Call analysis
Call profiling and analysis tells you where your code is really spending its time, instead of where you think it is, which leads to both performance improvements and a higher quality architecture for your code.
A client came to me with CPU spike causing traffic delays. The sysadmin hooked up xdebug and profiled some stuff during these spikes, but they couldn't make heads or tails of it. Your software allowed me to bill a couple hours I wouldn't have -- so the software paid for itself as soon as it downloaded.
Grinder
Sit back while Grinder monitors and filters through your site for new profile data, automatically analysing in background, and presenting the results before you think the request is even completed.
Compatibility
Works with MAMP out of the box*. Requires any version of xdebug for generating profile data.
* After installing MAMP, go into the preferences window, the PHP tab and disable the Zend Optimizer. Then open /Applications/MAMP/conf/php5/php.ini, find the line \';zend_extension="/Applications/MAMP/bin/php5/lib/php/extensions/no-debug-non-zts-20060613/xdebug.so"\' and remove the starting \';\'. Save and restart servers. You\'re done. By default, MAMP will use /tmp/cachegrind.* as the filepath for profiling data. This is also the default in grinder for MacCallGrind.