This reverts commit 676eb0c1ce0d380478eb16bdc5a3f2a7bc01c1d2;
as we will be reverting the change to show these extra output
tokens under bash, the pattern would not match anything.
Helped-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reverts commit 303775a25f0b4ac5d6ad2e96eb4404c24209cad8;
instead of trying to salvage the tap-breaking change, let's
revert the whole thing for now.
A user of progress API calls start_progress() conditionally and
depends on the display_progress() and stop_progress() functions to
become no-op when start_progress() hasn't been called.
As we added a call to trace2_region_enter() to start_progress(), the
calls to other trace2 API calls from the progress API functions must
make sure that these trace2 calls are skipped when start_progress()
hasn't been called on the progress struct. Specifically, do not
call trace2_region_leave() from stop_progress() when we haven't
called start_progress(), which would have called the matching
trace2_region_enter().
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When this developer tested how the git-sdk-64-minimal artifact could be
served to all the GitHub workflow runs that need it, Azure Blobs looked
like a pretty good choice: it is reliable, fast and we already use it in
Git for Windows to serve components like OpenSSL, cURL, etc
It came as an unpleasant surprise just _how many_ times this artifact
was downloaded. It exploded the bandwidth to a point where the free tier
would no longer be enough, threatening to block other, essential Git for
Windows services.
Let's switch back to using the Build Artifacts of our trusty Azure
Pipeline for the time being.
To avoid unnecessary hammering of the Azure Pipeline artifacts, we use
the GitHub Action `actions/upload-artifact` in the `windows-build` job
and the GitHub Action `actions/download-artifact` in the `windows-test`
and `vs-test` jobs (the latter now depends on `windows-build` for that
reason, too).
Helped-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
commit b0a5a12a60 ("unpack-trees: allow check_updates() to work on a
different index", 2020-03-27) allowed check_updates() to work on a
different index, but it called get_progress() which was hardcoded to
work on o->result much like check_updates() had been. Update it to also
accept an index parameter and have check_updates() pass that parameter
along so that both are working on the same index.
Noticed-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach codepaths that show progress meter to also use the
start_progress() and the stop_progress() calls as a "region" to be
traced.
* es/trace-log-progress:
trace2: log progress time and throughput
Code cleanup and typofixes
* ds/bloom-cleanup:
completion: offer '--(no-)patch' among 'git log' options
bloom: use num_changes not nr for limit detection
bloom: de-duplicate directory entries
Documentation: changed-path Bloom filters use byte words
bloom: parse commit before computing filters
test-bloom: fix usage typo
bloom: fix whitespace around tab length
"git fsck" ensures that the paths recorded in tree objects are
sorted and without duplicates, but it failed to notice a case where
a blob is followed by entries that sort before a tree with the same
name. This has been corrected.
* rs/fsck-duplicate-names-in-trees:
fsck: report non-consecutive duplicate names in trees
"git p4" learned to recover from a (broken) state where a directory
and a file are recorded at the same path in the Perforce repository
the same way as their clients do.
* ao/p4-d-f-conflict-recover:
git-p4: recover from inconsistent perforce history
"rebase -i" segfaulted when rearranging a sequence that has a
fix-up that applies another fix-up (which may or may not be a
fix-up of yet another step).
* js/rebase-autosquash-double-fixup-fix:
rebase --autosquash: fix a potential segfault
"git bisect replay" had trouble with input files when they used
CRLF line ending, which has been corrected.
* cw/bisect-replay-with-dos:
bisect: allow CRLF line endings in "git bisect replay" input
ccd469450a (date.c: switch to reentrant {gm,local}time_r, 2019-11-28)
removes the only gmtime() call we had and moves to gmtime_r() which
doesn't have the same portability problems.
Remove the compat gmtime code since it is no longer needed, and confirm
by successfull running t4212 in FreeBSD 9.3 amd64 (the oldest I could
get a hold off).
Further work might be needed to ensure 32bit time_t systems (like FreeBSD
i386) will handle correctly the overflows tested in t4212, but that is
orthogonal to this change, and it doesn't change the current behaviour
as neither gmtime() or gmtime_r() will ever return NULL on those systems
because time_t is unsigned.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With a rename/rename(1to2) conflict, we attempt to do a three-way merge
of the file contents, so that the correct contents can be placed in the
working tree at both paths. If the file is a binary, however, no
content merging is possible and we should just use the original version
of the file at each of the paths.
