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The reference updates performed as a part of 'git-receive-pack(1)', take
place one at a time. For each reference update, a new transaction is
created and committed. This is necessary to ensure we can allow
individual updates to fail without failing the entire command. The
command also supports an 'atomic' mode, which uses a single transaction
to update all of the references. But this mode has an all-or-nothing
approach, where if a single update fails, all updates would fail.
In 23fc8e4f61 (refs: implement batch reference update support,
2025-04-08), we introduced a new mechanism to batch reference updates.
Under the hood, this uses a single transaction to perform a batch of
reference updates, while allowing only individual updates to fail.
Utilize this newly introduced batch update mechanism in
'git-receive-pack(1)'. This provides a significant bump in performance,
especially when dealing with repositories with large number of
references.
With the reftable backend there is a 18x performance improvement, when
performing receive-pack with 10000 refs:
Benchmark 1: receive: many refs (refformat = reftable, refcount = 10000, revision = master)
Time (mean ± σ): 4.276 s ± 0.078 s [User: 0.796 s, System: 3.318 s]
Range (min … max): 4.185 s … 4.430 s 10 runs
Benchmark 2: receive: many refs (refformat = reftable, refcount = 10000, revision = HEAD)
Time (mean ± σ): 235.4 ms ± 6.9 ms [User: 75.4 ms, System: 157.3 ms]
Range (min … max): 228.5 ms … 254.2 ms 11 runs
Summary
receive: many refs (refformat = reftable, refcount = 10000, revision = HEAD) ran
18.16 ± 0.63 times faster than receive: many refs (refformat = reftable, refcount = 10000, revision = master)
In similar conditions, the files backend sees a 1.21x performance
improvement:
Benchmark 1: receive: many refs (refformat = files, refcount = 10000, revision = master)
Time (mean ± σ): 1.121 s ± 0.021 s [User: 0.128 s, System: 0.975 s]
Range (min … max): 1.097 s … 1.156 s 10 runs
Benchmark 2: receive: many refs (refformat = files, refcount = 10000, revision = HEAD)
Time (mean ± σ): 927.9 ms ± 22.6 ms [User: 99.0 ms, System: 815.2 ms]
Range (min … max): 903.1 ms … 978.0 ms 10 runs
Summary
receive: many refs (refformat = files, refcount = 10000, revision = HEAD) ran
1.21 ± 0.04 times faster than receive: many refs (refformat = files, refcount = 10000, revision = master)
As using batched updates requires the error handling to be moved to the
end of the flow, create and use a 'struct strset' to track the failed
refs and attribute the correct errors to them.
This change also uncovers an issue when a client provides multiple
updates to the same reference. For example:
$ git send-pack remote.git A:foo B:foo
Enumerating objects: 3, done.
Counting objects: 100% (3/3), done.
Delta compression using up to 20 threads
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 226 bytes | 226.00 KiB/s, done.
Total 3 (delta 1), reused 0 (delta 0), pack-reused 0 (from 0)
remote: error: cannot lock ref 'refs/heads/foo': reference already exists
To remote.git
! [remote rejected] A -> foo (failed to update ref)
! [remote failure] B -> foo (remote failed to report status)
As you can see, the remote runs into an error because it cannot lock the
target reference for the second update. Furthermore, the remote complains
that the first update has been rejected whereas the second update didn't
receive any status update because we failed to lock it. Reading this status
message alone a user would probably expect that `foo` has not been updated
at all. But that's not the case: while we claim that the ref wasn't updated,
it surprisingly points to `A` now.
One could argue that this is merely an error in how we report the result of
this push. But ultimately, the user's request itself is already broken and
doesn't make any sense in the first place and cannot ever lead to a sensible
outcome that honors the full request.
The conversion to batched transactions fixes the issue because we now try to
queue both updates in the same transaction. As such, the transaction itself
will notice this conflict and refuse the update altogether before we commit
any of the values.
Note that this requires changes to a couple of tests in t5408 that happened
to exercise this behaviour. Given that the generated output is misleading
and given that the user request cannot ever be fully honored this really
feels more like a bug than properly designed behaviour. As such, changing
the behaviour feels like the right thing to do.
Since now reference updates are batched, the 'reference-transaction'
hook will be invoked with all updates together. Currently git will 'die'
when the hook returns with a non-zero exit status in the 'prepared'
stage. For 'git-receive-pack(1)', this allowed users to reject an
individual reference update, git would have applied previous updates but
immediately abort further execution. This is definitely an incorrect
usage of this hook, since the right place to do this would be the
'update' hook. This patch retains the latter behavior, but
'reference-transaction' hook now changes to a all-or-nothing behavior
when a non-zero exit status is returned in the 'prepared' stage, since
batch updates use a transaction under the hood. This explains the change
in 't1416'.
