Ideas list entry: http://www.freebsd.org/projects/ideas/#p-performancetracking
The Performance Tracker entry is meant to monitor the performance of FreeBSD itself over the development time, e.g. someone makes a change to the kernel and the tracking system is able to show the performance impact to various subsystems (microbenchmarks) or to real world applications like apache or mysql (macrobenchmarks).
ErikCederstrand has been working on this project as part of his thesis. A set of scripts were written to create disk images, and a web interface was created to interface the data. This project is now on standby and needs to be matured and updated to e.g. use the SVN repo instead of CVS. Please contact ErikCederstrand is you're interested in working on this.