HHVM (also known as the HipHop Virtual Machine) is a virtual machine for PHP, with an associated just-in-time (JIT) compiler. Deploying HHVM on a MediaWiki wiki should lead to performance improvements across the board for most users.

HHVM was fully deployed to all wikis on 2014-11-25.[1] You can verify that it is enabled for you by visiting Special:Version on your wiki, and checking that it says "HHVM" instead of "PHP" in the "Installed software" table.

Our preliminary benchmarks[2] show that HHVM is significantly faster than the current PHP interpreter.


  • What does HHVM do?
    HHVM should decrease the loading time for:
    • Any page you view while logged in.
    • Saving pages that you've edited, whether you are logged in or not.
  • Why are some edits tagged?
    Initially, HHVM was an optional beta feature available only to users who requested it. Now it is universal for all users. The tags were hidden from the default view on November 10, 2014.
  • Why are edits made using gadgets not using HHVM?
    Most gadgets use the API to edit, which currently does not support this beta feature.
  • What are the known issues with HHVM?
    All bugs related to HHVM are tagged with the keyword "hhvm" on Phabricator , so you can use a tag search to see all open bugs.
  • Where should I report issues that I think are related to HHVM?
    If you're familiar with phabricator, feel free to file a bug there and tag it with the "hhvm" keyword. If you're familiar with IRC, join #wikimedia-tech and report it there. Or just leave a report on the talk page.

See also

  • The main project page: HHVM
  • w:HHVM – information on the English Wikipedia