Helped-by: Jeff King <peff@peff.net>
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Leakfixes.
* ps/leakfixes-part-10: (27 commits)
t: remove TEST_PASSES_SANITIZE_LEAK annotations
test-lib: unconditionally enable leak checking
t: remove unneeded !SANITIZE_LEAK prerequisites
t: mark some tests as leak free
t5601: work around leak sanitizer issue
git-compat-util: drop now-unused `UNLEAK()` macro
global: drop `UNLEAK()` annotation
t/helper: fix leaking commit graph in "read-graph" subcommand
builtin/branch: fix leaking sorting options
builtin/init-db: fix leaking directory paths
builtin/help: fix leaks in `check_git_cmd()`
help: fix leaking return value from `help_unknown_cmd()`
help: fix leaking `struct cmdnames`
help: refactor to not use globals for reading config
builtin/sparse-checkout: fix leaking sanitized patterns
split-index: fix memory leak in `move_cache_to_base_index()`
git: refactor builtin handling to use a `struct strvec`
git: refactor alias handling to use a `struct strvec`
strvec: introduce new `strvec_splice()` function
line-log: fix leak when rewriting commit parents
...
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Now that the default value for TEST_PASSES_SANITIZE_LEAK is `true` there
is no longer a need to have that variable declared in all of our tests.
Drop it.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The reference-transaction hook is invoked whenever there is a reference
update being performed. For each state of the transaction, we iterate
over the updates present and pass this information to the hook.
The `ref_update` structure is used to hold these updates within a
`transaction`. We use the same structure for holding reflog updates too.
Which means that the reference transaction hook is also obtaining
information about a reflog update. This is a bug, since:
- The hook is designed to work with reference updates and reflogs
updates are different.
- The hook doesn't have the required information to distinguish
reference updates from reflog updates.
This is particularly evident when the default branch (pointed by HEAD)
is updated, we see that the hook also receives information about HEAD
being changed. In reality, we only add a reflog update for HEAD, while
HEAD's values remains the same.
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Add 'symref-update' command to the '--stdin' mode of 'git-update-ref' to
allow updates of symbolic refs. The 'symref-update' command takes in a
<new-target>, which the <ref> will be updated to. If the <ref> doesn't
exist it will be created.
It also optionally takes either an `ref <old-target>` or `oid
<old-oid>`. If the <old-target> is provided, it checks to see if the
<ref> targets the <old-target> before the update. If <old-oid> is provided
it checks <ref> to ensure that it is a regular ref and <old-oid> is the
OID before the update. This by extension also means that this when a
zero <old-oid> is provided, it ensures that the ref didn't exist before.
The divergence in syntax from the regular `update` command is because if
we don't use a `(ref | oid)` prefix for the old_value, then there is
ambiguity around if the value provided should be treated as an oid or a
reference. This is more so the reason, because we allow anything
committish to be provided as an oid. While 'symref-verify' and
'symref-delete' also take in `<old-target>` we do not have this
divergence there as those commands only work with symrefs. Whereas
'symref-update' also works with regular refs and allows users to convert
regular refs to symrefs.
The command allows users to perform symbolic ref updates within a
transaction. This provides atomicity and allows users to perform a set
of operations together.
This command supports deref mode, to ensure that we can update
dereferenced regular refs to symrefs.
Helped-by: Patrick Steinhardt <ps@pks.im>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Add 'symref-create' command to the '--stdin' mode 'git-update-ref' to
allow creation of symbolic refs in a transaction. The 'symref-create'
command takes in a <new-target>, which the created <ref> will point to.
Also, support the 'core.prefersymlinkrefs' config, wherein if the config
is set and the filesystem supports symlinks, we create the symbolic ref
as a symlink. We fallback to creating a regular symref if creating the
symlink is unsuccessful.
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Add a new command 'symref-delete' to allow deletions of symbolic refs in
a transaction via the '--stdin' mode of the 'git-update-ref' command.
The 'symref-delete' command can, when given an <old-target>, delete the
provided <ref> only when it points to <old-target>.
This command is only compatible with the 'no-deref' mode because we
optionally want to check the 'old_target' of the ref being deleted.
De-referencing a symbolic ref would provide a regular ref and we already
have the 'delete' command for regular refs.
