function timer_start() {
        global $timestart;
        $mtime     = explode( ' ', microtime() );
        $timestart = $mtime[1] + $mtime[0];
        return true;
    }
    timer_start();
    function timer_stop( $display = 0, $precision = 3) {
        global $timestart, $timeend;
        $mtime     = explode( ' ', microtime() );
        $timeend   = $mtime[1] + $mtime[0];
        $timetotal = number_format( $timeend - $timestart, $precision );
        $r         = $timetotal < 1 ? $timetotal * 1000 . " ms" : $timetotal . " s";
        if ( $display ) {
            echo $r;
        }
        return $r;
    }

调用代码

<?php echo timer_stop();?>