Reported-by: Chunlin Zhang <zhangchunlin@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While iterating references (to discover the set of commits to write to
the commit-graph with 'git commit-graph write --reachable'),
'add_ref_to_set' can save 'fill_oids_from_commits()' some time by
peeling the references beforehand.
Move peeling out of 'fill_oids_from_commits()' and into
'add_ref_to_set()' to use 'peel_ref()' instead of 'deref_tag()'. Doing
so allows the commit-graph machinery to use the peeled value from
'$GIT_DIR/packed-refs' instead of having to load and parse tags.
While we're at it, discard non-commit objects reachable from ref tips.
This would be done automatically by 'fill_oids_from_commits()', but such
functionality will be removed in a subsequent patch after the call to
'lookup_commit_reference_gently' is dropped (at which point a non-commit
object in the commits oidset will become an error).
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When 'git commit-graph write --reachable' is invoked, the commit-graph
machinery calls 'for_each_ref()' to discover the set of reachable
commits.
Right now the 'add_ref_to_set' callback is not doing anything other than
adding an OID to the set of known-reachable OIDs. In a subsequent
commit, 'add_ref_to_set' will presumptively peel references. This
operation should be fast for repositories with an up-to-date
'$GIT_DIR/packed-refs', but may be slow in the general case.
So that it doesn't appear that 'git commit-graph write' is idling with
'--reachable' in the slow case, add a progress meter to provide some
output in the meantime.
In general, we don't expect a progress meter to appear at all, since
peeling references with a 'packed-refs' file is quick. If it's slow and
we do show a progress meter, the subsequent 'fill_oids_from_commits()'
will be fast, since all of the calls to
'lookup_commit_reference_gently()' will be no-ops.
Both progress meters are delayed, so it is unlikely that more than one
will appear. In either case, this intermediate state will go away in a
handful of patches, at which point there will be at most one progress
meter.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Serving a "git fetch" client over "git://" and "ssh://" protocols
using the on-wire protocol version 2 was buggy on the server end
when the client needs to make a follow-up request to
e.g. auto-follow tags.
* cc/upload-pack-v2-fetch-fix:
upload-pack: clear filter_options for each v2 fetch command
The code to skip unmerged paths in the index when sparse checkout
is in use would have made out-of-bound access of the in-core index
when the last path was unmerged, which has been corrected.
* ds/sparse-updates-oob-access-fix:
unpack-trees: avoid array out-of-bounds error
Instead of always building all branches at GitHub via Actions,
users can specify which branches to build.
* jk/ci-only-on-selected-branches:
ci: allow per-branch config for GitHub Actions
Teach "am", "commit", "merge" and "rebase", when they are run with
the "--quiet" option, to pass "--quiet" down to "gc --auto".
* jc/auto-gc-quiet:
auto-gc: pass --quiet down from am, commit, merge and rebase
auto-gc: extract a reusable helper from "git fetch"
Minor in-code comments and documentation updates around credential
API.
* cb/credential-doc-fixes:
credential: document protocol updates
credential: update gitcredentials documentation
credential: correct order of parameters for credential_match
credential: update description for credential_from_url_gently
The object walk with object filter "--filter=tree:0" can now take
advantage of the pack bitmap when available.
* tb/bitmap-walk-with-tree-zero-filter:
pack-bitmap: pass object filter to fill-in traversal
pack-bitmap.c: support 'tree:0' filtering
pack-bitmap.c: make object filtering functions generic
list-objects-filter: treat NULL filter_options as "disabled"
git-init(1)'s messages is subjected to i18n.
They should be tested by test_i18n* family.
Fix them.
