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The setup phase in 't/perf/p3400-rebase.sh' generates 100 commits to
simulate a noisy history. It currently uses a shell loop that invokes
'git add', 'git commit', 'test_seq', and 'sort' in each iteration.
This incurs significant overhead due to repeated process spawning.
Optimize the setup by using 'git fast-import' to generate the commit
history. Additionally, pre-compute the forward and reversed file contents
to avoid repetitive execution of 'seq' and 'sort'.
To ensure the test measures rebase performance against a consistent
object layout (rather than the suboptimal pack/loose objects created
by the raw import), perform a full repack (`git repack -a -d`) at the
end of the setup.
This reduces the setup time significantly while maintaining the validity
of the subsequent performance tests.
Performance enhancement (Average value of 5 tests):
Real Rebase
Before: 29.045s 13.34s
After: 21.989s 12.84s
Measured on Lenovo Yoga 2020, Ubuntu 24.04.
Signed-off-by: Tian Yuchen <a3205153416@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
80 lines
2.0 KiB
Bash
Executable File
80 lines
2.0 KiB
Bash
Executable File
#!/bin/sh
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test_description='Tests rebase performance'
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. ./perf-lib.sh
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test_perf_default_repo
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test_expect_success 'setup rebasing on top of a lot of changes' '
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git checkout -f -B base &&
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git checkout -B to-rebase &&
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git checkout -B upstream &&
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test_seq 1000 >content_fwd &&
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sort -nr content_fwd >content_rev &&
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(
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for i in $(test_seq 100)
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do
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test_tick &&
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echo "commit refs/heads/upstream" &&
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echo "committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE" &&
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echo "data <<EOF" &&
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echo "commit$i" &&
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echo "EOF" &&
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if test "$i" = 1; then
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echo "from refs/heads/upstream^0"
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fi &&
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echo "M 100644 inline unrelated-file$i" &&
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echo "data <<EOF" &&
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echo "change$i" &&
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cat content_fwd &&
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echo "EOF" &&
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echo "commit refs/heads/upstream" &&
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echo "committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE" &&
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echo "data <<EOF" &&
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echo "commit$i-reverse" &&
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echo "EOF" &&
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echo "M 100644 inline unrelated-file$i" &&
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echo "data <<EOF" &&
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echo "change$i" &&
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cat content_rev &&
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echo "EOF" || exit 1
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done
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) >fast_import_stream &&
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git fast-import <fast_import_stream &&
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git repack -a -d &&
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git checkout -f upstream &&
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git checkout to-rebase &&
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test_commit our-patch interesting-file
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'
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test_perf 'rebase on top of a lot of unrelated changes' '
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git rebase --onto upstream HEAD^ &&
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git rebase --onto base HEAD^
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'
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test_expect_success 'setup rebasing many changes without split-index' '
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git config core.splitIndex false &&
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git checkout -B upstream2 to-rebase &&
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git checkout -B to-rebase2 upstream
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'
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test_perf 'rebase a lot of unrelated changes without split-index' '
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git rebase --onto upstream2 base &&
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git rebase --onto base upstream2
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'
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test_expect_success 'setup rebasing many changes with split-index' '
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git config core.splitIndex true
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'
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test_perf 'rebase a lot of unrelated changes with split-index' '
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git rebase --onto upstream2 base &&
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git rebase --onto base upstream2
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'
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test_done
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