The line-range filter that mm/line-log-cleanup added uses names that
obscure its model. The cursors lno_post/lno_pre and the index lno_0
share an lno_ prefix but conflate the pre/post-image axis with the
0-based/1-based axis, the hunk state is a flat set of rhunk_* fields,
and the filter-state pointer is just s.
The filter bridges two layers of diff.c, and its fields already used
each layer's vocabulary, but in cryptic abbreviations. Spell them out
to the form the rest of the file uses, so that the patches that follow
can simplify and fix it with those clearer names in place:
- lno_post/lno_pre -> lno_in_postimage/lno_in_preimage, the
line-number cursors, matching the counters in struct emit_callback
- lno_0 -> idx_in_postimage, the 0-based range index
- the hunk-header geometry stays old/new (old_begin, new_begin, and
counts) to match the xdiff_emit_hunk_fn callback and the
"@@ -<old> +<new> @@" header it feeds, but moves from flat rhunk_*
fields into a "hunk" sub-struct, so accesses read
filter->hunk.old_begin
- flush_rhunk -> flush_range_hunk
- the filter-state pointer in each callback: s -> filter
Also rename the struct line_range_callback to line_range_filter: it is
a filter over xdiff output, not merely a callback.
No behavior change.
Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `git log -L` implementation has been refactored to use the
standard diff output pipeline, enabling pickaxe and diff-filter to
work as expected. Additionally, metadata-only diff formats like
--raw and --name-only are now supported with -L.
* mm/line-log-cleanup:
line-log: allow non-patch diff formats with -L
line-log: integrate -L output with the standard log-tree pipeline
revision: move -L setup before output_format-to-diff derivation
Correct use of sockaddr API in "git daemon".
* st/daemon-sockaddr-fixes:
daemon: guard NULL REMOTE_PORT in execute() logging
daemon: fix IPv6 address truncation in ip2str()
daemon: fix IPv6 address corruption in lookup_hostname()
The documentation for `push.default = simple` has been clarified to
better explain its behavior, making it clear that it pushes the
current branch to a same-named branch on the remote, and detailing
the upstream requirements for centralized workflows.
* ib/doc-push-default-simple:
doc: clarify push.default=simple behavior
The 'git-jump' command (in contrib/) has been taught to automatically
pick a mode (merge, diff, or ws) when invoked without arguments.
* gh/jump-auto-mode:
git-jump: pick a mode automatically when invoked without arguments
Formatting object name in full hexadecimal form has been optimized
by using a new strbuf_add_oid_hex() helper function.
* rs/strbuf-add-oid-hex:
hex: add and use strbuf_add_oid_hex()
Adding a decimal integer with strbuf_addf("%u") appears commonly;
they have been optimized by using a custom formatter.
* rs/strbuf-add-uint:
ls-tree: use strbuf_add_uint()
ls-files: use strbuf_add_uint()
cat-file: use strbuf_add_uint()
strbuf: add strbuf_add_uint()
"git push" learned to take a "remote group" name to push to, which
causes pushes to multiple places, just like "git fetch" would do.
* ua/push-remote-group:
push: support pushing to a remote group
remote: move remote group resolution to remote.c
remote: fix sign-compare warnings in push_cas_option
The "promisor.quiet" configuration variable was not used from
relevant submodules when commands like "grep --recurse-submodules"
triggered a lazy fetch, which has been corrected.
* th/promisor-quiet-per-repo:
promisor-remote: fix promisor.quiet to use the correct repository
Reachability bitmap generation has been significantly optimized. By
reordering tree traversal, caching object positions, and refining how
pseudo-merge bitmaps are constructed, the performance of "git repack
--write-midx-bitmaps" is improved, especially for large repositories
and when using pseudo-merges.
* tb/bitmap-build-performance:
pack-bitmap: build pseudo-merge bitmaps after regular bitmaps
pack-bitmap: remember pseudo-merge parents
pack-bitmap: sort bitmaps before XORing
pack-bitmap: cache object positions during fill
pack-bitmap: consolidate `find_object_pos()` success path
pack-bitmap: reuse stored selected bitmaps
pack-bitmap: check subtree bits before recursing
pack-bitmap: pass object position to `fill_bitmap_tree()`
A batch of documentation pages has been updated to use the modern
synopsis style.