While users can also use 'git symbolic-ref -d' to delete symbolic refs,
the 'symref-delete' command in 'git-update-ref' allows users to do so
within a transaction, which promises atomicity of the operation and can
be batched with other commands.
When no 'old_target' is provided it can also delete regular refs,
similar to how the 'delete' command can delete symrefs when no 'old_oid'
is provided.
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The 'symref-verify' command allows users to verify if a provided <ref>
contains the provided <old-target> without changing the <ref>. If
<old-target> is not provided, the command will verify that the <ref>
doesn't exist.
The command allows users to verify symbolic refs within a transaction,
and this means users can perform a set of changes in a transaction only
when the verification holds good.
Since we're checking for symbolic refs, this command will only work with
the 'no-deref' mode. This is because any dereferenced symbolic ref will
point to an object and not a ref and the regular 'verify' command can be
used in such situations.
Add required tests for symref support in 'verify'. Since we're here,
also add reflog checks for the pre-existing 'verify' tests, there is no
divergence from behavior, but we never tested to ensure that reflog
wasn't affected by the 'verify' command.
Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The `refs_create_symref()` function updates a symref to a given new
target. To do this, it uses a ref-backend specific function
`create_symref()`.
In the previous commits, we introduced symref support in transactions.
This means we can now use transactions to perform symref updates and
don't have to resort to `create_symref()`. Doing this allows us to
remove and cleanup `create_symref()`, which we will do in the following
commit.
Modify the expected error message for a test in
't/t0610-reftable-basics.sh', since the error is now thrown from
'refs.c'. This is because in transactional updates, F/D conflicts are
caught before we're in the reference backend.
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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They are equivalents and the former still exists, so as long as the
only change this commit makes are to rewrite test_i18ngrep to
test_grep, there won't be any new bug, even if there still are
callers of test_i18ngrep remaining in the tree, or when merged to
other topics that add new uses of test_i18ngrep.
This patch was produced more or less with
git grep -l -e 'test_i18ngrep ' 't/t[0-9][0-9][0-9][0-9]-*.sh' |
xargs perl -p -i -e 's/test_i18ngrep /test_grep /'
and a good way to sanity check the result yourself is to run the
above in a checkout of c4603c1c (test framework: further deprecate
test_i18ngrep, 2023-10-31) and compare the resulting working tree
contents with the result of applying this patch to the same commit.
You'll see that test_i18ngrep in a few t/lib-*.sh files corrected,
in addition to the manual reproduction.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Fix a memory leak that's been with us since this code was added in
ca02465b413 (push: use remote.$name.push as a refmap, 2013-12-03).
The "remote = remote_get(...)" added in the same commit would seem to
leak based only on the context here, but that function is a wrapper
for sticking the remotes we fetch into "the_repository->remote_state".
See fd3cb0501e1 (remote: move static variables into per-repository
struct, 2021-11-17) for the addition of code in repository.c that
free's the "remote" allocated here.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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This reverts commit 991b4d47f0accd3955d05927d5ce434e03ffbdb6, reversing
changes made to bcd020f88e1e22f38422ac3f73ab06b34ec4bef1.
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Stop moving the .git/hooks directory out of the way, or creating it
during test setup. Instead assume that it will contain
harmless *.sample files.
That we can assume that is discussed in point #4 of
f0d4d398e28 (test-lib: split up and deprecate test_create_repo(),
2021-05-10), those parts of this could and should have been done in
that change.
Removing the "mkdir -p" here will then validate that our templates are
being used, since we'd subsequently fail to create a hook in that
directory if it didn't exist. Subsequent commits will have those hooks
created by a "test_hook" wrapper, which will then being doing that
same validation.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Add a "test_hook" wrapper similar to the existing "test_config"
wrapper added in d960c47a881 (test-lib: add helper functions for
config, 2011-08-17).
This wrapper:
- Will clean up the hook with "test_when_finished", unless --setup is
provided.
- Will error if we clobber a hook, unless --clobber is provided.
- Takes a name like "update" instead of ".git/hooks/update".
- Accepts -C <dir>, like "test_config" and "test_commit".
By using a wrapper we'll be able to easily change all the hook-related
code that assumes that the template-created ".git/hooks" directory is
created by "init", "clone" etc. once another topic follows-up and
changes the test suite to stop creating trash directories using those
templates.
