Advanced CodeIgniter Profiling With XHProf | Nettuts+
This tutorial explains how to install Facebook's XHProf profiler on a production server and integrate it with CodeIgniter applications using hooks to monitor real-world performance. XHProf provides hierarchical function-level profiling with minimal overhead, showing wall time, CPU usage, and memory consumption, and includes features like call graphs, run comparisons, and aggregated analysis across multiple page loads. The guide covers installation from source on Ubuntu, CodeIgniter integration setup, and interpretation of profiling results to identify bottlenecks in database calls and external service requests.