Git
Git is a popular version control system designed to handle very large projects with speed and efficiency. See http://git.or.cz/ for more info.
The Windows users might be interested in the MinGW git port (binaries).
Contents
Git and OpenOffice.org
A functional git tree with the entire OOo history for testing purposes is here: http://go-oo.org/git. It is an imported CVS tree that was split into two parts:
- The sources themselves - ooo.git
- The 3rd party stuff (binary mozilla, zlib, berkeleydb, ...) - 3rdparty.git
The size of the sources is about 1.3G, the size of the 3rd party stuff is 591M. Please follow the instructions on http://go-oo.org/git to get the tree.
For testing purposes, even a git tree without history is available as git://go-oo.org/git/without-history/src680-m211.git. It is a full import of src680-m211 (with the 3rdparty libraries, localizations, etc.) The plan is to start the OOo git tree as a tree without history with the possibility to 'graft' the history into this (message, sample script).
Transformations
These transformations are done while converting from CVS:
- The OOo repository is split into the sources and 3rd party sources as described above
- 'cws_src680_xyz' branches are renamed to simple 'xyz'
- 'CWS_SRC680_XYZ_ANCHOR' tags are renamed to simple 'XYZ'
- 'INTEGRATION: CWS xyz' commits are grouped into one commit (they are generated by CWS tooling per-file), and treated as a merge in the git tree
- Tabs are converted to 4 spaces at the beginning of the lines in .c/.cxx/.h/.hxx/.mk/.src
- 'RESYNC:.*FILE MERGED', and 'RESYNC:.*FILE REMOVED' are grouped inside branches (with single 'RESYNC' log entry)
- May result in multiple 'RESYNC' commits inside the branch when a commit happened to another one in the middle of the resync
Requirements/TODO
- Convert CollabNet account names into real names
- maybe use the data from DomainDeveloper (complete that where necessary) if there's no easy way to extract the names from CollabNet
- Delete merged branches (from 'heads', not from history!)
- Provide the too old history as 'graft' - see eg. http://repo.or.cz/w/elinks.git?a=blob;f=contrib/grafthistory.sh
- Translations to a separate git tree as well?
- URE to a separate git tree?
- ODF Toolkit to a separate git tree?
- .pdf version of developer's guide consume quite some space as well - any chance to do something with it?
Comparison
General
Links to Git comparison with other SCMs: http://git.or.cz/gitwiki/GitLinks#comparison
Comparison of git with Subversion: http://git.or.cz/gitwiki/GitSvnComparsion
Machines used for the testing
CVS tests:
- ???
Git tests [let's call this one 'git machine' ;-)]:
- CPU: AMD Athlon(tm) 64 Processor 3200+
- RAM: 1G
- Disk (info from bonnie):
---Sequential Output (nosync)--- ---Sequential Input-- --Rnd Seek- -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --04k (03)- Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU one 1*2000 37819 77.6 44296 16.8 16982 5.1 35203 63.9 45915 6.6 152.4 0.4
- OS: SUSE 10.1
- Filesystem: ext3
- Net connection: ~20Mbit
SVN tests:
- ???
Notes
The git repository could [should! ;-)] be tuned for better results:
- Delete integrated branches - the history will be still preserved, just the number of open heads will reduce (by about 3000)
- Graft history - the old development can be 'hidden' and available just to those who really need it using a simple script, like http://repo.or.cz/w/elinks.git?a=blob;f=contrib/grafthistory.sh . This way we can save about 1G of download!
The Results
What | CVS | git | SVN |
---|---|---|---|
Size of data on the server [OOo sources] | 8.5G | 1.3G | |
Size of data on the server [3rd party] | 1.1G | 591M | |
Size of checkout [OOo sources] | 1.4G | 2.8G [files you can hack on (contains localize.sdf's) + the history] | 3.3G [files you can hack on + localize.sdf's from data-trunk + .svn directories] |
Size of checkout [3rd party] | 98M | 688M [files you can hack on + the history] | 199M [files you can hack on + .svn directories] |
Initial checkout time [OOo sources] | 117 minutes (Linux, 2MBit DSL), 26 minutes (Linux, 2MBit DSL, with compression (-z 6) | 130 minutes, (51 min for a pull) (Linux, 2MBit DSL) [from go-oo.org] 100min (Linux, 2MBit DSL, Wireless, no proxy) [from go-oo.org] (1586669 objects (counting, deltifying, indexing) 1144663 deltas to resolve) |
60 minutes (Windows, 34Mbit Line) 58 min [git machine] |
Initial checkout time [3rd party] | |||
Branch creation | Immediately | Immediately with local svn server, 25 sec with collab.net server | |
Branch switch | <15sec [to newly created], 3min to an old one | 12min 40sec [git machine] ?? | |
Diff | Immediately | 4min 13sec [git machine] | |
Commit | 13-25sec | ||
Merge | 10sec [new branch with few changes], <3min [long living branch, harder scenario] | ||
Resync | Same as 'Merge' - it's a merge from 'master' to the branch. | ||
Integration | Same as 'Merge' - it's a merge from a branch to the 'master'. | ||
Push | Not necessary | push back one branch in local network: 9 sec, push back repository 40 min | Not necessary |
'3rd party' in this context means the following modules: agg, beanshell, berkeleydb, bitstream_vera_fonts, boost, curl, dictionaries, epm, expat, freetype, hsqldb, icu, jpeg, libwpd, libxml2, moz, msfontextract, nas, neon, np_sdk, portaudio, python, sablot, sane, sndfile, stlport, vigra, xalan, xt, zlib.
Commands used for the tests:
What | CVS | git | SVN |
---|---|---|---|
checkout [OOo sources] | cvs -d:pserver:anoncvs@anoncvs.services.openoffice.org:/cvs co OpenOffice2 | git clone git://go-oo.org/git/openoffice.org/ooo.git openoffice.org (How does this work with a proxy) | svn checkout http://svn.stage.openoffice.org/svn/svn/trunk svn (This tree does not contain localize.sdf's, they are in trunk-data.) |
Branch creation | [all the following commands were issued in the openoffice.org subdir] git branch test |
[all the following commands were issued in the svn subdir] | |
Branch switch | git checkout test | svn switch http://svn.stage.openoffice.org/svn/svn/vendors/sun-cvs/tags/SRC680_m172 | |
Diff | vim vcl/unx/kde/salnativewidgets-kde.cxx [to do some changes] ; git diff | vim vcl/unx/kde/salnativewidgets-kde.cxx [to do some changes] ; svn diff | |
Commit | [with the changes from 'Diff'] git commit -a |
||
Merge [the simple scenario] | git branch test2 ; git checkout test2 ; vim vcl/unx/kde/salnativewidgets-kde.cxx [another changes] ; git commit -a ; git checkout test [preparation to have something to merge] git pull . test2 [the merge itself] |
||
Merge [the harder scenario] | git pull git://go-oo.org/git/openoffice.org/ooo.git unxsplash [an old CWS of mine - called cws_src680_unxsplash in the CVS] |
||
Resync | [it's usually not necessary to do resynces with git; but when needed to get a feature a branch would depend on, it's just a merge from remote 'master'] | ||
Integration | git checkout master ; git pull . test [or alternatively: git checkout master ; git merge 'merging test into master' master test] |