Git with broken hash generation to generate collisions between object IDs. Don't use this!
https://undefinedbehavior.de/posts/commit-vandalism/
9e5972413b
Overall time saving on "git status" is about 40% in the best case scenario, removing ..collect_untracked() as the most time consuming function. read and refresh index operations are now at the top (which should drop when index-helper and/or watchman support is added). More numbers and analysis below. webkit.git ========== 169k files. 6k dirs. Lots of test data (i.e. not touched most of the time) Base status ----------- Index version 4 in split index mode and cache-tree populated. No untracked cache. It shows how time is consumed by "git status". The same settings are used for other repos below. 18:28:10.199679 builtin/commit.c:1394 performance: 0.000000451 s: cmd_status:setup 18:28:10.474847 read-cache.c:1407 performance: 0.274873831 s: read_index 18:28:10.475295 read-cache.c:1407 performance: 0.000000656 s: read_index 18:28:10.728443 preload-index.c:131 performance: 0.253147487 s: read_index_preload 18:28:10.741422 read-cache.c:1254 performance: 0.012868340 s: refresh_index 18:28:10.752300 wt-status.c:623 performance: 0.010421357 s: wt_status_collect_changes_worktree 18:28:10.762069 wt-status.c:629 performance: 0.009644748 s: wt_status_collect_changes_index 18:28:11.601019 wt-status.c:632 performance: 0.838859547 s: wt_status_collect_untracked 18:28:11.605939 builtin/commit.c:1421 performance: 0.004835004 s: cmd_status:update_index 18:28:11.606580 trace.c:415 performance: 1.407878388 s: git command: 'git' 'status' Populating status ----------------- This is after enabling untracked cache and the cache is still empty. We see a slight increase in .._collect_untracked() and update_index (because new cache has to be written to $GIT_DIR/index). 18:28:18.915213 builtin/commit.c:1394 performance: 0.000000326 s: cmd_status:setup 18:28:19.197364 read-cache.c:1407 performance: 0.281901416 s: read_index 18:28:19.197754 read-cache.c:1407 performance: 0.000000546 s: read_index 18:28:19.451355 preload-index.c:131 performance: 0.253599607 s: read_index_preload 18:28:19.464400 read-cache.c:1254 performance: 0.012935336 s: refresh_index 18:28:19.475115 wt-status.c:623 performance: 0.010236920 s: wt_status_collect_changes_worktree 18:28:19.486022 wt-status.c:629 performance: 0.010801685 s: wt_status_collect_changes_index 18:28:20.362660 wt-status.c:632 performance: 0.876551366 s: wt_status_collect_untracked 18:28:20.396199 builtin/commit.c:1421 performance: 0.033447969 s: cmd_status:update_index 18:28:20.396939 trace.c:415 performance: 1.482695902 s: git command: 'git' 'status' Populated status ---------------- After the cache is populated, wt_status_collect_untracked() drops 82% from 0.838s to 0.144s. Overall time drops 45%. Top offenders are now read_index() and read_index_preload(). 18:28:20.408605 builtin/commit.c:1394 performance: 0.000000457 s: cmd_status:setup 18:28:20.692864 read-cache.c:1407 performance: 0.283980458 s: read_index 18:28:20.693273 read-cache.c:1407 performance: 0.000000661 s: read_index 18:28:20.958814 preload-index.c:131 performance: 0.265540254 s: read_index_preload 18:28:20.972375 read-cache.c:1254 performance: 0.013437429 s: refresh_index 18:28:20.983959 wt-status.c:623 performance: 0.011146646 s: wt_status_collect_changes_worktree 18:28:20.993948 wt-status.c:629 performance: 0.009879094 s: wt_status_collect_changes_index 18:28:21.138125 