Make parallel checkout configurable by introducing two new settings:
checkout.workers and checkout.thresholdForParallelism. The first defines
the number of workers (where one means sequential checkout), and the
second defines the minimum number of entries to attempt parallel
checkout.
To decide the default value for checkout.workers, the parallel version
was benchmarked during three operations in the linux repo, with cold
cache: cloning v5.8, checking out v5.8 from v2.6.15 (checkout I) and
checking out v5.8 from v5.7 (checkout II). The four tables below show
the mean run times and standard deviations for 5 runs in: a local file
system on SSD, a local file system on HDD, a Linux NFS server, and
Amazon EFS (all on Linux). Each parallel checkout test was executed with
the number of workers that brings the best overall results in that
environment.
Local SSD:
Sequential 10 workers Speedup
Clone 8.805 s ± 0.043 s 3.564 s ± 0.041 s 2.47 ± 0.03
Checkout I 9.678 s ± 0.057 s 4.486 s ± 0.050 s 2.16 ± 0.03
Checkout II 5.034 s ± 0.072 s 3.021 s ± 0.038 s 1.67 ± 0.03
Local HDD:
Sequential 10 workers Speedup
Clone 32.288 s ± 0.580 s 30.724 s ± 0.522 s 1.05 ± 0.03
Checkout I 54.172 s ± 7.119 s 54.429 s ± 6.738 s 1.00 ± 0.18
Checkout II 40.465 s ± 2.402 s 38.682 s ± 1.365 s 1.05 ± 0.07
Linux NFS server (v4.1, on EBS, single availability zone):
Sequential 32 workers Speedup
Clone 240.368 s ± 6.347 s 57.349 s ± 0.870 s 4.19 ± 0.13
Checkout I 242.862 s ± 2.215 s 58.700 s ± 0.904 s 4.14 ± 0.07
Checkout II 65.751 s ± 1.577 s 23.820 s ± 0.407 s 2.76 ± 0.08
EFS (v4.1, replicated over multiple availability zones):
Sequential 32 workers Speedup
Clone 922.321 s ± 2.274 s 210.453 s ± 3.412 s 4.38 ± 0.07
Checkout I 1011.300 s ± 7.346 s 297.828 s ± 0.964 s 3.40 ± 0.03
Checkout II 294.104 s ± 1.836 s 126.017 s ± 1.190 s 2.33 ± 0.03
The above benchmarks show that parallel checkout is most effective on
repositories located on an SSD or over a distributed file system. For
local file systems on spinning disks, and/or older machines, the
parallelism does not always bring a good performance. For this reason,
the default value for checkout.workers is one, a.k.a. sequential
checkout.
To decide the default value for checkout.thresholdForParallelism,
another benchmark was executed in the "Local SSD" setup, where parallel
checkout showed to be beneficial. This time, we compared the runtime of
a `git checkout -f`, with and without parallelism, after randomly
removing an increasing number of files from the Linux working tree. The
"sequential fallback" column below corresponds to the executions where
checkout.workers was 10 but checkout.thresholdForParallelism was equal
to the number of to-be-updated files plus one (so that we end up writing
sequentially). Each test case was sampled 15 times, and each sample had
a randomly different set of files removed. Here are the results:
sequential fallback 10 workers speedup
10 files 772.3 ms ± 12.6 ms 769.0 ms ± 13.6 ms 1.00 ± 0.02
20 files 780.5 ms ± 15.8 ms 775.2 ms ± 9.2 ms 1.01 ± 0.02
50 files 806.2 ms ± 13.8 ms 767.4 ms ± 8.5 ms 1.05 ± 0.02
100 files 833.7 ms ± 21.4 ms 750.5 ms ± 16.8 ms 1.11 ± 0.04
200 files 897.6 ms ± 30.9 ms 730.5 ms ± 14.7 ms 1.23 ± 0.05
500 files 1035.4 ms ± 48.0 ms 677.1 ms ± 22.3 ms 1.53 ± 0.09
1000 files 1244.6 ms ± 35.6 ms 654.0 ms ± 38.3 ms 1.90 ± 0.12
2000 files 1488.8 ms ± 53.4 ms 658.8 ms ± 23.8 ms 2.26 ± 0.12
From the above numbers, 100 files seems to be a reasonable default value
for the threshold setting.
