Commit 7fbbcb21b1 ("diff: batch fetching of missing blobs", 2019-04-05)
introduced batching of fetching missing blobs, so that the diff
machinery would have one fetch subprocess grab N blobs instead of N
processes each grabbing 1.
However, the diff machinery is not the only thing in a merge that needs
to work on blobs. The 3-way content merges need them as well. Rather
than download all the blobs 1 at a time, prefetch all the blobs needed
for regular content merges.
This does not cover all possible paths in merge-ort that might need to
download blobs. Others include:
- The blob_unchanged() calls to avoid modify/delete conflicts (when
blob renormalization results in an "unchanged" file)
- Preliminary content merges needed for rename/add and
rename/rename(2to1) style conflicts. (Both of these types of
conflicts can result in nested conflict markers from the need to do
two levels of content merging; the first happens before our new
prefetch_for_content_merges() function.)
The first of these wouldn't be an extreme amount of work to support, and
even the second could be theoretically supported in batching, but all of
these cases seem unusual to me, and this is a minor performance
optimization anyway; in the worst case we only get some of the fetches
batched and have a few additional one-off fetches. So for now, just
handle the regular 3-way content merges in our prefetching.
For the testcase from the previous commit, the number of downloaded
objects remains at 63, but this drops the number of fetches needed from
32 down to 20, a sizeable reduction.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
merge-ort was designed to minimize the amount of data needed and used,
and several changes were made to diffcore-rename to take advantage of
extra metadata to enable this data minimization (particularly the
relevant_sources variable for skipping "irrelevant" renames). This
effort obviously succeeded in drastically reducing computation times,
but should also theoretically allow partial clones to download much less
information. Previously, though, the "prefetch" command used in
diffcore-rename had never been modified and downloaded many blobs that
were unnecessary for merge-ort. This commit corrects that.
When doing basename comparisons, we want to fetch only the objects that
will be used for basename comparisons. If after basename fetching this
leaves us with no more relevant sources (or no more destinations), then
we won't need to do the full inexact rename detection and can skip
downloading additional source and destination files. Even if we have to
do that later full inexact rename detection, irrelevant sources are
culled after basename matching and before the full inexact rename
detection, so we can still avoid downloading the blobs for irrelevant
sources. Rename prefetch() to inexact_prefetch(), and introduce a
new basename_prefetch() to take advantage of this.
If we modify the testcase from commit 557ac0350d ("merge-ort: begin
performance work; instrument with trace2_region_* calls", 2021-01-23)
to pass
--sparse --filter=blob:none
to the clone command, and use the new trace2 "fetch_count" output from
a few commits ago to track both the number of fetch subcommands invoked
and the number of objects fetched across all those fetches, then for
the mega-renames testcase we observe the following:
BEFORE this commit, rebasing 35 patches:
strategy # of fetches total # of objects fetched
--------- ------------ --------------------------
recursive 62 11423
ort 30 11391
AFTER this commit, rebasing the same 35 patches:
ort 32 63
This means that the new code only needs to download less than 2 blobs
per patch being rebased. That is especially interesting given that the
repository at the start only had approximately half a dozen TOTAL blobs
downloaded to start with (because the default sparse-checkout of just
the toplevel directory was in use).
So, for this particular linux kernel testcase that involved ~26,000
renames on the upstream side (drivers/ -> pilots/) across which 35
patches were being rebased, this change reduces the number of blobs that
need to be downloaded by a factor of ~180.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
estimate_similarity() was setting up a diff_populate_filespec_options
every time it was called, requiring the caller of estimate_similarity()
to pass in some data needed to set up this option. Currently the needed
data consisted of a single variable (skip_unmodified), but we want to
also have the different estimate_similarity() callsites start using
different missing_object_cb functions as well. Rather than also passing
that data in, just have the caller pass in the whole
diff_populate_filespec_options, and reduce the number of times we need to
set it up.
As a side note, this also drops the number of calls to
has_promisor_remote() dramatically. If L is the number of basename
paths to compare, M is the number of inexact sources, and N is the
number of inexact destinations, then the number of calls to
has_promisor_remote() drops from L+M*N down to at most 2 -- one for each
of the sites that calls estimate_similarity(). has_promisor_remote() is
a very fast function so this almost certainly has no measurable
performance impact, but it seems cleaner to avoid calling that function
so many times.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Test clean-up.
* ab/test-lib-updates:
test-lib: split up and deprecate test_create_repo()
test-lib: do not show advice about init.defaultBranch under --verbose
test-lib: reformat argument list in test_create_repo()
submodule tests: use symbolic-ref --short to discover branch name
test-lib functions: add --printf option to test_commit
describe tests: convert setup to use test_commit
test-lib functions: add an --annotated option to "test_commit"
test-lib-functions: document test_commit --no-tag
test-lib-functions: reword "test_commit --append" docs
test-lib tests: remove dead GIT_TEST_FRAMEWORK_SELFTEST variable
test-lib: bring $remove_trash out of retirement
The "-m" option in "git log -m" that does not specify which format,
if any, of diff is desired did not have any visible effect; it now
implies some form of diff (by default "--patch") is produced.
