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From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Patrick Steinhardt <ps@pks.im>
Cc: git@vger.kernel.org, "Jeff King" <peff@peff.net>,
	"Felipe Contreras" <felipe.contreras@gmail.com>,
	"SZEDER Gábor" <szeder.dev@gmail.com>,
	"Chris Torek" <chris.torek@gmail.com>,
	"Junio C Hamano" <gitster@pobox.com>,
	"Taylor Blau" <me@ttaylorr.com>
Subject: Re: [PATCH v3 2/4] revision: stop retrieving reference twice
Date: Mon, 02 Aug 2021 14:53:30 +0200	[thread overview]
Message-ID: <87y29knh0x.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <db854806498b316b4f59c33d70a1ea9c1401fdb7.1627896460.git.ps@pks.im>


On Mon, Aug 02 2021, Patrick Steinhardt wrote:

> [[PGP Signed Part:Undecided]]
> When queueing up references for the revision walk, `handle_one_ref()`
> will resolve the reference's object ID and then queue the ID as pending
> object via `add_pending_oid()`. But `add_pending_oid()` will again try
> to resolve the object ID to an object, effectively duplicating the work
> its caller already did before.
>
> Fix the issue by instead calling `add_pending_object()`, which takes the
> already-resolved object as input. In a repository with lots of refs,
> this translates in a nearly 10% speedup:
>
>     Benchmark #1: HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev
>       Time (mean ± σ):      5.015 s ±  0.038 s    [User: 4.698 s, System: 0.316 s]
>       Range (min … max):    4.970 s …  5.089 s    10 runs
>
>     Benchmark #2: HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev
>       Time (mean ± σ):      4.606 s ±  0.029 s    [User: 4.260 s, System: 0.345 s]
>       Range (min … max):    4.565 s …  4.657 s    10 runs
>
>     Summary
>       'HEAD: rev-list --unsorted-input --objects --quiet --not --all --not $newrev' ran
>         1.09 ± 0.01 times faster than 'HEAD~: rev-list --unsorted-input --objects --quiet --not --all --not $newrev'

It might be worth calling out explicitly that it's not just
"effectively", but that add_pending_oid() is just a thin wrapper for
get_reference() followed by add_pending_object(), so we're guaranteed to
get the exact same result here as before, just without the duplicate
work.

I.e. we're not going down some other lookup path that uses object
lookups with different flags or whatever as a result of this change.

