A long time ago I made "The complete guide to rails performance" by Nate Perkobec. It's not free but it really taught my a lot about on the ways to achieve very

A long time ago I made "The complete guide to rails performance" by Nate Perkobec. It's not free but it really taught my a lot about on the ways to achieve very good performance with Ruby and Rails. Does anybody have any good resources on how to achieve better performance with ruby and something like async, concurrent ruby, threadpools and forking?