mirror of
https://github.com/git-for-windows/git.git
synced 2026-04-24 13:37:00 -05:00
abf05d856f
Building a list using commit_list_insert_by_date() has quadratic worst
case complexity. Avoid it by using prio_queue.
Use prio_queue_peek()+prio_queue_replace() instead of prio_queue_get()+
prio_queue_put() if possible, as the former only rebalance the
prio_queue heap once instead of twice.
In sane repositories this won't make much of a difference because the
number of items in the list or queue won't be very high:
Benchmark 1: ./git_v2.52.0 show-branch origin/main origin/next origin/seen origin/todo
Time (mean ± σ): 538.2 ms ± 0.8 ms [User: 527.6 ms, System: 9.6 ms]
Range (min … max): 537.0 ms … 539.2 ms 10 runs
Benchmark 2: ./git show-branch origin/main origin/next origin/seen origin/todo
Time (mean ± σ): 530.6 ms ± 0.4 ms [User: 519.8 ms, System: 9.8 ms]
Range (min … max): 530.1 ms … 531.3 ms 10 runs
Summary
./git show-branch origin/main origin/next origin/seen origin/todo ran
1.01 ± 0.00 times faster than ./git_v2.52.0 show-branch origin/main origin/next origin/seen origin/todo
That number is not limited, though, and in pathological cases like the
one in p6010 we see a sizable improvement:
Test v2.52.0 HEAD
------------------------------------------------------------------
6010.4: git show-branch 2.19(2.19+0.00) 0.03(0.02+0.00) -98.6%
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
106 lines
2.5 KiB
Bash
Executable File
106 lines
2.5 KiB
Bash
Executable File
#!/bin/sh
|
|
|
|
test_description='Test git merge-base'
|
|
|
|
. ./perf-lib.sh
|
|
|
|
test_perf_fresh_repo
|
|
|
|
#
|
|
# Creates lots of merges to make history traversal costly. In
|
|
# particular it creates 2^($max_level-1)-1 2-way merges on top of
|
|
# 2^($max_level-1) root commits. E.g., the commit history looks like
|
|
# this for a $max_level of 3:
|
|
#
|
|
# _1_
|
|
# / \
|
|
# 2 3
|
|
# / \ / \
|
|
# 4 5 6 7
|
|
#
|
|
# The numbers are the fast-import marks, which also are the commit
|
|
# messages. 1 is the HEAD commit and a merge, 2 and 3 are also merges,
|
|
# 4-7 are the root commits.
|
|
#
|
|
build_history () {
|
|
local max_level="$1" &&
|
|
local level="${2:-1}" &&
|
|
local mark="${3:-1}" &&
|
|
if test $level -eq $max_level
|
|
then
|
|
echo "reset refs/heads/master" &&
|
|
echo "from $ZERO_OID" &&
|
|
echo "commit refs/heads/master" &&
|
|
echo "mark :$mark" &&
|
|
echo "committer C <c@example.com> 1234567890 +0000" &&
|
|
echo "data <<EOF" &&
|
|
echo "$mark" &&
|
|
echo "EOF"
|
|
else
|
|
local level1=$((level+1)) &&
|
|
local mark1=$((2*mark)) &&
|
|
local mark2=$((2*mark+1)) &&
|
|
build_history $max_level $level1 $mark1 &&
|
|
build_history $max_level $level1 $mark2 &&
|
|
echo "commit refs/heads/master" &&
|
|
echo "mark :$mark" &&
|
|
echo "committer C <c@example.com> 1234567890 +0000" &&
|
|
echo "data <<EOF" &&
|
|
echo "$mark" &&
|
|
echo "EOF" &&
|
|
echo "from :$mark1" &&
|
|
echo "merge :$mark2"
|
|
fi
|
|
}
|
|
|
|
#
|
|
# Creates a new merge history in the same shape as build_history does,
|
|
# while reusing the same root commits. This way the two top commits
|
|
# have 2^($max_level-1) merge bases between them.
|
|
#
|
|
build_history2 () {
|
|
local max_level="$1" &&
|
|
local level="${2:-1}" &&
|
|
local mark="${3:-1}" &&
|
|
if test $level -lt $max_level
|
|
then
|
|
local level1=$((level+1)) &&
|
|
local mark1=$((2*mark)) &&
|
|
local mark2=$((2*mark+1)) &&
|
|
build_history2 $max_level $level1 $mark1 &&
|
|
build_history2 $max_level $level1 $mark2 &&
|
|
echo "commit refs/heads/master" &&
|
|
echo "mark :$mark" &&
|
|
echo "committer C <c@example.com> 1234567890 +0000" &&
|
|
echo "data <<EOF" &&
|
|
echo "$mark II" &&
|
|
echo "EOF" &&
|
|
echo "from :$mark1" &&
|
|
echo "merge :$mark2"
|
|
fi
|
|
}
|
|
|
|
test_expect_success 'setup' '
|
|
max_level=15 &&
|
|
build_history $max_level | git fast-import --export-marks=marks &&
|
|
git branch one &&
|
|
build_history2 $max_level | git fast-import --import-marks=marks --force &&
|
|
git branch two &&
|
|
git gc &&
|
|
git log --format=%H --no-merges >expect
|
|
'
|
|
|
|
test_perf 'git merge-base' '
|
|
git merge-base --all one two >actual
|
|
'
|
|
|
|
test_expect_success 'verify result' '
|
|
test_cmp expect actual
|
|
'
|
|
|
|
test_perf 'git show-branch' '
|
|
git show-branch one two
|
|
'
|
|
|
|
test_done
|