Commit Graph

53026 Commits

Author SHA1 Message Date
Derrick Stolee
2cf489a3bf multi-pack-index: store local property
A pack-file is 'local' if it is stored within the usual object
directory. If it is stored in an alternate, it is non-local.

Pack-files are stored using a 'pack_local' member in the packed_git
struct. Add a similar 'local' member to the multi_pack_index struct
and 'local' parameters to the methods that load and prepare multi-
pack-indexes.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 15:31:39 -07:00
Derrick Stolee
6d68e6a461 multi-pack-index: provide more helpful usage info
The multi-pack-index builtin has a very simple command-line
interface. Instead of simply reporting usage, give the user a
hint to why the arguments failed.

Reported-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 15:31:39 -07:00
Junio C Hamano
c00ba2233e Sync 'ds/multi-pack-index' to v2.19.0-rc0
* ds/multi-pack-index: (23 commits)
  midx: clear midx on repack
  packfile: skip loading index if in multi-pack-index
  midx: prevent duplicate packfile loads
  midx: use midx in approximate_object_count
  midx: use existing midx when writing new one
  midx: use midx in abbreviation calculations
  midx: read objects from multi-pack-index
  config: create core.multiPackIndex setting
  midx: write object offsets
  midx: write object id fanout chunk
  midx: write object ids in a chunk
  midx: sort and deduplicate objects from packfiles
  midx: read pack names into array
  multi-pack-index: write pack names in chunk
  multi-pack-index: read packfile list
  packfile: generalize pack directory list
  t5319: expand test data
  multi-pack-index: load into memory
  midx: write header information to lockfile
  multi-pack-index: add 'write' verb
  ...
2018-08-20 15:29:54 -07:00
Stefan Beller
2543a64187 range-diff: indent special lines as context
The range-diff coloring is a bit fuzzy when it comes to special lines of
a diff, such as indicating new and old files with +++ and ---, as it
would pickup the first character and interpret it for its coloring, which
seems annoying as in regular diffs, these lines are colored bold via
DIFF_METAINFO.

By indenting these lines by a white space, they will be treated as context
which is much more useful, an example [1] on the range diff series itself:

[...]
    + diff --git a/Documentation/git-range-diff.txt b/Documentation/git-range-diff.txt
    + new file mode 100644
    + --- /dev/null
    + +++ b/Documentation/git-range-diff.txt
    +@@
    ++git-range-diff(1)
[...]
    +
      diff --git a/Makefile b/Makefile
      --- a/Makefile
      +++ b/Makefile
[...]

The first lines that introduce the new file for the man page will have the
'+' sign colored and the rest of the line will be bold.

The later lines that indicate a change to the Makefile will be treated as
context both in the outer and inner diff, such that those lines stay
regular color.

[1] ./git-range-diff pr-1/dscho/branch-diff-v3...pr-1/dscho/branch-diff-v4
    These tags are found at https://github.com/gitgitgadget/git

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 14:33:28 -07:00
Stefan Beller
8d5ccb59de range-diff: make use of different output indicators
This change itself only changes the internal communication and should
have no visible effect to the user. We instruct the diff code that
produces the inner diffs to use other markers instead of the
usual markers for new, old and context lines.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 14:33:26 -07:00
Stefan Beller
7648b79eee diff.c: add --output-indicator-{new, old, context}
This will prove useful in range-diff in a later patch as we will be able to
differentiate between adding a new file (that line is starting with +++
and then the file name) and regular new lines.

It could also be useful for experimentation in new patch formats, i.e.
we could teach git to emit moved lines with lines other than +/-.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 14:33:24 -07:00
Jeff King
198b349da8 t/perf: add perf tests for fetches from a bitmapped server
A server with bitmapped packs can serve a clone very
quickly. However, fetches are not necessarily made any
faster, because we spend a lot less time in object traversal
(which is what bitmaps help with) and more time finding
deltas (because we may have to throw out on-disk deltas if
the client does not have the base).

