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Jeff King cd37996795 pack-objects: break out of want_object loop early
When pack-objects collects the list of objects to pack
(either from stdin, or via its internal rev-list), it
filters each one through want_object_in_pack().

This function loops through each existing packfile, looking
for the object. When we find it, we mark the pack/offset
combo for later use. However, we can't just return "yes, we
want it" at that point. If --honor-pack-keep is in effect,
we must keep looking to find it in _all_ packs, to make sure
none of them has a .keep. Likewise, if --local is in effect,
we must make sure it is not present in any non-local pack.

As a result, the sum effort of these calls is effectively
O(nr_objects * nr_packs). In an ordinary repository, we have
only a handful of packs, and this doesn't make a big
difference. But in pathological cases, it can slow the
counting phase to a crawl.

This patch notices the case that we have neither "--local"
nor "--honor-pack-keep" in effect and breaks out of the loop
early, after finding the first instance. Note that our worst
case is still "objects * packs" (i.e., we might find each
object in the last pack we look in), but in practice we will
often break out early. On an "average" repo, my git.git with
8 packs, this shows a modest 2% (a few dozen milliseconds)
improvement in the counting-objects phase of "git
pack-objects --all <foo" (hackily instrumented by sticking
exit(0) right after list_objects).

But in a much more pathological case, it makes a bigger
difference. I ran the same command on a real-world example
with ~9 million objects across 1300 packs. The counting time
dropped from 413s to 45s, an improvement of about 89%.

Note that this patch won't do anything by itself for a
normal "git gc", as it uses both --honor-pack-keep and
--local.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-29 11:05:07 -07:00
Documentation Sixth batch of topics for 2.10 2016-07-19 13:26:16 -07:00
block-sha1
builtin pack-objects: break out of want_object loop early 2016-07-29 11:05:07 -07:00
ci travis-ci: build documentation 2016-05-10 11:19:07 -07:00
compat Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
contrib Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
ewah
git-gui
gitk-git Merge branch 'master' of git://ozlabs.org/~paulus/gitk 2016-03-20 18:05:10 -07:00
gitweb Merge branch 'sk/gitweb-highlight-encoding' into HEAD 2016-05-18 14:40:10 -07:00
mergetools mergetools: add support for ExamDiff 2016-04-04 09:15:14 -07:00
perl git-svn: warn instead of dying when commit data is missing 2016-07-09 22:53:54 +00:00
po Merge branch 'va/i18n-even-more' 2016-07-13 11:24:10 -07:00
ppc
refs coccinelle: apply object_id Coccinelle transformations 2016-06-28 11:39:02 -07:00
t t/perf: add tests for many-pack scenarios 2016-07-29 11:05:06 -07:00
templates
vcs-svn vcs-svn: use error_errno() 2016-05-09 12:29:08 -07:00
xdiff Merge branch 'rs/xdiff-hunk-with-func-line' into maint 2016-06-27 09:56:24 -07:00
.gitattributes .gitattributes: set file type for C files 2016-07-07 14:11:15 -07:00
.gitignore test helpers: move test-* to t/helper/ subdirectory 2016-04-15 10:12:19 -07:00
.mailmap mailmap: use main email address for dturner 2016-07-06 10:57:01 -07:00
.travis.yml perf: accommodate for MacOSX 2016-06-21 11:18:17 -07:00
COPYING