In addition this will make it easy to have the hooks configured using
the "configuration-based hooks" topic, once we get around to
integrating that. I.e. we'll be able to run the tests in a mode where
we sometimes create a .git/hooks/<name>, and other times create a
script in another location, and point the relevant configuration
snippet to it.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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When deleting refs from the loose-files refs backend, then we need to be
careful to also delete the same ref from the packed refs backend, if it
exists. If we don't, then deleting the loose ref would "uncover" the
packed ref. We thus always have to queue up deletions of refs for both
the loose and the packed refs backend. This is done in two separate
transactions, where the end result is that the reference-transaction
hook is executed twice for the deleted refs.
This behaviour is quite misleading: it's exposing implementation details
of how the files backend works to the user, in contrast to the logical
updates that we'd really want to expose via the hook. Worse yet, whether
the hook gets executed once or twice depends on how well-packed the
repository is: if the ref only exists as a loose ref, then we execute it
once, otherwise if it is also packed then we execute it twice.
Fix this behaviour and don't execute the reference-transaction hook at
all when refs in the packed-refs backend if it's driven by the files
backend. This works as expected even in case the refs to be deleted only
exist in the packed-refs backend because the loose-backend always queues
refs in its own transaction even if they don't exist such that they can
be locked for concurrent creation. And it also does the right thing in
case neither of the backends has the ref because that would cause the
transaction to fail completely.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The reference-transaction hook is supposed to track logical changes to
references, but it currently also gets executed when packing refs in a
repository. This is unexpected and ultimately not all that useful:
packing refs is not supposed to result in any user-visible change to the
refs' state, and it ultimately is an implementation detail of how refs
stores work.
Fix this excessive execution of the hook when packing refs.
Reported-by: Waleed Khan <me@waleedkhan.name>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Add tests which demonstate that we're executing the
reference-transaction hook too often in some cases, which thus leaks
implementation details about the reference store's implementation
itself. Behaviour will be fixed in follow-up commits.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Carefully excluding t1309, which sees independent development elsewhere
at the time of writing, we transition above-mentioned tests to the
default branch name `main`. This trick was performed via
$ (cd t &&
sed -i -e 's/master/main/g' -e 's/MASTER/MAIN/g' \
-e 's/Master/Main/g' -e 's/naster/nain/g' -- t[01]*.sh &&
git checkout HEAD -- t1309\*)
Note that t5533 contains a variation of the name `master` (`naster`)
that we rename here, too.
This allows us to define `GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main`
for those tests.
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In addition to the manual adjustment to let the `linux-gcc` CI job run
the test suite with `master` and then with `main`, this patch makes sure
that GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME is set in all test scripts
that currently rely on the initial branch name being `master by default.
To determine which test scripts to mark up, the first step was to
force-set the default branch name to `master` in
- all test scripts that contain the keyword `master`,
- t4211, which expects `t/t4211/history.export` with a hard-coded ref to
initialize the default branch,
- t5560 because it sources `t/t556x_common` which uses `master`,
- t8002 and t8012 because both source `t/annotate-tests.sh` which also
uses `master`)
This trick was performed by this command:
$ sed -i '/^ *\. \.\/\(test-lib\|lib-\(bash\|cvs\|git-svn\)\|gitweb-lib\)\.sh$/i\
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=master\
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME\
' $(git grep -l master t/t[0-9]*.sh) \
t/t4211*.sh t/t5560*.sh t/t8002*.sh t/t8012*.sh
After that, careful, manual inspection revealed that some of the test
scripts containing the needle `master` do not actually rely on a
specific default branch name: either they mention `master` only in a
comment, or they initialize that branch specificially, or they do not
actually refer to the current default branch. Therefore, the
aforementioned modification was undone in those test scripts thusly:
$ git checkout HEAD -- \
t/t0027-auto-crlf.sh t/t0060-path-utils.sh \
t/t1011-read-tree-sparse-checkout.sh \
t/t1305-config-include.sh t/t1309-early-config.sh \
t/t1402-check-ref-format.sh t/t1450-fsck.sh \
t/t2024-checkout-dwim.sh \
t/t2106-update-index-assume-unchanged.sh \
t/t3040-subprojects-basic.sh t/t3301-notes.sh \
t/t3308-notes-merge.sh t/t3423-rebase-reword.sh \
t/t3436-rebase-more-options.sh \
t/t4015-diff-whitespace.sh t/t4257-am-interactive.sh \
t/t5323-pack-redundant.sh t/t5401-update-hooks.sh \
t/t5511-refspec.sh t/t5526-fetch-submodules.sh \
t/t5529-push-errors.sh t/t5530-upload-pack-error.sh \
t/t5548-push-porcelain.sh \
t/t5552-skipping-fetch-negotiator.sh \
t/t5572-pull-submodule.sh t/t5608-clone-2gb.sh \
t/t5614-clone-submodules-shallow.sh \
t/t7508-status.sh t/t7606-merge-custom.sh \
t/t9302-fast-import-unpack-limit.sh
We excluded one set of test scripts in these commands, though: the range
of `git p4` tests. The reason? `git p4` stores the (foreign) remote
branch in the branch called `p4/master`, which is obviously not the
default branch. Manual analysis revealed that only five of these tests
actually require a specific default branch name to pass; They were
modified thusly:
$ sed -i '/^ *\. \.\/lib-git-p4\.sh$/i\
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=master\
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME\
' t/t980[0167]*.sh t/t9811*.sh
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The test added by e5256c82e5 (refs: fix interleaving hook calls with
reference-transaction hook, 2020-08-07) uses hard-coded sha1 object ids
in its expected output. This causes it to fail when run with
GIT_TEST_DEFAULT_HASH=sha256.