As a first step to making this faster, this patch introduces
a new perf script to measure fetches into a repo of various
ages from a fully-bitmapped server.

We separately measure the work done by the server (in
pack-objects) and that done by the client (in index-pack).
Furthermore, we measure the size of the resulting pack.

Breaking it down like this (instead of just doing a regular
"git fetch") lets us see how much each side benefits from
any changes. And since we know the pack size, if we estimate
the network speed, then one could calculate a complete
wall-clock time for the operation (though the script does
not do this automatically).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 14:04:47 -07:00
Jeff King
22bec79d1a t/perf: add infrastructure for measuring sizes
The main objective of scripts in the perf framework is to
run "test_perf", which measures the time it takes to run
some operation. However, it can also be interesting to see
the change in the output size of certain operations.

This patch introduces test_size, which records a single
numeric output from the test and shows it in the aggregated
output (with pretty printing and relative size comparison).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 14:04:47 -07:00
Jeff King
5a924a62bb t/perf: factor out percent calculations
This will let us reuse the code when we add new values to
aggregate besides times.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 14:04:47 -07:00
Jeff King
968e77a5f8 t/perf: factor boilerplate out of test_perf
About half of test_perf() is boilerplate preparing to run
_any_ test, and the other half is specifically running a
timing test. Let's split it into two functions, so that we
can reuse the boilerplate in future commits.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 14:04:47 -07:00
Junio C Hamano
7e8bfb0412 Git 2.19-rc0
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-20 12:53:58 -07:00
Junio C Hamano
273b0a1f58 Merge branch 'ab/checkout-default-remote'
* ab/checkout-default-remote:
  t2024: mark test using "checkout -p" with PERL prerequisite
2018-08-20 12:53:46 -07:00
Junio C Hamano
d28017005f Merge branch 'hn/highlight-sideband-keywords'
The sideband code learned to optionally paint selected keywords at
the beginning of incoming lines on the receiving end.

* hn/highlight-sideband-keywords:
  sideband: do not read beyond the end of input
  sideband: highlight keywords in remote sideband output
2018-08-20 12:41:34 -07:00
Junio C Hamano
39e415cfd1 Merge branch 'nd/cherry-pick-quit-fix'
"git cherry-pick --quit" failed to remove CHERRY_PICK_HEAD even
though we won't be in a cherry-pick session after it returns, which
has been corrected.

* nd/cherry-pick-quit-fix:
  cherry-pick: fix --quit not deleting CHERRY_PICK_HEAD
2018-08-20 12:41:34 -07:00
Junio C Hamano
85c54ecc5f Merge branch 'sb/submodule-cleanup'
A few preliminary minor clean-ups in the area around submodules.

* sb/submodule-cleanup:
  builtin/submodule--helper: remove stray new line
  t7410: update to new style
2018-08-20 12:41:33 -07:00
Junio C Hamano
5a5c5e9565 Merge branch 'pw/rebase-i-merge-segv-fix'
"git rebase -i", when a 'merge <branch>' insn in its todo list
fails, segfaulted, which has been (minimally) corrected.

* pw/rebase-i-merge-segv-fix:
  rebase -i: fix SIGSEGV when 'merge <branch>' fails
  t3430: add conflicting commit
2018-08-20 12:41:33 -07:00
Junio C Hamano
36fd1e843b Merge branch 'pw/rebase-i-squash-number-fix'
When "git rebase -i" is told to squash two or more commits into
one, it labeled the log message for each commit with its number.
It correctly called the first one "1st commit", but the next one
was "commit #1", which was off-by-one.  This has been corrected.

* pw/rebase-i-squash-number-fix:
  rebase -i: fix numbering in squash message
2018-08-20 12:41:33 -07:00
Junio C Hamano
2a2c18f1c3 Merge branch 'sb/config-write-fix'
Recent update to "git config" broke updating variable in a
subsection, which has been corrected.