GIT-VERSION-GEN Git 2.9.2 2016-07-15 10:48:16 -07:00
INSTALL
LGPL-2.1
Makefile add generic most-recently-used list 2016-07-29 11:05:07 -07:00
README.md README.md: format CLI commands with code syntax 2016-05-31 08:54:24 -07:00
RelNotes Git 2.9.2 2016-07-15 10:48:16 -07:00
abspath.c Windows: shorten code by re-using convert_slashes() 2016-04-04 18:03:02 -07:00
aclocal.m4
advice.c i18n: advice: internationalize message for conflicts 2016-06-17 15:45:48 -07:00
advice.h
alias.c
alloc.c
archive-tar.c archive-tar: huge offset and future timestamps would not work on 32-bit 2016-07-15 10:51:55 -07:00
archive-zip.c
archive.c pathspec: rename free_pathspec() to clear_pathspec() 2016-06-02 14:09:22 -07:00
archive.h
argv-array.c
argv-array.h
attr.c Merge branch 'ss/exc-flag-is-a-collection-of-bits' into maint 2016-04-14 18:37:15 -07:00
attr.h
base85.c
bisect.c Merge branch 'jk/printf-format' 2016-07-19 13:22:22 -07:00
bisect.h
blob.c
blob.h
branch.c worktree.c: check whether branch is rebased in another worktree 2016-04-22 14:09:38 -07:00
branch.h worktree.c: check whether branch is rebased in another worktree 2016-04-22 14:09:38 -07:00
builtin.h
bulk-checkin.c
bulk-checkin.h
bundle.c bundle: don't leak an fd in case of early return 2016-04-01 10:33:18 -07:00
bundle.h
cache-tree.c struct name_entry: use struct object_id instead of unsigned char sha1[20] 2016-04-25 14:23:42 -07:00
cache-tree.h
cache.h find_pack_entry: replace last_found_pack with MRU cache 2016-07-29 11:05:07 -07:00
check-builtins.sh
check-racy.c check-racy.c: use error_errno() 2016-05-09 12:29:08 -07:00
check_bindir
color.c Merge branch 'jk/ansi-color' 2016-07-11 10:31:05 -07:00
color.h Merge branch 'js/color-on-windows-comment' 2016-07-11 10:31:09 -07:00
column.c
column.h
combine-diff.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
command-list.txt
commit-slab.h
commit.c Merge branch 'jk/printf-format' 2016-07-19 13:22:22 -07:00
commit.h Merge branch 'jk/printf-format' 2016-07-19 13:22:22 -07:00
common-main.c mingw: declare main()'s argv as const 2016-07-06 08:11:47 -07:00
config.c Merge branch 'jk/upload-pack-hook' 2016-07-06 13:38:11 -07:00
config.mak.in
config.mak.uname mingw: make isatty() recognize MSYS2's pseudo terminals (/dev/pty*) 2016-05-26 13:12:02 -07:00
configure.ac Merge branch 'ky/imap-send-openssl-1.1.0' into maint 2016-05-06 14:53:24 -07:00
connect.c connect: read $GIT_SSH_COMMAND from config file 2016-07-06 14:04:09 -07:00
connect.h
connected.c connected.c: use error_errno() 2016-05-09 12:29:08 -07:00
connected.h
convert.c convert.c: ident + core.autocrlf didn't work 2016-04-25 12:12:03 -07:00
convert.h
copy.c copy.c: use error_errno() 2016-05-09 12:29:08 -07:00
credential-cache--daemon.c Merge branch 'jk/common-main-2.8' into jk/common-main 2016-07-06 10:02:57 -07:00
credential-cache.c add an extra level of indirection to main() 2016-07-01 15:09:10 -07:00
credential-store.c add an extra level of indirection to main() 2016-07-01 15:09:10 -07:00
credential.c
credential.h
csum-file.c
csum-file.h
ctype.c
daemon.c Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
date.c local_tzoffset: detect errors from tm_to_time_t 2016-06-20 15:08:07 -07:00
decorate.c
decorate.h
delta.h
diff-delta.c
diff-lib.c
diff-no-index.c diff-no-index.c: use error_errno() 2016-05-09 12:29:08 -07:00
diff.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
