Finding the Four Month Bug: A Debugging Story

Excellent investigation into the "why" of a performance problem. All too often I can get to the bottom of a "what" of a performance problem, but answering "why" can be an entirely different ball-game.

Running this all the way to the ground must have felt so satisfying.

I really like good debugging stories; written well, they're like a very short mystery story, in which I get to follow the thought process and watch the bug being cornered and identified, and ultimately it goes in my personal arsenal of things to think about in the future if I'm ever in a similar situation.

Sadly, this one is ruined by having the answer stuck in the first paragraph with a great big "TL;DR" in it, so even if I read the whole thing now, I already know the answer which colours my thinking the whole way through. What a disappointment.

It's even got the word "story" in the title.

I second the recommendation of Debugging by Agans. It was recommended to me by one of the best debugging people at Apple, and the approaches it outlines have served me well in the years since.