wt-status.c:632 performance: 0.144084737 s: wt_status_collect_untracked 18:28:21.173678 builtin/commit.c:1421 performance: 0.035463949 s: cmd_status:update_index 18:28:21.174251 trace.c:415 performance: 0.766707355 s: git command: 'git' 'status' gentoo-x86.git ============== This repository is a strange one with a balanced, wide and shallow worktree (about 100k files and 23k dirs) and no .gitignore in worktree. .._collect_untracked() time drops 88%, total time drops 56%. Base status ----------- 18:20:40.828642 builtin/commit.c:1394 performance: 0.000000496 s: cmd_status:setup 18:20:41.027233 read-cache.c:1407 performance: 0.198130532 s: read_index 18:20:41.027670 read-cache.c:1407 performance: 0.000000581 s: read_index 18:20:41.171716 preload-index.c:131 performance: 0.144045594 s: read_index_preload 18:20:41.179171 read-cache.c:1254 performance: 0.007320424 s: refresh_index 18:20:41.185785 wt-status.c:623 performance: 0.006144638 s: wt_status_collect_changes_worktree 18:20:41.192701 wt-status.c:629 performance: 0.006780184 s: wt_status_collect_changes_index 18:20:41.991723 wt-status.c:632 performance: 0.798927029 s: wt_status_collect_untracked 18:20:41.994664 builtin/commit.c:1421 performance: 0.002852772 s: cmd_status:update_index 18:20:41.995458 trace.c:415 performance: 1.168427502 s: git command: 'git' 'status' Populating status ----------------- 18:20:48.968848 builtin/commit.c:1394 performance: 0.000000380 s: cmd_status:setup 18:20:49.172918 read-cache.c:1407 performance: 0.203734214 s: read_index 18:20:49.173341 read-cache.c:1407 performance: 0.000000562 s: read_index 18:20:49.320013 preload-index.c:131 performance: 0.146671391 s: read_index_preload 18:20:49.328039 read-cache.c:1254 performance: 0.007921957 s: refresh_index 18:20:49.334680 wt-status.c:623 performance: 0.006172020 s: wt_status_collect_changes_worktree 18:20:49.342526 wt-status.c:629 performance: 0.007731746 s: wt_status_collect_changes_index 18:20:50.257510 wt-status.c:632 performance: 0.914864222 s: wt_status_collect_untracked 18:20:50.338371 builtin/commit.c:1421 performance: 0.080776477 s: cmd_status:update_index 18:20:50.338900 trace.c:415 performance: 1.371462446 s: git command: 'git' 'status' Populated status ---------------- 18:20:50.351160 builtin/commit.c:1394 performance: 0.000000571 s: cmd_status:setup 18:20:50.577358 read-cache.c:1407 performance: 0.225917338 s: read_index 18:20:50.577794 read-cache.c:1407 performance: 0.000000617 s: read_index 18:20:50.734140 preload-index.c:131 performance: 0.156345564 s: read_index_preload 18:20:50.745717 read-cache.c:1254 performance: 0.011463075 s: refresh_index 18:20:50.755176 wt-status.c:623 performance: 0.008877929 s: wt_status_collect_changes_worktree 18:20:50.763768 wt-status.c:629 performance: 0.008471633 s: wt_status_collect_changes_index 18:20:50.854885 wt-status.c:632 performance: 0.090988721 s: wt_status_collect_untracked 18:20:50.857765 builtin/commit.c:1421 performance: 0.002789097 s: cmd_status:update_index 18:20:50.858411 trace.c:415 performance: 0.508647673 s: git command: 'git' 'status' linux-2.6 ========= Reference repo. Not too big. .._collect_status() drops 84%. Total time drops 42%. Base status ----------- 18:34:09.870122 builtin/commit.c:1394 performance: 0.000000385 s: cmd_status:setup 18:34:09.943218 read-cache.c:1407 performance: 0.072871177 s: read_index 18:34:09.943614 read-cache.c:1407 performance: 0.000000491 s: read_index 18:34:10.004364 