Kirk Pepperdine on Performance Tuning and Cloud Computing | Java.net
Early in the interview, Janice asked Kirk: "What misconceptions do you encounter among developers about performance tuning?"
Kirk's response wasn't what I would have expected. He answered:
Here's a major one: All developers believe they are good at performance tuning. They might be very good at writing performance code, and they might be very good at coding, but generally I find that most developers are not very good at performance tuning.
How can this be?
When developers are put in situations where they are asked to performance tune, they typically look at code and take some action. But they invariably forget the dynamics of the system. If you don't include the dynamics of the system when you performance tune or if you think you understand the dynamics of the system and guess wildly wrong - which is quite often the case - you end up doing the wrong thing, which frequently happens.
Kirk notes that software testers tend to be more successful when it comes to performance tuning than most developers, because they are more accustomed to working within a defined process.