Question

In my project I use my own framework, and sure I use my own logging time and memory. Now I found that my memory usage statistics different in different environments. Here I mean two environment: local Windows and production VPS Fedora.

Here is the logger view:

<style>
    div.lt-timer {
        opacity: 0.5; background: #FFF; color: #777; border-radius: 5px; border: 1px solid #CCC;
        font-size: 0.85em; position: fixed; max-width: 300px; max-height: 600px; overflow: auto;
        bottom: 10px; right: 10px; padding: 5px;
    }
    div.lt-timer h4 { text-align: center; font-weight: 700; }
</style>
<div class="lt-timer">
    <h4><?php echo $timer->getName(); ?></h4>
    <?php echo nl2br(implode('', $timer->getPoints())); ?>
    <h4>Total used memory: <?php echo round(memory_get_usage() / 1024, 2); ?> KB</h4>
</div>

Everything is fine, except this line, which gives difference:

<h4>Total used memory: <?php echo round(memory_get_usage() / 1024, 2); ?> KB</h4>

On Windows I’ve got about 598 KB, but for the same request I have 2976 KB on VPS Fedora.

I’ve also have tested for same test.php files containing this:

<?php
    $a = 999;
    $b = 999;
    $c = 999;

    echo memory_get_usage();
?>

And that’s what I got:

Local machine (Windows): 329280
Production machine (Fedora): 633392

Does eAccelerator or xCache could affect this statistics? Or where I’m wrong?

Answer 1

As of PHP 5.2.x, the memory_get_usage() function has a parameter.

 int memory_get_usage  ([ bool $real_usage = false  ] )

According to php.net, $real_usage is:

Set this to TRUE to get the real size of memory allocated from system. If not set or FALSE only the memory used by emalloc() is reported.

Additionally some sources say PHP needs to be loaded as a CGI in Apache to correctly get memory usage by process id using getmypid().