Correct the default target in Documentation/Makefile, and
future-proof all Makefiles from similar breakages by declaring the
default target (which happens to be "all") upfront.
* ad/set-default-target-in-makefiles:
Makefile: set default goals in makefiles
Explicitly set the default goal at the very top of various makefiles.
This is already present in some makefiles, but not all of them.
In particular, this corrects a regression introduced in a38edab7c8
(Makefile: generate doc versions via GIT-VERSION-GEN, 2024-12-06). That
commit added some config files as build targets for the Documentation
directory, and put the target configuration in a sensible place.
Unfortunately, that sensible place was above any other build target
definitions, meaning the default goal changed to being those
configuration files only, rather than the HTML and man page
documentation.
Signed-off-by: Adam Dinwoodie <adam@dinwoodie.org>
Helped-by: Junio C Hamano <gitster@pobox.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git pack-objects" and its wrapper "git repack" learned an option
to use an alternative path-hash function to improve delta-base
selection to produce a packfile with deeper history than window
size.
* ds/name-hash-tweaks:
pack-objects: prevent name hash version change
test-tool: add helper for name-hash values
p5313: add size comparison test
pack-objects: add GIT_TEST_NAME_HASH_VERSION
repack: add --name-hash-version option
pack-objects: add --name-hash-version option
pack-objects: create new name-hash function version
Add a new test-tool helper, name-hash, to output the value of the
name-hash algorithms for the input list of strings, one per line.
Since the name-hash values can be stored in the .bitmap files, it is
important that these hash functions do not change across Git versions.
Add a simple test to t5310-pack-bitmaps.sh to provide some testing of
the current values. Due to how these functions are implemented, it would
be difficult to change them without disturbing these values. The paths
used for this test are carefully selected to demonstrate some of the
behavior differences of the two current name hash versions, including
which conditions will cause them to collide.
Create a performance test that uses test_size to demonstrate how
collisions occur for these hash algorithms. This test helps inform
someone as to the behavior of the name-hash algorithms for their repo
based on the paths at HEAD.
My copy of the Git repository shows modest statistics around the
collisions of the default name-hash algorithm:
Test this tree
--------------------------------------------------
5314.1: paths at head 4.5K
5314.2: distinct hash value: v1 4.1K
5314.3: maximum multiplicity: v1 13
5314.4: distinct hash value: v2 4.2K
5314.5: maximum multiplicity: v2 9
Here, the maximum collision multiplicity is 13, but around 10% of paths
have a collision with another path.
In a more interesting example, the microsoft/fluentui [1] repo had these
statistics at time of committing:
Test this tree
--------------------------------------------------
5314.1: paths at head 19.5K
5314.2: distinct hash value: v1 8.2K
5314.3: maximum multiplicity: v1 279
5314.4: distinct hash value: v2 17.8K
5314.5: maximum multiplicity: v2 44
[1] https://github.com/microsoft/fluentui
That demonstrates that of the nearly twenty thousand path names, they
are assigned around eight thousand distinct values. 279 paths are
assigned to a single value, leading the packing algorithm to sort
objects from those paths together, by size.
With the v2 name hash function, the maximum multiplicity lowers to 44,
leaving some room for further improvement.
In a more extreme example, an internal monorepo had a much worse
collision rate:
Test this tree
--------------------------------------------------
5314.1: paths at head 227.3K
5314.2: distinct hash value: v1 72.3K
5314.3: maximum multiplicity: v1 14.4K
5314.4: distinct hash value: v2 166.5K
5314.5: maximum multiplicity: v2 138
Here, we can see that the v2 name hash function provides somem
improvements, but there are still a number of collisions that could lead
to repacking problems at this scale.
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As custom options are added to 'git pack-objects' and 'git repack' to
adjust how compression is done, use this new performance test script to
demonstrate their effectiveness in performance and size.
The recently-added --name-hash-version option allows for testing
different name hash functions. Version 2 intends to preserve some of the
locality of version 1 while more often breaking collisions due to long
filenames.
Distinguishing objects by more of the path is critical when there are
many name hash collisions and several versions of the same path in the
full history, giving a significant boost to the full repack case. The
locality of the hash function is critical to compressing something like
a shallow clone or a thin pack representing a push of a single commit.
This can be seen by running pt5313 on the open source fluentui
repository [1]. Most commits will have this kind of output for the thin
and big pack cases, though certain commits (such as [2]) will have
problematic thin pack size for other reasons.
[1] https://github.com/microsoft/fluentui
[2] a637a06df05360ce5ff21420803f64608226a875
Checked out at the parent of [2], I see the following statistics:
Test HEAD
---------------------------------------------------------------
5313.2: thin pack with version 1 0.37(0.44+0.02)
5313.3: thin pack size with version 1 1.2M
5313.4: big pack with version 1 2.04(7.77+0.23)
5313.5: big pack size with version 1 20.4M
5313.6: shallow fetch pack with version 1 1.41(2.94+0.11)
5313.7: shallow pack size with version 1 34.4M
5313.8: repack with version 1 95.70(676.41+2.87)
5313.9: repack size with version 1 439.3M
5313.10: thin pack with version 2 0.12(0.12+0.06)
5313.11: thin pack size with version 2 22.0K
5313.12: big pack with version 2 2.80(5.43+0.34)
5313.13: big pack size with version 2 25.9M
5313.14: shallow fetch pack with version 2 1.77(2.80+0.19)
5313.15: shallow pack size with version 2 33.7M
5313.16: repack with version 2 33.68(139.52+2.58)
5313.17: repack size with version 2 160.5M
To make comparisons easier, I will reformat this output into a different
table style:
| Test | V1 Time | V2 Time | V1 Size | V2 Size |
|--------------|---------|---------|---------|---------|
| Thin Pack | 0.37 s | 0.12 s | 1.2 M | 22.0 K |
| Big Pack | 2.04 s | 2.80 s | 20.4 M | 25.9 M |
| Shallow Pack | 1.41 s | 1.77 s | 34.4 M | 33.7 M |
| Repack | 95.70 s | 33.68 s | 439.3 M | 160.5 M |
The v2 hash function successfully differentiates the CHANGELOG.md files
from each other, which leads to significant improvements in the thin
pack (simulating a push of this commit) and the full repack. There is
some bloat in the "big pack" scenario and essentially the same results
for the shallow pack.
