你可以使用microtime 计算差异:

You can use microtime and calculate the difference:

$time_pre = microtime(true);
exec(...);
$time_post = microtime(true);
$exec_time = $time_post - $time_pre;

以下是 microtime 的 PHP 文档:http://php.net/manual/en/function.microtime.php

Here's the PHP docs for microtime: http://php.net/manual/en/function.microtime.php