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It's possible a user may complain about the way that Git interacts with
their interactive shell, e.g. autocompletion or shell prompt. In that
case, it's useful for us to know which shell they're using
interactively.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It may be useful to know which shell Git was built to try to point to,
in the event that shell-based Git commands are failing. $SHELL_PATH is
set during the build and used to launch the manpage viewer, as well as
by git-compat-util.h, and it's used during tests. 'git version
--build-options' is encouraged for use in bug reports, so it makes sense
to include this information there.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rather than teaching only one operation, like 'git fetch', how to write
down throughput to traces, we can learn about a wide range of user
operations that may seem slow by adding tooling to the progress library
itself. Operations which display progress are likely to be slow-running
and the kind of thing we want to monitor for performance anyways. By
showing object counts and data transfer size, we should be able to
make some derived measurements to ensure operations are scaling the way
we expect.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When using git p4 submit with the --prepare-p4-only option, the program
should prepare a single p4 changelist and notify the user that more
commits are pending and then stop processing.
A bug has been introduced by the p4-changelist hook feature that
causes the program to continue to try and process all pending
changelists at the same time.
The function applyCommit returns True when applying the commit
was successful and the program should continue. However, when the
optional flag --prepare-p4-only is set, the program should stop
after the first application.
Change the logic in the run method for P4Submit to check for the
flag --prepare-p4-only after successfully completing the applyCommit
method.
Be aware - this change will fix the existing test error in t9807.23
for --prepare-p4-only. However there is insufficent coverage for
this flag. If more than 1 commit is pending submission to P4, the
method will properly prepare the P4 changelist, however it will
still exit the application with an exitcode of 1.
The current documentation does not define what the exit code should be
in this condition.
(See: https://git-scm.com/docs/git-p4#Documentation/git-p4.txt---prepare-p4-only)
Signed-off-by: Ben Keene <seraphire@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
- Control+BackSpace: Delete word to the left of the cursor.
- Control+Delete : Delete word to the right of the cursor.
Originally introduced by BRIEF and Turbo Vision between 1985 and 1992,
they were adopted by most CUA-Compliant UIs, including those of: OS/2,
Windows, Mac OS, Qt, GTK, Open/Libre Office, Gecko, and GNU Emacs.
In both cases Tk already implements the functionality bound to other key
combination, so we use that.
Graphical examples:
Deleting to the left:
v------ pointer
X_WORD____X
^-----^------ selection
Deleting to the right:
v--------- pointer
X_WORD_X
^--^------ selection
Signed-off-by: Ismael Luceno <ismael.luceno@tttech-auto.com>
Signed-off-by: Pratyush Yadav <me@yadavpratyush.com>
Whenever GIT_CURL_VERBOSE is set, teach Git to behave as if
GIT_TRACE_CURL=1 and GIT_TRACE_CURL_NO_DATA=1 is set, instead of setting
CURLOPT_VERBOSE.
This is to prevent inadvertent revelation of sensitive data. In
particular, GIT_CURL_VERBOSE redacts neither the "Authorization" header
nor any cookies specified by GIT_REDACT_COOKIES.
Unifying the tracing mechanism also has the future benefit that any
improvements to the tracing mechanism will benefit both users of
GIT_CURL_VERBOSE and GIT_TRACE_CURL, and we do not need to remember to
implement any improvement twice.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Verify that when GIT_TRACE_CURL is set, Git prints out "Authorization:
Basic <redacted>" instead of the base64-encoded authorization details.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous changes to the line-log machinery focused on making the
first result appear faster. This was achieved by no longer walking the
entire commit history before returning the early results. There is still
another way to improve the performance: walk most commits much faster.
Let's use the changed-path Bloom filters to reduce time spent computing
diffs.
Since the line-log computation requires opening blobs and checking the
content-diff, there is still a lot of necessary computation that cannot
be replaced with changed-path Bloom filters. The part that we can reduce
is most effective when checking the history of a file that is deep in
several directories and those directories are modified frequently. In
this case, the computation to check if a commit is TREESAME to its first
parent takes a large fraction of the time. That is ripe for improvement
with changed-path Bloom filters.
We must ensure that prepare_to_use_bloom_filters() is called in
revision.c so that the bloom_filter_settings are loaded into the struct
rev_info from the commit-graph. Of course, some cases are still
forbidden, but in the line-log case the pathspec is provided in a
different way than normal.
Since multiple paths and segments could be requested, we compute the
struct bloom_key data dynamically during the commit walk. This could
likely be improved, but adds code complexity that is not valuable at
this time.
