fsockopen,fopen,file_get_contents 为啥fsockopen是最快的呢

fsockopen,fopen,file_get_contents 为什么fsockopen是最快的呢
query_time_class.inc.php

<?php<br />    class query_time_class{<br />        <br />        var $start_time;<br />        var $end_time;<br />        <br />        function query_start(){<br />            <br />            $this->start_time = 0;<br />            $this->end_time   = 0;<br />            $this->start_time = $this->get_cur_sec();<br />            <br />        }<br />        <br />        function query_end(){<br />            <br />            $this->end_time = $this->get_cur_sec();<br />            <br />        }<br />        <br />        function get_query_time(){<br />            <br />            $time = floatval($this->end_time - $this->start_time);<br />            $time = sprintf("%01.4f",$time);<br />            return $time;<br />            <br />        }<br />        <br />        function get_cur_sec(){<br />            <br />            list($msec,$sec) = explode(" ", microtime());<br />            $msec            = floatval($msec);<br />            $sec             = floatval($sec+$msec);<br />            return $sec;<br />            <br />        }<br />        function out_put(){<br />            <br />            $time   = $this->get_query_time();<br />            $output = "执行时间 {$time} 秒";<br />            echo $output;<br />            <br />        }<br />        <br />    } <br /><br /><br />?>

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