Display Timestamps when Debugging WordPress for Speed

do_action_timestamp.php

<?php

//----------------------------------------------------------------------------------------------
// Display Timestamps when Debugging WordPress for Speed
//----------------------------------------------------------------------------------------------
// 
// A GIST by Martin Adamko, martin(at)attitude.sk
// 
// It happens from time to time you need to know where the crack is. I assume you are willing
// to kick in the WP source and put some 'echos' in there. But WP has 2 functions to help you
// with that already: timer_start() and timer_stop(). Why not to use it?
// 
//----------------------------------------------------------------------------------------------
// 
// Some original core rewriting is needed, but you can do it again even after upgrading very
// easily. This piece is provided as is, without any waranty. Use at your own risk.
// 
// HOW TO USE IT:
// 
// 1/ Find file {WP Instalation Root}/wp-includes/plugin.php
// 2/ Locate functions do_action() and do_action_ref_array() in the source
//    line +-360: function do_action($tag, $args = '') {...
//    line +-450: function do_action_ref_array($tag, $args) {...
// 3/ Paste the code below just after the opening curly bracket and before the globals:
// 
//----------------------------------------------------------------------------------------------
// Start copy here:

if( WP_DEBUG) { // Make sure we are debugging
	global $last_time, $last_time_micro; // See the last values
	
	// First time we set 0
	$last_time = (!isset( $last_time) ) ? 0 : $last_time;
	// Get time since start, see the WP Codex for details.
	$new_time = timer_stop();
	
	// I care only for major delays and the shutdown time
	if($new_time-$last_time_micro > 0.1 || $tag == 'shutdown') {
		// It fires as a HTML comment so should not mess the site
		echo "<!--delta: ".($new_time-$last_time)."; tag: $tag; time: ".$new_time."-->\n";
		// Rememter this major delay time as the new big point
		$last_time=$new_time;
	}
	// Just remember this time
	$last_time_micro = $new_time;
}

// Done.
//----------------------------------------------------------------------------------------------
// Leave a comment if you have any questions.
//----------------------------------------------------------------------------------------------

// ?>