(apologies for cross-posting)
I'm happy to announce that HHVM is available on all Wikimedia wikis for
intrepid beta testers. HHVM, you'll recall, is an alternative runtime for
PHP that provides substantial performance improvements over the standard
PHP interpreter. Simply put: HHVM is software that runs on Wikimedia's
servers to make your reading and editing experience faster.
You can read more about HHVM here:
https://www.mediawiki.org/wiki/HHVM
* How do I enable HHVM?
You can enable HHVM by opting in to the beta feature. This short animated
gif will show you how: <http://people.wikimedia.org/~ori/hhvm_beta.gif>.
Enabling the beta feature will set a special cookie in your browser. Our
servers are configured to route requests bearing this cookie to a pool of
servers that are running HHVM.
* How do I know that it's working?
Opting-in to the beta feature does not change the user interface in any
way. If you like, you can copy the following code snippet to the global.js
subpage of your user page on MetaWiki:
https://meta.wikimedia.org/wiki/User:Ori.livneh/global.js
If you copy this script to your global.js, the personal bar will be
annotated with the name of the PHP runtime used to generate the page and
the backend response time. It looks like this:
http://people.wikimedia.org/~ori/hhvm_script.png
Edits made by users with HHVM enabled will be tagged with 'HHVM'. The tag
is there as a precaution, to help us clean up if we discover that HHVM is
mangling edits somehow. We don't expect this to happen.
* What sort of performance changes should I expect?
We expect HHVM to have a substantial impact on the time it takes to load,
preview, and save pages.
At the moment, API requests are not being handled by HHVM. Because
VisualEditor uses the API to save articles, opting in to the HHVM beta
feature will not impact the performance of VisualEditor. We hope to have
HHVM handling API requests next week.
* What sort of issues might I encounter?
Most of the bugs that we have encountered so far resulted from minute
differences in how PHP5 and HHVM handle various edge-cases. These bugs
typically cause a MediaWiki error page to be shown.
If you encounter an error, please report it on Bugzilla and tag with it the
'HHVM' keyword.
We're not done yet, but this is an important milestone. The roll-out of
HHVM as a beta feature caps many months of hard work from many developers,
both salaried and volunteer, from the Wikimedia Foundation, Wikimedia
Deutschland, and the broader Wikimedia movement. I want to take this
opportunity to express my appreciation to the following individuals, listed
in alphabetical order:
Aaron Schulz, Alexandros Kosiaris, Brad Jorsch, Brandon Black, Brett
Simmers, Bryan Davis, Chad Horohoe, Chris Steipp, Erik Bernhardson, Erik
Möller, Faidon Liambotis, Filippo Giunchedi, Giuseppe Lavagetto, Greg
Grossmeier, Jack McBarn, Katie Filbert, Kunal Mehta, Mark Bergsma, Max
Semenik, Niklas Laxström, Rob Lanphier, and Tim Starling.
More good things to come! :)