Note: Up to 1000 files, we observe a drop in the execution time of the
parallel code with an increase in the number of files. This is a rather
odd behavior, but it was observed in multiple repetitions. Above 1000
files, the execution time increases according to the number of files, as
one would expect.
About the test environments: Local SSD tests were executed on an
i7-7700HQ (4 cores with hyper-threading) running Manjaro Linux. Local
HDD tests were executed on an Intel(R) Xeon(R) E3-1230 (also 4 cores
with hyper-threading), HDD Seagate Barracuda 7200.14 SATA 3.1, running
Debian. NFS and EFS tests were executed on an Amazon EC2 c5n.xlarge
instance, with 4 vCPUs. The Linux NFS server was running on a m6g.large
instance with 2 vCPUSs and a 1 TB EBS GP2 volume. Before each timing,
the linux repository was removed (or checked out back to its previous
state), and `sync && sysctl vm.drop_caches=3` was executed.
Co-authored-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
SECURITY.md that is facing individual contributors and end users
has been introduced. Also a procedure to follow when preparing
embargoed releases has been spelled out.
* js/security-md:
Document how we do embargoed releases
SECURITY: describe how to report vulnerabilities
"git commit" learned "--trailer <key>[=<value>]" option; together
with the interpret-trailers command, this will make it easier to
support custom trailers.
* zh/commit-trailer:
commit: add --trailer option
"git format-patch -v<n>" learned to allow a reroll count that is
not an integer.
* zh/format-patch-fractional-reroll-count:
format-patch: allow a non-integral version numbers
A simple IPC interface gets introduced to build services like
fsmonitor on top.
* jh/simple-ipc:
t0052: add simple-ipc tests and t/helper/test-simple-ipc tool
simple-ipc: add Unix domain socket implementation
unix-stream-server: create unix domain socket under lock
unix-socket: disallow chdir() when creating unix domain sockets
unix-socket: add backlog size option to unix_stream_listen()
unix-socket: eliminate static unix_stream_socket() helper function
simple-ipc: add win32 implementation
simple-ipc: design documentation for new IPC mechanism
pkt-line: add options argument to read_packetized_to_strbuf()
pkt-line: add PACKET_READ_GENTLE_ON_READ_ERROR option
pkt-line: do not issue flush packets in write_packetized_*()
pkt-line: eliminate the need for static buffer in packet_write_gently()
Explain pieces of the format-patch output upfront before the rest
of the documentation starts referring to them.
* jc/doc-format-patch-clarify:
format-patch: give an overview of what a "patch" message is
Remove the final hint that we used to have a scripted "git rebase".
* ab/remove-rebase-usebuiltin:
rebase: remove transitory rebase.useBuiltin setting & env
Whenever we fix critical vulnerabilities, we follow some sort of
protocol (e.g. setting a coordinated release date, keeping the fix under
embargo until that time, coordinating with packagers and/or hosting
sites, etc).
Similar in spirit to `Documentation/howto/maintain-git.txt`, let's
formalize the details in a document.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git commit --fixup=<commit>", which was to tweak the changes made
to the contents while keeping the original log message intact,
learned "--fixup=(amend|reword):<commit>", that can be used to
tweak both the message and the contents, and only the message,
respectively.
* cm/rebase-i-fixup-amend-reword:
doc/git-commit: add documentation for fixup=[amend|reword] options
t3437: use --fixup with options to create amend! commit
t7500: add tests for --fixup=[amend|reword] options
commit: add a reword suboption to --fixup
commit: add amend suboption to --fixup to create amend! commit
sequencer: export and rename subject_length()
Follow-up fixes to "cm/rebase-i" topic.
