In a new post to the HHVM blog, Brett Simmers looks at the recent announcement from Wikipedia and how they made the switch to HHVM and the impact it made.

If you’ve been watching our GitHub wiki, following us on Twitter, or reading the wikitech-l mailing list, you’ve probably known for a while that Wikipedia has been transitioning to HHVM. This has been a long process involving lots of work from many different people, and as of a few weeks ago, all non-cached API and web traffic is being served by HHVM. This blog post from the Wikimedia Foundation contains some details about the switch, as does their page about HHVM.

Brett spends the rest of the post talking about his time working with the Wikimedia foundation and some of the hurdles they had to tackle along the way. This included things outside of PHP too like an issue with their Lua extension and compile changes in the installed PCRE version (no JIT). He also shares some of the statistics (in graph form) of the results of the move to HHVM from normal PHP5 - an impressive drop of around 7 seconds, median save time. He also includes a graph showing the server loads and the resulting (very impressive) drop from the move.