Performance problem on require, require_once, include php statements #493

Hi all,
I'm experimenting bad performance and the problem seems to be when calling require, require_once, include statements.

Here's a very simple file test.php I used to test the problem. The file simply load 3 files test1.php, test2.php and test3.php.

<?php
$start = microtime(true);
require('./test1.php');
$stop = microtime(true);
echo "require: " . ($stop - $start) . '<br>';

$start = microtime(true);
require_once('./test2.php');
$stop = microtime(true);
echo "require_once: " . ($stop - $start) . '<br>';

$start = microtime(true);
include('./test3.php');
$stop = microtime(true);
echo "include: " . ($stop - $start) . '<br>';

Files test1.php, test2.php and test3.php are as follow:

<?php
echo 1; // 2 and 3 in the corrisponding file

When I call test.php from the container (using the image php:7.0-apache), the response time is 10x worst than when I execute the same simple code directly from the host (same apache and same php7).

I'm using Debian 8 also for the Host and Docker Cloud for orchestration.
Here's the output of "docker info":
Containers: 51
Running: 16
Paused: 0
Stopped: 35
Images: 388
Server Version: 1.11.2-cs5
Storage Driver: aufs
Root Dir: /var/lib/docker/aufs
Backing Filesystem: extfs
Dirs: 839
Dirperm1 Supported: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge null host weavemesh
Kernel Version: 3.16.0-4-amd64
Operating System: Debian GNU/Linux 8 (jessie)
OSType: linux
Architecture: x86_64
CPUs: 4
Total Memory: 7.789 GiB
Name: xxxxxxx
ID: 2PC2:2IGQ:KT26:O4KM:RFID:HUWW:Y2FO:LYSK:MNZR:KXKY:OPFO:G2CX
Docker Root Dir: /var/lib/docker
Debug mode (client): false
Debug mode (server): false
Username: xxxxxxxxxx
Registry: https://index.docker.io/v1/
WARNING: No memory limit support
WARNING: No swap limit support
WARNING: No kernel memory limit support
WARNING: No oom kill disable support
WARNING: No cpu cfs quota support
WARNING: No cpu cfs period support