public static function display_blocking_page() {
        global $PERF;

        $page = self::get_locked_page_at($PERF->sessionlock['start']);
        $output = "Script ".me()." was blocked for ";
        $output .= number_format($PERF->sessionlock['wait'], 3);
        if ($page != null) {
            $output .= " second(s) by script: ";
            $output .= $page['url'];
        } else {
            $output .= " second(s) by an unknown script.";
        }

        return $output;
    }