Thanks, I summarized them on: http://www.brendangregg.com/FlameGraphs/cpuflamegraphs.html . They are really helpful for seeing the big picture of CPU usage, and quantifying the contribution by different code paths.

The flamegraph code is on github (https://github.com/brendangregg/FlameGraph). There's other implementations too (see http://www.brendangregg.com/flamegraphs.html#Updates).

We're using them primarily to analyze CPU usage of the Linux and FreeBSD kernels, Java, and Node.js. We had an earlier post about the Node.js ones: http://techblog.netflix.com/2014/11/nodejs-in-flames.html