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Ævar Arnfjörð Bjarmason b65abcafc7 grep: use PCRE v2 for optimized fixed-string search
Bring back optimized fixed-string search for "grep", this time with
PCRE v2 as an optional backend. As noted in [1] with kwset we were
slower than PCRE v1 and v2 JIT with the kwset backend, so that
optimization was counterproductive.

This brings back the optimization for "--fixed-strings", without
changing the semantics of having a NUL-byte in patterns. As seen in
previous commits in this series we could support it now, but I'd
rather just leave that edge-case aside so we don't have one behavior
or the other depending what "--fixed-strings" backend we're using. It
makes the behavior harder to understand and document, and makes tests
for the different backends more painful.

This does change the behavior under non-C locales when "log"'s
"--encoding" option is used and the heystack/needle in the
content/command-line doesn't have a matching encoding. See the recent
change in "t4210: skip more command-line encoding tests on MinGW" in
this series. I think that's OK. We did nothing sensible before
then (just compared raw bytes that had no hope of matching). At least
now the user will get some idea why their grep/log never matches in
that edge case.

I could also support the PCRE v1 backend here, but that would make the
code more complex. I'd rather aim for simplicity here and in future
changes to the diffcore. We're not going to have someone who
absolutely must have faster search, but for whom building PCRE v2
isn't acceptable.

The difference between this series of commits and the current "master"
is, using the same t/perf commands shown in the last commit:

plain grep:

    Test                             origin/master     HEAD
    -------------------------------------------------------------------------
    7821.1: fixed grep int           0.55(1.67+0.56)   0.41(0.98+0.60) -25.5%
    7821.2: basic grep int           0.58(1.65+0.52)   0.41(0.96+0.57) -29.3%
    7821.3: extended grep int        0.57(1.66+0.49)   0.42(0.93+0.60) -26.3%
    7821.4: perl grep int            0.54(1.67+0.50)   0.43(0.88+0.65) -20.4%
    7821.6: fixed grep uncommon      0.21(0.52+0.42)   0.16(0.24+0.51) -23.8%
    7821.7: basic grep uncommon      0.20(0.49+0.45)   0.17(0.28+0.47) -15.0%
    7821.8: extended grep uncommon   0.20(0.54+0.39)   0.16(0.25+0.50) -20.0%
    7821.9: perl grep uncommon       0.20(0.58+0.36)   0.16(0.23+0.50) -20.0%
    7821.11: fixed grep æ            0.35(1.24+0.43)   0.16(0.23+0.50) -54.3%
    7821.12: basic grep æ            0.36(1.29+0.38)   0.16(0.20+0.54) -55.6%
    7821.13: extended grep æ         0.35(1.23+0.44)   0.16(0.24+0.50) -54.3%
    7821.14: perl grep æ             0.35(1.33+0.34)   0.16(0.28+0.46) -54.3%

grep with -i:

    Test                                origin/master     HEAD
    ----------------------------------------------------------------------------
    7821.1: fixed grep -i int           0.62(1.81+0.70)   0.47(1.11+0.64) -24.2%
    7821.2: basic grep -i int           0.67(1.90+0.53)   0.46(1.07+0.62) -31.3%
    7821.3: extended grep -i int        0.62(1.92+0.53)   0.53(1.12+0.58) -14.5%
    7821.4: perl grep -i int            0.66(1.85+0.58)   0.45(1.10+0.59) -31.8%
    7821.6: fixed grep -i uncommon      0.21(0.54+0.43)   0.17(0.20+0.55) -19.0%
    7821.7: basic grep -i uncommon      0.20(0.52+0.45)   0.17(0.29+0.48) -15.0%
    7821.8: extended grep -i uncommon   0.21(0.52+0.44)   0.17(0.26+0.50) -19.0%
    7821.9: perl grep -i uncommon       0.21(0.53+0.44)   0.17(0.20+0.56) -19.0%
    7821.11: fixed grep -i æ            0.26(0.79+0.44)   0.16(0.29+0.46) -38.5%
    7821.12: basic grep -i æ            0.26(0.79+0.42)   0.16(0.20+0.54) -38.5%
    7821.13: extended grep -i æ         0.26(0.84+0.39)   0.16(0.24+0.50) -38.5%
    7821.14: perl grep -i æ             0.16(0.24+0.49)   0.17(0.25+0.51) +6.3%

plain log:

