INSTALL

-- This document is as yet incomplete --

0. Install the XHProf extension for PHP
1. Extract everything into a directory somewhere
2. Create a symlink from xhprof_runs.php to the xprof_runs_<database of your choice>.php directory in xhprof_lib\utils\
3. Create the table required for xhprof_runs.php, there should be sample instructions inside that document alongside
the constructor.
4. Edit xhprof_lib/config.php with your database credentials, control IPs, and other fun stuff
5. Load up index.php, ensure happiness
6. Edit the virtual host configuration for the site you'd like to profile to 
php_admin_value auto_prepend_file="<path>/external/header.php"
php_admin_value auto_append_file="<path>/external/footer.php"
7. Bump your server, hope for the best
8. Hitting a file with ?_profile=1 should profile the page and give you a link at the bottom

There's a decent blog post on setting this up, as well as tips on how to use it at: http://phpadvent.org/2010/profiling-with-xhgui-by-paul-reinheimer