In the case of the Git repository, these numbers show some of the issues
with this approach:
| Test | V1 Time | V2 Time | V1 Size | V2 Size |
|--------------|---------|---------|---------|---------|
| Thin Pack | 0.02 s | 0.02 s | 1.1 K | 1.1 K |
| Big Pack | 1.69 s | 1.95 s | 13.5 M | 14.5 M |
| Shallow Pack | 1.26 s | 1.29 s | 12.0 M | 12.2 M |
| Repack | 29.51 s | 29.01 s | 237.7 M | 238.2 M |
Here, the attempts to remove conflicts in the v2 function seem to cause
slight bloat to these sizes. This shows that the Git repository benefits
a lot from cross-path delta pairs.
The results are similar with the nodejs/node repo:
| Test | V1 Time | V2 Time | V1 Size | V2 Size |
|--------------|---------|---------|---------|---------|
| Thin Pack | 0.02 s | 0.02 s | 1.6 K | 1.6 K |
| Big Pack | 4.61 s | 3.26 s | 56.0 M | 52.8 M |
| Shallow Pack | 7.82 s | 7.51 s | 104.6 M | 107.0 M |
| Repack | 88.90 s | 73.75 s | 740.1 M | 764.5 M |
Here, the v2 name-hash causes some size bloat more often than it reduces
the size, but it also universally improves performance time, which is an
interesting reversal. This must mean that it is helping to short-circuit
some delta computations even if it is not finding the most efficient
ones. The performance improvement cannot be explained only due to the
I/O cost of writing the resulting packfile.
The Linux kernel repository was the initial target of the default name
hash value, and its naming conventions are practically build to take the
most advantage of the default name hash values:
| Test | V1 Time | V2 Time | V1 Size | V2 Size |
|--------------|----------|----------|---------|---------|
| Thin Pack | 0.17 s | 0.07 s | 4.6 K | 4.6 K |
| Big Pack | 17.88 s | 12.35 s | 201.1 M | 159.1 M |
| Shallow Pack | 11.05 s | 22.94 s | 269.2 M | 273.8 M |
| Repack | 727.39 s | 566.95 s | 2.5 G | 2.5 G |
Here, the thin and big packs gain some performance boosts in time, with
a modest gain in the size of the big pack. The shallow pack, however, is
more expensive to compute, likely because similarly-named files across
different directories are farther apart in the name hash ordering in v2.
The repack also gains benefits in computation time but no meaningful
change to the full size.
Finally, an internal Javascript repo of moderate size shows significant
gains when repacking with --name-hash-version=2 due to it having many name
hash collisions. However, it's worth noting that only the full repack
case has significant differences from the v1 name hash:
| Test | V1 Time | V2 Time | V1 Size | V2 Size |
|-----------|-----------|----------|---------|---------|
| Thin Pack | 8.28 s | 7.28 s | 16.8 K | 16.8 K |
| Big Pack | 12.81 s | 11.66 s | 29.1 M | 29.1 M |
| Shallow | 4.86 s | 4.06 s | 42.5 M | 44.1 M |
| Repack | 3126.50 s | 496.33 s | 6.2 G | 855.6 M |
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git describe" optimization.
* jk/describe-perf:
describe: split "found all tags" and max_candidates logic
describe: stop traversing when we run out of names
describe: stop digging for max_candidates+1
t/perf: add tests for git-describe
t6120: demonstrate weakness in disjoint-root handling
The perf test suite prefers to use test_file_size over 'wc -c' when
inside of a test_size block. One advantage is that accidentally writign
"wc -c file" (instead of "wc -c <file") does not inadvertently break the
tests (since the former will include the filename in the output of wc).
Both of the two uses of test_size use "wc -c", but let's convert those
to the more conventional test_file_size helper instead.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We don't have a perf script for git-describe, despite it often being
accused of slowness. Let's add a few simple tests to start with.
Rather than use the existing tags from our test repo, we'll make our own
so that we have a known quantity and position. We'll add a "new" tag
near the tip of HEAD, and an "old" one that is at the very bottom. And
then our tests are:
1. Describing HEAD naively requires walking all the way down to the
old tag as we collect candidates. This gives us a baseline for what
"slow" looks like.
2. Doing the same with --candidates=1 can potentially be fast, because
we can quie after finding "new". But we don't, and it's also slow.
3. Likewise we should be able to quit when there are no more tags to
find. This can happen naturally if a repo has few tags, but also if
you restrict the set of tags with --match.
Here are the results running against linux.git. Note that I have a
commit-graph built for the repo, so "slow" here is ~700ms. Without a
commit graph it's more like 9s!
Test HEAD
--------------------------------------------------------------
6100.2: describe HEAD 0.70(0.66+0.04)
6100.3: describe HEAD with one max candidate 0.70(0.66+0.04)
6100.4: describe HEAD with one tag 0.70(0.64+0.06)
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous two changes introduced a commit walking heuristic for finding
the most likely base branch for a given source. This algorithm walks
first-parent histories until reaching a collision.
This walk _should_ be very fast. Exceptions include cases where a
commit-graph file does not exist, leading to a full walk of all reachable
commits to compute generation numbers, or a case where no collision in the
first-parent history exists, leading to a walk of all first-parent history
to the root commits.
The p1500 test script guarantees a complete commit-graph file during its
setup, so we will not test that scenario. Do create a new root commit in an
effort to test the scenario of parallel first-parent histories.
Even with the extra root commit, these tests take no longer than 0.02
seconds on my machine for the Git repository. However, the results are
slightly more interesting in a copy of the Linux kernel repository:
Test
---------------------------------------------------------------
1500.2: ahead-behind counts: git for-each-ref 0.12
1500.3: ahead-behind counts: git branch 0.12
1500.4: ahead-behind counts: git tag 0.12
1500.5: contains: git for-each-ref --merged 0.04
1500.6: contains: git branch --merged 0.04
1500.7: contains: git tag --merged 0.04
1500.8: is-base check: test-tool reach (refs) 0.03
1500.9: is-base check: test-tool reach (tags) 0.03
1500.10: is-base check: git for-each-ref 0.03
1500.11: is-base check: git for-each-ref (disjoint-base) 0.07
Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Implement a straightforward performance test demonstrating the benefit
of pseudo-merge bitmaps by measuring how long it takes to count
reachable objects in a few different scenarios:
- without bitmaps, to demonstrate a reasonable baseline
- with bitmaps, but without pseudo-merges
- with bitmaps and pseudo-merges
Results from running this test on git.git are as follows:
Test this tree
-----------------------------------------------------------------------------------
5333.2: git rev-list --count --all --objects (no bitmaps) 3.54(3.45+0.08)
5333.3: git rev-list --count --all --objects (no pseudo-merges) 0.43(0.40+0.03)
5333.4: git rev-list --count --all --objects (with pseudo-merges) 0.12(0.11+0.01)
On a private repository which is much larger, and has many spikey parts
of history that aren't merged into the 'master' branch, the results are
as follows:
Test this tree
---------------------------------------------------------------------------------------
5333.1: git rev-list --count --all --objects (no bitmaps) 122.29(121.31+0.97)
5333.2: git rev-list --count --all --objects (no pseudo-merges) 21.88(21.30+0.58)
5333.3: git rev-list --count --all --objects (with pseudo-merges) 5.05(4.77+0.28)
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Take care to redirect stdin, otherwise the output of wc would also contain
the file name.
Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Acked-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Streaming spans of packfile data used to be done only from a
single, primary, pack in a repository with multiple packfiles. It
has been extended to allow reuse from other packfiles, too.
* tb/multi-pack-verbatim-reuse: (26 commits)
t/perf: add performance tests for multi-pack reuse
pack-bitmap: enable reuse from all bitmapped packs
pack-objects: allow setting `pack.allowPackReuse` to "single"
t/test-lib-functions.sh: implement `test_trace2_data` helper
pack-objects: add tracing for various packfile metrics
pack-bitmap: prepare to mark objects from multiple packs for reuse
pack-revindex: implement `midx_pair_to_pack_pos()`
pack-revindex: factor out `midx_key_to_pack_pos()` helper
midx: implement `midx_preferred_pack()`
git-compat-util.h: implement checked size_t to uint32_t conversion
pack-objects: include number of packs reused in output
pack-objects: prepare `write_reused_pack_verbatim()` for multi-pack reuse
pack-objects: prepare `write_reused_pack()` for multi-pack reuse
pack-objects: pass `bitmapped_pack`'s to pack-reuse functions
pack-objects: keep track of `pack_start` for each reuse pack
pack-objects: parameterize pack-reuse routines over a single pack
pack-bitmap: return multiple packs via `reuse_partial_packfile_from_bitmap()`
pack-bitmap: simplify `reuse_partial_packfile_from_bitmap()` signature
ewah: implement `bitmap_is_empty()`
pack-bitmap: pass `bitmapped_pack` struct to pack-reuse functions
...
Stale URLs have been updated to their current counterparts (or
archive.org) and HTTP links are replaced with working HTTPS links.
* js/update-urls-in-doc-and-comment:
doc: refer to internet archive
doc: update links for andre-simon.de
doc: switch links to https
doc: update links to current pages
To ensure that we don't regress either the size or runtime performance
of multi-pack reuse, add a performance test to measure both of these.
The test partitions the objects in GIT_TEST_PERF_LARGE_REPO into 1, 10,
and 100 packs, and then tries to perform a "clone" at each stage with
both single- and multi-pack reuse enabled.
Note that the `repack_into_n_chunks()` function in this new test script
differs from the existing `repack_into_n()`. The former partitions the
repository into N equal-sized chunks, while the latter produces N packs
of five commits each (plus their objects), and then another pack with
the remainder.
On git.git, I can produce the following results on my machine:
Test this tree
--------------------------------------------------------------------------------
5332.3: clone for 1-pack scenario (single-pack reuse) 1.57(2.99+0.15)
5332.4: clone size for 1-pack scenario (single-pack reuse) 231.8M
5332.5: clone for 1-pack scenario (multi-pack reuse) 1.79(2.96+0.21)
5332.6: clone size for 1-pack scenario (multi-pack reuse) 231.7M
5332.9: clone for 10-pack scenario (single-pack reuse) 3.89(16.75+0.35)
5332.10: clone size for 10-pack scenario (single-pack reuse) 209.9M
5332.11: clone for 10-pack scenario (multi-pack reuse) 1.56(2.99+0.17)
5332.12: clone size for 10-pack scenario (multi-pack reuse) 224.4M
5332.15: clone for 100-pack scenario (single-pack reuse) 8.24(54.31+0.59)
5332.16: clone size for 100-pack scenario (single-pack reuse) 278.3M
5332.17: clone for 100-pack scenario (multi-pack reuse) 2.13(2.44+0.33)
5332.18: clone size for 100-pack scenario (multi-pack reuse) 357.9M
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git for-each-ref --no-sort" still sorted the refs alphabetically
which paid non-trivial cost. It has been redefined to show output
in an unspecified order, to allow certain optimizations to take
advantage of.
* vd/for-each-ref-unsorted-optimization:
t/perf: add perf tests for for-each-ref
ref-filter.c: use peeled tag for '*' format fields
for-each-ref: clean up documentation of --format
ref-filter.c: filter & format refs in the same callback
ref-filter.c: refactor to create common helper functions
ref-filter.c: rename 'ref_filter_handler()' to 'filter_one()'
ref-filter.h: add functions for filter/format & format-only
ref-filter.h: move contains caches into filter
ref-filter.h: add max_count and omit_empty to ref_format
ref-filter.c: really don't sort when using --no-sort
These sites offer https versions of their content.
Using the https versions provides some protection for users.
Signed-off-by: Josh Soref <jsoref@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add performance tests for 'for-each-ref'. The tests exercise different
combinations of filters/formats/options, as well as the overall performance
of 'git for-each-ref | git cat-file --batch-check' to demonstrate the
performance difference vs. 'git for-each-ref' with "%(*fieldname)" format
specifiers.
All tests are run against a repository with 40k loose refs - 10k commits,
each having a unique:
- branch
- custom ref (refs/custom/special_*)
- annotated tag pointing at the commit
- annotated tag pointing at the other annotated tag (i.e., a nested tag)
After those tests are finished, the refs are packed with 'pack-refs --all'
and the same tests are rerun.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our coding guidelines say to not use `test` with `-a` and `-o` because
it can easily lead to bugs. Convert trivial cases where we still use
these to instead instead concatenate multiple invocations of `test` via
`&&` and `||`, respectively.
While not all of the converted instances can cause ambiguity, it is
worth getting rid of all of them regardless:
- It becomes easier to reason about the code as we do not have to
argue why one use of `-a`/`-o` is okay while another one isn't.
- We don't encourage people to use these expressions.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Set the requires-full-index to false for "check-attr".