diff.h Merge branch 'mm/diff-renames-default' 2016-04-03 10:29:22 -07:00
diffcore-break.c diff: rename struct diff_filespec's sha1_valid member 2016-06-28 11:39:02 -07:00
diffcore-delta.c
diffcore-order.c
diffcore-pickaxe.c diffcore-pickaxe: support case insensitive match on non-ascii 2016-07-01 12:44:57 -07:00
diffcore-rename.c diff: rename struct diff_filespec's sha1_valid member 2016-06-28 11:39:02 -07:00
diffcore.h diff: rename struct diff_filespec's sha1_valid member 2016-06-28 11:39:02 -07:00
dir.c Merge branch 'nd/worktree-various-heads' 2016-05-23 14:54:29 -07:00
dir.h Merge branch 'nd/worktree-various-heads' 2016-05-23 14:54:29 -07:00
editor.c editor.c: use error_errno() 2016-05-09 12:29:08 -07:00
entry.c entry.c: use error_errno() 2016-05-09 12:29:08 -07:00
environment.c Merge branch 'js/windows-dotgit' into maint 2016-05-26 13:17:23 -07:00
exec_cmd.c
exec_cmd.h
fast-import.c Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
fetch-pack.c fetch-pack: isolate sigpipe in demuxer thread 2016-04-20 13:33:56 -07:00
fetch-pack.h
fmt-merge-msg.h
fsck.c Merge branch 'jc/fsck-nul-in-commit' 2016-05-17 14:38:34 -07:00
fsck.h
generate-cmdlist.sh
gettext.c gettext: add is_utf8_locale() 2016-07-01 12:44:57 -07:00
gettext.h gettext: add is_utf8_locale() 2016-07-01 12:44:57 -07:00
git-add--interactive.perl add--interactive: respect diff.compactionHeuristic 2016-06-16 11:38:58 -07:00
git-archimport.perl
git-bisect.sh i18n: unmark die messages for translation 2016-06-17 15:46:10 -07:00
git-compat-util.h Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
git-cvsexportcommit.perl
git-cvsimport.perl
git-cvsserver.perl typofix: assorted typofixes in comments, documentation and messages 2016-05-06 13:16:37 -07:00
git-difftool--helper.sh difftool/mergetool: make the form of yes/no questions consistent 2016-04-25 15:15:17 -07:00
git-difftool.perl difftool: handle unmerged files in dir-diff mode 2016-05-16 14:53:05 -07:00
git-filter-branch.sh
git-instaweb.sh
git-merge-octopus.sh i18n: git-sh-setup.sh: mark strings for translation 2016-06-17 15:45:48 -07:00
git-merge-one-file.sh
git-merge-resolve.sh
git-mergetool--lib.sh Merge branch 'nf/mergetool-prompt' 2016-05-03 14:08:17 -07:00
git-mergetool.sh Merge branch 'nf/mergetool-prompt' into HEAD 2016-05-18 14:40:07 -07:00
git-p4.py Merge branch 'ls/p4-tmp-refs' 2016-07-19 13:22:24 -07:00
git-parse-remote.sh i18n: git-parse-remote.sh: mark strings for translation 2016-04-19 12:07:49 -07:00
git-quiltimport.sh
git-rebase--am.sh rebase: update comment about FreeBSD /bin/sh 2016-06-17 11:04:38 -07:00
git-rebase--interactive.sh Merge branch 'ps/rebase-i-auto-unstash-upon-abort' 2016-07-13 11:24:17 -07:00
git-rebase--merge.sh Merge branch 'em/newer-freebsd-shells-are-fine-with-returns' into maint 2016-07-06 13:06:41 -07:00
git-rebase.sh i18n: git-sh-setup.sh: mark strings for translation 2016-06-17 15:45:48 -07:00
git-relink.perl
git-remote-testgit.sh
git-request-pull.sh
git-send-email.perl Merge branch 'jc/send-email-skip-backup' 2016-07-11 10:31:04 -07:00
git-sh-i18n.sh i18n: rebase-interactive: mark here-doc strings for translation 2016-06-17 15:45:48 -07:00
git-sh-setup.sh Merge branch 'va/i18n-even-more' 2016-07-13 11:24:10 -07:00
git-stash.sh i18n: git-sh-setup.sh: mark strings for translation 2016-06-17 15:45:48 -07:00
git-submodule.sh Merge branch 'va/i18n-even-more' 2016-07-13 11:24:10 -07:00
