mirror of
https://github.com/git/git.git
synced 2026-01-11 21:33:13 +09:00
a3540ed20e
In process_ranges_merge_commit(), the line-level log first creates an
array of diff queues by iterating over all parents of a merge commit
and computing a tree diff for each. Then in a second loop it iterates
over those diff queues, and if it finds that none of the interesting
paths were modified in one of them, then it will return early. This
means that when none of the interesting paths were modified between a
merge and its first parent, then the tree diff between the merge and
its second (Nth...) parent was computed in vain.
Unify these two loops, so when it iterates over all parents of a merge
commit, then it first computes the tree diff between the merge and
that particular parent and then processes the resulting diff queue
right away. This way we can spare some tree diff computing, thereby
speeding up line-level log in repositories with mergy history:
# git.git, 25.8% of commits are merges:
Benchmark 1: ./git_v2.51.0 -C ~/src/git log -L:'lookup_commit(':commit.c v2.51.0
Time (mean ± σ): 1.001 s ± 0.009 s [User: 0.906 s, System: 0.095 s]
Range (min … max): 0.991 s … 1.023 s 10 runs
Benchmark 2: ./git -C ~/src/git log -L:'lookup_commit(':commit.c v2.51.0
Time (mean ± σ): 445.5 ms ± 3.4 ms [User: 358.8 ms, System: 84.3 ms]
Range (min … max): 440.1 ms … 450.3 ms 10 runs
Summary
'./git -C ~/src/git log -L:'lookup_commit(':commit.c v2.51.0' ran
2.25 ± 0.03 times faster than './git_v2.51.0 -C ~/src/git log -L:'lookup_commit(':commit.c v2.51.0'
# linux.git, 7.5% of commits are merges:
Benchmark 1: ./git_v2.51.0 -C ~/src/linux.git log -L:build_restore_work_registers:arch/mips/mm/tlbex.c v6.16
Time (mean ± σ): 3.246 s ± 0.007 s [User: 2.835 s, System: 0.409 s]
Range (min … max): 3.232 s … 3.255 s 10 runs
Benchmark 2: ./git -C ~/src/linux.git log -L:build_restore_work_registers:arch/mips/mm/tlbex.c v6.16
Time (mean ± σ): 2.467 s ± 0.014 s [User: 2.113 s, System: 0.353 s]
Range (min … max): 2.455 s … 2.505 s 10 runs
Summary
'./git -C ~/src/linux.git log -L:build_restore_work_registers:arch/mips/mm/tlbex.c v6.16' ran
1.32 ± 0.01 times faster than './git_v2.51.0 -C ~/src/linux.git log -L:build_restore_work_registers:arch/mips/mm/tlbex.c v6.16'
And since now each iteration computes a tree diff and processes its
result, there is no reason to store the diff queues for each merge
parent anymore, so replace that diff queue array with a loop-local
diff queue variable. With this change the static free_diffqueues()
helper function in 'line-log.c' has no more callers left, remove it.
Signed-off-by: SZEDER Gábor <szeder.dev@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