Modern PHP

Chapter 12. HHVM and Hack

Think what you will about the Facebook application, but I have nothing but praise for the brilliant folks working at Facebook. Facebook Open Source has developed several important projects in the last few years, two of which have had significant impact in the PHP community.

The first initiative is HHVM, or the Hip Hop Virtual Machine. This alternative PHP engine was released in October 2013. Its just-in-time (JIT) compiler provides performance many times better than PHP-FPM. In fact, WP Engine recently migrated to HHVM and realized 3.9x faster custom Wordpress installations. MediaWiki also transitioned to HHVM, and it has realized drastic improvements in both response times and throughput.

The second initiative is Hack, a new server-side language that is a modification of the PHP language. Hack is mostly backward-compatible with PHP code, although it extends the PHP language with strict typing, new data structures, and a real-time type checking server. That being said, Hack’s own developers prefer to call Hack a dialect of PHP and not a new language.

HHVM

Since 1994, if you said PHP interpreter you meant the Zend Engine. The Zend Engine was PHP. It was the one and only PHP interpreter. Then Mark Zuckerberg came along and created this little thing called Thefacebook on February 4, 2004. Mr. Zuckerberg and his growing company wrote the Facebook application predominantly with PHP because the language is easy to learn and simple to deploy. The PHP language ...