Add a test to ensure that the index is not expanded whether the files
are outside or inside the sparse-checkout cone when the sparse index is
enabled.
The `p2000` tests demonstrate a ~63% execution time reduction for
'git check-attr' using a sparse index.
Test before after
-----------------------------------------------------------------------
2000.106: git check-attr -a f2/f4/a (full-v3) 0.05 0.05 +0.0%
2000.107: git check-attr -a f2/f4/a (full-v4) 0.05 0.05 +0.0%
2000.108: git check-attr -a f2/f4/a (sparse-v3) 0.04 0.02 -50.0%
2000.109: git check-attr -a f2/f4/a (sparse-v4) 0.04 0.01 -75.0%
Helped-by: Victoria Dye <vdye@github.com>
Signed-off-by: Shuqi Liang <cheskaqiqi@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The index is read in 'worktree.c' at two points:
1.The 'validate_no_submodules' function, which checks if there are any
submodules present in the worktree.
2.The 'check_clean_worktree' function, which verifies if a worktree is
'clean', i.e., there are no untracked or modified but uncommitted files.
This is done by running the 'git status' command, and an error message
is thrown if the worktree is not clean. Given that 'git status' is
already sparse-aware, the function is also sparse-aware.
Hence we can just set the requires-full-index to false for
"git worktree".
Add tests that verify that 'git worktree' behaves correctly when the
sparse index is enabled and test to ensure the index is not expanded.
The `p2000` tests demonstrate a ~20% execution time reduction for
'git worktree' using a sparse index:
(Note:the p2000 test results didn't reflect the huge speedup because of
the index reading time is minuscule comparing to the filesystem
operations.)
Test before after
-----------------------------------------------------------------------
2000.102: git worktree add....(full-v3) 3.15 2.82 -10.5%
2000.103: git worktree add....(full-v4) 3.14 2.84 -9.6%
2000.104: git worktree add....(sparse-v3) 2.59 2.14 -16.4%
2000.105: git worktree add....(sparse-v4) 2.10 1.57 -25.2%
Helped-by: Victoria Dye <vdye@github.com>
Signed-off-by: Shuqi Liang <cheskaqiqi@gmail.com>
Acked-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The index is read in 'cmd_diff_tree' at two points:
1. The first index read was added in fd66bcc31f (diff-tree: read the
index so attribute checks work in bare repositories, 2017-12-06) to deal
with reading '.gitattributes' content. 77efbb366a (attr: be careful
about sparse directories, 2021-09-08) established that, in a sparse
index, we do _not_ try to load a '.gitattributes' file from within a
sparse directory.
2. The second index access point is involved in rename detection,
specifically when reading from stdin.This was initially added in
f0c6b2a2fd ([PATCH] Optimize diff-tree -[CM]--stdin, 2005-05-27), where
'setup' was set to 'DIFF_SETUP_USE_SIZE_CACHE |DIFF_SETUP_USE_CACHE'.
That assignment was later modified to drop the'DIFF_SETUP_USE_CACHE' in
ff7fe37b05 (diff.c: move read_index() code back to the caller,
2018-08-13).However, 'DIFF_SETUP_USE_SIZE_CACHE' seems to be unused as
of 6e0b8ed6d3 (diff.c: do not use a separate "size cache"., 2007-05-07)
and nothing about 'detect_rename' otherwise indicates index usage.
Hence we can just set the requires-full-index to false for "diff-tree".
Add tests that verify that 'git diff-tree' behaves correctly when the
sparse index is enabled and test to ensure the index is not expanded.
The `p2000` tests demonstrate a ~98% execution time reduction for
'git diff-tree' using a sparse index:
Test before after
-----------------------------------------------------------------------
2000.94: git diff-tree HEAD (full-v3) 0.05 0.04 -20.0%
2000.95: git diff-tree HEAD (full-v4) 0.06 0.05 -16.7%
2000.96: git diff-tree HEAD (sparse-v3) 0.59 0.01 -98.3%
2000.97: git diff-tree HEAD (sparse-v4) 0.61 0.01 -98.4%
2000.98: git diff-tree HEAD -- f2/f4/a (full-v3) 0.05 0.05 +0.0%
2000.99: git diff-tree HEAD -- f2/f4/a (full-v4) 0.05 0.04 -20.0%
2000.100: git diff-tree HEAD -- f2/f4/a (sparse-v3) 0.58 0.01 -98.3%
2000.101: git diff-tree HEAD -- f2/f4/a (sparse-v4) 0.55 0.01 -98.2%
Helped-by: Victoria Dye <vdye@github.com>
Signed-off-by: Shuqi Liang <cheskaqiqi@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach "diff-files" not to expand sparse-index unless needed.
* sl/diff-files-sparse:
diff-files: integrate with sparse index
t1092: add tests for `git diff-files`
Remove full index requirement for `git diff-files`. Refactor the
ensure_expanded and ensure_not_expanded functions by introducing a
common helper function, ensure_index_state. Add test to ensure the index
is no expanded in `git diff-files`.
The `p2000` tests demonstrate a ~96% execution time reduction for 'git
diff-files' and a ~97% execution time reduction for 'git diff-files'
for a file using a sparse index:
Test before after
-----------------------------------------------------------------------
2000.94: git diff-files (full-v3) 0.09 0.08 -11.1%
2000.95: git diff-files (full-v4) 0.09 0.09 +0.0%
2000.96: git diff-files (sparse-v3) 0.52 0.02 -96.2%
2000.97: git diff-files (sparse-v4) 0.51 0.02 -96.1%
2000.98: git diff-files -- f2/f4/a (full-v3) 0.06 0.07 +16.7%
2000.99: git diff-files -- f2/f4/a (full-v4) 0.08 0.08 +0.0%
2000.100: git diff-files -- f2/f4/a (sparse-v3) 0.46 0.01 -97.8%
2000.101: git diff-files -- f2/f4/a (sparse-v4) 0.51 0.02 -96.1%
Signed-off-by: Shuqi Liang <cheskaqiqi@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The on-disk reverse index that allows mapping from the pack offset
to the object name for the object stored at the offset has been
enabled by default.
* tb/pack-revindex-on-disk:
t: invert `GIT_TEST_WRITE_REV_INDEX`
config: enable `pack.writeReverseIndex` by default
pack-revindex: introduce `pack.readReverseIndex`
pack-revindex: introduce GIT_TEST_REV_INDEX_DIE_ON_DISK
pack-revindex: make `load_pack_revindex` take a repository
t5325: mark as leak-free
pack-write.c: plug a leak in stage_tmp_packfiles()
Back in e37d0b8730 (builtin/index-pack.c: write reverse indexes,
2021-01-25), Git learned how to read and write a pack's reverse index
from a file instead of in-memory.
