README

ancestor: caching the parent list to improve performance

When computing the DAG depth, we walk through all ancestors: this commit adds
memoization during that first step. Then, the memorized parents are fetched
from a dict instead of calling parents() on each vertex.

This tweak, according to Kcachegrind, improves ancestor() performance by 16%
when cloning a big repository.

Basic install:

 $ make            # see install targets
 $ make install    # do a system-wide install
 $ hg debuginstall # sanity-check setup
 $ hg              # see help

See http://www.selenic.com/mercurial/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.