Inotify Extension
This extension is not distributed with Mercurial.
Author: Bryan O'Sullivan
Download site: [http://hg.kublai.com/mercurial/patches/inotify]
Overview
This extension uses the linux 2.6 inotify API to make status instantaneous for even very large repositories, by subscribing to the paths in the repository instead of having to check them all at every status command.
Configuration
Configure your .hgrc to enable the extension by adding following lines:
[extensions] inotify=/path/to/inotify