我发布了一个可以复制的奇怪行为(至少在 apache2+php5 上)。
我不知道我是否做错了，但让我解释一下我试图实现的目标。

我需要发送大 block 的二进制数据(比如 30)并在最后分析平均 Kbit/s:

我总结每个 block 的输出时间，每个 block 的大小，并在最后执行我的 Kbit/s 计算。

    <?php

// build my binary chunk
$var= '';
$o=10000;
while($o--)
{
    $var.= pack('N', 85985);
}

// get the size, prepare the memory.
$size = strlen($var);
$tt_sent = 0;
$tt_time = 0;

// I send my chunk 30 times
for ($i = 0; $i < 30; $i++)
{
    // start time
    $t = microtime(true);
    echo $var."\n";
    ob_flush();
    flush();
    $e = microtime(true);
    // end time
    // the difference should reprenent what it takes to the server to 
    // transmit chunk to client right ?

    // add this chuck bench to the total
    $tt_time += round($e-$t,4);
    $tt_sent += $size;
}

// total result
echo "\n total: ".(($tt_sent*8)/($tt_time)/1024)."\n";

?>

    <?php

// build my binary chunk
$var= '';
$o=10000;
while($o--)
{
    $var.= pack('N', 85985);
}

// get the size, prepare the memory.
$size = strlen($var);
$tt_sent = 0;
$tt_time = 0;

// I send my chunk 30 times
for ($i = 0; $i < 30; $i++)
{
    // start time
    $t = microtime(true);
    echo $var."\n";
    ob_flush();
    flush();
    $e = microtime(true);
    // end time
    // the difference should reprenent what it takes to the server to 
    // transmit chunk to client right ?

    // add this chuck bench to the total
    $tt_time += round($e-$t,4);
    $tt_sent += $size;

    usleep(1000000);
}

// total result
echo "\n total: ".(($tt_sent*8)/($tt_time)/1024)."\n";

?>

最佳答案

我不确定这些测试的确定性，但我觉得这很有趣。在我的盒子上，我平均约为 170000 kb/s .从一个联网的盒子，这个数字上升到大约 280000 kb/s .我想我们必须假设 microtime(true) 是相当准确的，即使我读到它依赖于操作系统。您使用的是基于 Linux 的系统吗？真正的问题是我们如何计算 1 秒内传输的千比特？我尝试预测 1 秒内可以发送多少 block ，然后存储计算的 Kb/s 以在最后进行平均。我在flush() 之前添加了sleep(1)，这导致预期的kb/s 为负。

感觉有些不对劲，我很想知道您是否改进了测试方法。祝你好运!

<?php
// build my binary chunk
$var= '';
$o=10000;

//Alternative to get actual bytes
$m1 = memory_get_usage();
while($o--)
{
    $var.= pack('N', 85985);
}
$m2 = memory_get_usage();

//Your size estimate
$size = strlen($var);

//Calculate alternative bytes
$bytes = ($m2 - $m1); //40108

//Convert to Kilobytes 1 Kilobyte = 1024 bytes
$kilobytes = $size/1024;

//Convert to Kilobits 1 byte = 8 bits
$kilobits = $kilobytes * 8;

//Display our data for the record
echo "<pre>size: $size</pre>";
echo "<pre>bytes: $bytes</pre>";
echo "<pre>kilobytes: $kilobytes</pre>";
echo "<pre>kilobits: $kilobits</pre>";
echo "<hr />";

//The test count
$count = 100;

//Initialize total kb/s variable
$total = 0;

for ($i = 0; $i < $count; $i++)
{
    // Start Time
    $start = microtime(true);

    // Utilize html comment to prevent browser from parsing
    echo "<!-- $var -->";

    // End Time
    $end = microtime(true);

    // Seconds it took to flush binary chunk
    $seconds = $end - $start;

    // Calculate how many chunks we can send in 1 second
    $chunks = (1/$seconds);

    // Calculate the kilobits per second
    $kbs = $chunks * $kilobits;

    // Store the kbs and we'll average all of them out of the loop
    $total += $kbs;
}

//Process the average (data generation) kilobits per second
$average = $total/$count;

echo "<h4>Average kbit/s: $average</h4>";

关于PHP 输出缓冲区基准测试(与 usleep 一起使用时微时间不准确？)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/5730996/