* sb/config-write-fix:
  git-config: document accidental multi-line setting in deprecated syntax
  config: fix case sensitive subsection names on writing
  t1300: document current behavior of setting options
2018-08-20 12:41:32 -07:00
Junio C Hamano
87aa1595e7 Merge branch 'ab/submodule-relative-url-tests'
Test updates.

* ab/submodule-relative-url-tests:
  submodule: add more exhaustive up-path testing
2018-08-20 12:41:32 -07:00
Junio C Hamano
5ade034464 Merge branch 'en/incl-forward-decl'
Code hygiene improvement for the header files.

* en/incl-forward-decl:
  Remove forward declaration of an enum
  compat/precompose_utf8.h: use more common include guard style
  urlmatch.h: fix include guard
  Move definition of enum branch_track from cache.h to branch.h
  alloc: make allocate_alloc_state and clear_alloc_state more consistent
  Add missing includes and forward declarations
2018-08-20 12:41:32 -07:00
Junio C Hamano
36f0f344e7 Merge branch 'jt/repack-promisor-packs'
After a partial clone, repeated fetches from promisor remote would
have accumulated many packfiles marked with .promisor bit without
getting them coalesced into fewer packfiles, hurting performance.
"git repack" now learned to repack them.

* jt/repack-promisor-packs:
  repack: repack promisor objects if -a or -A is set
  repack: refactor setup of pack-objects cmd
2018-08-20 12:40:31 -07:00
Junio C Hamano
e72db08f15 Merge branch 'wc/make-funnynames-shared-lazy-prereq'
A test prerequisite defined by various test scripts with slightly
different semantics has been consolidated into a single copy and
made into a lazily defined one.

* wc/make-funnynames-shared-lazy-prereq:
  t: factor out FUNNYNAMES as shared lazy prereq
2018-08-20 11:33:55 -07:00
Junio C Hamano
6bbd1034d8 Merge branch 'jh/partial-clone-doc'
Doc updates.

* jh/partial-clone-doc:
  partial-clone: render design doc using asciidoc
2018-08-20 11:33:55 -07:00
Junio C Hamano
4601516b41 Merge branch 'js/chain-lint-attrfix'
Test fix.

* js/chain-lint-attrfix:
  chainlint: fix for core.autocrlf=true
2018-08-20 11:33:54 -07:00
Junio C Hamano
ce9c6a3c78 Merge branch 'sb/pull-rebase-submodule'
"git pull --rebase -v" in a repository with a submodule barfed as
an intermediate process did not understand what "-v(erbose)" flag
meant, which has been fixed.

* sb/pull-rebase-submodule:
  git-submodule.sh: accept verbose flag in cmd_update to be non-quiet
2018-08-20 11:33:54 -07:00
Junio C Hamano
81eab6871e Merge branch 'js/range-diff'
"git tbdiff" that lets us compare individual patches in two
iterations of a topic has been rewritten and made into a built-in
command.

* js/range-diff: (21 commits)
  range-diff: use dim/bold cues to improve dual color mode
  range-diff: make --dual-color the default mode
  range-diff: left-pad patch numbers
  completion: support `git range-diff`
  range-diff: populate the man page
  range-diff --dual-color: skip white-space warnings
  range-diff: offer to dual-color the diffs
  diff: add an internal option to dual-color diffs of diffs
  color: add the meta color GIT_COLOR_REVERSE
  range-diff: use color for the commit pairs
  range-diff: add tests
  range-diff: do not show "function names" in hunk headers
  range-diff: adjust the output of the commit pairs
  range-diff: suppress the diff headers
  range-diff: indent the diffs just like tbdiff
  range-diff: right-trim commit messages
  range-diff: also show the diff between patches
  range-diff: improve the order of the shown commits
  range-diff: first rudimentary implementation
  Introduce `range-diff` to compare iterations of a topic branch
  ...
2018-08-20 11:33:53 -07:00
Junio C Hamano
dc0f6f9e1d Merge branch 'nd/no-the-index'
The more library-ish parts of the codebase learned to work on the
in-core index-state instance that is passed in by their callers,
instead of always working on the singleton "the_index" instance.