A pack's reverse index is a mapping from pack position (that is, the
order that objects appear together in a ".pack") to their position in
lexical order (that is, the order that objects are listed in an ".idx"
file).
Reverse indexes are consulted often during pack-objects, as well as
during auxiliary operations that require mapping between pack offsets,
pack order, and index index.
They are useful in GitHub's infrastructure, where we have seen a
dramatic increase in performance when writing ".rev" files[1]. In
particular:
- an ~80% reduction in the time it takes to serve fetches on a popular
repository, Homebrew/homebrew-core.
- a ~60% reduction in the peak memory usage to serve fetches on that
same repository.
- a collective savings of ~35% in CPU time across all pack-objects
invocations serving fetches across all repositories in a single
datacenter.
Reverse indexes are also beneficial to end-users as well as forges. For
example, the time it takes to generate a pack containing the objects for
the 10 most recent commits in linux.git (representing a typical push) is
significantly faster when on-disk reverse indexes are available:
$ { git rev-parse HEAD && printf '^' && git rev-parse HEAD~10 } >in
$ hyperfine -L v false,true 'git.compile -c pack.readReverseIndex={v} pack-objects --delta-base-offset --revs --stdout <in >/dev/null'
Benchmark 1: git.compile -c pack.readReverseIndex=false pack-objects --delta-base-offset --revs --stdout <in >/dev/null
Time (mean ± σ): 543.0 ms ± 20.3 ms [User: 616.2 ms, System: 58.8 ms]
Range (min … max): 521.0 ms … 577.9 ms 10 runs
Benchmark 2: git.compile -c pack.readReverseIndex=true pack-objects --delta-base-offset --revs --stdout <in >/dev/null
Time (mean ± σ): 245.0 ms ± 11.4 ms [User: 335.6 ms, System: 31.3 ms]
Range (min … max): 226.0 ms … 259.6 ms 13 runs
Summary
'git.compile -c pack.readReverseIndex=true pack-objects --delta-base-offset --revs --stdout <in >/dev/null' ran
2.22 ± 0.13 times faster than 'git.compile -c pack.readReverseIndex=false pack-objects --delta-base-offset --revs --stdout <in >/dev/null'
The same is true of writing a pack containing the objects for the 30
most-recent commits:
$ { git rev-parse HEAD && printf '^' && git rev-parse HEAD~30 } >in
$ hyperfine -L v false,true 'git.compile -c pack.readReverseIndex={v} pack-objects --delta-base-offset --revs --stdout <in >/dev/null'
Benchmark 1: git.compile -c pack.readReverseIndex=false pack-objects --delta-base-offset --revs --stdout <in >/dev/null
Time (mean ± σ): 866.5 ms ± 16.2 ms [User: 1414.5 ms, System: 97.0 ms]
Range (min … max): 839.3 ms … 886.9 ms 10 runs
Benchmark 2: git.compile -c pack.readReverseIndex=true pack-objects --delta-base-offset --revs --stdout <in >/dev/null
Time (mean ± σ): 581.6 ms ± 10.2 ms [User: 1181.7 ms, System: 62.6 ms]
Range (min … max): 567.5 ms … 599.3 ms 10 runs
Summary
'git.compile -c pack.readReverseIndex=true pack-objects --delta-base-offset --revs --stdout <in >/dev/null' ran
1.49 ± 0.04 times faster than 'git.compile -c pack.readReverseIndex=false pack-objects --delta-base-offset --revs --stdout <in >/dev/null'
...and savings on trivial operations like computing the on-disk size of
a single (packed) object are even more dramatic:
$ git rev-parse HEAD >in
$ hyperfine -L v false,true 'git.compile -c pack.readReverseIndex={v} cat-file --batch-check="%(objectsize:disk)" <in'
Benchmark 1: git.compile -c pack.readReverseIndex=false cat-file --batch-check="%(objectsize:disk)" <in
Time (mean ± σ): 305.8 ms ± 11.4 ms [User: 264.2 ms, System: 41.4 ms]
Range (min … max): 290.3 ms … 331.1 ms 10 runs
Benchmark 2: git.compile -c pack.readReverseIndex=true cat-file --batch-check="%(objectsize:disk)" <in
Time (mean ± σ): 4.0 ms ± 0.3 ms [User: 1.7 ms, System: 2.3 ms]
Range (min … max): 1.6 ms … 4.6 ms 1155 runs
Summary
'git.compile -c pack.readReverseIndex=true cat-file --batch-check="%(objectsize:disk)" <in' ran
76.96 ± 6.25 times faster than 'git.compile -c pack.readReverseIndex=false cat-file --batch-check="%(objectsize:disk)" <in'
In the more than two years since e37d0b8730 was merged, Git's
implementation of on-disk reverse indexes has been thoroughly tested,
both from users enabling `pack.writeReverseIndexes`, and from GitHub's
deployment of the feature. The latter has been running without incident
for more than two years.
This patch changes Git's behavior to write on-disk reverse indexes by
default when indexing a pack, which should make the above operations
faster for everybody's Git installation after a repack.
(The previous commit explains some potential drawbacks of using on-disk
reverse indexes in certain limited circumstances, that essentially boil
down to a trade-off between time to generate, and time to access. For
those limited cases, the `pack.readReverseIndex` escape hatch can be
used).
[1]: https://github.blog/2021-04-29-scaling-monorepo-maintenance/#reverse-indexes
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Acked-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git for-each-ref" learns '%(ahead-behind:<base>)' that computes the
distances from a single reference point in the history with bunch
of commits in bulk.
* ds/ahead-behind:
commit-reach: add tips_reachable_from_bases()
for-each-ref: add ahead-behind format atom
commit-reach: implement ahead_behind() logic
commit-graph: introduce `ensure_generations_valid()`
commit-graph: return generation from memory
commit-graph: simplify compute_generation_numbers()
commit-graph: refactor compute_topological_levels()
for-each-ref: explicitly test no matches
for-each-ref: add --stdin option
Update 'git write-tree' to allow using the sparse-index in memory
without expanding to a full one.
The recursive algorithm for update_one() was already updated in 2de37c5
(cache-tree: integrate with sparse directory entries, 2021-03-03) to
handle sparse directory entries in the index. Hence we can just set the
requires-full-index to false for "write-tree".