There are two cases to care about: merge commits and "ordinary" commits.
Merge commits have multiple parents, but if we are TREESAME to our first
parent in every range, then pass the blame for all ranges to the first
parent. Ordinary commits have the same condition, but each is done
slightly differently in the process_ranges_[merge|ordinary]_commit()
methods. By checking if the changed-path Bloom filter can guarantee
TREESAME, we can avoid that tree-diff cost. If the filter says "probably
changed", then we need to run the tree-diff and then the blob-diff if
there was a real edit.
The Linux kernel repository is a good testing ground for the performance
improvements claimed here. There are two different cases to test. The
first is the "entire history" case, where we output the entire history
to /dev/null to see how long it would take to compute the full line-log
history. The second is the "first result" case, where we find how long
it takes to show the first value, which is an indicator of how quickly a
user would see responses when waiting at a terminal.
To test, I selected the paths that were changed most frequently in the
top 10,000 commits using this command (stolen from StackOverflow [1]):
git log --pretty=format: --name-only -n 10000 | sort | \
uniq -c | sort -rg | head -10
which results in
121 MAINTAINERS
63 fs/namei.c
60 arch/x86/kvm/cpuid.c
59 fs/io_uring.c
58 arch/x86/kvm/vmx/vmx.c
51 arch/x86/kvm/x86.c
45 arch/x86/kvm/svm.c
42 fs/btrfs/disk-io.c
42 Documentation/scsi/index.rst
(along with a bogus first result). It appears that the path
arch/x86/kvm/svm.c was renamed, so we ignore that entry. This leaves the
following results for the real command time:
| | Entire History | First Result |
| Path | Before | After | Before | After |
|------------------------------|--------|--------|--------|--------|
| MAINTAINERS | 4.26 s | 3.87 s | 0.41 s | 0.39 s |
| fs/namei.c | 1.99 s | 0.99 s | 0.42 s | 0.21 s |
| arch/x86/kvm/cpuid.c | 5.28 s | 1.12 s | 0.16 s | 0.09 s |
| fs/io_uring.c | 4.34 s | 0.99 s | 0.94 s | 0.27 s |
| arch/x86/kvm/vmx/vmx.c | 5.01 s | 1.34 s | 0.21 s | 0.12 s |
| arch/x86/kvm/x86.c | 2.24 s | 1.18 s | 0.21 s | 0.14 s |
| fs/btrfs/disk-io.c | 1.82 s | 1.01 s | 0.06 s | 0.05 s |
| Documentation/scsi/index.rst | 3.30 s | 0.89 s | 1.46 s | 0.03 s |
It is worth noting that the least speedup comes for the MAINTAINERS file
which is
* edited frequently,
* low in the directory heirarchy, and
* quite a large file.
All of those points lead to spending more time doing the blob diff and
less time doing the tree diff. Still, we see some improvement in that
case and significant improvement in other cases. A 2-4x speedup is
likely the more typical case as opposed to the small 5% change for that
file.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous patch made it possible to perform line-level filtering
during history traversal instead of in an expensive preprocessing
step, but it still requires some simpler preprocessing steps, notably
topo-ordering. However, nowadays we have commit-graphs storing
generation numbers, which make it possible to incrementally traverse
the history in topological order, without the preparatory limit_list()
and sort_in_topological_order() steps; see b45424181e (revision.c:
generation-based topo-order algorithm, 2018-11-01).
This patch combines the two, so we can do both the topo-ordering and
the line-level filtering during history traversal, eliminating even
those simpler preprocessing steps, and thus further reducing the delay
before showing the first commit modifying the given line range.
The 'revs->limited' flag plays the central role in this, because, due
to limitations of the current implementation, the generation
number-based topo-ordering is only enabled when this flag remains
unset. Line-level log, however, always sets this flag in
setup_revisions() ever since the feature was introduced in 12da1d1f6f
(Implement line-history search (git log -L), 2013-03-28). The reason
for setting 'limited' is unclear, though, because the line-level log
itself doesn't directly depend on it, and it doesn't affect how the
limit_list() function limits the revision range. However, there is an
indirect dependency: the line-level log requires topo-ordering, and
the "traditional" sort_in_topological_order() requires an already
limited commit list since e6c3505b44 (Make sure we generate the whole
commit list before trying to sort it topologically, 2005-07-06). The
new, generation numbers-based topo-ordering doesn't require a limited
commit list anymore.