    Test                                     origin/master     HEAD
    --------------------------------------------------------------------------------
    4221.1: fixed log --grep='int'           7.24(6.95+0.28)   7.20(6.95+0.18) -0.6%
    4221.2: basic log --grep='int'           7.31(6.97+0.22)   7.20(6.93+0.21) -1.5%
    4221.3: extended log --grep='int'        7.37(7.04+0.24)   7.22(6.91+0.25) -2.0%
    4221.4: perl log --grep='int'            7.31(7.04+0.21)   7.19(6.89+0.21) -1.6%
    4221.6: fixed log --grep='uncommon'      6.93(6.59+0.32)   7.04(6.66+0.37) +1.6%
    4221.7: basic log --grep='uncommon'      6.92(6.58+0.29)   7.08(6.75+0.29) +2.3%
    4221.8: extended log --grep='uncommon'   6.92(6.55+0.31)   7.00(6.68+0.31) +1.2%
    4221.9: perl log --grep='uncommon'       7.03(6.59+0.33)   7.12(6.73+0.34) +1.3%
    4221.11: fixed log --grep='æ'            7.41(7.08+0.28)   7.05(6.76+0.29) -4.9%
    4221.12: basic log --grep='æ'            7.39(6.99+0.33)   7.00(6.68+0.25) -5.3%
    4221.13: extended log --grep='æ'         7.34(7.00+0.25)   7.15(6.81+0.31) -2.6%
    4221.14: perl log --grep='æ'             7.43(7.13+0.26)   7.01(6.60+0.36) -5.7%

log with -i:

    Test                                        origin/master     HEAD
    ------------------------------------------------------------------------------------
    4221.1: fixed log -i --grep='int'           7.31(7.07+0.24)   7.23(7.00+0.22) -1.1%
    4221.2: basic log -i --grep='int'           7.40(7.08+0.28)   7.19(6.92+0.20) -2.8%
    4221.3: extended log -i --grep='int'        7.43(7.13+0.25)   7.27(6.99+0.21) -2.2%
    4221.4: perl log -i --grep='int'            7.34(7.10+0.24)   7.10(6.90+0.19) -3.3%
    4221.6: fixed log -i --grep='uncommon'      7.07(6.71+0.32)   7.11(6.77+0.28) +0.6%
    4221.7: basic log -i --grep='uncommon'      6.99(6.64+0.28)   7.12(6.69+0.38) +1.9%
    4221.8: extended log -i --grep='uncommon'   7.11(6.74+0.32)   7.10(6.77+0.27) -0.1%
    4221.9: perl log -i --grep='uncommon'       6.98(6.60+0.29)   7.05(6.64+0.34) +1.0%
    4221.11: fixed log -i --grep='æ'            7.85(7.45+0.34)   7.03(6.68+0.32) -10.4%
    4221.12: basic log -i --grep='æ'            7.87(7.49+0.29)   7.06(6.69+0.31) -10.3%
    4221.13: extended log -i --grep='æ'         7.87(7.54+0.31)   7.09(6.69+0.31) -9.9%
    4221.14: perl log -i --grep='æ'             7.06(6.77+0.28)   6.91(6.57+0.31) -2.1%

