mysql - Find out where your PHP code is slowing down (Performance Issue)

Question

Here's my first question at SO.

I have a internal application for my company which I've been recently ask to maintain. The applications is built in PHP and its fairly well coded (OO, DB Abstraction, Smarty) nothing WTF-ish.

The problem is the applications is very slow.

How do I go about finding out what's slowing the application down? I've optimized the code to make very few DB queries, so I know that it is the PHP code which is taking a while to execute. I need to get some tools which can help me with this and need to devise a strategy for checking my code.

I can do the checking/strategy work myself, but I need more PHP tools to figure out where my app is crapping up.

Thoughts?

Answer 1

I've used XDebug profiling recently in a similiar situation. It outputs a full profile report that can be read with many common profiling apps ( Can't give you a list though, I just used the one that came with slackware ).