So don't set 'revs->limited' for line-level log, unless it is really
necessary, namely:
- The user explicitly requested parent rewriting, because that is
still done in the line_log_filter() preprocessing step (see
previous patch), which requires sort_in_topological_order() and in
turn limit_list() as well.
- A commit-graph file is not available or it doesn't yet contain
generation numbers. In these cases we had to fall back on
sort_in_topological_order() and in turn limit_list(). The
existing condition with generation_numbers_enabled() has already
ensured that the 'limited' flag is set in these cases; this patch
just makes sure that the line-level log sets 'revs->topo_order'
before that condition.
While the reduced delay before showing the first commit is measurable
in git.git, it takes a bigger repository to make it clearly noticable.
In both cases below the line ranges were chosen so that they were
modified rather close to the starting revisions, so the effect of this
change is most noticable.
# git.git
$ time git --no-pager log -L:read_alternate_refs:sha1-file.c -1 v2.23.0
Before:
real 0m0.107s
user 0m0.091s
sys 0m0.013s
After:
real 0m0.058s
user 0m0.050s
sys 0m0.005s
# linux.git
$ time git --no-pager log \
-L:build_restore_work_registers:arch/mips/mm/tlbex.c -1 v5.2
Before:
real 0m1.129s
user 0m1.061s
sys 0m0.069s
After:
real 0m0.096s
user 0m0.087s
sys 0m0.009s
Additional testing by Derrick Stolee: Since this patch improves
the performance for the first result, I repeated the experiment
from the previous patch on the Linux kernel repository, reporting
real time here:
Command: git log -L 100,200:MAINTAINERS -n 1 >/dev/null
Before: 0.71 s
After: 0.05 s
Now, we have dropped the full topo-order of all ~910,000 commits
before reporting the first result. The remaining performance
improvements then are:
1. Update the parent-rewriting logic to be incremental similar to
how "git log --graph" behaves.
2. Use changed-path Bloom filters to reduce the time spend in the
tree-diff to see if the path(s) changed.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As diff_tree_oid() computes a diff, it will terminate early if the
total number of changed paths is strictly larger than max_changes.
This includes the directories that changed, not just the file paths.
However, only the file paths are reflected in the resulting diff
queue's "nr" value.
Use the "num_changes" from diffopt to check if the diff terminated
early. This is incredibly important, as it can result in incorrect
filters! For example, the first commit in the Linux kernel repo
reports only 471 changes, but since these are nested inside several
directories they expand to 513 "real" changes, and in fact the
total list of changes is not reported. Thus, the computed filter
for this commit is incorrect.
Demonstrate the subtle difference by using one fewer file change
in the 'get bloom filter for commit with 513 changes' test. Before,
this edited 513 files inside "bigDir" which hit this inequality.
However, dropping the file count by one demonstrates how the
previous inequality was incorrect but the new one is correct.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The current line-level log implementation performs a preprocessing
step in prepare_revision_walk(), during which the line_log_filter()
function filters and rewrites history to keep only commits modifying
the given line range. This preprocessing affects both responsiveness
and correctness:
- Git doesn't produce any output during this preprocessing step.
Checking whether a commit modified the given line range is
somewhat expensive, so depending on the size of the given revision
range this preprocessing can result in a significant delay before
the first commit is shown.
- Limiting the number of displayed commits (e.g. 'git log -3 -L...')
doesn't limit the amount of work during preprocessing, because
that limit is applied during history traversal. Alas, by that
point this expensive preprocessing step has already churned
through the whole revision range to find all commits modifying the
revision range, even though only a few of them need to be shown.
- It rewrites parents, with no way to turn it off. Without the user
explicitly requesting parent rewriting any parent object ID shown
should be that of the immediate parent, just like in case of a
pathspec-limited history traversal without parent rewriting.
However, after that preprocessing step rewrote history, the
subsequent "regular" history traversal (i.e. get_revision() in a
loop) only sees commits modifying the given line range.