So as with e05b027627 ("grep: use PCRE v2 for optimized fixed-string
search", 2019-06-26) there's a huge improvement in performance for
"grep", but in "log" most of our time is spent elsewhere, so we don't
notice it that much.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-01 14:33:14 -07:00
.github
Documentation grep: make the behavior for NUL-byte in patterns sane 2019-07-01 14:33:14 -07:00
block-sha1
builtin Merge branch 'jt/partial-clone-missing-ref-delta-base' 2019-06-21 11:24:09 -07:00
ci
compat
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ewah
git-gui
gitk-git
gitweb
mergetools
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perl
po Merge branch 'fr_review' of git://github.com/jnavila/git 2019-06-07 16:51:09 +08:00
ppc
refs
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sha1dc
sha256
t grep: drop support for \0 in --fixed-strings <pattern> 2019-07-01 14:33:14 -07:00
templates
trace2 Merge branch 'sg/trace2-rename' 2019-05-30 10:50:45 -07:00
vcs-svn
xdiff
.clang-format clang-format: use git grep to generate the ForEachMacros list 2019-06-04 14:50:40 -07:00
.editorconfig
.gitattributes
.gitignore
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INSTALL
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README.md
RelNotes The first batch after 2.22 2019-06-13 13:23:03 -07:00
abspath.c
aclocal.m4
advice.c
advice.h
alias.c
alias.h
alloc.c
alloc.h
apply.c fill_stat_cache_info(): prepare for an fsmonitor fix 2019-05-28 12:43:42 -07:00
apply.h
archive-tar.c
archive-zip.c
archive.c
archive.h
argv-array.c
argv-array.h
attr.c
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azure-pipelines.yml
banned.h
base85.c
bisect.c
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blame.c
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blob.c
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branch.c Merge branch 'nd/merge-quit' 2019-06-13 13:19:41 -07:00
branch.h Merge branch 'nd/merge-quit' 2019-06-13 13:19:41 -07:00
builtin.h
bulk-checkin.c
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bundle.c bundle verify: error out if called without an object database 2019-05-28 13:04:14 -07:00
bundle.h
cache-tree.c
cache-tree.h
cache.h fill_stat_cache_info(): prepare for an fsmonitor fix 2019-05-28 12:43:42 -07:00
chdir-notify.c
chdir-notify.h
check-builtins.sh
check_bindir
checkout.c
checkout.h
color.c
color.h
column.c
column.h
combine-diff.c
command-list.txt
commit-graph.c
commit-graph.h
commit-reach.c
commit-reach.h
commit-slab-decl.h
commit-slab-impl.h
commit-slab.h
commit.c
commit.h
common-main.c
config.c
config.h
config.mak.dev
config.mak.in
config.mak.uname
configure.ac
connect.c
connect.h
connected.c
connected.h
convert.c
convert.h
copy.c
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-islands.c
delta-islands.h
delta.h
detect-compiler
diff-delta.c
diff-lib.c mark_fsmonitor_valid(): mark the index as changed if needed 2019-05-28 12:43:43 -07:00
diff-no-index.c
diff.c Merge branch 'sb/format-patch-base-patch-id-fix' 2019-06-13 13:18:46 -07:00
diff.h Merge branch 'sb/format-patch-base-patch-id-fix' 2019-06-13 13:18:46 -07:00
diffcore-break.c
diffcore-delta.c
diffcore-order.c
diffcore-pickaxe.c
diffcore-rename.c
diffcore.h
dir-iterator.c
dir-iterator.h
dir.c
dir.h
editor.c
