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([155.69.180.3]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82318662dd9sm9693397b3a.19.2026.01.26.08.56.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Jan 2026 08:56:27 -0800 (PST) From: Tian Yuchen To: git@vger.kernel.org Cc: gitster@pobox.com Subject: [PATCH V1][RFC] t/perf/p3400: speed up setup using fast-import Date: Tue, 27 Jan 2026 00:56:18 +0800 Message-ID: <20260126165618.596944-1-a3205153416@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 makes the whole process slow. Optimize the setup by using 'git fast-import' to generate the commit history in a single stream. Additionally, pre-compute the forward and reversed file contents to avoid repetitive execution of 'seq' and 'sort'. Performance enhancement: Before: 29.045s After: 18.081s Measured on Lenovo Yoga 2020, Ubuntu 24.04. Signed-off-by: Tian Yuchen --- t/perf/p3400-rebase.sh | 53 +++++++++++++++++++++++++++++------------- 1 file changed, 37 insertions(+), 16 deletions(-) diff --git a/t/perf/p3400-rebase.sh b/t/perf/p3400-rebase.sh index e6b0277729..9251a09b4f 100755 --- a/t/perf/p3400-rebase.sh +++ b/t/perf/p3400-rebase.sh @@ -9,25 +9,46 @@ test_expect_success 'setup rebasing on top of a lot of changes' ' git checkout -f -B base && git checkout -B to-rebase && git checkout -B upstream && - for i in $(test_seq 100) - do - # simulate huge diffs - echo change$i >unrelated-file$i && - test_seq 1000 >>unrelated-file$i && - git add unrelated-file$i && - test_tick && - git commit -m commit$i unrelated-file$i && - echo change$i >unrelated-file$i && - test_seq 1000 | sort -nr >>unrelated-file$i && - git add unrelated-file$i && - test_tick && - git commit -m commit$i-reverse unrelated-file$i || - return 1 - done && + + test_seq 1000 >content_fwd && + test_seq 1000 | sort -nr >content_rev && + + ( + for i in $(test_seq 100) + do + echo "commit refs/heads/upstream" && + echo "committer WGYDY $i +0000" && + echo "data < $i +0000" && + echo "data <