* ja/doc-synopsis-style-again:
doc: convert git-imap-send synopsis and options to new style
doc: convert git-apply synopsis and options to new style
doc: convert git-am synopsis and options to new style
doc: convert git-grep synopsis and options to new style
doc: git bisect: clarify the usage of the synopsis vs actual command
doc: convert git-bisect to synopsis style
The check for non-stale commits in the priority queue used by
`paint_down_to_common` and `ahead_behind` has been optimized by
replacing an O(N) scan with an O(1) counter, yielding performance
improvements in repositories with wide histories.
* kk/commit-reach-optim:
commit-reach: replace queue_has_nonstale() scan with O(1) tracking
commit-reach: deduplicate queue entries in paint_down_to_common
object.h: fix stale entries in object flag allocation table
"git stash -p" has been optimized by reusing cached index
entries in its temporary index, avoiding unnecessary lstat()
calls on unchanged files.
* aj/stash-patch-optimize-temporary-index:
stash: reuse cached index entries in --patch temporary index
'git restore --staged' has been optimized to avoid unnecessarily expanding
the sparse index when operating on paths within the sparse checkout
definition, by handling sparse directory entries at the tree level.
* ds/restore-sparse-index:
restore: avoid sparse index expansion
t1092: test 'git restore' with sparse index
The GIT_WORK_TREE variable prepared to invoke the push-to-checkout
hook was leaking into the environment even when there was no hook
used and broke the default push-to-deploy (i.e., let "git checkout"
update the working tree only when the working tree is clean).
* ar/receive-pack-worktree-env:
receive-pack: fix updateInstead with core.worktree
The "git pack-objects --path-walk" traversal has been integrated
with several object filters, including blobless and sparse filters.
* ds/path-walk-filters:
path-walk: support `combine` filter
path-walk: support `object:type` filter
path-walk: support `tree:0` filter
t6601: tag otherwise-unreachable trees
pack-objects: support sparse:oid filter with path-walk
path-walk: add pl_sparse_trees to control tree pruning
path-walk: support blob size limit filter
backfill: die on incompatible filter options
path-walk: support blobless filter
path-walk: always emit directly-requested objects
t/perf: add pack-objects filter and path-walk benchmark
pack-objects: pass --objects with --path-walk
t5620: make test work with path-walk var
"Friday noon" asked in the morning on Sunday was parsed to be one
day before the specified time, which has been corrected.
* ta/approxidate-noon-fix:
approxidate: use deferred mday adjustments for "specials"
approxidate: make "specials" respect fixed day-of-month
t0006: add support for approxidate test date adjustment
approxidate: make "today" wrap to midnight
The "name" argument in git_connect() and related functions has been
converted to a "service" enum to improve type safety and clarify its
purpose.
* jk/connect-service-enum:
transport-helper: fix typo in BUG() message
connect: use "service" enum for "name" argument
"git cat-file --batch" learns an in-line command "mailmap"
that lets the user toggle use of mailmap.
* sa/cat-file-batch-mailmap-switch:
cat-file: add mailmap subcommand to --batch-command
The logic to lazy-load trees from the commit-graph has been made
more robust by falling back to reading the commit object when
the commit-graph is no longer available.
* jk/commit-graph-lazy-load-fallback:
commit: fall back to full read when maybe_tree is NULL
The fsmonitor daemon has been implemented for Linux.
* pt/fsmonitor-linux:
fsmonitor: convert shown khash to strset in do_handle_client
fsmonitor: add tests for Linux
fsmonitor: add timeout to daemon stop command
fsmonitor: close inherited file descriptors and detach in daemon
run-command: add close_fd_above_stderr option
fsmonitor: implement filesystem change listener for Linux
fsmonitor: rename fsm-settings-darwin.c to fsm-settings-unix.c
fsmonitor: rename fsm-ipc-darwin.c to fsm-ipc-unix.c
fsmonitor: use pthread_cond_timedwait for cookie wait
compat/win32: add pthread_cond_timedwait
fsmonitor: fix hashmap memory leak in fsmonitor_run_daemon
fsmonitor: fix khash memory leak in do_handle_client
t9210, t9211: disable GIT_TEST_SPLIT_INDEX for scalar clone tests
The graph output from commands like "git log --graph" can now be
limited to a specified number of lanes, preventing overly wide output
in repositories with many branches.