* cm/rebase-i-updates:
doc/rebase -i: fix typo in the documentation of 'fixup' command
t/t3437: fixup the test 'multiple fixup -c opens editor once'
t/t3437: use named commits in the tests
t/t3437: simplify and document the test helpers
t/t3437: check the author date of fixed up commit
t/t3437: remove the dependency of 'expected-message' file from tests
t/t3437: fixup here-docs in the 'setup' test
t/lib-rebase: update the documentation of FAKE_LINES
rebase -i: clarify and fix 'fixup -c' rebase-todo help
sequencer: rename a few functions
sequencer: fixup the datatype of the 'flag' argument
"rebase -i" is getting cleaned up and also enhanced.
* cm/rebase-i:
doc/git-rebase: add documentation for fixup [-C|-c] options
rebase -i: teach --autosquash to work with amend!
t3437: test script for fixup [-C|-c] options in interactive rebase
rebase -i: add fixup [-C | -c] command
sequencer: use const variable for commit message comments
sequencer: pass todo_item to do_pick_commit()
rebase -i: comment out squash!/fixup! subjects from squash message
sequencer: factor out code to append squash message
rebase -i: only write fixup-message when it's needed
"git repack" so far has been only capable of repacking everything
under the sun into a single pack (or split by size). A cleverer
strategy to reduce the cost of repacking a repository has been
introduced.
* tb/geometric-repack:
builtin/pack-objects.c: ignore missing links with --stdin-packs
builtin/repack.c: reword comment around pack-objects flags
builtin/repack.c: be more conservative with unsigned overflows
builtin/repack.c: assign pack split later
t7703: test --geometric repack with loose objects
builtin/repack.c: do not repack single packs with --geometric
builtin/repack.c: add '--geometric' option
packfile: add kept-pack cache for find_kept_pack_entry()
builtin/pack-objects.c: rewrite honor-pack-keep logic
p5303: measure time to repack with keep
p5303: add missing &&-chains
builtin/pack-objects.c: add '--stdin-packs' option
revision: learn '--no-kept-objects'
packfile: introduce 'find_kept_pack_entry()'
The text says something called a "patch" is prepared one for each
commit, it is suitable for e-mail submission, and "am" is the
command to use it, but does not say what the "patch" really is.
The description in the page also refers to the "three-dash" line,
but it is unclear what it is, unless the reader is given a more
detailed overview of what the "patch" is.
Add a brief paragraph to give an overview of what the output looks
like.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove the rebase.useBuiltin setting and the now-obsolete
GIT_TEST_REBASE_USE_BUILTIN test flag.
This was left in place after my d03ebd411c (rebase: remove the
rebase.useBuiltin setting, 2019-03-18) to help anyone who'd used the
experimental flag and wanted to know that it was the default, or that
they should transition their test environment to use the builtin
rebase unconditionally.
It's been more than long enough for those users to get a headsup about
this. So remove all the scaffolding that was left inplace after
d03ebd411c. I'm also removing the documentation entry, if anyone
still has this left in their configuration they can do some source
archaeology to figure out what it used to do, which makes more sense
than exposing every git user reading the documentation to this legacy
configuration switch.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `-v<n>` option of `format-patch` can give nothing but an
integral iteration number to patches in a series. Some people,
however, prefer to mark a new iteration with only a small fixup
with a non integral iteration number (e.g. an "oops, that was
wrong" fix-up patch for v4 iteration may be labeled as "v4.1").
Allow `format-patch` to take such a non-integral iteration
number.
`<n>` can be any string, such as '3.1' or '4rev2'. In the case
where it is a non-integral value, the "Range-diff" and "Interdiff"
headers will not include the previous version.
Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Historically, Git has supported the 'Signed-off-by' commit trailer
using the '--signoff' and the '-s' option from the command line.
But users may need to provide other trailer information from the
command line such as "Helped-by", "Reported-by", "Mentored-by",
Now implement a new `--trailer <token>[(=|:)<value>]` option to pass
other trailers to `interpret-trailers` and insert them into commit
messages.
Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git log --format='...'" learned "%(describe)" placeholder.
* rs/pretty-describe:
archive: expand only a single %(describe) per archive
pretty: document multiple %(describe) being inconsistent
t4205: assert %(describe) test coverage
pretty: add merge and exclude options to %(describe)
pretty: add %(describe)
"git stash show" learned to optionally show untracked part of the
stash.
* dl/stash-show-untracked:
stash show: learn stash.showIncludeUntracked
stash show: teach --include-untracked and --only-untracked
Rename detection rework continues.
* en/ort-perf-batch-8:
diffcore-rename: compute dir_rename_guess from dir_rename_counts
diffcore-rename: limit dir_rename_counts computation to relevant dirs
diffcore-rename: compute dir_rename_counts in stages
diffcore-rename: extend cleanup_dir_rename_info()
diffcore-rename: move dir_rename_counts into dir_rename_info struct
diffcore-rename: add function for clearing dir_rename_count
Move computation of dir_rename_count from merge-ort to diffcore-rename
diffcore-rename: add a mapping of destination names to their indices
diffcore-rename: provide basic implementation of idx_possible_rename()
diffcore-rename: use directory rename guided basename comparisons
A new configuration variable has been introduced to allow choosing
which version of the generation number gets used in the
commit-graph file.
* ds/commit-graph-generation-config:
commit-graph: use config to specify generation type
commit-graph: create local repository pointer
Brief design documentation for new IPC mechanism allowing
foreground Git client to talk with an existing daemon process
at a known location using a named pipe or unix domain socket.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Charvi Mendiratta <charvi077@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Disable the recent mergetool's hideresolved feature by default for
backward compatibility and safety.
* jn/mergetool-hideresolved-is-optional:
doc: describe mergetool configuration in git-mergetool(1)
mergetool: do not enable hideResolved by default
In the EXAMPLES section, git-push(1) says that 'git push origin' pushes
the current branch to the value of the 'remote.origin.merge'
configuration.
This wording (which dates back to b2ed944af7 (push: switch default from
"matching" to "simple", 2013-01-04)) is incorrect. There is no such
configuration as 'remote.<name>.merge'. This likely was originally
intended to read "branch.<name>.merge" instead.
Indeed, when 'push.default' is 'simple' (which is the default value, and
is applicable in this scenario per "without additional configuration"),
setup_push_upstream() dies if the branch's local name does not match
'branch.<name>.merge'.
Correct this long-standing typo to resolve some recent confusion on the
intended behavior of this example.
Reported-by: Adam Sharafeddine <adam.shrfdn@gmail.com>
Reported-by: Fabien Terrani <terranifabien@gmail.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In particular, this describes mergetool.hideResolved, which can help
users discover this setting (either because it may be useful to them
or in order to understand mergetool's behavior if they have forgotten
setting it in the past).
Tested by running
make -C Documentation git-mergetool.1
man Documentation/git-mergetool.1
and reading through the page.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When 98ea309b3f (mergetool: add hideResolved configuration,
2021-02-09) introduced the mergetool.hideResolved setting to reduce
the clutter in viewing non-conflicted sections of files in a
mergetool, it enabled it by default, explaining:
No adverse effects were noted in a small survey of popular mergetools[1]
so this behavior defaults to `true`.
In practice, alas, adverse effects do appear. A few issues:
1. No indication is shown in the UI that the base, local, and remote
versions shown have been modified by additional resolution. This
is inherent in the design: the idea of mergetool.hideResolved is to
convince a mergetool that expects pristine local, base, and remote
files to show partially resolved verisons of those files instead;
there is no additional source of information accessible to the
mergetool to see where the resolution has happened.
