view README @ 18822:381c0ef72a56

manifestmerge: use dicthelpers.diff and join

This patch improves manifestmerge performance significantly.

In a repository with 170,000 files, the following results were observed on a
clean working directory. Revision '.' adds one file.

hg perfmergecalculate -r .
- before: 0.41 seconds
- after: 0.13 seconds

hg perfmergecalculate -r .^
- before: 0.53 seconds
- after: 0.24 seconds

Comparing against '.' is much faster than comparing against '.^' because with
'.', the wctx and p2 manifest strings have the same identity, so comparisons
are simply pointer equality. With '.^', the strings have different identities
so we need to perform memcmps.

Any operation that uses manifestmerge benefits.
- hg update . goes from 2.04 seconds to 1.75
- hg update .^ goes from 2.52 seconds to 2.25
- hg rebase -r . -d .~6 (involves 4 merges) goes from 11.8 seconds to 10.8

Mercurial
=========

Mercurial is a fast, easy to use, distributed revision control tool
for software developers.

Basic install:

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

Running without installing:

 $ make local      # build for inplace usage
 $ ./hg --version  # should show the latest version

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