* ps/graph-lane-limit:
graph: add truncation mark to capped lanes
graph: add --graph-lane-limit option
graph: limit the graph width to a hard-coded max
"git bisect" now uses the selected terms (e.g., old/new) more
consistently in its output.
* jr/bisect-custom-terms-in-output:
rev-parse: use selected alternate terms to look up refs
bisect: print bisect terms in single quotes
bisect: use selected alternate terms in status output
Revision traversal optimization.
* kk/tips-reachable-from-bases-optim:
t6600: add tests for duplicate tips in tips_reachable_from_bases()
commit-reach: use object flags for tips_reachable_from_bases()
REMOTE_ADDR and REMOTE_PORT are both set by the same code path in
handle(), so when the existing REMOTE_ADDR check passes, REMOTE_PORT
is guaranteed to be non-NULL. Guard REMOTE_PORT as well so that a
future change that breaks this invariant does not pass NULL to
printf's %s, which is undefined behavior.
Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The sockaddr struct size (ai_addrlen) is passed as the output buffer
size to inet_ntop(). For IPv6, sizeof(sockaddr_in6) is 28 bytes but
INET6_ADDRSTRLEN is 46, so long IPv6 addresses are silently truncated.
Fix this by passing sizeof(ip) instead, which is the actual size of
the destination buffer. Drop the now-unused len parameter from
ip2str() and update all callers.
Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
getaddrinfo() is called with AF_UNSPEC hints, so it may return IPv6
results. However, the code unconditionally casts ai_addr to
sockaddr_in and passes AF_INET to inet_ntop(). On IPv6-only hosts,
this reads from the wrong struct offset, producing garbage IP
addresses.
Fix this by checking ai_family and extracting the address pointer
into a local variable before calling inet_ntop() once with the
correct family. Die on unexpected address families.
Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that -L flows through log_tree_diff_flush() and diff_flush(),
metadata-only diff formats work because they only read filepair
fields (status, mode, path, oid) already set on the pre-computed
pairs.
Expand the allowlist in setup_revisions() to also accept --raw,
--name-only, --name-status, and --summary. Diff stat formats
(--stat, --numstat, --shortstat, --dirstat) remain blocked because
they call compute_diffstat() on full blob content and would show
whole-file statistics rather than range-scoped ones.
Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`git log -L` has bypassed log_tree_diff() and log_tree_diff_flush()
since the feature was introduced, short-circuiting from
log_tree_commit() directly into line_log_print(). This skips the
no_free save/restore (noted in a NEEDSWORK comment added by
f8781bfda3), the always_show_header fallback, show_diff_of_diff(),
and diff_free() cleanup.
Restructure so that -L flows through log_tree_diff() ->
log_tree_diff_flush(), the same path used by the normal
single-parent and merge diff codepaths:
- Rename line_log_print() to line_log_queue_pairs() and strip it
down to just queuing pre-computed filepairs. The show_log(),
separator, diffcore_std(), and diff_flush() calls are removed
since log_tree_diff_flush() handles all of those.
- In log_tree_diff(), call line_log_queue_pairs() then
log_tree_diff_flush(), mirroring the diff_tree_oid() + flush
pattern used by the single-parent and merge codepaths.
- Remove the early return in log_tree_commit() that is no longer
needed now that -L output flows through log_tree_diff() and
log_tree_diff_flush(); this restores no_free save/restore,
always_show_header, and diff_free() cleanup.
Because show_log() is now deferred until after diffcore_std() inside
log_tree_diff_flush(), pickaxe (-S, -G, --find-object) and
--diff-filter now properly suppress commits when all pairs are
filtered out.
The blank-line separator between commit header and diff changes
slightly: the old code printed one unconditionally, while
log_tree_diff_flush() only emits one for verbose headers. This
matches the rest of log output.
