grit://cooking/bench/rebase/onto@synth-10k

grit rebase · onto @synth-10k

Rebase onto upstream vs git rebase on synth-10k history fixture

repo: 10,000-file synthetic repository; canonical cached shape, scenario variants documented by the runner · 10,000 files · 1,000 commits · 800 refs

$ grit-bench daily --only rebase/onto@synth-10k2026-10-27 · grit 8dbc58e77 · git version 2.43.0

tool	median	min	max	runs	peak memory
git	42 ms	9.8 ms	52 ms	80	14 MB
grit	13 ms	12 ms	14 ms	80	18 MB

grit is 3.3× fastermemory: 1.3× more

every timed run (log scale)

git

grit

7.8 ms65 ms

How it's measured

before each run

grit-bench prepare-history-rewrite --git git

git runs

$ set -eu; GIT_CONFIG_NOSYSTEM=1 GIT_CONFIG_GLOBAL='/tmp/grit-bench-global-config' GIT_CONFIG_SYSTEM=/dev/null GIT_AUTHOR_NAME=Bench GIT_AUTHOR_EMAIL=b@example.com GIT_COMMITTER_NAME=Bench GIT_COMMITTER_EMAIL=b@example.com GIT_COMMITTER_DATE='1700000100 +0000' git rebase HEAD~1000 >/dev/null

grit runs

$ set -eu; grit rebase HEAD~1000 >/dev/null

Where the time goesone extra traced run per tool, outside the timed runs

git · median run 42 ms

index: refresh

31 ms

index: preload

3.3 ms

index: do_write_index

2.3 ms

run: git maintenance

1.6 ms

index: do_read_index

0.7 ms

unpack_trees: unpack_trees

0.1 ms

cache_tree: read

0.0 ms

cache_tree: write

0.0 ms

unpack_trees: traverse_trees

0.0 ms

grit · median run 13 ms

grit.repository.open ×2

0.4 ms

grit.config.load ×4

0.1 ms

grit.pack.index.open

0.0 ms

Every day8 days

date	grit commit	git	grit	grit vs git	grit peak
2026-10-27	8dbc58e77	42 ms	13 ms	3.3× faster	18 MB
2026-10-26	c7cf2c443	100 ms	19 ms	5.1× faster	20 MB
2026-10-25	2824ad391	54 ms	16 ms	3.4× faster	18 MB
2026-10-24	157a05dde	53 ms	17 ms	3.2× faster	22 MB
2026-10-23	bddf92f86	50 ms	42 ms	1.2× faster	45 MB
2026-10-22	4c131b942	—	not run	—	—
2026-10-21	d4844e92a	—	not run	—	—
2026-10-20	4754ad0b9	—	not run	—	—