PHP code runs performance tests

function xn_start(){
    global $xn_start_time;
    global $xn_start_memory;
    /**
     * 代码性能测试代码
     */
    $xn_start_memory = memory_get_usage();                 //开始内存
    $xn_start_time = microtime(true);
}


function xn_end(){
    global $xn_start_time;
    global $xn_start_memory;
    echo '开始内存:' . $xn_start_memory . '<br>';

    $end_time = microtime(true);                        //获取程序执行结束的时间
    $run_time = ($end_time - $xn_start_time);       //计算差值 秒
    echo "[页面执行时间：{$run_time}]秒<br>";
    $end_memory = memory_get_usage();
    echo '运行后内存：'. $end_memory . '<br>';

    echo '使用的内存:' . ($end_memory - $xn_start_memory) . '<br>';
    echo '回到正常内存：'.memory_get_usage();


    die;
}

Use
performed at the beginning of the code xn_start ();
end of code execution xn_end ();

Output of content:

Memory start: 1153552
Seconds: [.02082896232605 Execution Time]
after running out of memory: 1344856
memory usage: 191 304
back to normal memory: 1344856