Consequently, it can only show the object ID of the last ancestor
that modified the given line range (which might happen to be the
immediate parent, but many-many times it isn't).
This patch addresses both the correctness and, at least for the common
case, the responsiveness issues by integrating line-level log
filtering into the regular revision walking machinery:
- Make process_ranges_arbitrary_commit(), the static function in
'line-log.c' deciding whether a commit modifies the given line
range, public by removing the static keyword and adding the
'line_log_' prefix, so it can be called from other parts of the
revision walking machinery.
- If the user didn't explicitly ask for parent rewriting (which, I
believe, is the most common case):
- Call this now-public function during regular history traversal,
namely from get_commit_action() to ignore any commits not
modifying the given line range.
Note that while this check is relatively expensive, it must be
performed before other, much cheaper conditions, because the
tracked line range must be adjusted even when the commit will
end up being ignored by other conditions.
- Skip the line_log_filter() call, i.e. the expensive
preprocessing step, in prepare_revision_walk(), because, thanks
to the above points, the revision walking machinery is now able
to filter out commits not modifying the given line range while
traversing history.
This way the regular history traversal sees the unmodified
history, and is therefore able to print the object ids of the
immediate parents of the listed commits. The eliminated
preprocessing step can greatly reduce the delay before the first
commit is shown, see the numbers below.
- However, if the user did explicitly ask for parent rewriting via
'--parents' or a similar option, then stick with the current
implementation for now, i.e. perform that expensive filtering and
history rewriting in the preprocessing step just like we did
before, leaving the initial delay as long as it was.
I tried to integrate line-level log filtering with parent rewriting
into the regular history traversal, but, unfortunately, several
subtleties resisted... :) Maybe someday we'll figure out how to do
that, but until then at least the simple and common (i.e. without
parent rewriting) 'git log -L:func:file' commands can benefit from the
reduced delay.
This change makes the failing 'parent oids without parent rewriting'
test in 't4211-line-log.sh' succeed.
The reduced delay is most noticable when there's a commit modifying
the line range near the tip of a large-ish revision range:
# no parent rewriting requested, no commit-graph present
$ time git --no-pager log -L:read_alternate_refs:sha1-file.c -1 v2.23.0
Before:
real 0m9.570s
user 0m9.494s
sys 0m0.076s
After:
real 0m0.718s
user 0m0.674s
sys 0m0.044s
A significant part of the remaining delay is spent reading and parsing
commit objects in limit_list(). With the help of the commit-graph we
can eliminate most of that reading and parsing overhead, so here are
the timing results of the same command as above, but this time using
the commit-graph:
Before:
real 0m8.874s
user 0m8.816s
sys 0m0.057s
After:
real 0m0.107s
user 0m0.091s
sys 0m0.013s
The next patch will further reduce the remaining delay.
To be clear: this patch doesn't actually optimize the line-level log,
but merely moves most of the work from the preprocessing step to the
history traversal, so the commits modifying the line range can be
shown as soon as they are processed, and the traversal can be
terminated as soon as the given number of commits are shown.
Consequently, listing the full history of a line range, potentially
all the way to the root commit, will take the same time as before (but
at least the user might start reading the output earlier).
Furthermore, if the most recent commit modifying the line range is far
away from the starting revision, then that initial delay will still be
significant.
Additional testing by Derrick Stolee: In the Linux kernel repository,
the MAINTAINERS file was changed ~3,500 times across the ~915,000
commits. In addition to that edit frequency, the file itself is quite
large (~18,700 lines). This means that a significant portion of the
computation is taken up by computing the patch-diff of the file. This
patch improves the real time it takes to output the first result quite
a bit:
Command: git log -L 100,200:MAINTAINERS -n 1 >/dev/null
Before: 3.88 s
After: 0.71 s
If we drop the "-n 1" in the command, then there is no change in
end-to-end process time. This is because the command still needs to
walk the entire commit history, which negates the point of this
patch. This is expected.
As a note for future reference, the ~4.3 seconds in the old code
spends ~2.6 seconds computing the patch-diffs, and the rest of the
time is spent walking commits and computing diffs for which paths
changed at each commit. The changed-path Bloom filters could improve
the end-to-end computation time (i.e. no "-n 1" in the command).
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
