Micro-optimizing critical path performance within a Scala application can be an extremely important development task, but even after nearly three decades of the JVM’s existence, the tricks, techniques and methodologies are too often treated as a black art, understood only by a select few.

The purpose of this talk to is to peel back the curtain on some of the general patterns and ideas behind micro-optimization on the JVM. While Cats Effect IO is used as a running practical example, this is not a Cats Effect specific talk, nor even a discussion of functional programming! Instead, this talk focuses on the fundamentals of how the JVM works, how hardware works, how the Scala compiler works, and how we can exploit this knowledge when needed to write code which is dramatically faster without sacrificing functionality.