entry.c fill_stat_cache_info(): prepare for an fsmonitor fix 2019-05-28 12:43:42 -07:00
environment.c
exec-cmd.c
exec-cmd.h
fast-import.c
fetch-negotiator.c
fetch-negotiator.h
fetch-object.c
fetch-object.h
fetch-pack.c Merge branch 'jt/clone-server-option' 2019-05-30 10:50:46 -07:00
fetch-pack.h
fmt-merge-msg.h
fsck.c
fsck.h
fsmonitor.c
fsmonitor.h mark_fsmonitor_valid(): mark the index as changed if needed 2019-05-28 12:43:43 -07:00
fuzz-commit-graph.c
fuzz-pack-headers.c
fuzz-pack-idx.c
generate-cmdlist.sh
gettext.c
gettext.h
git-add--interactive.perl
git-archimport.perl
git-bisect.sh
git-compat-util.h
git-cvsexportcommit.perl
git-cvsimport.perl
git-cvsserver.perl
git-difftool--helper.sh
git-filter-branch.sh
git-instaweb.sh
git-legacy-stash.sh
git-merge-octopus.sh
git-merge-one-file.sh
git-merge-resolve.sh
git-mergetool--lib.sh
git-mergetool.sh
git-p4.py Merge branch 'mm/p4-unshelve-windows-fix' 2019-06-17 10:15:19 -07:00
git-parse-remote.sh
git-quiltimport.sh
git-rebase--preserve-merges.sh
git-request-pull.sh request-pull: warn if the remote object is not the same as the local one 2019-05-28 13:06:25 -07:00
git-send-email.perl Merge branch 'ab/send-email-transferencoding-fix' 2019-06-13 13:18:46 -07:00
git-sh-i18n.sh
git-sh-setup.sh
git-submodule.sh
git-svn.perl
git-web--browse.sh
git.c Merge branch 'po/git-help-on-git-itself' 2019-06-17 10:15:19 -07:00
git.rc
gpg-interface.c
gpg-interface.h
graph.c
graph.h
grep.c grep: use PCRE v2 for optimized fixed-string search 2019-07-01 14:33:14 -07:00
grep.h grep: remove the kwset optimization 2019-07-01 14:33:14 -07:00
hash.h
hashmap.c
hashmap.h
help.c Merge branch 'jk/help-unknown-ref-fix' 2019-06-13 13:19:42 -07:00
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
interdiff.c
interdiff.h
iterator.h
json-writer.c
json-writer.h
khash.h
kwset.c
kwset.h
levenshtein.c
levenshtein.h
line-log.c
line-log.h
line-range.c
line-range.h
linear-assignment.c
linear-assignment.h
list-objects-filter-options.c Merge branch 'md/list-objects-filter-parse-msgfix' 2019-06-21 11:24:10 -07:00
list-objects-filter-options.h list-objects-filter: disable 'sparse:path' filters 2019-05-29 11:05:34 -07:00
list-objects-filter.c Merge branch 'md/list-objects-filter-memfix' 2019-06-21 11:24:09 -07:00
list-objects-filter.h
list-objects.c
list-objects.h
list.h
ll-merge.c
ll-merge.h
lockfile.c
lockfile.h
log-tree.c
log-tree.h
ls-refs.c upload-pack: strip namespace from symref data 2019-05-28 10:02:00 -07:00
ls-refs.h
mailinfo.c
mailinfo.h
mailmap.c
mailmap.h
match-trees.c
mem-pool.c
mem-pool.h
merge-blobs.c
merge-blobs.h
merge-recursive.c Merge branch 'en/merge-directory-renames-fix' 2019-06-06 14:03:36 -07:00
merge-recursive.h
merge.c
mergesort.c
mergesort.h
midx.c
midx.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-store.h Merge branch 'ds/object-info-for-prefetch-fix' 2019-06-17 10:15:14 -07:00
object.c
object.h
oidmap.c
oidmap.h
oidset.c
oidset.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
packfile.c Merge branch 'mh/import-transport-fd-fix' 2019-06-13 13:19:43 -07:00
packfile.h
pager.c
parse-options-cb.c Merge branch 'nd/diff-parseopt' 2019-05-30 10:50:44 -07:00
parse-options.c Merge branch 'nd/diff-parseopt' 2019-05-30 10:50:44 -07:00
parse-options.h
patch-delta.c
patch-ids.c