preload-index.c:131 performance: 0.060748102 s: read_index_preload 18:34:10.008190 read-cache.c:1254 performance: 0.003714285 s: refresh_index 18:34:10.012087 wt-status.c:623 performance: 0.002775446 s: wt_status_collect_changes_worktree 18:34:10.016054 wt-status.c:629 performance: 0.003862140 s: wt_status_collect_changes_index 18:34:10.214747 wt-status.c:632 performance: 0.198604837 s: wt_status_collect_untracked 18:34:10.216102 builtin/commit.c:1421 performance: 0.001244166 s: cmd_status:update_index 18:34:10.216817 trace.c:415 performance: 0.347670735 s: git command: 'git' 'status' Populating status ----------------- 18:34:16.595102 builtin/commit.c:1394 performance: 0.000000456 s: cmd_status:setup 18:34:16.666600 read-cache.c:1407 performance: 0.070992413 s: read_index 18:34:16.667012 read-cache.c:1407 performance: 0.000000606 s: read_index 18:34:16.729375 preload-index.c:131 performance: 0.062362492 s: read_index_preload 18:34:16.732565 read-cache.c:1254 performance: 0.003075517 s: refresh_index 18:34:16.736148 wt-status.c:623 performance: 0.002422201 s: wt_status_collect_changes_worktree 18:34:16.739990 wt-status.c:629 performance: 0.003746618 s: wt_status_collect_changes_index 18:34:16.948505 wt-status.c:632 performance: 0.208426710 s: wt_status_collect_untracked 18:34:16.961744 builtin/commit.c:1421 performance: 0.013151887 s: cmd_status:update_index 18:34:16.962233 trace.c:415 performance: 0.368537535 s: git command: 'git' 'status' Populated status ---------------- 18:34:16.970026 builtin/commit.c:1394 performance: 0.000000631 s: cmd_status:setup 18:34:17.046235 read-cache.c:1407 performance: 0.075904673 s: read_index 18:34:17.046644 read-cache.c:1407 performance: 0.000000681 s: read_index 18:34:17.113564 preload-index.c:131 performance: 0.066920253 s: read_index_preload 18:34:17.117281 read-cache.c:1254 performance: 0.003604055 s: refresh_index 18:34:17.121115 wt-status.c:623 performance: 0.002508345 s: wt_status_collect_changes_worktree 18:34:17.125089 wt-status.c:629 performance: 0.003871636 s: wt_status_collect_changes_index 18:34:17.156089 wt-status.c:632 performance: 0.030895703 s: wt_status_collect_untracked 18:34:17.169861 builtin/commit.c:1421 performance: 0.013686404 s: cmd_status:update_index 18:34:17.170391 trace.c:415 performance: 0.201474531 s: git command: 'git' 'status' Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> |
||
|---|---|---|
| block-sha1 | ||
| builtin | ||
| compat | ||
| contrib | ||
| Documentation | ||
| ewah | ||
| git-gui | ||
| gitk-git | ||
| gitweb | ||
| mergetools | ||
| perl | ||
| po | ||
| ppc | ||
| t | ||
| templates | ||
| vcs-svn | ||
| xdiff | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| abspath.c | ||
| aclocal.m4 | ||
| advice.c | ||
| advice.h | ||
| alias.c | ||
| alloc.c | ||
| archive-tar.c | ||
| archive-zip.c | ||
| archive.c | ||
| archive.h | ||
| argv-array.c | ||
| argv-array.h | ||
| attr.c | ||
| attr.h | ||
| base85.c | ||
| bisect.c | ||
| bisect.h | ||
| blob.c | ||
| blob.h | ||
| branch.c | ||
| branch.h | ||
| builtin.h | ||
| bulk-checkin.c | ||
| bulk-checkin.h | ||
| bundle.c | ||
| bundle.h | ||
| cache-tree.c | ||
| cache-tree.h | ||
| cache.h | ||
| check_bindir | ||
| check-builtins.sh | ||
| check-racy.c | ||
| color.c | ||
| color.h | ||
| column.c | ||
| column.h | ||
| combine-diff.c | ||
| command-list.txt | ||
| commit-slab.h | ||
| commit.c | ||
| commit.h | ||
| config.c | ||
| config.mak.in | ||
