PHP Profilers – A Quick summary

More an aid to memory then anything, here’s the PHP profilers I’ve recently heard about:

XDebug by Derick Rethans
The oldest and most well known profiler. Needs modification of the server’s PHP file to run. Compatible with KCachegrind/WinCacheGrind, MacCallGrind and Webgrind and remote debugging tools. Produces quite large debug files (typically 900Kb to 10Mb compare to XHProf’s 110Kb).
XHProf by Facebook Inc (available via PECL)
Large amount of information provided and allows you to “drill down” by various sections – allows comparison of “diffs” between runs to check performance enhancements. Needs modification of the server’s PHP file to run. Also compatible with the *Grind systems. Used by Facebook and Manga High’s online maths games website, but only currently runs on Linux/FreeBSD. Seems to be preferred by iBuildings (see Profiling with XHProf) which is how I originally heard about it.
PHP Quick Profiler (PQP) by Particle tree
Needs modifications to your PHP code, but does not need the server’s PHP modifying (so it can be used on shared hosting easily). Nice and bright. Used by ParticleTree on their Wufoo product.