Some useful links about Xhprof.

Profiling PHP Part 1: Intro to Xhprof & Xhgui

https://blog.engineyard.com/2014/profiling-with-xhprof-xhgui-part-1

Profiling PHP Part 2: Xhgui In-Depth

https://blog.engineyard.com/2014/profiling-with-xhprof-xhgui-part-2

Benchmarking / Profiling with XHprof

http://amrsamy.com/benchmarking-profiling-xhprof/

Printscreeens from techportal.inviqa.com and amrsamy.com.