporary object creation will see the most benefit.

Anyhoo, slightly different pattern where the main benefits will most likely be from the cache locality or whatever, assuming I can even make a placement new arena allocator which is better than the performance of the regular C++ new. Never know, might even add more overhead than just tracking a bunch of raw C++ pointers as I can't imagine there's even a drop of performance which C++ new left on the table?