Improve the real or perceived speed of the site, or monitor performance metrics.
You may be more interested in the Profiling module.
Role memory limit is a small module that allow you to set php_memory_limit per role and command line usage (drush).
A cache plugin for Panels (and other CTools displays) that is aware of content changes.
This module was put together in order to provide access to the status of current Hudson builds without ssh tunneling.
This module provides a mongodb storage backend for webform submissions.
A set of performance testing scenarios for Commerce Kickstart.