To be precise - using false gives me 0 bytes, using true gives me a rly big difference in bytes used

Thank you for this bug report. To properly diagnose the problem, we
need a short but complete example script to be able to reproduce
this bug ourselves. 

A proper reproducing script starts with ,
is max. 10-20 lines long and does not require any external 
resources such as databases, etc. If the script requires a 
database to demonstrate the issue, please make sure it creates 
all necessary tables, stored procedures etc.

Please avoid embedding huge scripts into the report.

See <https://3v4l.org/0SjGE> for expected behavior.

This problem is valid for devster's 'Ubench' script too:
---
<?php

error_reporting(-1);
ini_set('display_errors', '1');
ini_set('display_startup_errors', '1');
mb_internal_encoding('UTF-8');
mb_http_output('UTF-8');
gc_enable();

// https://github.com/devster/ubench
require_once 'src/Ubench.php';

$bench = new Ubench;
$testSum = 0;
$bench->start();
// Execute some code
for ($i = 0; $i < 1000000; $i++) { $j= $i; }
$bench->end();

// Get elapsed time and memory
echo "<br />" . $bench->getTime();
echo "<br />" . $bench->getTime(true); // elapsed microtime in float
echo "<br />" . $bench->getTime(false, '%d%s');

echo "<br />" . $bench->getMemoryPeak();
echo "<br />" . $bench->getMemoryPeak(true); // memory peak in bytes
echo "<br />" . $bench->getMemoryPeak(false, '%.3f%s');

// Returns the memory usage at the end mark
echo "<br />" . $bench->getMemoryUsage();

exit();

?>

> Tested it on 3v4l.org and the results are the same, 5.5.0-5.6.12 always win

Can you please post a link to the 3v4l.org test?

https://3v4l.org/COXWa

You have claimed

> The fix is to use at line #1 memory_get_usage(false) which
> returns 40-50 times!!! bigger memory usage (for example
> 1.6-1.8MB instead of 40-45KB)

and later corrected

> using false gives me 0 bytes, using true gives me a rly big
> difference in bytes used

However, <https://3v4l.org/COXWa> doesn't show this behavior.

UBench returns this on my setup (nothing changed):
2.00Mb
2097152
2.000Mb
2.00Mb

Yes, that is exactly what is reported on <https://3v4l.org/COXWa>
for PHP 7. However,

  2097152 / 1024 / 1024 = 2

Should I show my script for monitoring how much memory each function uses? Results are stored in SQLite database

http://wikisend.com/download/556368/metrics.db
[URL=http://wikisend.com/download/556368/metrics.db]metrics.db[/URL]