Decisions About Overhead

Premature optimization is all about the decisions we programmers make on overhead, before the overhead is actually witnessed in the running system. You might call it potential overhead that spins cycles on valuable resources while other code is competing for that same resource. The decisions about how to best go about minimizing overhead in software are made while its being designed. While writing code, we notice, staring at a particular function and the structures within, that this should be altered. There is no way that all this initialization work needs to happen here before the real objective of the function even starts. And so the decision to optimize, right then and there, is made. In the most straightforward cases, yes, it's worth the five or ten minutes of re-factoring and testing it takes for the obvious improvements. But even the simple ones amount to a much decision making without the relevant data.