PHP必须跟踪特定脚本使用的CPU时间，以强制执行max_execution_time限制。

有没有办法在脚本中访问此内容？我想在测试中包括一些日志记录，以了解实际PHP中的CPU消耗了多少（脚本坐着并等待数据库时，时间没有增加）。

我正在使用Linux机器。

在unixoid系统上（以及在Windows上的php 7+中），您可以使用getrusage，例如：

// Script start
$rustart = getrusage();

// Code ...

// Script end
function rutime($ru, $rus, $index) {
    return ($ru["ru_$index.tv_sec"]*1000 + intval($ru["ru_$index.tv_usec"]/1000))
     -  ($rus["ru_$index.tv_sec"]*1000 + intval($rus["ru_$index.tv_usec"]/1000));
}

$ru = getrusage();
echo "This process used " . rutime($ru, $rustart, "utime") .
    " ms for its computations\n";
echo "It spent " . rutime($ru, $rustart, "stime") .
    " ms in system calls\n";

请注意，如果您为每个测试生成一个php实例，则无需计算差异。

如果您只需要时钟时间而不是CPU执行时间，那么计算起来很简单：

//place this before any script you want to calculate time
$time_start = microtime(true); 

//sample script
for($i=0; $i<1000; $i++){
 //do anything
}

$time_end = microtime(true);

//dividing with 60 will give the execution time in minutes otherwise seconds
$execution_time = ($time_end - $time_start)/60;

//execution time of the script
echo '<b>Total Execution Time:</b> '.$execution_time.' Mins';
// if you get weird results, use number_format((float) $execution_time, 10) 

请注意，这将包括PHP等待外部资源（例如磁盘或数据库）等待的时间，该时间未用于max_execution_time。

talal7860的答案的短版

<?php
// At start of script
$time_start = microtime(true); 

// Anywhere else in the script
echo 'Total execution time in seconds: ' . (microtime(true) - $time_start);

如前所述，这是“时钟时间”而不是“ cpu时间”

最简单的方法：

<?php

$time1 = microtime(true);

//script code
//...

$time2 = microtime(true);
echo 'script execution time: ' . ($time2 - $time1); //value in seconds

<?php
// Randomize sleeping time
usleep(mt_rand(100, 10000));

// As of PHP 5.4.0, REQUEST_TIME_FLOAT is available in the $_SERVER superglobal array.
// It contains the timestamp of the start of the request with microsecond precision.
$time = microtime(true) - $_SERVER["REQUEST_TIME_FLOAT"];

echo "Did nothing in $time seconds\n";
?>

我从phihag答案中创建了一个ExecutionTime类，您可以直接使用它：

class ExecutionTime
{
     private $startTime;
     private $endTime;

     public function start(){
         $this->startTime = getrusage();
     }

     public function end(){
         $this->endTime = getrusage();
     }

     private function runTime($ru, $rus, $index) {
         return ($ru["ru_$index.tv_sec"]*1000 + intval($ru["ru_$index.tv_usec"]/1000))
     -  ($rus["ru_$index.tv_sec"]*1000 + intval($rus["ru_$index.tv_usec"]/1000));
     }    

     public function __toString(){
         return "This process used " . $this->runTime($this->endTime, $this->startTime, "utime") .
        " ms for its computations\nIt spent " . $this->runTime($this->endTime, $this->startTime, "stime") .
        " ms in system calls\n";
     }
 }

用法：

$executionTime = new ExecutionTime();
$executionTime->start();
// code
$executionTime->end();
echo $executionTime;

注意：在PHP 5中，getrusage函数仅在Unix-oid系统中起作用。从PHP 7开始，它也可以在Windows上运行。

developerfusion.com上的Gringod给出了很好的答案：

<!-- put this at the top of the page --> 
<?php 
   $mtime = microtime(); 
   $mtime = explode(" ",$mtime); 
   $mtime = $mtime[1] + $mtime[0]; 
   $starttime = $mtime; 
;?> 

<!-- put other code and html in here -->


<!-- put this code at the bottom of the page -->
<?php 
   $mtime = microtime(); 
   $mtime = explode(" ",$mtime); 
   $mtime = $mtime[1] + $mtime[0]; 
   $endtime = $mtime; 
   $totaltime = ($endtime - $starttime); 
   echo "This page was created in ".$totaltime." seconds"; 
;?>

从（http://www.developerfusion.com/code/2058/determine-execution-time-in-php/）

如果将秒输出格式如下，它将变得更漂亮：

echo "Process took ". number_format(microtime(true) - $start, 2). " seconds.";

将打印

Process took 6.45 seconds.

这比

Process took 6.4518549156189 seconds.

