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38d4debb6d
This brings back some of the performance lost in optimizing recency order inside pack objects. We were doing extreme amounts of object re-traversal: for the 2.14 million objects in the Linux kernel repository, we were calling add_to_write_order() over 1.03 billion times (a 0.2% hit rate, making 99.8% of of these calls extraneous). Two optimizations take place here- we can start our objects array iteration from a known point where we left off before we started trying to find our tags, and we don't need to do the deep dives required by add_family_to_write_order() if the object has already been marked as filled. These two optimizations bring some pretty spectacular results via `perf stat`: task-clock: 83373 ms --> 43800 ms (50% faster) cycles: 221,633,461,676 --> 116,307,209,986 (47% fewer) instructions: 149,299,179,939 --> 122,998,800,184 (18% fewer) Helped-by: Ramsay Jones (format string fix in "die" message) Signed-off-by: Dan McGee <dpmcgee@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
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GIT - the stupid content tracker
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"git" can mean anything, depending on your mood.
- random three-letter combination that is pronounceable, and not
actually used by any common UNIX command. The fact that it is a
mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the
dictionary of slang.
- "global information tracker": you're in a good mood, and it actually
works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.
Git is an Open Source project covered by the GNU General Public License.
It was originally written by Linus Torvalds with help of a group of
hackers around the net. It is currently maintained by Junio C Hamano.
Please read the file INSTALL for installation instructions.
See Documentation/gittutorial.txt to get started, then see
Documentation/everyday.txt for a useful minimum set of commands, and
Documentation/git-commandname.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with "man gittutorial" or "git help tutorial", and the
documentation of each command with "man git-commandname" or "git help
commandname".
CVS users may also want to read Documentation/gitcvs-migration.txt
("man gitcvs-migration" or "git help cvs-migration" if git is
installed).
Many Git online resources are accessible from http://git-scm.com/
including full documentation and Git related tools.
The user discussion and development of Git take place on the Git
mailing list -- everyone is welcome to post bug reports, feature
requests, comments and patches to git@vger.kernel.org. To subscribe
to the list, send an email with just "subscribe git" in the body to
majordomo@vger.kernel.org. The mailing list archives are available at
http://marc.theaimsgroup.com/?l=git and other archival sites.
The messages titled "A note from the maintainer", "What's in
git.git (stable)" and "What's cooking in git.git (topics)" and
the discussion following them on the mailing list give a good
reference for project status, development direction and
remaining tasks.