Use futures to improve clustered repository main page performance
Ref T11954. In cluster configurations, we get repository information by making HTTP calls over Conduit.
These are slower than local calls, so clustering imposes a performance penalty. However, we can use futures and parallelize them so that clustering actually improves overall performance.
When not running in clustered mode, this just makes us run stuff inline.
- Browsed Git, Mercurial and Subversion repositories.
- Locally, saw a 700ms wall time page drop to 200ms.
Reviewed By: chad
Maniphest Tasks: T11954
Differential Revision: https://secure.phabricator.com/D17009