I read through this book last year, and it was a very good book. I loved the first half, and it hits on something that I tell other engineers about performance

I read through this book last year, and it was a very good book. I loved the first half, and it hits on something that I tell other engineers about performance, which is that while your performance tool will tell you the truth, it will tell you the truth about a very narrow question. That means that you should be using it as a hypothesis testing tool, which means developing the hypothesis first based on an understanding of how the computer works. I'm pretty sure it's the first half, on how to think about software to generate these hypotheses, that sells the book. However, the last third/half lost me. It primarily discusses (and advertises) the usage of one tracing tool that the author built. All performance tools, particularly the tracing tools which tend to be very heavy, have strengths and weaknesses, and you are going to need to mix your tools if you want to really understand things. It's well worth the money and the time for the first half of the book, though.