Go on, 'Prove it'. Write a version that's faster.

I know it's doable, because I have done it.

You don't seem to understand yet how complex it will be. My guess is ~10x the number of lines of code. It'll be significantly less readable, let alone debuggable.

(btw changing from stack to vector and reserving memory outright for the allocations has virtually no change in performance.)

> The program stack isn't magically special

This is what you're missing. Yes, it is magical because the hardware optimizes for that path. That's why it's faster than what you'd think from first principles.

> it isn't going to beat writing a single value to memory

If you examine the kernel trace from this, you'll find that it has the exact same memory usage and bandwidth (and about twice the ipc). Magical, yes.

Go on, 'Prove it'. Write a version that's faster.

You're trying to say that pushing a function call frame is faster than writing a single value to memory and incrementing an index, and when asked to prove it you made something that allocates and deallocates chunks of memory to a linked list where every access takes multiple pointer dereferences.