git-svn.perl git-svn: clone: Fail on missing url argument 2016-07-03 06:04:47 +00:00
git-web--browse.sh
git.c common-main: call git_setup_gettext() 2016-07-01 15:09:10 -07:00
git.rc
gpg-interface.c gpg-interface: check gpg signature creation status 2016-06-17 17:03:57 -07:00
gpg-interface.h
graph.c Merge branch 'js/log-to-diffopt-file' 2016-07-19 13:22:15 -07:00
graph.h pretty: pass graph width to pretty formatting for use in '%>|(N)' 2016-06-16 11:43:36 -07:00
grep.c Merge branch 'nd/icase' 2016-07-19 13:22:17 -07:00
grep.h grep/pcre: prepare locale-dependent tables for icase matching 2016-07-01 12:44:57 -07:00
hashmap.c
hashmap.h
help.c t0006: skip "far in the future" test when unsigned long is not long enough 2016-07-15 09:05:53 -07:00
help.h
hex.c hex: add oid_to_hex_r() 2016-06-28 11:39:02 -07:00
http-backend.c Merge branch 'jk/common-main-2.8' into jk/common-main 2016-07-06 10:02:57 -07:00
http-fetch.c common-main: call git_setup_gettext() 2016-07-01 15:09:10 -07:00
http-push.c Merge branch 'jk/common-main-2.8' into jk/common-main 2016-07-06 10:02:57 -07:00
http-walker.c
http.c Merge branch 'ep/http-curl-trace' 2016-07-06 13:38:06 -07:00
http.h Merge branch 'ep/http-curl-trace' 2016-07-06 13:38:06 -07:00
ident.c Merge branch 'da/user-useconfigonly' into HEAD 2016-05-18 14:40:05 -07:00
imap-send.c Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
khash.h
kwset.c
kwset.h
levenshtein.c
levenshtein.h
line-log.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
line-log.h
line-range.c
line-range.h
list-objects.c struct name_entry: use struct object_id instead of unsigned char sha1[20] 2016-04-25 14:23:42 -07:00
list-objects.h list-objects: pass full pathname to callbacks 2016-03-16 10:41:04 -07:00
ll-merge.c Merge branch 'jc/ll-merge-internal' 2016-05-17 14:38:32 -07:00
ll-merge.h
lockfile.c
lockfile.h
log-tree.c Merge branch 'js/log-to-diffopt-file' 2016-07-19 13:22:15 -07:00
log-tree.h
mailinfo.c
mailinfo.h
mailmap.c Merge branch 'nd/error-errno' 2016-05-17 14:38:28 -07:00
mailmap.h
match-trees.c match-trees: convert several leaf functions to use struct object_id 2016-04-25 14:26:29 -07:00
merge-blobs.c
merge-blobs.h
merge-recursive.c merge-recursive: convert merge_recursive_generic() to object_id 2016-06-28 11:39:02 -07:00
merge-recursive.h merge-recursive: convert merge_recursive_generic() to object_id 2016-06-28 11:39:02 -07:00
merge.c
mergesort.c
mergesort.h
mru.c add generic most-recently-used list 2016-07-29 11:05:07 -07:00
mru.h add generic most-recently-used list 2016-07-29 11:05:07 -07:00
name-hash.c
notes-cache.c
notes-cache.h
notes-merge.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
notes-merge.h
notes-utils.c
notes-utils.h
notes.c use string_list initializer consistently 2016-06-13 10:37:51 -07:00
notes.h
object.c
object.h
pack-bitmap-write.c Merge branch 'jk/path-name-safety-2.6' into jk/path-name-safety-2.7 2016-03-16 10:42:32 -07:00
pack-bitmap.c Merge branch 'jk/path-name-safety-2.6' into jk/path-name-safety-2.7 2016-03-16 10:42:32 -07:00
pack-bitmap.h
pack-check.c
pack-objects.c
pack-objects.h
pack-revindex.c
pack-revindex.h
pack-write.c sha1_file: drop free_pack_by_name 2016-07-29 11:05:06 -07:00
pack.h
pager.c
parse-options-cb.c Merge branch 'jk/parseopt-string-list' into jk/string-list-static-init 2016-06-13 10:37:48 -07:00
