RubyConf 2016 - Diving into the Details with DTrace by Colin Jones "Argh, why is this so slow?!" We've all asked questions like this without getting satisfying answers. And so we slog along, finding workarounds and architecting around the slow bits. But what if we had a friend who could see things we can't? Someone who could say whether our guesses were right, and what to look at next? DTrace is that friend, and it's here to help! In this talk, I'll show you how DTrace can answer incredibly general and specific questions about systems performance, and help us to generate new ones. Along the way, we'll see that it's easier to use than you might think!