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When traversing commits, a pathspec item can be used to limit the traversal to commits that modify the specified paths. And the commit-graph includes a Bloom filter to exclude commits that definitely did not modify a given pathspec item. During commit traversal, the Bloom filter can significantly improve performance. However, it is disabled if the specified pathspec item contains wildcard characters or magic signatures. For performance reason, enable Bloom filter even if a pathspec item contains wildcard characters by filtering only the non-wildcard part of the pathspec item. The function of pathspec magic signature is generally to narrow down the path specified by the pathspecs. So, enable Bloom filter when the magic signature is "top", "glob", "attr", "--depth" or "literal". "exclude" is used to select paths other than the specified path, rather than serving as a filtering function, so it cannot be used together with the Bloom filter. Since Bloom filter is not case insensitive even in case insensitive system (e.g. MacOS), it cannot be used together with "icase" magic. With this optimization, we get some improvements for pathspecs with wildcards or magic signatures. First, in the Git repository we see these modest results: git log -100 -- "t/*" Benchmark 1: new Time (mean ± σ): 20.4 ms ± 0.6 ms Range (min … max): 19.3 ms … 24.4 ms Benchmark 2: old Time (mean ± σ): 23.4 ms ± 0.5 ms Range (min … max): 22.5 ms … 24.7 ms git log -100 -- ":(top)t" Benchmark 1: new Time (mean ± σ): 16.2 ms ± 0.4 ms Range (min … max): 15.3 ms … 17.2 ms Benchmark 2: old Time (mean ± σ): 18.6 ms ± 0.5 ms Range (min … max): 17.6 ms … 20.4 ms But in a larger repo, such as the LLVM project repo below, we get even better results: git log -100 -- "libc/*" Benchmark 1: new Time (mean ± σ): 16.0 ms ± 0.6 ms Range (min … max): 14.7 ms … 17.8 ms Benchmark 2: old Time (mean ± σ): 26.7 ms ± 0.5 ms Range (min … max): 25.4 ms … 27.8 ms git log -100 -- ":(top)libc" Benchmark 1: new Time (mean ± σ): 15.6 ms ± 0.6 ms Range (min … max): 14.4 ms … 17.7 ms Benchmark 2: old Time (mean ± σ): 19.6 ms ± 0.5 ms Range (min … max): 18.6 ms … 20.6 ms Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Lidong Yan <yldhome2d2@gmail.com> 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.adoc to get started, then see
Documentation/giteveryday.adoc for a useful minimum set of commands, and
Documentation/git-<commandname>.adoc 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.adoc
(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 and Documentation/CodingGuidelines).
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
To subscribe to the list, send an email to git+subscribe@vger.kernel.org (see https://subspace.kernel.org/subscribing.html for details). The mailing list archives are available at https://lore.kernel.org/git/, https://marc.info/?l=git and other archival sites.
Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
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