For those not following the PHP development. We backported the DTraces probes from the abandoned PHP 6.0 branch, back to the new trunk PHP 5.3.99-dev. It is called 5.3.99 because the PHP dev community has not decided yet on a version number (5.4 or 6.0). To compile PHP with DTrace, on Solaris or Mac OS do: $ svn co http://svn.php.net/repository/php/php-src/trunk php $ cd php $ ./buildconf --force