I used to work for this little web development agency in Poole who do lots of work using an eCommerce solution called Magento.
Magento is a very extensible (read as doesn’t do what you want but you can add it in) LAMP stack application.
Due to the extendable nature of Magento, and its general lack of performance, I spent lots of time making it go faster.
The main tool I used for this is XHProf, a PHP profiler written by some folks at Facebook.
It’s pretty neat, install a PHP module, add a couple of lines into your php application ( index.php for Magento ) and you’ll get some lovely .xhprof output files.
This is where the issue arises as these files can only be viewed using the XHProf gui, which works via web pages and requires another Apache vhost unless you store it inside your web app :/
What I could never find was an online service that I could throw my generated files at, UNTIL NOW!!!
No it’s not pretty, but it goes, enjoy.