| config.mak.uname | ||
| configure.ac | ||
| connect.c | ||
| connect.h | ||
| connected.c | ||
| connected.h | ||
| convert.c | ||
| convert.h | ||
| copy.c | ||
| COPYING | ||
| credential-cache--daemon.c | ||
| credential-cache.c | ||
| credential-store.c | ||
| credential.c | ||
| credential.h | ||
| csum-file.c | ||
| csum-file.h | ||
| ctype.c | ||
| daemon.c | ||
| date.c | ||
| decorate.c | ||
| decorate.h | ||
| delta.h | ||
| diff-delta.c | ||
| diff-lib.c | ||
| diff-no-index.c | ||
| diff.c | ||
| diff.h | ||
| diffcore-break.c | ||
| diffcore-delta.c | ||
| diffcore-order.c | ||
| diffcore-pickaxe.c | ||
| diffcore-rename.c | ||
| diffcore.h | ||
| dir.c | ||
| dir.h | ||
| editor.c | ||
| entry.c | ||
| environment.c | ||
| exec_cmd.c | ||
| exec_cmd.h | ||
| fast-import.c | ||
| fetch-pack.c | ||
| fetch-pack.h | ||
| fmt-merge-msg.h | ||
| fsck.c | ||
| fsck.h | ||
| generate-cmdlist.sh | ||
| gettext.c | ||
| gettext.h | ||
| git-add--interactive.perl | ||
| git-am.sh | ||
| git-archimport.perl | ||
| git-bisect.sh | ||
| git-compat-util.h | ||
| git-cvsexportcommit.perl | ||
| git-cvsimport.perl | ||
| git-cvsserver.perl | ||
| git-difftool--helper.sh | ||
| git-difftool.perl | ||
| git-filter-branch.sh | ||
| git-instaweb.sh | ||
| git-merge-octopus.sh | ||
| git-merge-one-file.sh | ||
| git-merge-resolve.sh | ||
| git-mergetool--lib.sh | ||
| git-mergetool.sh | ||
| git-p4.py | ||
| git-parse-remote.sh | ||
| git-pull.sh | ||
| git-quiltimport.sh | ||
| git-rebase--am.sh | ||
| git-rebase--interactive.sh | ||
| git-rebase--merge.sh | ||
| git-rebase.sh | ||
| git-relink.perl | ||
| git-remote-testgit.sh | ||
| git-request-pull.sh | ||
| git-send-email.perl | ||
| git-sh-i18n.sh | ||
| git-sh-setup.sh | ||
| git-stash.sh | ||
| git-submodule.sh | ||
| git-svn.perl | ||
| GIT-VERSION-GEN | ||
| git-web--browse.sh | ||
| git.c | ||
| git.rc | ||
| git.spec.in | ||
| gpg-interface.c | ||
| gpg-interface.h | ||
| graph.c | ||
| graph.h | ||
| grep.c | ||
| grep.h | ||
| hashmap.c | ||
| hashmap.h | ||
| help.c | ||
| help.h | ||
| hex.c | ||
| http-backend.c | ||
| http-fetch.c | ||
| http-push.c | ||
| http-walker.c | ||
| http.c | ||
| http.h | ||
| ident.c | ||
| imap-send.c | ||
| INSTALL | ||
| khash.h | ||
| kwset.c | ||
| kwset.h | ||
| levenshtein.c | ||
| levenshtein.h | ||
| LGPL-2.1 | ||
| line-log.c | ||
| line-log.h | ||
| line-range.c | ||
| line-range.h | ||
| list-objects.c | ||
| list-objects.h | ||
| ll-merge.c | ||
| ll-merge.h | ||
| lockfile.c | ||
| lockfile.h | ||
| log-tree.c | ||
| log-tree.h | ||
| mailmap.c | ||
| mailmap.h | ||
| Makefile | ||
| match-trees.c | ||
| merge-blobs.c | ||
| merge-blobs.h | ||
| merge-recursive.c | ||
| merge-recursive.h | ||
| merge.c | ||
| mergesort.c | ||
| mergesort.h | ||
| name-hash.c | ||
| notes-cache.c | ||
| notes-cache.h | ||
| notes-merge.c | ||
| notes-merge.h | ||
| notes-utils.c | ||
| notes-utils.h | ||
| notes.c | ||
| notes.h | ||
| object.c | ||
| object.h | ||
| pack-bitmap-write.c | ||
| pack-bitmap.c | ||
| pack-bitmap.h | ||
| pack-check.c | ||
| pack-objects.c | ||
| pack-objects.h | ||
| pack-revindex.c | ||
| pack-revindex.h | ||
| pack-write.c | ||
| pack.h | ||
| pager.c | ||
| parse-options-cb.c | ||
| parse-options.c | ||
| parse-options.h | ||
| patch-delta.c | ||
| patch-ids.c | ||
| patch-ids.h | ||
| path.c | ||
| pathspec.c | ||
| pathspec.h | ||
| pkt-line.c | ||
| pkt-line.h | ||
