From: Adrian Ratiu <adrian.ratiu@collabora•com>
To: Patrick Steinhardt <ps@pks•im>,
Cc: git@vger•kernel.org,
Subject: Re: Performance regression in "update" hooks
Date: Mon, 02 Mar 2026 15:37:51 +0200 [thread overview]
Message-ID: <87bjh673o0.fsf@gentoo.mail-host-address-is-not-set> (raw)
In-Reply-To: <aaU5lZwEuR4OrxCl@pks.im>
On Mon, 02 Mar 2026, Patrick Steinhardt <ps@pks•im> wrote:
> Hi,
>
> Bencher has alerted me that there's been two performance regressions in
> git-receive-pack(1) [1] and git-fetch(1) [2].
>
> The first one is quite easy to reproduce with the benchmarks at [3] and
> bisects to fc148b146a (receive-pack: convert update hooks to new API,
> 2026-01-28):
>
> $ cd receive-refs
> $ ./run --revisions /path/to/your/git/repo \
> fc148b146ad41be71a7852c4867f0773cbfe1ff9~,fc148b146ad41be71a7852c4867f0773cbfe1ff9 \
> --parameter-list refformat reftable \
> --parameter-list refcount 10000
>
> Benchmark 1: receive: many refs (refformat = reftable, refcount = 10000, revision = fc148b146ad41be71a7852c4867f0773cbfe1ff9~)
> Time (mean ± σ): 182.0 ms ± 2.7 ms [User: 91.5 ms, System: 89.3 ms]
> Range (min … max): 175.8 ms … 185.0 ms 15 runs
>
> Benchmark 2: receive: many refs (refformat = reftable, refcount = 10000, revision = fc148b146ad41be71a7852c4867f0773cbfe1ff9)
> Time (mean ± σ): 484.6 ms ± 27.6 ms [User: 176.2 ms, System: 376.1 ms]
> Range (min … max): 406.2 ms … 495.1 ms 10 runs
>
> Summary
> receive: many refs (refformat = reftable, refcount = 10000, revision = fc148b146ad41be71a7852c4867f0773cbfe1ff9~) ran
> 2.66 ± 0.16 times faster than receive: many refs (refformat = reftable, refcount = 10000, revision = fc148b146ad41be71a7852c4867f0773cbfe1ff9)
>
> I've Cc'd Adrian.
Hi Patrick,
I looked at the commits before and after the many-refs test regression
and it appears the regressions started after Junio landed v2 of the
config series in next [1], which might cause it.
v2 was not ready to land. I sent v3 yesterday addressing all the
feedback, didn't even realize v2 landed. :)
Does the regression go away if you revert [1] ?
I don't have the benchmark setup and it might be easier for you to
confirm?
Many thanks!
1:
commit 6a04cca28e210f0c51cfefcb52475c7ede6e99fb
Merge: d6ebc97cb1 4b12cd3ae3
Author: Junio C Hamano <gitster@pobox•com>
AuthorDate: Fri Feb 27 15:16:30 2026 -0800
Commit: Junio C Hamano <gitster@pobox•com>
CommitDate: Fri Feb 27 15:16:30 2026 -0800
Merge branch 'ar/config-hooks' into next
Allow hook commands to be defined (possibly centrally) in the
configuration files, and run multiple of them for the same hook
event.
* ar/config-hooks:
hook: add -z option to "git hook list"
hook: allow out-of-repo 'git hook' invocations
hook: allow event = "" to overwrite previous values
hook: allow disabling config hooks
hook: include hooks from the config
hook: add "git hook list" command
hook: run a list of hooks to prepare for multihook support
hook: add internal state alloc/free callbacks
next prev parent reply other threads:[~2026-03-02 13:38 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-02 7:17 Performance regression in "update" hooks Patrick Steinhardt
2026-03-02 13:37 ` Adrian Ratiu [this message]
2026-03-02 14:12 ` Adrian Ratiu
2026-03-02 14:27 ` Patrick Steinhardt
2026-03-02 17:50 ` Jeff King
2026-03-02 18:02 ` Adrian Ratiu
2026-03-02 18:54 ` Junio C Hamano
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