Benchmarking PHP page load times

Question

How could I measure the time taken to load a page (with various different PHP statements)?

Somewhat like the stats available here - http://talks.php.net/show/drupal08/24

Answer 1

The Output in that presentation seem to be copied from Siege (http://www.joedog.org/index/siege-home).

Another quite useful tool for "real world" performance testing your whole application stack is Firebug (http://getfirebug.com/) and YSlow (http://developer.yahoo.com/yslow/)