Also reject --full-diff, which is not yet supported with -L: the
filepairs are pre-computed during the history walk and scoped to
tracked line ranges, so there is currently no full-tree diff to
fall back to for display.
Update tests accordingly.
Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The line_level_traverse block sets a default DIFF_FORMAT_PATCH when
no output format has been explicitly requested. This default must
be visible to the "Did the user ask for any diff output?" check
that derives revs->diff from revs->diffopt.output_format.
Currently the -L block runs after that derivation, so revs->diff
stays 0 when no explicit format is given. This does not matter yet
because log_tree_commit() short-circuits into line_log_print()
before consulting revs->diff, but the next commit will route -L
through the normal log_tree_diff() path, which checks revs->diff.
Move the block above the derivation so the default DIFF_FORMAT_PATCH
is in place when revs->diff is computed. No behavior change on its
own.
Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
These functions were deprecated in a series of commits merged in
52882024 (Merge branch 'ps/commit-list-functions-renamed', 2026-02-13).
The compatibility was for in-flight topics at the time.
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Replace `free_commit_list` with `commit_list_free`. The former was
deprecated in 9f18d089 (commit: rename `free_commit_list()` to conform
to coding guidelines, 2026-01-15).
This allows us to remove all the deprecated functions in the
next commit:
• `copy_commit_list`
• `reverse_commit_list`
• `free_commit_list`
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Kristoffer Haugsbakk <code@khaugsbakk.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When generating bitmaps, `bitmap_builder_init()` starts with an initial
selection of commits to receive bitmap coverage, and then determines a
set of "maximal" commits based on its input.
Commit 089f751360 (pack-bitmap-write: build fewer intermediate bitmaps,
2020-12-08) has extensive details, but the gist is as follows:
Each selected commit starts with one commit_mask bit in its "commit
mask" bitmap. Then, we walk the first-parent history in topological
order and OR each commit's mask into its (first) parent. Whenever that
OR results in the parent having more bits set, the child is deemed to be
non-maximal, and the frontier is pushed further back along the first
parent history.
That approach works extremely well for ordinary selected commits, whose
first-parent histories often describe real sharing between the bitmaps
we are going to write.
It struggles, however, to efficiently generate pseudo-merge bitmaps.
Unlike ordinary commits for which the above algorithm is designed,
pseudo-merges don't represent any "real" commit in history, just a
grouping of non-bitmapped reference tips. In that sense, their first
parent is just a part of a larger set, and treating them like ordinary
selected commits imposes a significant slow-down when generating bitmaps
with pseudo-merges enabled.
Consider partitioning all non-bitmapped reference tips into eight
individual pseudo-merges via the following configuration:
[bitmapPseudoMerge "all"]
pattern=refs/
threshold=now
stableSize=10000000
maxMerges=8
, the cost of generating a bitmap from scratch rises significantly:
+------------------+-----------------+---------------+---------------------+
| | no pseudo-merge | pseudo-merges | Delta |
| | | (HEAD^) | |
+------------------+-----------------+---------------+---------------------+
| elapsed | 294.1 s | 575.0 s | +280.9 s (+95.5%) |
| cycles | 1,365.5 B | 2,686.9 B | +1,321.4 B (+96.8%) |
| instructions | 1,389.8 B | 2,546.6 B | +1,156.8 B (+83.2%) |
| CPI | 0.983 | 1.055 | +0.073 (+7.4%) |
+------------------+-----------------+---------------+---------------------+
This is a particularly poor trade-off, because the time saved by these
pseudo-merges during, e.g.,
$ git rev-list --count --all --objects --use-bitmap-index
is only:
$ hyperfine -L v true,false -n 'pseudo-merges: {v}' '
GIT_TEST_USE_PSEUDO_MERGES={v} git.compile rev-list --count \
--objects --all --use-bitmap-index
'
Benchmark 1: pseudo-merges: true
Time (mean ± σ): 2.613 s ± 0.012 s [User: 2.308 s, System: 0.305 s]
Range (min … max): 2.594 s … 2.633 s 10 runs
Benchmark 2: pseudo-merges: false
Time (mean ± σ): 52.205 s ± 0.170 s [User: 51.500 s, System: 0.697 s]
Range (min … max): 51.956 s … 52.458 s 10 runs
Summary
pseudo-merges: true ran
19.98 ± 0.11 times faster than pseudo-merges: false
In other words, we pay a nearly ~5 minute penalty to generate
pseudo-merge bitmaps, but only save ~50 seconds during traversal.