The `p2000` tests demonstrate a ~96% execution time reduction for 'git
write-tree' using a sparse index:
Test before after
-----------------------------------------------------------------
2000.78: git write-tree (full-v3) 0.34 0.33 -2.9%
2000.79: git write-tree (full-v4) 0.32 0.30 -6.3%
2000.80: git write-tree (sparse-v3) 0.47 0.02 -95.8%
2000.81: git write-tree (sparse-v4) 0.45 0.02 -95.6%
Signed-off-by: Shuqi Liang <cheskaqiqi@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git describe compares the index with the working tree when (and only
when) it is run with the "--dirty" flag. This is done by the
run_diff_index() function. The function has been made aware of the
sparse-index in the series that led to 8d2c3732 (Merge branch
'ld/sparse-diff-blame', 2021-12-21). Hence we can just set the
requires-full-index to false for "describe".
Performance metrics
Test HEAD~1 HEAD
-------------------------------------------------------------------------------------------------
2000.2: git describe --dirty (full-v3) 0.08(0.09+0.01) 0.08(0.06+0.03) +0.0%
2000.3: git describe --dirty (full-v4) 0.09(0.07+0.03) 0.08(0.05+0.04) -11.1%
2000.4: git describe --dirty (sparse-v3) 0.88(0.82+0.06) 0.02(0.01+0.05) -97.7%
2000.5: git describe --dirty (sparse-v4) 0.68(0.60+0.08) 0.02(0.02+0.04) -97.1%
2000.6: echo >>new && git describe --dirty (full-v3) 0.08(0.04+0.05) 0.08(0.05+0.04) +0.0%
2000.7: echo >>new && git describe --dirty (full-v4) 0.08(0.07+0.03) 0.08(0.05+0.04) +0.0%
2000.8: echo >>new && git describe --dirty (sparse-v3) 0.75(0.69+0.07) 0.02(0.03+0.03) -97.3%
2000.9: echo >>new && git describe --dirty (sparse-v4) 0.81(0.73+0.09) 0.02(0.01+0.05) -97.5%
Signed-off-by: Raghul Nanth A <nanth.raghul@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This argument was added in 7cae7627c4 (builtin/grep.c: integrate with
sparse index, 2022-09-22), but it was a carry-over from an earlier
version where the --sparse flag was added to the 'git grep' builtin.
This argument does not exist, so currently the
p2000-sparse-operations.sh performance test script fails when reaching
this step.
With this fix, the script works with these numbers for my copy of the
Git source code repository:
Test HEAD
------------------------------------------------------------
2000.30: git grep --cached ... (full-v3) 0.34(1.20+0.14)
2000.31: git grep --cached ... (full-v4) 0.31(1.15+0.13)
2000.32: git grep --cached ... (sparse-v3) 0.26(1.13+0.12)
2000.33: git grep --cached ... (sparse-v4) 0.27(1.13+0.12)
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Both 'git for-each-ref --merged=<X>' and 'git branch --merged=<X>' use
the ref-filter machinery to select references or branches (respectively)
that are reachable from a set of commits presented by one or more
--merged arguments. This happens within reach_filter(), which uses the
revision-walk machinery to walk history in a standard way.
However, the commit-reach.c file is full of custom searches that are
more efficient, especially for reachability queries that can terminate
early when reachability is discovered. Add a new
tips_reachable_from_bases() method to commit-reach.c and call it from
within reach_filter() in ref-filter.c. This affects both 'git branch'
and 'git for-each-ref' as tested in p1500-graph-walks.sh.
For the Linux kernel repository, we take an already-fast algorithm and
make it even faster:
Test HEAD~1 HEAD
-------------------------------------------------------------------
1500.5: contains: git for-each-ref --merged 0.13 0.02 -84.6%
1500.6: contains: git branch --merged 0.14 0.02 -85.7%
1500.7: contains: git tag --merged 0.15 0.03 -80.0%
(Note that we remove the iterative 'git rev-list' test from p1500
because it no longer makes sense as a comparison to 'git for-each-ref'
and would just waste time running it for these comparisons.)
The algorithm is implemented in commit-reach.c in the method
tips_reachable_from_base(). This method takes a string_list of tips and
assigns the 'util' for each item with the value 1 if the base commit can
reach those tips.
Like other reachability queries in commit-reach.c, the fastest way to
search for "can A reach B?" is to do a depth-first search up to the
generation number of B, preferring to explore first parents before later
parents. While we must walk all reachable commits up to that generation
number when the answer is "no", the depth-first search can answer "yes"
much faster than other approaches in most cases.
This search becomes trickier when there are multiple targets for the
depth-first search. The commits with lower generation number are more
likely to be within the history of the start commit, but we don't want
to waste time searching commits of low generation number if the commit
target with lowest generation number has already been found.
The trick here is to take the input commits and sort them by generation
number in ascending order. Track the index within this order as
min_generation_index. When we find a commit, if its index in the list is
equal to min_generation_index, then we can increase the generation
number boundary of our search to the next-lowest value in the list.
With this mechanism, the number of commits to search is minimized with
respect to the depth-first search heuristic. We will walk all commits up
to the minimum generation number of a commit that is _not_ reachable
from the start, but we will walk only the necessary portion of the
depth-first search for the reachable commits of lower generation.
Add extra tests for this behavior in t6600-test-reach.sh as the
interesting data shape of that repository can sometimes demonstrate
corner case bugs.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The previous change implemented the ahead_behind() method, including an
algorithm to compute the ahead/behind values for a number of commit tips
relative to a number of commit bases. Now, integrate that algorithm as
part of 'git for-each-ref' hidden behind a new format atom,
ahead-behind. This naturally extends to 'git branch' and 'git tag'
builtins, as well.
This format allows specifying multiple bases, if so desired, and all
matching references are compared against all of those bases. For this
reason, failing to read a reference provided from these atoms results in
an error.
In order to translate the ahead_behind() method information to the
format output code in ref-filter.c, we must populate arrays of
ahead_behind_count structs. In struct ref_array, we store the full array
that will be passed to ahead_behind(). In struct ref_array_item, we
store an array of pointers that point to the relvant items within the
full array. In this way, we can pull all relevant ahead/behind values
directly when formatting output for a specific item. It also ensures the
lifetime of the ahead_behind_count structs matches the time that the
array is being used.