parse-options.c parse-options.c: make OPTION_COUNTUP respect "unspecified" values 2016-05-05 11:52:45 -07:00
parse-options.h
patch-delta.c
patch-ids.c patch-ids: make commit_patch_id() a public helper function 2016-04-26 10:49:57 -07:00
patch-ids.h patch-ids: make commit_patch_id() a public helper function 2016-04-26 10:49:57 -07:00
path.c Merge branch 'lp/typofixes' into maint 2016-05-26 13:17:21 -07:00
pathspec.c pathspec: rename free_pathspec() to clear_pathspec() 2016-06-02 14:09:22 -07:00
pathspec.h pathspec: rename free_pathspec() to clear_pathspec() 2016-06-02 14:09:22 -07:00
pkt-line.c
pkt-line.h
preload-index.c
pretty.c Merge branch 'nd/graph-width-padded' into maint 2016-07-11 10:44:09 -07:00
prio-queue.c
prio-queue.h
progress.c
progress.h
prompt.c
prompt.h
quote.c Merge branch 'nd/icase' 2016-07-19 13:22:17 -07:00
quote.h Merge branch 'nd/icase' 2016-07-19 13:22:17 -07:00
reachable.c reachable.c: use error_errno() 2016-05-09 12:29:08 -07:00
reachable.h
read-cache.c add: add --chmod=+x / --chmod=-x options 2016-06-07 17:43:39 -07:00
ref-filter.c
ref-filter.h
reflog-walk.c reflog: continue walking the reflog past root commits 2016-06-06 15:06:44 -07:00
reflog-walk.h
refs.c refs: move resolve_ref_unsafe into common code 2016-04-10 11:35:41 -07:00
refs.h refs.h: fix misspelt "occurred" in a comment 2016-06-10 14:53:32 -07:00
remote-curl.c Merge branch 'jk/common-main-2.8' into jk/common-main 2016-07-06 10:02:57 -07:00
remote-testsvn.c common-main: call git_extract_argv0_path() 2016-07-01 15:09:10 -07:00
remote.c Merge branch 'nd/remote-plural-ours-plus-theirs' into maint 2016-05-26 13:17:18 -07:00
remote.h
replace_object.c
rerere.c Merge branch 'jc/rerere-multi' 2016-05-23 14:54:38 -07:00
rerere.h Merge branch 'jc/rerere-multi' 2016-04-25 15:17:15 -07:00
resolve-undo.c
resolve-undo.h
revision.c Merge branch 'mj/log-show-signature-conf' 2016-07-11 10:31:08 -07:00
revision.h Merge branch 'lt/pretty-expand-tabs' 2016-04-13 14:12:36 -07:00
run-command.c run-command: add pipe_command helper 2016-06-17 17:03:56 -07:00
run-command.h run-command: add pipe_command helper 2016-06-17 17:03:56 -07:00
send-pack.c send-pack: use buffered I/O to talk to pack-objects 2016-06-08 16:02:40 -07:00
send-pack.h
sequencer.c Merge branch 'va/i18n-even-more' 2016-07-13 11:24:10 -07:00
sequencer.h
server-info.c server-info.c: use error_errno() 2016-05-09 12:29:08 -07:00
setup.c i18n: setup: mark strings for translation 2016-06-17 15:45:48 -07:00
sh-i18n--envsubst.c add an extra level of indirection to main() 2016-07-01 15:09:10 -07:00
sha1-array.c
sha1-array.h
sha1-lookup.c
sha1-lookup.h
sha1_file.c find_pack_entry: replace last_found_pack with MRU cache 2016-07-29 11:05:07 -07:00
sha1_name.c Merge branch 'bc/object-id' 2016-05-06 14:45:44 -07:00
shallow.c
shell.c common-main: call git_setup_gettext() 2016-07-01 15:09:10 -07:00
shortlog.h shortlog: support outputting to streams other than stdout 2016-06-24 14:25:49 -07:00
show-index.c common-main: call git_setup_gettext() 2016-07-01 15:09:10 -07:00
sideband.c Merge branch 'lf/recv-sideband-cleanup' 2016-07-19 13:22:14 -07:00
sideband.h sideband.c: make send_sideband() return void 2016-06-16 11:40:19 -07:00
sigchain.c
sigchain.h
split-index.c typofix: assorted typofixes in comments, documentation and messages 2016-05-06 13:16:37 -07:00
split-index.h