The problem stems from injecting pseudo-merges into the bitmap builder
as if they were normal commits. The maximal commit selection algorithm
was simply not designed for that case, and performs predictably poorly.
The only reason we reused the maximal commit selection routine for
pseudo-merges alongside regular non-pseudo-merge commits is because we
represent them both as commit objects (where the pseudo-merge commits
just represent a made-up commit as opposed to one that actually exists
in a repository's object store).
Instead, build the regular selected commit bitmaps first, considering
only non-pseudo-merge commits in `bitmap_builder_init()`. Once those
bitmaps have been stored, build each pseudo-merge bitmap separately and
attach its parent and object bitmaps to the corresponding pseudo-merge
entry before writing the extension.
This keeps the regular bitmap build shaped like the no-pseudo-merge
case. The later pseudo-merge fill can still stop at stored selected
ancestor bitmaps, so it does not have to rewalk each pseudo-merge
closure from scratch.
When an existing bitmap has the same pseudo-merge parent set, reuse and
remap that whole pseudo-merge bitmap before falling back to
fill_bitmap_commit(). This preserves the benefit of stable pseudo-merges
while keeping the on-disk format and reader behavior unchanged.
As a result, the overhead cost for generating pseudo-merges in the above
configuration is much smaller:
+------------------+-----------------+---------------+-------------------+
| | no pseudo-merge | pseudo-merges | Delta |
| | | (HEAD) | |
+------------------+-----------------+---------------+-------------------+
| elapsed | 294.1 s | 328.4 s | +34.3 s (+11.7%) |
| cycles | 1,365.5 B | 1,529.3 B | +163.7 B (+12.0%) |
| instructions | 1,389.8 B | 1,552.8 B | +163.0 B (+11.7%) |
| CPI | 0.983 | 0.985 | +0.002 (+0.2%) |
+------------------+-----------------+---------------+-------------------+
Recall that at the start of this series, generating reachability bitmaps
took 612.5 seconds *without* pseudo-merges. With this commit, it is
still ~46.38% *faster* to generate reachability bitmaps *with*
pseudo-merges than it was to generate bitmaps wihtout them at the
beginning of this series.
The changes to implement this are mostly straightforward. We exclude
pseudo-merge commits from the existing bitmap generation, and walk over
them in a separate pass, by either reusing an existing on-disk
pseudo-merge, or passing the pseudo-merge commit itself back to the
existing routine in `fill_bitmap_commit()`.
(Note that the routine to build pseudo-merge bitmaps is the same both
before and after this change, the difference is only that we do not let
psuedo-merges participate in determining the set of maximal commits.)
The only wrinkle is that `fill_bitmap_commit()` must be taught to not
expect that all tree objects have been parsed, which is the case for any
portion of history reachable by one or more pseudo-merge(s), but not by
any non-pseudo-merge commit selected for bitmapping.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
write_pseudo_merges() currently builds an array of temporary bitmaps for
the parent set of each pseudo-merge, then serializes those bitmaps later
while writing the extension.
Move those parent bitmaps onto the corresponding bitmapped_commit
entries instead. This keeps the on-disk output unchanged, but gives the
parent bitmap the same lifetime and access pattern that later changes
will use when pseudo-merge object bitmaps are built before the write
step.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Reachability bitmaps may be stored as XORs against nearby bitmaps, up to
10 away. However, when callers provide selected commits in an arbitrary
order, the writer may miss good ancestor/descendant pairs and produce
much larger bitmap files without changing query coverage.
Sort the selected bitmaps in date order (from oldest to newest) before
computing XOR offsets, leaving pseudo-merge bitmaps alone (which we will
deal with separately in following commits).