Add specific tests of the ahead/behind counts in t6600-test-reach.sh, as
it has an interesting repository shape. In particular, its merging
strategy and its use of different commit-graphs would demonstrate over-
counting if the ahead_behind() method did not already account for that
possibility.
Also add tests for the specific for-each-ref, branch, and tag builtins.
In the case of 'git tag', there are intersting cases that happen when
some of the selected tips are not commits. This requires careful logic
around commits_nr in the second loop of filter_ahead_behind(). Also, the
test in t7004 is carefully located to avoid being dependent on the GPG
prereq. It also avoids using the test_commit helper, as that will add
ticks to the time and disrupt the expected timestamps in later tag
tests.
Also add performance tests in a new p1300-graph-walks.sh script. This
will be useful for more uses in the future, but for now compare the
ahead-behind counting algorithm in 'git for-each-ref' to the naive
implementation by running 'git rev-list --count' processes for each
input.
For the Git source code repository, the improvement is already obvious:
Test this tree
---------------------------------------------------------------
1500.2: ahead-behind counts: git for-each-ref 0.07(0.07+0.00)
1500.3: ahead-behind counts: git branch 0.07(0.06+0.00)
1500.4: ahead-behind counts: git tag 0.07(0.06+0.00)
1500.5: ahead-behind counts: git rev-list 1.32(1.04+0.27)
But the standard performance benchmark is the Linux kernel repository,
which demosntrates a significant improvement:
Test this tree
---------------------------------------------------------------
1500.2: ahead-behind counts: git for-each-ref 0.27(0.24+0.02)
1500.3: ahead-behind counts: git branch 0.27(0.24+0.03)
1500.4: ahead-behind counts: git tag 0.28(0.27+0.01)
1500.5: ahead-behind counts: git rev-list 4.57(4.03+0.54)
The 'git rev-list' test exists in this change as a demonstration, but it
will be removed in the next change to avoid wasting time on this
comparison.
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When UTF is enabled for a PCRE match, the corresponding flags are
added to the pcre2_compile() call, but PCRE2_UCP wasn't included.
This prevents extending the meaning of the character classes to
include those new valid characters and therefore result in failed
matches for expressions that rely on that extention, for ex:
$ git grep -P '\bÆvar'
Add PCRE2_UCP so that \w will include Æ and therefore \b could
correctly match the beginning of that word.
This has an impact on performance that has been estimated to be
between 20% to 40% and that is shown through the added performance
test.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Acked-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When running 'read-tree' with a single tree and no prefix,
'prime_cache_tree()' is called after the tree is unpacked. In that
situation, skip a redundant call to 'cache_tree_update()' in
'unpack_trees()' by enabling the 'skip_cache_tree_update' unpack option.
Removing the redundant cache tree update provides a substantial performance
improvement to 'git read-tree <tree-ish>', as shown by a test added to
'p0006-read-tree-checkout.sh':
Test before after
----------------------------------------------------------------------
read-tree br_ballast_plus_1 3.94(1.80+1.57) 3.00(1.14+1.28) -23.9%
Note that the 'read-tree' in 't1022-read-tree-partial-clone.sh' is updated
to read two trees, rather than one. The test was first introduced in
d3da223f22 (cache-tree: prefetch in partial clone read-tree, 2021-07-23) to
exercise the 'cache_tree_update()' code path, as used in 'git merge'. Since
this patch drops the call to 'cache_tree_update()' in single-tree 'git
read-tree', change the test to use the two-tree variant so that
'cache_tree_update()' is called as intended.
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Enable the 'skip_cache_tree_update' option in the variants that call
'prime_cache_tree()' after 'unpack_trees()' (specifically, 'git reset
--mixed' and 'git reset --hard'). This avoids redundantly rebuilding the
cache tree in both 'cache_tree_update()' at the end of 'unpack_trees()' and
in 'prime_cache_tree()', resulting in a small (but consistent) performance
improvement. From the newly-added 'p7102-reset.sh' test:
Test before after
--------------------------------------------------------------------
7102.1: reset --hard (...) 2.11(0.40+1.54) 1.97(0.38+1.47) -6.6%
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Add a performance test comparing the execution times of 'prime_cache_tree()'
and 'cache_tree_update(_, WRITE_TREE_SILENT | WRITE_TREE_REPAIR)'. The goal
of comparing these two is to identify which is the faster method for
rebuilding an invalid cache tree, ultimately to remove one when both are
(reundantly) called in immediate succession.
Both methods are fast, so the new tests in 'p0090-cache-tree.sh' must call
each tested function multiple times to ensure the reported times (to 0.01s
resolution) convey the differences between them.
The tests compare the timing of a 'test-tool cache-tree' run as a no-op (to
capture a baseline for the overhead associated with running the tool),
'cache_tree_update()', and 'prime_cache_tree()' on four scenarios:
- A completely valid cache tree
- A cache tree with 2 invalid paths
- A cache tree with 50 invalid paths
- A completely empty cache tree
Example results:
Test this tree
-----------------------------------------------------------
0090.2: no-op, clean 1.27(0.48+0.52)
0090.3: prime_cache_tree, clean 2.02(0.83+0.85)
0090.4: cache_tree_update, clean 1.30(0.49+0.54)
0090.5: no-op, invalidate 2 1.29(0.48+0.54)
0090.6: prime_cache_tree, invalidate 2 1.98(0.81+0.83)
0090.7: cache_tree_update, invalidate 2 2.12(0.94+0.86)
0090.8: no-op, invalidate 50 1.32(0.50+0.55)
0090.9: prime_cache_tree, invalidate 50 2.10(0.86+0.89)
0090.10: cache_tree_update, invalidate 50 2.35(1.14+0.90)
0090.11: no-op, empty 1.33(0.50+0.54)
0090.12: prime_cache_tree, empty 2.04(0.84+0.87)
0090.13: cache_tree_update, empty 2.51(1.27+0.92)
These timings show that, while 'cache_tree_update()' is faster when the
cache tree is completely valid, it is equal to or slower than
'prime_cache_tree()' when there are any invalid paths. Since the redundant
calls are mostly in scenarios where the cache tree will be at least
partially invalid (e.g., 'git reset --hard'), 'prime_cache_tree()' will
likely perform better than 'cache_tree_update()' in typical cases.
Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
"git grep" learned to expand the sparse-index more lazily and on
demand in a sparse checkout.
* sy/sparse-grep:
builtin/grep.c: integrate with sparse index
Turn on sparse index and remove ensure_full_index().