strbuf.c Merge branch 'jk/getwholeline-getdelim-empty' into maint 2016-04-14 18:57:46 -07:00
strbuf.h Merge branch 'pb/strbuf-read-file-doc' into maint 2016-07-06 13:06:45 -07:00
streaming.c
streaming.h
string-list.c string_list: use string-list API in unsorted_string_list_lookup() 2016-04-25 11:48:27 -07:00
string-list.h
submodule-config.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
submodule-config.h submodule-config: keep shallow recommendation around 2016-05-27 10:40:45 -07:00
submodule.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
submodule.h Merge branch 'jk/submodule-c-credential' 2016-05-17 14:38:25 -07:00
symlinks.c
tag.c verify-tag: move tag verification code to tag.c 2016-04-22 14:06:46 -07:00
tag.h verify-tag: move tag verification code to tag.c 2016-04-22 14:06:46 -07:00
tar.h
tempfile.c
tempfile.h
thread-utils.c
thread-utils.h
trace.c
trace.h
trailer.c
trailer.h
transport-helper.c i18n: transport-helper.c: change N_() call to _() 2016-06-17 15:45:49 -07:00
transport.c i18n: transport: mark strings for translation 2016-06-17 15:45:48 -07:00
transport.h
tree-diff.c Merge branch 'jk/avoid-unbounded-alloca' into maint 2016-07-06 13:06:39 -07:00
tree-walk.c tree-walk: convert tree_entry_extract() to use struct object_id 2016-04-25 14:26:28 -07:00
tree-walk.h tree-walk: convert tree_entry_extract() to use struct object_id 2016-04-25 14:26:28 -07:00
tree.c struct name_entry: use struct object_id instead of unsigned char sha1[20] 2016-04-25 14:23:42 -07:00
tree.h
unicode_width.h
unimplemented.sh
unix-socket.c
unix-socket.h
unpack-trees.c unpack-trees: fix English grammar in do-this-before-that messages 2016-06-27 08:29:36 -07:00
unpack-trees.h
update_unicode.sh
upload-pack.c Merge branch 'jk/common-main' 2016-07-19 13:22:19 -07:00
url.c
url.h
urlmatch.c
urlmatch.h
usage.c usage.c: add warning_errno() and error_errno() 2016-05-09 12:29:08 -07:00
userdiff.c userdiff: add built-in pattern for CSS 2016-06-03 14:45:56 -07:00
userdiff.h
utf8.c
utf8.h typofix: assorted typofixes in comments, documentation and messages 2016-05-06 13:16:37 -07:00
varint.c
varint.h
version.c
version.h
versioncmp.c
walker.c walker: let walker_say take arbitrary formats 2016-07-08 10:11:23 -07:00
walker.h walker: let walker_say take arbitrary formats 2016-07-08 10:11:23 -07:00
wildmatch.c typofix: assorted typofixes in comments, documentation and messages 2016-05-06 13:16:37 -07:00
wildmatch.h
worktree.c Merge branch 'nd/worktree-cleanup-post-head-protection' 2016-07-06 13:38:11 -07:00
worktree.h branch: do not rename a branch under bisect or rebase 2016-04-22 14:09:39 -07:00
wrap-for-bin.sh wrap-for-bin.sh: regenerate bin-wrappers when switching branches 2016-05-10 13:23:34 -07:00
wrapper.c Merge branch 'jk/write-file' 2016-07-19 13:22:23 -07:00
write_or_die.c write_or_die: remove the unused write_or_whine() function 2016-06-10 10:54:27 -07:00
ws.c
wt-status.c Merge branch 'bc/cocci' 2016-07-19 13:22:16 -07:00
wt-status.h wt-status.c: split bisect detection out of wt_status_get_state() 2016-04-22 14:09:39 -07:00
xdiff-interface.c xdiff: don't trim common tail with -W 2016-05-31 13:08:56 -07:00
xdiff-interface.h
zlib.c

README.md

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 http://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 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.

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