On our same testing repository from previous commits, this change shrunk
our selection of 1,261 bitmaps from ~635.46 MiB to 176.4 MiB for a
~72.24% reduction in the on-disk size of our *.bitmap file. The time to
generate the smaller bitmap file decreased by ~3.69 seconds, though this
is likely mostly noise.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous commits removed some redundant work from bitmap generation
by avoiding unnecessary tree recursion and by reusing selected bitmaps
that have already been computed.
Even with those changes in place, there is still an extremely hot path
from `fill_bitmap_commit()` and `fill_bitmap_tree()` to translate object
IDs into their corresponding bit positions in order to generate their
bitmaps.
In a small repository, this overhead is not significant. However, in a
very large repository (e.g., the one that we have been using as a
benchmark over the past several commits with ~57M total objects), the
overhead of locating object bit positions (often repeatedly) adds up
significantly.
Combat this by adding a small, direct-mapped cache to the bitmap writer
which maps object IDs to their corresponding bit positions. Size the
cache according to the number of objects being written, with fixed lower
and upper bounds so small repositories do not pay for a large table and
large repositories can avoid most repeated packlist and MIDX lookups.
On my machine with (a somewhat outdated) GCC 15.2.0, each entry in the
cache is 40 bytes wide:
$ pahole -C bitmap_pos_cache_entry pack-bitmap-write.o
struct bitmap_pos_cache_entry {
struct object_id oid; /* 0 36 */
uint32_t pos; /* 36 4 */
/* size: 40, cachelines: 1, members: 2 */
/* last cacheline: 40 bytes */
};
, and we will allocate up to 2^21 entries for a maximum total of 80 MiB
of cache overhead.
In our example repository from above and in earlier commits, this
results in a ~9.4% reduction in runtime relative to the previous commit:
+------------------+-------------+-------------+---------------------+
| | HEAD^ | HEAD | Delta |
+------------------+-------------+-------------+---------------------+
| elapsed | 324.8 s | 294.1 s | -30.7 s (-9.4%) |
| cycles | 1,508.6 B | 1,365.5 B | -143.0 B (-9.5%) |
| instructions | 1,436.6 B | 1,389.8 B | -46.9 B (-3.3%) |
| CPI | 1.050 | 0.983 | -0.068 (-6.4%) |
+------------------+-------------+-------------+---------------------+
When generating bitmaps on this repository (to produce the above
timings), the cache grew to its maximum size of 80 MiB, and resulted in
1.024B cache hits and 59.957M cache misses.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Both sides of `find_object_pos()` report success in the same way by
setting the optional `found` out-parameter and return the resolved
bitmap position.
Prepare for adding more bookkeeping around object-position lookups by
storing the result in a local `pos` variable and sharing the success
return path between the packlist and MIDX cases.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When `fill_bitmap_commit()` reaches an ancestor that was selected for
its own bitmap and processed earlier, its object closure is already
stored in `writer->bitmaps` as an EWAH bitmap. As a result, walking
through that commit's tree and parents again is redundant.
Teach `fill_bitmap_commit()` to notice that case. For non-root commits in
the walk, look for a stored selected bitmap and OR it into the bitmap
being built. If one exists, skip the commit, its tree, and its parents.
Building bitmaps from scratch on the same test repository from the
previous commits yields a significant speed-up:
+------------------+-------------+-------------+---------------------+
| | HEAD^ | HEAD | Delta |
+------------------+-------------+-------------+---------------------+
| elapsed | 562.8 s | 324.8 s | -237.9 s (-42.3%) |
| cycles | 2,621.3 B | 1,508.6 B | -1,112.7 B (-42.4%) |
| instructions | 2,348.9 B | 1,436.6 B | -912.3 B (-38.8%) |
| CPI | 1.116 | 1.050 | -0.066 (-5.9%) |
+------------------+-------------+-------------+---------------------+
In our testing repository, there are 1,261 commits selected for bitmap
coverage, and 1,382 maximal commits induced as a result of that. Of the
1,382 calls made to `fill_bitmap_commit()` (one per maximal commit), 131
of them can be short-circuited at some point during their traversal as a
consequence of this change.
In large repositories where the cost of filling the bitmap for any
individual commit is large, being able to short-circuit even ~9.5% of
the calls to `fill_bitmap_commit()` results in a significant savings.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
