如果你想以秒为单位显示时间:

<?php

class debugTimer
{
    private $startTime;
    private $callsCounter;

    function __construct()
    {
        $this->startTime = microtime(true);
        $this->callsCounter = 0;
    }

    public function getTimer(): float
    {
        $timeEnd = microtime(true);
        $time = $timeEnd - $this->startTime;
        $this->callsCounter++;
        return $time;
    }

    public function getCallsNumber(): int
    {
        return $this->callsCounter;
    }
}

$timer = new debugTimer();
usleep(100);
echo '<br />\n
    ' . $timer->getTimer() . ' seconds before call #' . $timer->getCallsNumber();

usleep(100);
echo '<br />\n
    ' . $timer->getTimer() . ' seconds before call #' . $timer->getCallsNumber();

这里有一个非常简单而简短的方法

<?php
$time_start = microtime(true);
//the loop begin
//some code
//the loop end
$time_end = microtime(true);
$total_time = $time_end - $time_start;
echo $total_time; // or whatever u want to do with the time
?>

这里有一个函数，可以计时PHP代码的任何部分的执行，很像Python的timeit模块:https://gist.github.com/flaviovs/35aab0e85852e548a60a

如何使用:

include('timeit.php');
const SOME_CODE = '
        strlen("foo bar");
';
$t = timeit(SOME_CODE);
print "$t[0] loops; $t[2] per loop\n";

结果:

$ php x.php 
100000 loops; 18.08us per loop

免责声明:我是本文主旨的作者

EDIT: timeit现在是https://github.com/flaviovs/timeit上一个独立的、独立的项目

我的方法是使用hrtime，它是为性能指标而创建的，它独立于系统时间。Hrtime不受系统时间变化的影响。hrtime自PHP 7.3.0起可用

$start = hrtime(true);
sleep(5); // do something, in your case a loop
$end = hrtime(true);
$eta = $end - $start;
// convert nanoseconds to milliseconds
$eta /= 1e+6;
echo "Code block was running for $eta milliseconds";

输出:

代码块运行了5000.495206毫秒

看()。

这样会更清楚

<?php

$start = hrtime(true);

while (...) {
}

$duration = hrtime(true) - $start;
echo  $duration * 1000 ." -> microseconds". PHP_EOL; 
echo  $duration * 1000000 ." -> milliseconds". PHP_EOL; 
echo  $duration * 1e6 ." -> milliseconds". PHP_EOL; 

结果

37180000 -> microseconds
37180000000 -> milliseconds
37180000000 -> milliseconds