It isn't listed in the article, but I wrote about this in my blog also: <a href="http://blog.reverberate.org/2013/05/deep-wizardry-stack-unwinding.html" rel="nofollow">http://blog.reverberate.org/2013/05/deep-wizardry-stack-unwi...</a>
What's the simplified explanation how perf uses CPU performance counters to know what functions are called. I mean, what kind of book-keeping is going on that allows it to map instructions executed to symbols (functions) called?