I'm recently realized that I have built up a lot of intuition over the years for how to improve the performance of interesting applications on real systems. I follow a lot of these procedures. Recently, I've been trying to explain to others how to do this, but I've been explaining it in an ad-hoc manner, as it comes up. Turns out, Brendan Gregg has already explained it all in a systematic, digestible way.
Really brilliant stuff. Computer systems are discoverable, we can always figure out what's going on with enough patience, reasoning, a systematic approach, and the right tools. I'm glad to have a resource I can send to others, and that I can hopefully learn more from.
In my opinion, you should go ahead and do it.
It's available on Safari where I'm a subscriber, but I grabbed a copy anyway - it's not just good, but pretty damn unique in that it supplies a wide breadth while maintaining good depth of coverage.