c291293b2e
In b495697b82 (fetch-pack: avoid repeatedly re-scanning pack directory, 2013-01-26), we noticed that everything_local() could waste time trying to find and parse objects which we _expect_ to be missing. The solution was to put has_sha1_file() in front of parse_object() to skip the more-expensive parse attempt. That optimization was negated later when has_sha1_file() learned to do the same re-scan in 45e8a74873 (has_sha1_file: re-check pack directory before giving up, 2013-08-30). We can restore it by using the "quick" flag to tell has_sha1_file (actually has_object_file these days) that we prefer speed to thoroughness for this call. See also the fixes in 5827a0354 and 0eeb077be7 for prior art and discussion on using the "quick" flag for these cases. The recently-added performance regression test in p5551 demonstrates the problem. You can see the original fix: Test b495697b82^ b495697b82 -------------------------------------------------------- 5551.4: fetch 1.68(1.33+0.35) 0.87(0.69+0.18) -48.2% and then the regression: Test 45e8a74873^ 45e8a74873 --------------------------------------------------------- 5551.4: fetch 0.96(0.77+0.19) 2.55(2.04+0.50) +165.6% and now our fix: Test HEAD^ HEAD -------------------------------------------------------- 5551.4: fetch 7.21(6.58+0.63) 5.47(5.04+0.43) -24.1% You can also see that other things have gotten a lot slower since 2013. We'll deal with those in separate patches. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
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 version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-.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).
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 (read Documentation/SubmittingPatches for instructions on patch submission). 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 https://public-inbox.org/git/, http://marc.info/?l=git and other archival sites.
The maintainer frequently sends the "What's cooking" reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (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