doc/README

performance: speedup computation of unserved revisions

In their current state, revset calls can be very costly, as we test
predicates on the entire repository. The "unserved" filter is used
in multiple applications, and in particular in some branch cache
loading operations. We need to make it fast.

This change drops revset calls in favor of direct testing of the
phase of a changeset.

Performance test on my Mercurial checkout

- 19857 total changesets,
- 1584 obsolete changesets,
- 13310 obsolescence markers.

Before:
  ! unserved
  ! wall 0.030477

After:
  ! unserved
  ! wall 0.011844

Performance test on a Mozilla central checkout:

- 117293 total changesets,
- 1 obsolete changeset,
- 1 obsolescence marker.

Before:
  ! unserved
  ! wall 0.111259

After:
  ! unserved
  ! wall 0.000084

Mercurial's documentation is kept in reStructuredText format, which is
a simple plain text format that's easy to read and edit:

  http://docutils.sourceforge.net/rst.html

It's also convertible to a variety of other formats including standard
UNIX man page format and HTML. You'll need to install Docutils:

  http://docutils.sourceforge.net/

Use the Makefile in this directory to generate the man and HTML pages.