* nd/no-the-index: (24 commits)
  blame.c: remove implicit dependency on the_index
  apply.c: remove implicit dependency on the_index
  apply.c: make init_apply_state() take a struct repository
  apply.c: pass struct apply_state to more functions
  resolve-undo.c: use the right index instead of the_index
  archive-*.c: use the right repository
  archive.c: avoid access to the_index
  grep: use the right index instead of the_index
  attr: remove index from git_attr_set_direction()
  entry.c: use the right index instead of the_index
  submodule.c: use the right index instead of the_index
  pathspec.c: use the right index instead of the_index
  unpack-trees: avoid the_index in verify_absent()
  unpack-trees: convert clear_ce_flags* to avoid the_index
  unpack-trees: don't shadow global var the_index
  unpack-trees: add a note about path invalidation
  unpack-trees: remove 'extern' on function declaration
  ls-files: correct index argument to get_convert_attr_ascii()
  preload-index.c: use the right index instead of the_index
  dir.c: remove an implicit dependency on the_index in pathspec code
  ...
2018-08-20 11:33:53 -07:00
Junio C Hamano
ace1f99cc8 Merge branch 'es/chain-lint-more'
Improve built-in facility to catch broken &&-chain in the tests.

* es/chain-lint-more:
  chainlint: add test of pathological case which triggered false positive
  chainlint: recognize multi-line quoted strings more robustly
  chainlint: let here-doc and multi-line string commence on same line
  chainlint: recognize multi-line $(...) when command cuddled with "$("
  chainlint: match 'quoted' here-doc tags
  chainlint: match arbitrary here-docs tags rather than hard-coded names
2018-08-20 11:33:53 -07:00
Junio C Hamano
a15bfa517d Merge branch 'sg/t5310-empty-input-fix'
Test fix.

* sg/t5310-empty-input-fix:
  t5310-pack-bitmaps: fix bogus 'pack-objects to file can use bitmap' test
2018-08-20 11:33:52 -07:00
Junio C Hamano
d18d09bb81 Merge branch 'js/mingw-o-append'
Among the three codepaths we use O_APPEND to open a file for
appending, one used for writing GIT_TRACE output requires O_APPEND
implementation that behaves sensibly when multiple processes are
writing to the same file.  POSIX emulation used in the Windows port
has been updated to improve in this area.

* js/mingw-o-append:
  mingw: enable atomic O_APPEND
2018-08-20 11:33:52 -07:00
Junio C Hamano
0c54cdaf65 Merge branch 'jk/for-each-object-iteration'
The API to iterate over all objects learned to optionally list
objects in the order they appear in packfiles, which helps locality
of access if the caller accesses these objects while as objects are
enumerated.

* jk/for-each-object-iteration:
  for_each_*_object: move declarations to object-store.h
  cat-file: use a single strbuf for all output
  cat-file: split batch "buf" into two variables
  cat-file: use oidset check-and-insert
  cat-file: support "unordered" output for --batch-all-objects
  cat-file: rename batch_{loose,packed}_object callbacks
  t1006: test cat-file --batch-all-objects with duplicates
  for_each_packed_object: support iterating in pack-order
  for_each_*_object: give more comprehensive docstrings
  for_each_*_object: take flag arguments as enum
  for_each_*_object: store flag definitions in a single location
2018-08-20 11:33:52 -07:00
Junio C Hamano
42a6274b62 Merge branch 'ab/fetch-tags-noclobber'
Test and doc clean-ups.