(By contrast, a mergetool generating the partial resolution from
conflict markers for itself would be able to hilight the resolved
sections with a different color.)
A user accustomed to seeing the files without partial resolution
gets no indication that this behavior has changed when they upgrade
Git.
2. If the computed merge did not line up the files correctly (for
example due to repeated sections in the file), the partially
resolved files can be misleading and do not have enough information
to reconstruct what happened and compute the correct merge result.
3. Resolving a conflict can involve information beyond the textual
conflict. For example, if the local and remote versions added
overlapping functionality in different ways, seeing the full
unresolved versions of each alongside the base gives information
about each side's intent that makes it possible to come up with a
resolution that combines those two intents. By contrast, when
starting with partially resolved versions of those files, one can
produce a subtly wrong resolution that includes redundant extra
code added by one side that is not needed in the approach taken
on the other.
All that said, a user wanting to focus on textual conflicts with
reduced clutter can still benefit from mergetool.hideResolved=true as
a way to deemphasize sections of the code that resolve cleanly without
requiring any changes to the invoked mergetool. The caveats described
above are reduced when the user has explicitly turned this on, because
then the user is aware of them.
Flip the default to 'false'.
Reported-by: Dana Dahlstrom <dahlstrom@google.com>
Helped-by: Seth House <seth@eseth.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Every %(describe) placeholder in $Format:...$ strings in files with the
attribute export-subst is expanded by calling git describe. This can
potentially result in a lot of such calls per archive. That's OK for
local repositories under control of the user of git archive, but could
be a problem for hosted repositories.
Expand only a single %(describe) placeholder per archive for now to
avoid denial-of-service attacks. We can make this limit configurable
later if needed, but let's start out simple.
Reported-by: Jeff King <peff@peff.net>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous commit teaches `git stash show --include-untracked`. It
may be desirable for a user to be able to always enable the
--include-untracked behavior. Teach the stash.showIncludeUntracked
config option which allows users to do this in a similar manner to
stash.showPatch.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Stash entries can be made with untracked files via
`git stash push --include-untracked`. However, because the untracked
files are stored in the third parent of the stash entry and not the
stash entry itself, running `git stash show` does not include the
untracked files as part of the diff.
With --include-untracked, untracked paths, which are recorded in the
third-parent if it exists, are shown in addition to the paths that have
modifications between the stash base and the working tree in the stash.
It is possible to manually craft a malformed stash entry where duplicate
untracked files in the stash entry will mask tracked files. We detect
and error out in that case via a custom unpack_trees() callback:
stash_worktree_untracked_merge().
Also, teach stash the --only-untracked option which only shows the
untracked files of a stash entry. This is similar to `git show stash^3`
but it is nice to provide a convenient abstraction for it so that users
do not have to think about the underlying implementation.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There were some early changes in the 2.31 cycle to optimize some setup
in diffcore-rename.c[1], some later changes to measure performance[2],
and finally some significant changes to improve rename detection
performance. The final one was merged with the note
Performance optimization work on the rename detection continues.
That works for the commit log, but feels misleading as a release note
since all the changes were within one cycle. Simplify this to just
Performance improvements for rename detection.
The former wording could be seen as hinting that more performance
improvements will come in 2.32, which is true, but we can just cover
those in the 2.32 release notes when the time comes.
[1] a5ac31b5b1 (Merge branch 'en/diffcore-rename', 2021-01-25)
[2] d3a035b055 (Merge branch 'en/merge-ort-perf', 2021-02-11)
[3] 12bd17521c (Merge branch 'en/diffcore-rename', 2021-03-01)
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As part of the hash-transition, git can operate on more than just SHA-1
repositories. Replace "sha1"-specific documentation with hash-agnostic
terminology.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
