revlog: optimize _chunkraw when startrev==endrev
In many cases, _chunkraw() is called with startrev==endrev. When
this is true, we can avoid an extra index lookup and some other
minor operations.
On the mozilla-unified repo, `hg perfrevlogchunks -c` says this
has the following impact:
! read w/ reused fd
! wall 0.371846 comb 0.370000 user 0.350000 sys 0.020000 (best of 27)
! wall 0.337930 comb 0.330000 user 0.300000 sys 0.030000 (best of 30)
! read batch w/ reused fd
! wall 0.014952 comb 0.020000 user 0.000000 sys 0.020000 (best of 197)
! wall 0.014866 comb 0.010000 user 0.000000 sys 0.010000 (best of 196)
So, we've gone from ~25x slower than batch to ~22.5x slower.
At this point, there's probably not much else we can do except
implement an optimized function in the index itself, including in C.
====
hg
====
---------------------------------------
Mercurial source code management system
---------------------------------------
:Author: Matt Mackall <mpm@selenic.com>
:Organization: Mercurial
:Manual section: 1
:Manual group: Mercurial Manual
.. contents::
:backlinks: top
:class: htmlonly
:depth: 1
Synopsis
""""""""
**hg** *command* [*option*]... [*argument*]...
Description
"""""""""""
The **hg** command provides a command line interface to the Mercurial
system.
Command Elements
""""""""""""""""
files...
indicates one or more filename or relative path filenames; see
`File Name Patterns`_ for information on pattern matching
path
indicates a path on the local machine
revision
indicates a changeset which can be specified as a changeset
revision number, a tag, or a unique substring of the changeset
hash value
repository path
either the pathname of a local repository or the URI of a remote
repository.
.. include:: hg.1.gendoc.txt
Files
"""""
``/etc/mercurial/hgrc``, ``$HOME/.hgrc``, ``.hg/hgrc``
This file contains defaults and configuration. Values in
``.hg/hgrc`` override those in ``$HOME/.hgrc``, and these override
settings made in the global ``/etc/mercurial/hgrc`` configuration.
See |hgrc(5)|_ for details of the contents and format of these
files.
``.hgignore``
This file contains regular expressions (one per line) that
describe file names that should be ignored by **hg**. For details,
see |hgignore(5)|_.
``.hgsub``
This file defines the locations of all subrepositories, and
tells where the subrepository checkouts came from. For details, see
:hg:`help subrepos`.
``.hgsubstate``
This file is where Mercurial stores all nested repository states. *NB: This
file should not be edited manually.*
``.hgtags``
This file contains changeset hash values and text tag names (one
of each separated by spaces) that correspond to tagged versions of
the repository contents. The file content is encoded using UTF-8.
``.hg/last-message.txt``
This file is used by :hg:`commit` to store a backup of the commit message
in case the commit fails.
``.hg/localtags``
This file can be used to define local tags which are not shared among
repositories. The file format is the same as for ``.hgtags``, but it is
encoded using the local system encoding.
Some commands (e.g. revert) produce backup files ending in ``.orig``,
if the ``.orig`` file already exists and is not tracked by Mercurial,
it will be overwritten.
Bugs
""""
Probably lots, please post them to the mailing list (see Resources_
below) when you find them.
See Also
""""""""
|hgignore(5)|_, |hgrc(5)|_
Author
""""""
Written by Matt Mackall <mpm@selenic.com>
Resources
"""""""""
Main Web Site: https://mercurial-scm.org/
Source code repository: https://www.mercurial-scm.org/repo/hg
Mailing list: https://www.mercurial-scm.org/mailman/listinfo/mercurial/
Copying
"""""""
Copyright (C) 2005-2016 Matt Mackall.
Free use of this software is granted under the terms of the GNU General
Public License version 2 or any later version.
.. include:: common.txt