* ab/fetch-tags-noclobber:
  pull doc: fix a long-standing grammar error
  fetch tests: correct a comment "remove it" -> "remove them"
  push tests: assert re-pushing annotated tags
  push tests: add more testing for forced tag pushing
  push tests: fix logic error in "push" test assertion
  push tests: remove redundant 'git push' invocation
  fetch tests: change "Tag" test tag to "testTag"
2018-08-20 11:33:52 -07:00
Junio C Hamano
03e904cbd6 Merge branch 'ng/mergetool-lose-final-prompt'
"git mergetool" stopped and gave an extra prompt to continue after
the last path has been handled, which did not make much sense.

* ng/mergetool-lose-final-prompt:
  mergetool: don't suggest to continue after last file
2018-08-20 11:33:51 -07:00
Junio C Hamano
3bc484af74 Merge branch 'jt/commit-graph-per-object-store'
Test update.

* jt/commit-graph-per-object-store:
  t5318: avoid unnecessary command substitutions
2018-08-20 11:33:51 -07:00
Junio C Hamano
5dd54744b8 Merge branch 'ds/commit-graph-fsck'
Test fix.

* ds/commit-graph-fsck:
  t5318: use 'test_cmp_bin' to compare commit-graph files
2018-08-20 11:33:51 -07:00
Junio C Hamano
c5c2162a32 Merge branch 'jt/fetch-negotiator-skipping'
Test fix.

* jt/fetch-negotiator-skipping:
  t5552: suppress upload-pack trace output
2018-08-20 11:33:51 -07:00
Junio C Hamano
4d34122eef Merge branch 'jc/gpg-status'
"git verify-tag" and "git verify-commit" have been taught to use
the exit status of underlying "gpg --verify" to signal bad or
untrusted signature they found.

* jc/gpg-status:
  gpg-interface: propagate exit status from gpg back to the callers
2018-08-20 11:33:50 -07:00
Junio C Hamano
6e8f3d1ca0 Merge branch 'jc/update-index-doc'
Doc update.

* jc/update-index-doc:
  update-index: there no longer is `apply --index-info`
2018-08-20 11:33:50 -07:00
Junio C Hamano
7d916990ba Merge branch 'en/update-index-doc'
Doc update.

* en/update-index-doc:
  git-update-index.txt: reword possibly confusing example
2018-08-20 11:33:50 -07:00
Junio C Hamano
13bf260ac7 Merge branch 'js/typofixes'
Comment update.

* js/typofixes:
  remote-curl: remove spurious period
  git-compat-util.h: fix typo
2018-08-20 11:33:50 -07:00
Junio C Hamano
93ded333bc Merge branch 'sk/instaweb-rh-update'
"git instaweb" has been adjusted to run better with newer Apache on
RedHat based distros.

* sk/instaweb-rh-update:
  git-instaweb: fix apache2 config with apache >= 2.4
  git-instaweb: support Fedora/Red Hat apache module path
2018-08-20 11:33:49 -07:00
Junio C Hamano
02c51a2fd8 Merge branch 'en/t7406-fixes'
Test fixes.

* en/t7406-fixes:
  t7406: avoid using test_must_fail for commands other than git
  t7406: prefer test_* helper functions to test -[feds]
  t7406: avoid having git commands upstream of a pipe
  t7406: simplify by using diff --name-only instead of diff --raw
  t7406: fix call that was failing for the wrong reason
2018-08-20 11:33:49 -07:00
Junio C Hamano
750eb11d8f Merge branch 'js/rebase-merges-exec-fix'
The "--exec" option to "git rebase --rebase-merges" placed the exec
commands at wrong places, which has been corrected.

* js/rebase-merges-exec-fix:
  rebase --exec: make it work with --rebase-merges
  t3430: demonstrate what -r, --autosquash & --exec should do
2018-08-20 11:33:48 -07:00
Junio C Hamano
14677d25ab Merge branch 'ab/test-must-be-empty-for-master'
Test updates.

* ab/test-must-be-empty-for-master:
  tests: make use of the test_must_be_empty function
2018-08-20 11:33:48 -07:00
Junio C Hamano
34f229790d Merge branch 'ab/newhash-is-sha256'
Documentation update.

