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Theodore Leblond 76e7c8a7ed compat/poll: sleep 1 millisecond to avoid busy wait 
SwitchToThread() only gives away the rest of the current time slice
to another thread in the current process. So if the thread that feeds
the file decscriptor we're polling is not in the current process, we
get busy-waiting.

I played around with this quite a bit. After trying some more complex
schemes, I found that what worked best is to just sleep 1 millisecond
between iterations. Though it's a very short time, it still completely
eliminates the busy wait condition, without hurting perf.

There code uses SleepEx(1, TRUE) to sleep. See this page for a good
discussion of why that is better than calling SwitchToThread, which
is what was used previously:
http://stackoverflow.com/questions/1383943/switchtothread-vs-sleep1

Note that calling SleepEx(0, TRUE) does *not* solve the busy wait.

The most striking case was when testing on a UNC share with a large repo,
on a single CPU machine. Without the fix, it took 4 minutes 15 seconds,
and with the fix it took just 1:08! I think it's because git-upload-pack's
busy wait was eating the CPU away from the git process that's doing the
real work. With multi-proc, the timing is not much different, but tons of
CPU time is still wasted, which can be a killer on a server that needs to
do bunch of other things.

I also tested the very fast local case, and didn't see any measurable
difference. On a big repo with 4500 files, the upload-pack took about 2
seconds with and without the fix.

[jc: this was first accepted in msysgit tree in May 2012 via a pull
request and Paolo Bonzini has also accepted the same fix to Gnulib
around the same time; see $gmane/247518 for a bit more detail]

Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Acked-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-29 09:55:38 -07:00
block-sha1
builtin Merge branch 'jl/nor-or-nand-and' into maint 2014-04-09 12:03:26 -07:00
compat compat/poll: sleep 1 millisecond to avoid busy wait 2014-04-29 09:55:38 -07:00
contrib comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
Documentation Git 1.9.2 2014-04-09 12:04:34 -07:00
git-gui
gitk-git
gitweb comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
mergetools
perl code and test: fix misuses of "nor" 2014-03-31 15:29:33 -07:00
po i18n: proposed command missing leading dash 2014-03-05 22:10:24 +08:00
ppc
t Merge branch 'jl/nor-or-nand-and' into maint 2014-04-09 12:03:26 -07:00
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 Merge branch 'jk/commit-dates-parsing-fix' into maint 2014-03-18 14:04:01 -07:00
check-builtins.sh
check-racy.c
check_bindir
color.c
color.h
column.c comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
column.h
combine-diff.c
command-list.txt
commit-slab.h
commit.c
commit.h Merge branch 'bp/commit-p-editor' into maint 2014-04-08 12:07:06 -07:00
config.c Merge branch 'jk/config-path-include-fix' into maint 2014-03-18 14:00:15 -07:00
config.mak.in
config.mak.uname Merge branch 'jk/commit-dates-parsing-fix' into maint 2014-04-09 11:59:38 -07:00
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 Merge branch 'jk/commit-dates-parsing-fix' into maint 2014-03-18 14:04:01 -07:00
decorate.c
decorate.h
delta.h comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
diff-delta.c
diff-lib.c pathspec: convert some match_pathspec_depth() to ce_path_match() 2014-02-24 14:36:52 -08:00
diff-no-index.c Merge branch 'jc/fix-diff-no-index-diff-opt-parse' into maint 2014-04-09 11:59:16 -07:00
diff.c comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
diff.h
diffcore-break.c
diffcore-delta.c
diffcore-order.c
diffcore-pickaxe.c
diffcore-rename.c
diffcore.h Merge branch 'nd/diff-quiet-stat-dirty' into maint 2014-03-18 13:59:56 -07:00
dir.c pathspec: pass directory indicator to match_pathspec_item() 2014-02-24 14:37:19 -08:00
dir.h pathspec: pass directory indicator to match_pathspec_item() 2014-02-24 14:37:19 -08:00
editor.c
entry.c Merge branch 'mh/remove-subtree-long-pathname-fix' into maint 2014-04-03 13:39:05 -07:00
environment.c
exec_cmd.c
exec_cmd.h
fast-import.c
fetch-pack.c Merge branch 'jk/shallow-update-fix' into maint 2014-04-03 13:39:03 -07:00
fetch-pack.h
fmt-merge-msg.h
fsck.c date: check date overflow against time_t 2014-02-24 10:12:58 -08:00
fsck.h
generate-cmdlist.sh
gettext.c
gettext.h
git-add--interactive.perl code and test: fix misuses of "nor" 2014-03-31 15:29:33 -07:00
git-am.sh comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
git-archimport.perl
git-bisect.sh
git-compat-util.h Merge branch 'jk/commit-dates-parsing-fix' into maint 2014-04-09 11:59:38 -07:00
git-cvsexportcommit.perl
git-cvsimport.perl
git-cvsserver.perl
git-difftool--helper.sh
git-difftool.perl difftool: support repositories with .git-files 2014-02-24 09:53:57 -08:00
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 rebase -i: do not "echo" random user-supplied strings 2014-03-17 12:24:14 -07:00
git-rebase--merge.sh
git-rebase.sh
git-relink.perl
git-remote-testgit.sh
git-request-pull.sh
git-send-email.perl Merge branch 'rk/send-email-ssl-cert' into maint 2014-02-13 13:38:19 -08:00
git-sh-i18n.sh
git-sh-setup.sh
git-stash.sh Merge branch 'jc/stash-pop-not-popped' into maint 2014-04-03 13:39:03 -07:00
git-submodule.sh
git-svn.perl
GIT-VERSION-GEN Git 1.9.2 2014-04-09 12:04:34 -07:00
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
hash.c
hash.h
help.c
help.h
hex.c
http-backend.c
http-fetch.c
http-push.c
http-walker.c
http.c
http.h comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
ident.c
imap-send.c
INSTALL
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
log-tree.c
log-tree.h
mailmap.c
mailmap.h
Makefile Merge branch 'jl/nor-or-nand-and' into maint 2014-04-09 12:03:26 -07:00
match-trees.c
merge-blobs.c
merge-blobs.h
merge-recursive.c Merge branch 'bk/refresh-missing-ok-in-merge-recursive' into maint 2014-03-18 14:02:38 -07:00
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-check.c
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 Merge branch 'jk/config-path-include-fix' into maint 2014-03-18 14:00:15 -07:00
pathspec.c pathspec: convert some match_pathspec_depth() to ce_path_match() 2014-02-24 14:36:52 -08:00
pathspec.h
pkt-line.c
pkt-line.h comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
preload-index.c pathspec: convert some match_pathspec_depth() to ce_path_match() 2014-02-24 14:36:52 -08:00
pretty.c Merge branch 'jk/commit-dates-parsing-fix' into maint 2014-03-18 14:04:01 -07:00
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 Merge branch 'bk/refresh-missing-ok-in-merge-recursive' into maint 2014-03-18 14:02:38 -07:00
README
reflog-walk.c
reflog-walk.h
refs.c
refs.h
RelNotes Start preparing for 1.9.1 2014-04-03 13:40:00 -07:00
remote-curl.c
remote-testsvn.c
remote.c Merge branch 'jl/nor-or-nand-and' into maint 2014-04-09 12:03:26 -07:00
remote.h
replace_object.c
rerere.c pathspec: pass directory indicator to match_pathspec_item() 2014-02-24 14:37:19 -08:00
rerere.h
resolve-undo.c pathspec: convert some match_pathspec_depth() to ce_path_match() 2014-02-24 14:36:52 -08:00
resolve-undo.h
revision.c pathspec: convert some match_pathspec_depth() to ce_path_match() 2014-02-24 14:36:52 -08:00
revision.h
run-command.c commit: fix patch hunk editing with "commit -p -m" 2014-03-18 11:25:12 -07:00
run-command.h run-command: mark run_hook_with_custom_index as deprecated 2014-03-18 11:26:12 -07:00
send-pack.c
send-pack.h
sequencer.c
sequencer.h
server-info.c
setup.c
sh-i18n--envsubst.c
sha1-array.c
sha1-array.h
sha1-lookup.c
sha1-lookup.h
sha1_file.c code and test: fix misuses of "nor" 2014-03-31 15:29:33 -07:00
sha1_name.c
shallow.c shallow: verify shallow file after taking lock 2014-03-17 15:03:32 -07:00
shell.c
shortlog.h
show-index.c
sideband.c
sideband.h
sigchain.c
sigchain.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 comments: fix misuses of "nor" 2014-03-31 15:29:27 -07:00
test-ctype.c
test-date.c
test-delta.c
test-dump-cache-tree.c
test-genrandom.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.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
transport-helper.c
transport.c
transport.h
tree-diff.c
tree-walk.c
tree-walk.h
tree.c
tree.h
unimplemented.sh
unix-socket.c
unix-socket.h
unpack-trees.c
unpack-trees.h
upload-pack.c shallow: automatically clean up shallow tempfiles 2014-02-27 12:07:13 -08:00
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
walker.c
walker.h
wildmatch.c
wildmatch.h
wrap-for-bin.sh
wrapper.c
write_or_die.c
ws.c
wt-status.c Merge branch 'mm/status-porcelain-format-i18n-fix' into maint 2014-04-08 12:07:06 -07:00
wt-status.h status: disable translation when --porcelain is used 2014-03-26 12:56:30 -07:00
xdiff-interface.c
xdiff-interface.h
zlib.c

README 

////////////////////////////////////////////////////////////////

	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/everyday.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.