Erlang and Elixir are both dynamically typed and do dynamic dispatch. Erlang does not know the types flowing through a call site in advance and therefore has t

Erlang and Elixir are both dynamically typed and do dynamic dispatch. Erlang does not know the types flowing through a call site in advance and therefore has to do dynamic dispatch. In particular, Erlang has a "code server" that all calls throughout the system must thunk through, versus a statically typed language where a call is optimized to a single JMP instruction. Smarter JITs, like Java's HotSpot, can also do this, and HotSpot is smart enough to inline both virtual and dynamic dispatch at runtime. BEAM can't. Erlang's closest thing to a JIT (HiPE) cannot inline calls across modules, has no support for deoptimization, and is in effect a naive, crappy, AOT compiler which does the bare minimum to work in an otherwise dynamic environment. Source: I made this... it was basically Elixir before Elixir: http://reia-lang.org/ http://reia-lang.org/ These days I like languages that can actually avoid this overhead through the use of static typing, like Rust. Note that it isn't necessarily bad that Erlang works this way. When it comes to Erlang's core strength: coordinating the concurrent activities of a massive number of processes/clients, it really does shine. Just don't use it for anything CPU-intensive.