* ab/newhash-is-sha256:
  doc hash-function-transition: pick SHA-256 as NewHash
  doc hash-function-transition: note the lack of a changelog
2018-08-20 11:33:48 -07:00
Nguyễn Thái Ngọc Duy
4592e6080f cache-tree: verify valid cache-tree in the test suite
This makes sure that cache-tree is consistent with the index. The main
purpose is to catch potential problems by saving the index in
unpack_trees() but the line in write_index() would also help spot
missing invalidation in other code.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-18 09:47:46 -07:00
Nguyễn Thái Ngọc Duy
5697ca9aa5 unpack-trees: add missing cache invalidation
Any changes to the output index should be (confusingly) marked in the
source index with invalidate_ce_path(). This is used to make sure we
still have valid untracked cache and cache-tree extensions in the end.

We do a pretty good job of invalidating except in two places.
verify_clean_subdirectory() is part of verify_absent() and
verify_absent_sparse(). The former is usually called by merged_entry()
or directly in threeway_merge(). The latter is obviously used by
sparse checkout.

In these three call sites, only merged_entry() follows up with
invalidate_ce_path(). The other two don't, but they should not trigger
this ce removal because this is about D/F conflicts [1]. But let's be
safe and invalidate_ce_path() here as well.

The second place is keep_entry() which is also used by threeway_merge()
to keep higher stage entries. In order to reuse cache-tree we need to
invalidate these paths as well. It's not a problem in the past because
whenever a higher stage entry is present, cache-tree will not be
created [2]. Now we salvage cache-tree even when higher stage entries
are present, we need more invalidation.

[1] c81935348b (Fix switching to a branch with D/F when current branch
    has file D. - 2007-03-15)

[2] This is probably too strict. We should be able to create and save
    cache-tree for the directories that do not have conflict entries
    in cache_tree_update(). And this becomes more important when
    cache-tree plays bigger role in terms of performance.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-18 09:47:46 -07:00
Nguyễn Thái Ngọc Duy
836ef2b69f unpack-trees: reuse (still valid) cache-tree from src_index
We do n-way merge by walking the source index and n trees at the same
time and add merge results to a new temporary index called o->result.
The merge result for any given path could be either

- keep_entry(): same old index entry in o->src_index is reused
- merged_entry(): either a new entry is added, or an existing one updated
- deleted_entry(): one entry from o->src_index is removed

For some reason [1] we keep making sure that the source index's
cache-tree is still valid if used by o->result: for all those
merged/deleted entries, we invalidate the same path in o->src_index,
so only cache-trees covering the "keep_entry" parts remain good.

Because of this, the cache-tree from o->src_index can be perfectly
reused in o->result. And in fact we already rely on this logic to
reuse untracked cache in edf3b90553 (unpack-trees: preserve index
extensions - 2017-05-08). Move the cache-tree to o->result before
doing cache_tree_update() to reduce hashing cost.

Since cache_tree_update() has risen up as one of the most expensive
parts in unpack_trees() after the last few patches. This does help
reduce unpack_trees() time significantly (on webkit.git):

    before       after
  --------------------------------------------------------------------
    0.080394752  0.051258167 s:  read cache .git/index
    0.216010838  0.212106298 s:  preload index
    0.008534301  0.280521764 s:  refresh index
    0.251992198  0.218160442 s:   traverse_trees
    0.377031383  0.374948191 s:   check_updates
    0.372768105  0.037040114 s:   cache_tree_update
    1.045887251  0.672031609 s:  unpack_trees
    0.314983512  0.317456290 s:  write index, changed mask = 2e
    0.062572653  0.038382654 s:    traverse_trees
    0.000022544  0.000042731 s:    check_updates
    0.073795585  0.050930053 s:   unpack_trees
    0.073807557  0.051099735 s:  diff-index
    1.938191592  1.614241153 s: git command: git checkout -