patch-ids.h
path.c
path.h
pathspec.c
pathspec.h
pkt-line.c
pkt-line.h
preload-index.c mark_fsmonitor_valid(): mark the index as changed if needed 2019-05-28 12:43:43 -07:00
pretty.c
pretty.h
prio-queue.c
prio-queue.h
progress.c Merge branch 'sg/progress-off-by-one-fix' 2019-05-30 10:50:45 -07:00
progress.h
prompt.c
prompt.h
protocol.c
protocol.h
quote.c
quote.h
range-diff.c
range-diff.h
reachable.c
reachable.h
read-cache.c Merge branch 'js/fsmonitor-unflake' 2019-06-17 10:15:18 -07:00
rebase-interactive.c
rebase-interactive.h
ref-filter.c
ref-filter.h
reflog-walk.c
reflog-walk.h
refs.c Merge branch 'nd/worktree-name-sanitization' 2019-06-13 13:19:40 -07:00
refs.h Merge branch 'nd/worktree-name-sanitization' 2019-06-13 13:19:40 -07:00
refspec.c
refspec.h
remote-curl.c i18n: fix typos found during l10n for git 2.22.0 2019-06-03 11:10:53 -07:00
remote-testsvn.c
remote.c
remote.h
replace-object.c
replace-object.h
repository.c
repository.h
rerere.c
rerere.h
resolve-undo.c
resolve-undo.h
revision.c grep: don't use PCRE2?_UTF8 with "log --encoding=<non-utf8>" 2019-06-28 09:11:09 -07:00
revision.h
run-command.c
run-command.h
send-pack.c
send-pack.h
sequencer.c Merge branch 'pw/rebase-edit-message-for-replayed-merge' 2019-06-13 13:19:43 -07:00
sequencer.h
serve.c
serve.h
server-info.c Merge branch 'ew/server-info-remove-crufts' 2019-06-17 10:15:15 -07:00
setup.c
sh-i18n--envsubst.c
sha1-array.c
sha1-array.h
sha1-file.c Merge branch 'ds/object-info-for-prefetch-fix' 2019-06-17 10:15:14 -07:00
sha1-lookup.c
sha1-lookup.h
sha1-name.c Merge branch 'jk/get-oid-indexed-object-name' 2019-05-19 16:45:35 +09:00
sha1dc_git.c
sha1dc_git.h
shallow.c
shell.c
shortlog.h
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
sub-process.c
sub-process.h
submodule-config.c
submodule-config.h
submodule.c
submodule.h
symlinks.c
tag.c
tag.h
tar.h
tempfile.c
tempfile.h
thread-utils.c
thread-utils.h
tmp-objdir.c
tmp-objdir.h
trace.c
trace.h
trace2.c
trace2.h trace2: rename environment variables to GIT_TRACE2* 2019-05-28 10:20:34 -07:00
trailer.c
trailer.h
transport-helper.c Merge branch 'mh/import-transport-fd-fix' 2019-06-13 13:19:43 -07:00
transport-internal.h
transport.c
transport.h
tree-diff.c
tree-walk.c
tree-walk.h
tree.c
tree.h
unicode-width.h Merge branch 'bb/unicode-12.1-reiwa' 2019-06-17 10:15:18 -07:00
unimplemented.sh
unix-socket.c
unix-socket.h
unpack-trees.c
unpack-trees.h
upload-pack.c Merge branch 'jk/HEAD-symref-in-xfer-namespaces' 2019-06-17 10:15:15 -07:00
upload-pack.h
url.c url: do not allow %00 to represent NUL in URLs 2019-06-04 14:48:25 -07:00
url.h
urlmatch.c
urlmatch.h
usage.c
userdiff.c Merge branch 'ml/userdiff-rust' 2019-06-21 11:24:08 -07:00
userdiff.h
utf8.c
utf8.h
varint.c
varint.h
version.c
version.h
versioncmp.c
walker.c
walker.h
wildmatch.c
wildmatch.h
worktree.c Merge branch 'nd/corrupt-worktrees' 2019-06-13 13:19:41 -07:00
worktree.h
wrap-for-bin.sh
wrapper.c
write-or-die.c
ws.c
wt-status.c Merge branch 'jk/unused-params-final-batch' 2019-06-13 13:19:34 -07:00
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zlib.c

README.md

Build Status

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.

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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