Before this patch, `git-grep` utilizes the ensure_full_index() method to
expand the index and search all the entries. Because this method
requires walking all the trees and constructing the index, it is the
slow part within the whole command.
To achieve better performance, this patch uses grep_tree() to search the
sparse directory entries and get rid of the ensure_full_index() method.
Why grep_tree() is a better choice over ensure_full_index()?
1) grep_tree() is as correct as ensure_full_index(). grep_tree() looks
into every sparse-directory entry (represented by a tree) recursively
when looping over the index, and the result of doing so matches the
result of expanding the index.
2) grep_tree() utilizes pathspecs to limit the scope of searching.
ensure_full_index() always expands the index, which means it will
always walk all the trees and blobs in the repo without caring if
the user only wants a subset of the content, i.e. using a pathspec.
On the other hand, grep_tree() will only search the contents that
match the pathspec, and thus possibly walking fewer trees.
3) grep_tree() does not construct and copy back a new index, while
ensure_full_index() does. This also saves some time.
----------------
Performance test
- Summary:
p2000 tests demonstrate a ~71% execution time reduction for
`git grep --cached bogus -- "f2/f1/f1/*"` using tree-walking logic.
However, notice that this result varies depending on the pathspec
given. See below "Command used for testing" for more details.
Test HEAD~ HEAD
-------------------------------------------------------
2000.78: git grep ... (full-v3) 0.35 0.39 (≈)
2000.79: git grep ... (full-v4) 0.36 0.30 (≈)
2000.80: git grep ... (sparse-v3) 0.88 0.23 (-73.8%)
2000.81: git grep ... (sparse-v4) 0.83 0.26 (-68.6%)
- Command used for testing:
git grep --cached bogus -- "f2/f1/f1/*"
The reason for specifying a pathspec is that, if we don't specify a
pathspec, then grep_tree() will walk all the trees and blobs to find the
pattern, and the time consumed doing so is not too different from using
the original ensure_full_index() method, which also spends most of the
time walking trees. However, when a pathspec is specified, this latest
logic will only walk the area of trees enclosed by the pathspec, and the
time consumed is reasonably a lot less.
Generally speaking, because the performance gain is acheived by walking
less trees, which are specified by the pathspec, the HEAD time v.s.
HEAD~ time in sparse-v[3|4], should be proportional to
"pathspec enclosed area" v.s. "all area", respectively. Namely, the
wider the <pathspec> is encompassing, the less the performance
difference between HEAD~ and HEAD, and vice versa.
That is, if we don't specify a pathspec, the performance difference [1]
is indistinguishable: both methods walk all the trees and take generally
same amount of time (even with the index construction time included for
ensure_full_index()).
[1] Performance test result without pathspec (hence walking all trees):
Command used:
git grep --cached bogus
Test HEAD~ HEAD
---------------------------------------------------
2000.78: git grep ... (full-v3) 6.17 5.19 (≈)
2000.79: git grep ... (full-v4) 6.19 5.46 (≈)
2000.80: git grep ... (sparse-v3) 6.57 6.44 (≈)
2000.81: git grep ... (sparse-v4) 6.65 6.28 (≈)
--------------------------
NEEDSWORK about submodules
There are a few NEEDSWORKs that belong to improvements beyond this
topic. See the NEEDSWORK in builtin/grep.c::grep_submodule() for
more context. The other two NEEDSWORKs in t1092 are also relative.
Suggested-by: Derrick Stolee <derrickstolee@github.com>
Helped-by: Derrick Stolee <derrickstolee@github.com>
Helped-by: Victoria Dye <vdye@github.com>
Helped-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Shaoxuan Yuan <shaoxuan.yuan02@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Despite POSIX states that:
> The old egrep and fgrep commands are likely to be supported for many
> years to come as implementation extensions, allowing historical
> applications to operate unmodified.
GNU grep 3.8 started to warn[1]:
> The egrep and fgrep commands, which have been deprecated since
> release 2.5.3 (2007), now warn that they are obsolescent and should
> be replaced by grep -E and grep -F.
Prepare for their removal in the future.
[1]: https://lists.gnu.org/archive/html/info-gnu/2022-09/msg00001.html
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Hoist the remainder of "scalar" out of contrib/ to the main part of
the codebase.
* vd/scalar-to-main:
Documentation/technical: include Scalar technical doc
t/perf: add 'GIT_PERF_USE_SCALAR' run option
t/perf: add Scalar performance tests
scalar-clone: add test coverage
scalar: add to 'git help -a' command list
scalar: implement the `help` subcommand
git help: special-case `scalar`
scalar: include in standard Git build & installation
scalar: fix command documentation section header
The pack bitmap file gained a bitmap-lookup table to speed up
locating the necessary bitmap for a given commit.
* ac/bitmap-lookup-table:
pack-bitmap-write: drop unused pack_idx_entry parameters
bitmap-lookup-table: add performance tests for lookup table
pack-bitmap: prepare to read lookup table extension
pack-bitmap-write: learn pack.writeBitmapLookupTable and add tests
pack-bitmap-write.c: write lookup table extension
bitmap: move `get commit positions` code to `bitmap_writer_finish`
Documentation/technical: describe bitmap lookup table extension
Add a 'GIT_PERF_USE_SCALAR' environment variable (and corresponding perf
config 'useScalar') to register a repository created with any of:
* test_perf_fresh_repo
* test_perf_default_repo
* test_perf_large_repo
as a Scalar enlistment. This is intended to allow a developer to test the
impact of Scalar on already-defined performance scenarios.
Suggested-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Create 'p9210-scalar.sh' for testing Scalar performance and comparing
performance of Git operations in Scalar registrations and standard
repositories. Example results:
Test this tree
------------------------------------------------------------------------
9210.2: scalar clone 14.82(18.00+3.63)
9210.3: git clone 26.15(36.67+6.90)
9210.4: git status (scalar) 0.04(0.01+0.01)
9210.5: git status (non-scalar) 0.10(0.02+0.11)
9210.6: test_commit --append --no-tag A (scalar) 0.08(0.02+0.03)
9210.7: test_commit --append --no-tag A (non-scalar) 0.13(0.03+0.11)
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix broken "&&-" chains and failures in early iterations of a loop.
* es/fix-chained-tests:
t5329: notice a failure within a loop
t: detect and signal failure within loop
t1092: fix buggy sparse "blame" test
t2407: fix broken &&-chains in compound statement