  reply	other threads:[~2021-08-02 12:54 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-28  5:33 [PATCH v2 0/3] Speed up connectivity checks via bitmaps Patrick Steinhardt
2021-06-28  5:33 ` [PATCH v2 1/3] p5400: add perf tests for git-receive-pack(1) Patrick Steinhardt
2021-06-28  7:49   ` Ævar Arnfjörð Bjarmason
2021-06-29  6:18     ` Patrick Steinhardt
2021-06-29 12:09       ` Ævar Arnfjörð Bjarmason
2021-06-28  5:33 ` [PATCH v2 2/3] receive-pack: skip connectivity checks on delete-only commands Patrick Steinhardt
2021-06-28  8:00   ` Ævar Arnfjörð Bjarmason
2021-06-28  8:06     ` Ævar Arnfjörð Bjarmason
2021-06-29  6:26     ` Patrick Steinhardt
2021-06-30  1:31   ` Jeff King
2021-06-30  1:35     ` Jeff King
2021-06-30 13:52     ` Patrick Steinhardt
2021-06-28  5:33 ` [PATCH v2 3/3] connected: implement connectivity check using bitmaps Patrick Steinhardt
2021-06-28 20:23   ` Taylor Blau
2021-06-29 22:44     ` Taylor Blau
2021-06-30  2:04       ` Jeff King
2021-06-30  3:07         ` Taylor Blau
2021-06-30  5:45           ` Jeff King
2021-07-02 17:44             ` Taylor Blau
2021-07-02 21:21               ` Jeff King
2021-06-30  1:51   ` Jeff King
2021-07-20 14:26     ` Patrick Steinhardt
2021-08-02  9:37 ` [PATCH v3 0/4] Speed up connectivity checks Patrick Steinhardt
2021-08-02  9:38   ` [PATCH v3 1/4] connected: do not sort input revisions Patrick Steinhardt
2021-08-02 12:49     ` Ævar Arnfjörð Bjarmason
2021-08-03  8:50       ` Patrick Steinhardt
2021-08-04 11:01         ` Ævar Arnfjörð Bjarmason
2021-08-02 19:00     ` Junio C Hamano
2021-08-03  8:55       ` Patrick Steinhardt
2021-08-03 21:47         ` Junio C Hamano
2021-08-02  9:38   ` [PATCH v3 2/4] revision: stop retrieving reference twice Patrick Steinhardt
2021-08-02 12:53     ` Ævar Arnfjörð Bjarmason [this message]
2021-08-02  9:38   ` [PATCH v3 3/4] revision: avoid loading object headers multiple times Patrick Steinhardt
2021-08-02 12:55     ` Ævar Arnfjörð Bjarmason
2021-08-05 10:12       ` Patrick Steinhardt
2021-08-02 19:40     ` Junio C Hamano
2021-08-03  9:07       ` Patrick Steinhardt
2021-08-06 14:17         ` Patrick Steinhardt
2021-08-02  9:38   ` [PATCH v3 4/4] revision: avoid hitting packfiles when commits are in commit-graph Patrick Steinhardt
2021-08-02 20:01     ` Junio C Hamano
2021-08-03  9:16       ` Patrick Steinhardt
2021-08-03 21:56         ` Junio C Hamano
2021-08-05 11:01           ` Patrick Steinhardt
2021-08-05 16:16             ` Junio C Hamano
2021-08-04 10:51         ` Ævar Arnfjörð Bjarmason
2021-08-05 11:25   ` [PATCH v4 0/6] Speed up connectivity checks Patrick Steinhardt
2021-08-05 11:25     ` [PATCH v4 1/6] revision: separate walk and unsorted flags Patrick Steinhardt
2021-08-05 18:47       ` Junio C Hamano
2021-08-05 11:25     ` [PATCH v4 2/6] connected: do not sort input revisions Patrick Steinhardt
2021-08-05 18:44       ` Junio C Hamano
2021-08-06  6:00         ` Patrick Steinhardt
2021-08-06 16:50           ` Junio C Hamano
2021-08-05 11:25     ` [PATCH v4 3/6] revision: stop retrieving reference twice Patrick Steinhardt
2021-08-05 11:25     ` [PATCH v4 4/6] revision: avoid loading object headers multiple times Patrick Steinhardt
2021-08-05 11:25     ` [PATCH v4 5/6] commit-graph: split out function to search commit position Patrick Steinhardt
2021-08-05 11:25     ` [PATCH v4 6/6] revision: avoid hitting packfiles when commits are in commit-graph Patrick Steinhardt
2021-08-09  8:00 ` [PATCH v5 0/5] Speed up connectivity checks Patrick Steinhardt
2021-08-09  8:02   ` Patrick Steinhardt
2021-08-09  8:11 ` Patrick Steinhardt
2021-08-09  8:11   ` [PATCH v5 1/5] revision: separate walk and unsorted flags Patrick Steinhardt
2021-08-09  8:11   ` [PATCH v5 2/5] connected: do not sort input revisions Patrick Steinhardt
2021-08-09  8:11   ` [PATCH v5 3/5] revision: stop retrieving reference twice Patrick Steinhardt
2021-08-09  8:11   ` [PATCH v5 4/5] commit-graph: split out function to search commit position Patrick Steinhardt
2021-08-09  8:12   ` [PATCH v5 5/5] revision: avoid hitting packfiles when commits are in commit-graph Patrick Steinhardt

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