[1] I'm pretty sure the reason is an oversight in 34110cd4e3 (Make
    'unpack_trees()' have a separate source and destination index -
    2008-03-06). That patch aims to _not_ update the source index at
    all. The invalidation should have been done on o->result in that
    patch. But then there was no cache-tree on o->result even then so
    it's pointless to do so.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-18 09:47:46 -07:00
Nguyễn Thái Ngọc Duy
f1e11c6510 unpack-trees: reduce malloc in cache-tree walk
This is a micro optimization that probably only shines on repos with
deep directory structure. Instead of allocating and freeing a new
cache_entry in every iteration, we reuse the last one and only update
the parts that are new each iteration.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-18 09:47:46 -07:00
Nguyễn Thái Ngọc Duy
b4da37380b unpack-trees: optimize walking same trees with cache-tree
In order to merge one or many trees with the index, unpack-trees code
walks multiple trees in parallel with the index and performs n-way
merge. If we find out at start of a directory that all trees are the
same (by comparing OID) and cache-tree happens to be available for
that directory as well, we could avoid walking the trees because we
already know what these trees contain: it's flattened in what's called
"the index".

The upside is of course a lot less I/O since we can potentially skip
lots of trees (think subtrees). We also save CPU because we don't have
to inflate and apply the deltas. The downside is of course more
fragile code since the logic in some functions are now duplicated
elsewhere.

"checkout -" with this patch on webkit.git (275k files):

    baseline      new
  --------------------------------------------------------------------
    0.056651714   0.080394752 s:  read cache .git/index
    0.183101080   0.216010838 s:  preload index
    0.008584433   0.008534301 s:  refresh index
    0.633767589   0.251992198 s:   traverse_trees
    0.340265448   0.377031383 s:   check_updates
    0.381884638   0.372768105 s:   cache_tree_update
    1.401562947   1.045887251 s:  unpack_trees
    0.338687914   0.314983512 s:  write index, changed mask = 2e
    0.411927922   0.062572653 s:    traverse_trees
    0.000023335   0.000022544 s:    check_updates
    0.423697246   0.073795585 s:   unpack_trees
    0.423708360   0.073807557 s:  diff-index
    2.559524127   1.938191592 s: git command: git checkout -

Another measurement from Ben's running "git checkout" with over 500k
trees (on the whole series):

    baseline        new
  ----------------------------------------------------------------------
    0.535510167     0.556558733     s: read cache .git/index
    0.3057373       0.3147105       s: initialize name hash
    0.0184082       0.023558433     s: preload index
    0.086910967     0.089085967     s: refresh index
    7.889590767     2.191554433     s: unpack trees
    0.120760833     0.131941267     s: update worktree after a merge
    2.2583504       2.572663167     s: repair cache-tree
    0.8916137       0.959495233     s: write index, changed mask = 28
    3.405199233     0.2710663       s: unpack trees
    0.000999667     0.0021554       s: update worktree after a merge
    3.4063306       0.273318333     s: diff-index
    16.9524923      9.462943133     s: git command: git.exe checkout

This command calls unpack_trees() twice, the first time on 2way merge
and the second 1way merge. In both times, "unpack trees" time is
reduced to one third. Overall time reduction is not that impressive of
course because index operations take a big chunk. And there's that
repair cache-tree line.

PS. A note about cache-tree invalidation and the use of it in this
code.

We do invalidate cache-tree in _source_ index when we add new entries
to the (temporary) "result" index. But we also use the cache-tree from
source index in this optimization. Does this mean we end up having no
cache-tree in the source index to activate this optimization?

The answer is twisted: the order of finding a good cache-tree and
invalidating it matters. In this case we check for a good cache-tree
first in all_trees_same_as_cache_tree(), then we start to merge things
and potentially invalidate that same cache-tree in the process. Since
cache-tree invalidation happens after the optimization kicks in, we're
still good. But we may lose that cache-tree at the very first
call_unpack_fn() call in traverse_by_cache_tree().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-18 09:47:46 -07:00