最便宜，最肮脏的方法是简单microtime()地在要基准测试的代码中进行调用。在数据库查询之前和之后立即执行此操作，很容易从脚本执行时间的其余时间中删除这些持续时间。

提示：您的PHP执行时间很少会导致脚本超时。如果脚本超时，则几乎总是要调用外部资源。

PHP microtime文档：http : //us.php.net/microtime

我认为您应该看看xdebug。概要分析选项将使您在了解许多与过程相关的项目上有一个良好的开端。

http://www.xdebug.org/

要显示分钟和秒，您可以使用：

    $startTime = microtime(true);
    $endTime = microtime(true);
    $diff = round($endTime - $startTime);
    $minutes = floor($diff / 60); //only minutes
    $seconds = $diff % 60;//remaining seconds, using modulo operator
    echo "script execution time: minutes:$minutes, seconds:$seconds"; //value in seconds

我编写了一个检查剩余执行时间的函数。

警告： Windows和Linux平台上的执行时间计数不同。

/**
 * Check if more that `$miliseconds` ms remains
 * to error `PHP Fatal error:  Maximum execution time exceeded`
 * 
 * @param int $miliseconds
 * @return bool
 */
function isRemainingMaxExecutionTimeBiggerThan($miliseconds = 5000) {
    $max_execution_time = ini_get('max_execution_time');
    if ($max_execution_time === 0) {
        // No script time limitation
        return true;
    }
    if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
        // On Windows: The real time is measured.
        $spendMiliseconds = (microtime(true) - $_SERVER["REQUEST_TIME_FLOAT"]) * 1000;
    } else {
        // On Linux: Any time spent on activity that happens outside the execution
        //           of the script such as system calls using system(), stream operations
        //           database queries, etc. is not included.
        //           @see http://php.net/manual/en/function.set-time-limit.php
        $resourceUsages = getrusage();
        $spendMiliseconds = $resourceUsages['ru_utime.tv_sec'] * 1000 + $resourceUsages['ru_utime.tv_usec'] / 1000;
    }
    $remainingMiliseconds = $max_execution_time * 1000 - $spendMiliseconds;
    return ($remainingMiliseconds >= $miliseconds);
}

使用：

while (true) {
    // so something

    if (!isRemainingMaxExecutionTimeBiggerThan(5000)) {
        // Time to die.
        // Safely close DB and done the iteration.
    }
}

您可能只想知道脚本各部分的执行时间。对部分或整个脚本进行计时的最灵活方法是创建3个简单函数（此处提供了过程代码，但您可以通过在其周围放置class timer {}并进行一些调整来将其变成一个类）。此代码有效，只需复制并粘贴并运行：

$tstart = 0;
$tend = 0;

function timer_starts()
{
global $tstart;

$tstart=microtime(true); ;

}

function timer_ends()
{
global $tend;

$tend=microtime(true); ;

}

function timer_calc()
{
global $tstart,$tend;

return (round($tend - $tstart,2));
}

timer_starts();
file_get_contents('http://google.com');
timer_ends();
print('It took '.timer_calc().' seconds to retrieve the google page');

$_SERVER['REQUEST_TIME']

也去看看。即

...
// your codes running
...
echo (time() - $_SERVER['REQUEST_TIME']);

或者，您可以将这一行放入代码块中并检查php日志，对于真正缓慢的功能，它非常有用：

trigger_error("Task done at ". strftime('%H:%m:%S', time()), E_USER_NOTICE); 

要使用XDebug + Cachegrind进行认真的调试，请参阅https://blog.nexcess.net/2011/01/29/diagnosing-slow-php-execution-with-xdebug-and-kcachegrind/

为了进一步扩展Hamid的答案，我编写了一个可以重复启动和停止的帮助程序类（用于在循环内进行概要分析）。

   class ExecutionTime
   {
      private $startTime;
      private $endTime;
      private $compTime = 0;
      private $sysTime = 0;

      public function Start(){
         $this->startTime = getrusage();
      }

      public function End(){
         $this->endTime = getrusage();
         $this->compTime += $this->runTime($this->endTime, $this->startTime, "utime");
         $this->systemTime += $this->runTime($this->endTime, $this->startTime, "stime");
      }

      private function runTime($ru, $rus, $index) {
         return ($ru["ru_$index.tv_sec"]*1000 + intval($ru["ru_$index.tv_usec"]/1000))
         -  ($rus["ru_$index.tv_sec"]*1000 + intval($rus["ru_$index.tv_usec"]/1000));
      }

      public function __toString(){
         return "This process used " . $this->compTime . " ms for its computations\n" .
                "It spent " . $this->systemTime . " ms in system calls\n";
      }
   }

返回microtime（true）-$ _SERVER [“ REQUEST_TIME_FLOAT”];