time-plugins-load.php

<?php

if ( did_action( 'muplugins_loaded' ) || ! isset( $_GET['time_plugins_load'] ) ) {
	return;
}

Time_Plugins_Load::load();

/**
 * Hijacks plugins load process and captures timing information.
 *
 * Do NOT run this unless you understand what it is doing. Probably not even then.
 */
class Time_Plugins_Load {

	protected static $start;
	protected static $stop;
	protected static $last;
	protected static $plugins_loaded;
	protected static $results = array();

	public static function load() {

		add_filter( 'option_active_plugins', array( __CLASS__, 'option_active_plugins' ) );
		add_action( 'plugins_loaded', array( __CLASS__, 'plugins_loaded' ), 20 );
		add_action( 'wp_footer', array( __CLASS__, 'footer' ) );
		add_action( 'admin_footer', array( __CLASS__, 'footer' ) );
	}

	/**
	 * @param array $active_plugins
	 *
	 * @return array
	 */
	public static function option_active_plugins( $active_plugins ) {

		remove_filter( __FUNCTION__, array( __CLASS__, __FUNCTION__, ) );
		$network_plugins = is_multisite() ? wp_get_active_network_plugins() : false;
		self::$start     = self::$last = microtime( true );

		foreach ( $active_plugins as $plugin ) {
			if ( ! validate_file( $plugin ) // $plugin must validate as file
			     && '.php' == substr( $plugin, - 4 ) // $plugin must end with '.php'
			     && file_exists( WP_PLUGIN_DIR . '/' . $plugin ) // $plugin must exist
			     // not already included as a network plugin
			     && ( ! $network_plugins || ! in_array( WP_PLUGIN_DIR . '/' . $plugin, $network_plugins ) )
			) {
				$plugin_path = WP_PLUGIN_DIR . '/' . $plugin;
				wp_register_plugin_realpath( $plugin_path );
				include_once( $plugin_path );
				$current                  = microtime( true );
				self::$results[ $plugin ] = ( $current - self::$last ) * 1000;
				self::$last               = $current;
			}
		}

		self::$stop = microtime( true );

		return array();
	}

	public static function plugins_loaded() {

		self::$plugins_loaded = microtime( true );
	}

	public static function footer() {

		if ( ! current_user_can( 'manage_options' ) ) {
			return;
		}

		echo '<pre>';
		print_r( self::$results );
		echo '<br />';
		print_r( 'File load total (ms): ' . array_sum( self::$results ) );
		echo '<br />';
		print_r( 'Start to plugins_loaded end (ms): ' . ( self::$plugins_loaded - self::$start ) * 1000 );
		echo '</pre>';
	}
}