Let's make use of the oid variables we define earlier, as the rest of
the nearby tests do.
Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In order to not repeatedly search for the reference-transaction hook in
case it's getting called multiple times, we use a caching mechanism to
only call `find_hook()` once. What was missed though is that the return
value of `find_hook()` actually comes from a static strbuf, which means
it will get overwritten when calling `find_hook()` again. As a result,
we may call the wrong hook with parameters of the reference-transaction
hook.
This scenario was spotted in the wild when executing a git-push(1) with
multiple references, where there are interleaving calls to both the
update and the reference-transaction hook. While initial calls to the
reference-transaction hook work as expected, it will stop working after
the next invocation of the update hook. The result is that we now start
calling the update hook with parameters and stdin of the
reference-transaction hook.
This commit fixes the issue by storing a copy of `find_hook()`'s return
value in the cache.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The low-level reference transactions used to update references are
currently completely opaque to the user. While certainly desirable in
most usecases, there are some which might want to hook into the
transaction to observe all queued reference updates as well as observing
the abortion or commit of a prepared transaction.
One such usecase would be to have a set of replicas of a given Git
repository, where we perform Git operations on all of the repositories
at once and expect the outcome to be the same in all of them. While
there exist hooks already for a certain subset of Git commands that
could be used to implement a voting mechanism for this, many others
currently don't have any mechanism for this.
The above scenario is the motivation for the new "reference-transaction"
hook that reaches directly into Git's reference transaction mechanism.
The hook receives as parameter the current state the transaction was
moved to ("prepared", "committed" or "aborted") and gets via its
standard input all queued reference updates. While the exit code gets
ignored in the "committed" and "aborted" states, a non-zero exit code in
the "prepared" state will cause the transaction to be aborted
prematurely.
Given the usecase described above, a voting mechanism can now be
implemented via this hook: as soon as it gets called, it will take all
of stdin and use it to cast a vote to a central service. When all
replicas of the repository agree, the hook will exit with zero,
otherwise it will abort the transaction by returning non-zero. The most
important upside is that this will catch _all_ commands writing
references at once, allowing to implement strong consistency for
reference updates via a single mechanism.
In order to test the impact on the case where we don't have any
"reference-transaction" hook installed in the repository, this commit
introduce two new performance tests for git-update-refs(1). Run against
an empty repository, it produces the following results:
Test origin/master HEAD
--------------------------------------------------------------------
1400.2: update-ref 2.70(2.10+0.71) 2.71(2.10+0.73) +0.4%
1400.3: update-ref --stdin 0.21(0.09+0.11) 0.21(0.07+0.14) +0.0%
The performance test p1400.2 creates, updates and deletes a branch a
thousand times, thus averaging runtime of git-update-refs over 3000
invocations. p1400.3 instead calls `git-update-refs --stdin` three times
and queues a thousand creations, updates and deletes respectively.
As expected, p1400.3 consistently shows no noticeable impact, as for
each batch of updates there's a single call to access(3P) for the
negative hook lookup. On the other hand, for p1400.2, one can see an
impact caused by this patchset. But doing five runs of the performance
tests where each one was run with GIT_PERF_REPEAT_COUNT=10, the overhead
ranged from -1.5% to +1.1%. These inconsistent performance numbers can
be explained by the overhead of spawning 3000 processes. This shows that
the overhead of assembling the hook path and executing access(3P) once
to check if it's there is mostly outweighed by the operating system's
overhead.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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