* so/log-m-implies-p:
diff-merges: let "-m" imply "-p"
diff-merges: rename "combined_imply_patch" to "merges_imply_patch"
stash list: stop passing "-m" to "git log"
git-svn: stop passing "-m" to "git rev-list"
diff-merges: move specific diff-index "-m" handling to diff-index
t4013: test "git diff-index -m"
t4013: test "git diff-tree -m"
t4013: test "git log -m --stat"
t4013: test "git log -m --raw"
t4013: test that "-m" alone has no effect in "git log"
Optimize out repeated rename detection in a sequence of mergy
operations.
* en/ort-perf-batch-11:
merge-ort, diffcore-rename: employ cached renames when possible
merge-ort: handle interactions of caching and rename/rename(1to1) cases
merge-ort: add helper functions for using cached renames
merge-ort: preserve cached renames for the appropriate side
merge-ort: avoid accidental API mis-use
merge-ort: add code to check for whether cached renames can be reused
merge-ort: populate caches of rename detection results
merge-ort: add data structures for in-memory caching of rename detection
t6429: testcases for remembering renames
fast-rebase: write conflict state to working tree, index, and HEAD
fast-rebase: change assert() to BUG()
Documentation/technical: describe remembering renames optimization
t6423: rename file within directory that other side renamed
"git fetch" over protocol v2 left its side of the socket open after
it finished speaking, which unnecessarily wasted the resource on
the other side.
* jk/fetch-pack-v2-half-close-early:
fetch-pack: signal v2 server that we are done making requests
Use the hashfile API in the codepath that writes the index file to
reduce code duplication.
* ds/write-index-with-hashfile-api:
read-cache: delete unused hashing methods
read-cache: use hashfile instead of git_hash_ctx
csum-file.h: increase hashfile buffer size
hashfile: use write_in_full()
Recent "git clone" left a temporary directory behind when the
transport layer returned an failure.
* jk/clone-clean-upon-transport-error:
clone: clean up directory after transport_fetch_refs() failure
"git send-email" learned the "--sendmail-cmd" command line option
and the "sendemail.sendmailCmd" configuration variable, which is a
more sensible approach than the current way of repurposing the
"smtp-server" that is meant to name the server to instead name the
command to talk to the server.
* ga/send-email-sendmail-cmd:
git-send-email: add option to specify sendmail command
The code to handle the "--format" option in "for-each-ref" and
friends made too many string comparisons on %(atom)s used in the
format string, which has been corrected by converting them into
enum when the format string is parsed.
* zh/ref-filter-atom-type:
ref-filter: introduce enum atom_type
ref-filter: add objectsize to used_atom
The description of "fast-forward" in the glossary has been updated.
* ry/clarify-fast-forward-in-glossary:
docs: improve fast-forward in glossary content
The parallel checkout codepath did not initialize object ID field
used to talk to the worker processes in a futureproof way.
* mt/parallel-checkout-with-padded-oidcpy:
parallel-checkout: send the new object_id algo field to the workers
We historically rejected a very short string as an author name
while accepting a patch e-mail, which has been loosened.
* ef/mailinfo-short-name:
mailinfo: don't discard names under 3 characters
Dash bug https://bugs.launchpad.net/ubuntu/+source/dash/+bug/139097
lets the shell erroneously perform field splitting on the expansion of a
command substitution during declaration of a local variable. It causes
the parallel-checkout tests to fail e.g. when running them with
/bin/dash on MacOS 11.4, where they error out like this:
./t2080-parallel-checkout-basics.sh: 33: local: 0: bad variable name
That's because the output of wc -l contains leading spaces and the
returned number of lines is treated as another variable to declare, i.e.
as in "local workers= 0".
Work around it by enclosing the command substitution in quotes.
Helped-by: Matheus Tavares Bernardino <matheus.bernardino@usp.br>
Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some platforms, like NonStop do not automatically restart fsync()
when interrupted by a signal, even when that signal is setup with
SA_RESTART.
This can lead to test breakage, e.g., where "--progress" is used,
thus SIGALRM is sent often, and can interrupt an fsync() syscall.
Make sure we deal with such a case by retrying the syscall
ourselves. Luckily, we call fsync() fron a single wrapper,
fsync_or_die(), so the fix is fairly isolated.
Reported-by: Randall S. Becker <randall.becker@nexbridge.ca>
Helped-by: Jeff King <peff@peff.net>
Helped-by: Taylor Blau <me@ttaylorr.com>
[jc: the above two did most of the work---I just tied the loose end]
Helped-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A recent change to make git-completion.bash use $__git_cmd_idx
in more places broke a number of completions on zsh because it
modified __git_main but did not update __git_zsh_main.
Notably, completions for "add", "branch", "mv" and "push" were
broken as a result of this change.
In addition to the undefined variable usage, "git mv <tab>" also
prints the following error:
__git_count_arguments:7: bad math expression:
operand expected at `"1"'
_git_mv:[:7: unknown condition: -gt
Remove the quotes around $__git_cmd_idx in __git_count_arguments
and set __git_cmd_idx=1 early in __git_zsh_main to fix the
regressions from 59d85a2a05.
This was tested on zsh 5.7.1 (x86_64-apple-darwin19.0).
Suggested-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: David Aguilar <davvid@gmail.com>
Acked-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Contributor for a new language must complete translations of a small set
of l10n messages.
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
