This document discusses using HHVM as a drop-in replacement for PHP to speed up Magento webshops. HHVM is a just-in-time compiler created by Facebook that translates PHP to bytecode and machine code, resulting in performance improvements of 5-10 times over regular PHP in some cases. While HHVM is not fully compatible with Magento, over 100 fixes have been contributed to HHVM to address Magento-related bugs. Benchmarks show significant improvements in response times and higher transaction rates when using HHVM with Magento compared to PHP.

1. Magento on
HHVM
Speeding up your webshop with a drop-in PHP
replacement.

2. Daniel Sloof
https://twitter.com/daniel_sloof
https://github.com/danslo
dsloof@engineyard.com

3. Some background
Specification
Ruby Language
JRuby Rubinius IronRuby
Java Language
Oracle Harmony Dalvik
Implementation
Sensible Language Design
Zend PHP
PHP Language
Zend PHP HHVM
PHP

4. What is HHVM?
● HipHop Virtual Machine
● Created by engineers at Facebook
● Essentially a reimplementation of PHP
● Originally translated PHP to C++, now
translates PHP to bytecode
● Just-in-time compiler, turning generated
bytecode into machine code
● In some cases 5 to 10 times faster than
regular PHP

5. Bytecode compilation
● PHP5 style bytecode Yes
Modified? Invalidate cache
Compile to
Bytecode
Run Bytecode
No
execution
● APC-like caching of
bytecode
● Performance is quite
similar to Zend PHP

6. Just In Time Compiler
Modified?
Have
Native?
Hot?
Invalidate Cache
Compile to
Bytecode
Compile to Native Run Bytecode
Run Native
No
No
Yes
Yes
Yes No

7. What was the problem?
● HHVM not entirely compatible with PHP
● Magento’s PHP triggering many of these
incompatibilities
● Choosing between
○ Forking Magento to work around HHVM
○ Fixing issues within the extensive HHVM C++
codebase

8. Resulted in... fixing HHVM
● Already over 100 commits fixing Magento
related HHVM bugs;
○ SimpleXML (majority of bugfixes)
○ sessions
○ number_format
○ __get and __set
○ many more...
● All of these patches already merged back
into the official (github) repository
● Still actively involved and committed to make
HHVM a good place for Magento

9. Resulted in... fixing HHVM
Activity for the HHVM project on github in June
“Of the top 15 contributors, only 9 are facebook employees.”

10. Important configuration
● hhvm.enable_zend_sorting = 1
○ PHP user sorting “If two members compare as
equal, their relative order in the sorted array is
undefined.”
○ HHVM implements a faster sorting algorithm that
has a different (undefined) order.
○ Magento relies on this undefined behavior.
● hhvm.enable_obj_destruct_call = 1
○ HHVM by default does not call destructors for
objects that are alive at the end of the request.
○ Magento Connect Downloader uses object
destructors to send output to the browser.

11. What that means for Magento...
● Community and Enterprise Editions running
stable.
● Passes near 100% of the Test Automation
Framework.
● Large boost in improvement.
● Works with FastCGI, so keep most of your
current web-configuration, rewrites, etc.

12. Benchmarks
Before we go to the results...
● Magento 1.9 with sample data
● Standard nginx / php-fpm / percona stack
(with PHP 5.5 opcode cache)
● Standard HHVM configuration (repo-authoritative
mode disabled, JIT enabled)
● Tool of choice: siege

13. Benchmarks: Response time
Average across 50 requests

14. Benchmarks: Transaction rate
While increasing siege concurrency until avg.
response time ~2 seconds

15. Benchmarks: Other

16. What about
<insert caching solution here>?
● HHVM does not get in the way
● Dynamic content still needs to be generated
● Replaces PHP - not Varnish, Redis, FPC,
Block Cache, etc.
● As long as you are burning CPU cycles
(always), you will benefit from HHVM
● Think about speeding up indexing, order
placement, routing, etc.

17. What about PHPNG / PHP7?
● Better performance than PHP5.5, but still
trails behind HHVM quite significantly.
● Not ready.
http://goo.gl/MyUBeu

18. How do we know it is stable?
● Unfortunately there are no unit tests for
(core) Magento 1.x
● Brushed up the Test Automation Framework
● Automated setup of test environment using
Chef
● Nightly builds to check Magento compatibility
on HHVM to make it easier to spot
regressions

19. On the topic of debugging
● HHVM comes with something called HPHPd
● CLI Based, comparable to GDB
● No (known) support for any IDEs
Latest stable release
has xdebug support!

20. What is Hack?
Moving to HHVM gets even more awesome.
● Statically typed language
● Type annotations
● Generics
● Async
● Lambda’s
● Collections
● Built-in user attributes
http://hacklang.org/

21. Hack: Annotating

22. Hack:
Constructor Argument Promotion

23. Hack: Special Attributes

24. What about the future?
● Facebook is committed to open source:
several employees work on it exclusively.
● HHVM tracks a number of popular
frameworks and runs their PHPUnit suites
● Magento 2 is part of that list
http://hhvm.com/frameworks/

25. What about the future?
Open Source Benchmark Suite
● Automatic installation of popular frameworks
(Magento, Drupal, Wordpress, etc).
● Configures your web server
● Generates reliable performance metrics to
compare PHP implementations (HHVM,
PHP7).
https://github.com/hhvm/oss-performance/

26. What about the future?

27. Can we gradually migrate?
Store not entirely compatible with HHVM and
still want to run it.
● Problem is isolated to a (subset of) page(s):
use web-server configuration to split load.
● Problem is more widespread (incompatible
global observers, ioncube, etc):
https://github.com/danslo/HiphopIndexer/

28. Thank you!
Questions?