return microtime(true) - $_SERVER["REQUEST_TIME_FLOAT"];

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。

如果你像这样格式化秒的输出，它会更漂亮:

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.

在页面底部居中打印的小脚本，在服务器调用时以微秒精度开始脚本执行。

为了不扭曲结果，并与页面中的内容100%兼容，我使用浏览器端本地javascript代码段在页面上编写结果。

//Uncomment the line below to test with 2 seconds 
//usleep(2000000);

$prec = 5; // numbers after comma
$time = number_format(microtime(true) - $_SERVER['REQUEST_TIME_FLOAT'], $prec, '.', '');
echo "<script>
    if(!tI) { 
        var tI=document.createElement('div');
        tI.style.fontSize='8px';
        tI.style.marginBottom='5px';
        tI.style.position='absolute';
        tI.style.bottom='0px';
        tI.style.textAlign='center';
        tI.style.width='98%';
        document.body.appendChild(tI);
    }
    tI.innerHTML='$time';
</script>";

另一种方法是使代码片段尽可能小，并使用样式表中的类对其进行样式化。

替换回显…;与以下部分分开: echo "<script>if(!tI){var tI=document.createElement('div');tI. classname ='ldtme';document.body.appendChild(tI);}tI. innerhtml ='$time'; 在CSS中创建并填充.ldtme{…}类。

这里列出了几种方法。但每个人都有自己的优点和缺点。而且(在我看来)所有较长的答案的可读性都很糟糕。

所以我决定把这些都放在一个答案中，这是容易使用和阅读的。

使用

$start = get_timers();
for( $i = 0; $i < 100000; $i++ ){
  // Code to check
}
$end = get_timers();
display_timer_statistics( $start, $end );

函数定义

function display_timer_statistics( $start_timers, $end_timers ){

    // Settings
    $key_width = '100px';
    $decimals = 4;
    $decimals_wallclock = $decimals;
    $decimals_request_time_float = $decimals;

    // Variables
    $start_resource_usage_timer = $start_timers[0];
    $start_wallclock = $start_timers[1];
    $end_resource_usage_timer = $end_timers[0];
    $end_wallclock = $end_timers[1];

    // # User time
    // Add seconds and microseconds for the start/end, and subtract from another
    $end_user_time_seconds = $end_resource_usage_timer["ru_utime.tv_sec"]*1000;
    $end_user_time_microseconds = intval($end_resource_usage_timer["ru_utime.tv_usec"]/1000);
    $start_user_time_seconds = $start_resource_usage_timer["ru_utime.tv_sec"]*1000;
    $start_user_time_microseconds = intval($start_resource_usage_timer["ru_utime.tv_usec"]/1000);
    $total_user_time = ($end_user_time_seconds + $end_user_time_microseconds) - ($start_user_time_seconds + $start_user_time_microseconds);

    // # System time
    // Add seconds and microseconds for the start/end, and subtract from another
    $end_system_time_seconds = $end_resource_usage_timer["ru_stime.tv_sec"]*1000;
    $end_system_time_microseconds = intval($end_resource_usage_timer["ru_stime.tv_usec"]/1000);
    $start_system_time_seconds = $start_resource_usage_timer["ru_stime.tv_sec"]*1000;
    $start_system_time_microseconds = intval($start_resource_usage_timer["ru_stime.tv_usec"]/1000);
    $total_system_time = ($end_system_time_seconds + $end_system_time_microseconds) - ($start_system_time_seconds + $start_system_time_microseconds);

    // Wallclock
    $total_wallclock_time = number_format( ( $end_wallclock - $start_wallclock), $decimals_wallclock );

    // Server request_time_float
    $request_time_float = microtime(true) - $_SERVER["REQUEST_TIME_FLOAT"];
    $request_time_float = number_format( $request_time_float, $decimals_request_time_float );

    // Print
    $span_start = "<span style='width: $key_width; display: inline-block;'>";
    $span_end = "</span>";

    $output = "# RUNTIME AND TIMERS " . PHP_EOL ;
    $output .= PHP_EOL;
    $output .= $span_start . $total_user_time . $span_end . " User time (utime)" . PHP_EOL;
    $output .= $span_start . $total_system_time . $span_end . " System time (stime)" . PHP_EOL;
    $output .= PHP_EOL;
    $output .= $span_start . $total_wallclock_time . $span_end . " Wallclock" . PHP_EOL;
    $output .= PHP_EOL;
    $output .= $span_start . $request_time_float . $span_end . " REQUEST_TIME_FLOAT" . PHP_EOL . PHP_EOL . PHP_EOL;

    echo nl2br( $output );
}

function get_timers(){
    return [ getrusage(), microtime( true ) ];
}

术语表

这些都是从PHP文档中获取的

挂钟=花了多长时间 ru =资源使用率 utime =用户使用的时间 stime =使用的系统时间 tv_sec =秒。 tv_usec =以微秒计。 电视= ??不知道

如果你需要的是挂钟时间，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) 

注意，这将包括PHP等待外部资源(如磁盘或数据库)的时间，而max_execution_time没有使用这个时间。