In Membrane, we use nested structs and (usually small) maps for element state, which is basically a GenServer state. There are rather no heavy loops over it, but we figured out that access to structs impacts performance significantly. So we replaced Elixir’s Access by macros that construct pattern matches in the compile time. That turned out to provide significant speedup in some of our benchmarks. Not sure if that’s what you’re looking for, but I guess speeding up structs/maps themselves could give Membrane another boost.

It’s been some time, but the benchmark we had wasn’t straightforward to run, so I made another one: membrane_benchmarks/core_beamchmark at master · membraneframework-labs/membrane_benchmarks · GitHub

Hope it’s useful

Here’s some prior discussion that seems like a good starting point:

A big change worth learning about for this specific case (Elixir structs) is the new_map_lit machinery that landed in OTP 21:

https://github.com/erlang/otp/pull/1498