| preload-index.c | ||
| pretty.c | ||
| prio-queue.c | ||
| prio-queue.h | ||
| progress.c | ||
| progress.h | ||
| prompt.c | ||
| prompt.h | ||
| quote.c | ||
| quote.h | ||
| reachable.c | ||
| reachable.h | ||
| read-cache.c | ||
| README | ||
| reflog-walk.c | ||
| reflog-walk.h | ||
| refs.c | ||
| refs.h | ||
| RelNotes | ||
| remote-curl.c | ||
| remote-testsvn.c | ||
| remote.c | ||
| remote.h | ||
| replace_object.c | ||
| rerere.c | ||
| rerere.h | ||
| resolve-undo.c | ||
| resolve-undo.h | ||
| revision.c | ||
| revision.h | ||
| run-command.c | ||
| run-command.h | ||
| send-pack.c | ||
| send-pack.h | ||
| sequencer.c | ||
| sequencer.h | ||
| server-info.c | ||
| setup.c | ||
| sh-i18n--envsubst.c | ||
| sha1_file.c | ||
| sha1_name.c | ||
| sha1-array.c | ||
| sha1-array.h | ||
| sha1-lookup.c | ||
| sha1-lookup.h | ||
| shallow.c | ||
| shell.c | ||
| shortlog.h | ||
| show-index.c | ||
| sideband.c | ||
| sideband.h | ||
| sigchain.c | ||
| sigchain.h | ||
| split-index.c | ||
| split-index.h | ||
| strbuf.c | ||
| strbuf.h | ||
| streaming.c | ||
| streaming.h | ||
| string-list.c | ||
| string-list.h | ||
| submodule.c | ||
| submodule.h | ||
| symlinks.c | ||
| tag.c | ||
| tag.h | ||
| tar.h | ||
| test-chmtime.c | ||
| test-config.c | ||
| test-ctype.c | ||
| test-date.c | ||
| test-delta.c | ||
| test-dump-cache-tree.c | ||
| test-dump-split-index.c | ||
| test-genrandom.c | ||
| test-hashmap.c | ||
| test-index-version.c | ||
| test-line-buffer.c | ||
| test-match-trees.c | ||
| test-mergesort.c | ||
| test-mktemp.c | ||
| test-parse-options.c | ||
| test-path-utils.c | ||
| test-prio-queue.c | ||
| test-read-cache.c | ||
| test-regex.c | ||
| test-revision-walking.c | ||
| test-run-command.c | ||
| test-scrap-cache-tree.c | ||
| test-sha1-array.c | ||
| test-sha1.c | ||
| test-sha1.sh | ||
| test-sigchain.c | ||
| test-string-list.c | ||
| test-subprocess.c | ||
| test-svn-fe.c | ||
| test-urlmatch-normalization.c | ||
| test-wildmatch.c | ||
| thread-utils.c | ||
| thread-utils.h | ||
| trace.c | ||
| trace.h | ||
| trailer.c | ||
| trailer.h | ||
| transport-helper.c | ||
| transport.c | ||
| transport.h | ||
| tree-diff.c | ||
| tree-walk.c | ||
| tree-walk.h | ||
| tree.c | ||
| tree.h | ||
| unicode_width.h | ||
| unimplemented.sh | ||
| unix-socket.c | ||
| unix-socket.h | ||
| unpack-trees.c | ||
| unpack-trees.h | ||
| update_unicode.sh | ||
| upload-pack.c | ||
| url.c | ||
| url.h | ||
| urlmatch.c | ||
| urlmatch.h | ||
| usage.c | ||
| userdiff.c | ||
| userdiff.h | ||
| utf8.c | ||
| utf8.h | ||
| varint.c | ||
| varint.h | ||
| version.c | ||
| version.h | ||
| versioncmp.c | ||
| walker.c | ||
| walker.h | ||
| wildmatch.c | ||
| wildmatch.h | ||
| wrap-for-bin.sh | ||
| wrapper.c | ||
| write_or_die.c | ||
| ws.c | ||
| wt-status.c | ||
| wt-status.h | ||
| xdiff-interface.c | ||
| xdiff-interface.h | ||
| zlib.c | ||
////////////////////////////////////////////////////////////////
Git - the stupid content tracker
////////////////////////////////////////////////////////////////
"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 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.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.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 (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 http://news.gmane.org/gmane.comp.version-control.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.