我写了一个检查剩余执行时间的函数。

警告:执行时间计数在Windows和Linux平台上是不同的。

/**
 * 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.
    }
}

我创建了一个ExecutionTime类的phihag答案，你可以使用开箱即用:

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函数只适用于类unix系统。从PHP 7开始，它也可以在Windows上工作。

developerfusion.com的Gringod给出了一个很好的答案:

<!-- 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/)

我认为您应该看看xdebug。分析选项将为您了解许多与流程相关的项目提供一个良好的开端。

http://www.xdebug.org/

在unix系统上(在Windows上的php 7+中也是如此)，你可以使用getrusage，像这样:

// 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";

注意，如果要为每个测试生成一个php实例，则不需要计算差异。

talal7860回答的简短版本

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

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

正如所指出的，这是“wallclock时间”而不是“cpu时间”