(For more resources related to this topic, see here.)

HipHop Virtual Machine

As we can write a whole book (or two) about HHVM, we will just give the key ideas here. HHVM is a virtual machine that will translate any called PHP file into a HHVM byte code in the same spirit as the Java or .NET virtual machine. HHVM transforms your PHP code into a lower level language that is much faster to execute. Of course, the transformation time (compiling) does cost a lot of resources, therefore, HHVM is shipped with a cache mechanism similar to APC. This way, the compiled PHP files are stored and reused when the original file is requested. With HHVM, you keep the PHP flexibility and ease in writing, but you now have a performance like that of C++. Hear the words of the HHVM team at Facebook:

"HHVM (aka the HipHop Virtual Machine) is a new open-source virtual machine designed for executing programs written in PHP. HHVM uses a just-in-time compilation approach to achieve superior performance while maintaining the flexibility that PHP developers are accustomed to. To date, HHVM (and its predecessor HPHPc) has realized over a 9x increase in web request throughput and over a 5x reduction in memory consumption for Facebook compared with the Zend PHP 5.2 engine + APC.

HHVM can be run as a standalone webserver (in other words, without the Apache webserver and the "modphp" extension). HHVM can also be used together with a FastCGI-based webserver, and work is in progress to make HHVM work smoothly with Apache."

If you think this is too good to be true, you're right! Indeed, HHVM have a major drawback. HHVM was and still is focused on the needs of Facebook. Therefore, you might have a bad time trying to use your custom made PHP applications inside it. Nevertheless, this opportunity to speed up large PHP applications has been seen by talented developers who improve it, day after day, in order to support more and more framework. As our interest is in Magento, I will introduce you Daniel Sloof who is a developer from Netherland. More interestingly, Daniel has done (and still does) an amazing work at adapting HHVM for Magento.

Here are the commands to install Daniel Sloof's version of HHVM for Magento:

1. $ sudo apt-get install git

2. $ git clone https://github.com/danslo/hhvm.git

3. $ sudo chmod +x configure_ubuntu_12.04.sh

4. $ sudo ./configure_ubuntu_12.04.sh

5. $ sudo CMAKE_PREFIX_PATH=`pwd`/.. make

If you thought that the first step was long, you will be astonished by the time required to actually build HHVM. Nevertheless, the wait is definitely worth it. The following screenshot shows how your terminal will look for the next hour or so:

Create a file named hhvm.hdf under /etc/hhvm and write the following code inside:

Server {
  Port = 80
  SourceRoot = /var/www/_MAGENTO_HOME_
}

Eval {
  Jit = true
}
Log {
  Level = Error
  UseLogFile = true
  File = /var/log/hhvm/error.log
  Access {
    * {
      File = /var/log/hhvm/access.log
      Format = %h %l %u %t \"%r\" %>s %b
    }
  }
}

VirtualHost {
  * {
    Pattern = .*
    RewriteRules {
      dirindex {
        pattern = ^/(.*)/$
        to = $1/index.php
        qsa = true
      }
    }
  }
}

StaticFile {
  FilesMatch {
    * {
      pattern = .*\.(dll|exe)
      headers {
        * = Content-Disposition: attachment
      }
    }
  }
  Extensions {
    css = text/css
    gif = image/gif
    html = text/html
    jpe = image/jpeg
    jpeg = image/jpeg
    jpg = image/jpeg
    png = image/png
    tif = image/tiff
    tiff = image/tiff
    txt = text/plain
  }
}

Now, run the following command:

$ sudo ./hhvm –mode daemon –config /etc/hhvm.hdf

The hhvm executable is under hhvm/hphp/hhvm. Is all of this worth it? Here's the response:

ab -n 100 -c 5 http://192.168.0.105192.168.0.105/index.php/furniture
/livingroom.html

Server Software:        
Server Hostname:        192.168.0.105192.168.0.105
Server Port:            80

Document Path:          /index.php/furniture/living-room.html
Document Length:        35552 bytes

Concurrency Level:      5
Time taken for tests:   4.970 seconds
Requests per second:    20.12 [#/sec] (mean)
Time per request:       248.498 [ms] (mean)
Time per request:       49.700 [ms] (mean, across all concurrent requests)
Transfer rate:          707.26 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    2  12.1      0      89
Processing:   107  243  55.9    243     428
Waiting:      107  242  55.9    242     427
Total:        110  245  56.7    243     428

We literally reach a whole new world here. Indeed, our Magento instance is six times faster than after all our previous optimizations and about 20 times faster than the default Magento served by Apache. The following graph shows the performances:

Our Magento instance is now flying at lightening speed, but what are the drawbacks? Is it still as stable as before? All the optimization we did so far, are they still effective? Can we go even further? In what follows, we present a non-exhaustive list of answers:

• Fancy extensions and modules may (and will) trigger HHVM incompatibilities.

• Magento is a relatively old piece of software and combining it with a cutting edge technology such as HHVM can have some unpredictable (and undesirable) effects.

• HHVM is so complex that fixing a Magento-related bug requires a lot of skill and dedication.

• HHVM takes care of PHP, not of cache mechanisms or the accelerator we installed before. Therefore, APC, memcached, and Varnish are still running and helping to improve our performances.

• If you become addicted to performances, HHVM is now supporting Fast-CGI through Nginx and Apache. You can find out more about that at: http://www.hhvm.com/blog/1817/fastercgi-with-hhvm.

Summary

In this article, we successfully used the HipHop Virtual Machine (HHVM) from Facebook to serve Magento. This improvement optimizes our Magento performance incredibly (20 times faster), that is, the time required initially was 110 seconds while now it is less then 5 seconds.

Resources for Article:

Further resources on this subject:

• Magento: Exploring Themes [article]
• Getting Started with Magento Development [article]
• Enabling your new theme in Magento [article]