1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
From 62b5a35a33ad6a4537e2ae75a49036e4173fcc87 Mon Sep 17 00:00:00 2001
Message-Id: <62b5a35a33ad6a4537e2ae75a49036e4173fcc87.1631166322.git.ps@pks.im>
In-Reply-To: <fe7df03a9a2fa434ebce38b2cd5e6da42f8b2692.1631166322.git.ps@pks.im>
References: <fe7df03a9a2fa434ebce38b2cd5e6da42f8b2692.1631166322.git.ps@pks.im>
From: Patrick Steinhardt <ps@pks.im>
Date: Wed, 1 Sep 2021 15:09:54 +0200
Subject: [PATCH 11/14] fetch-pack: optimize loading of refs via commit graph
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
In order to negotiate a packfile, we need to dereference refs to see
which commits we have in common with the remote. To do so, we first look
up the object's type -- if it's a tag, we peel until we hit a non-tag
object. If we hit a commit eventually, then we return that commit.
In case the object ID points to a commit directly, we can avoid the
initial lookup of the object type by opportunistically looking up the
commit via the commit-graph, if available, which gives us a slight speed
bump of about 2% in a huge repository with about 2.3M refs:
Benchmark #1: HEAD~: git-fetch
Time (mean ± σ): 31.634 s ± 0.258 s [User: 28.400 s, System: 5.090 s]
Range (min … max): 31.280 s … 31.896 s 5 runs
Benchmark #2: HEAD: git-fetch
Time (mean ± σ): 31.129 s ± 0.543 s [User: 27.976 s, System: 5.056 s]
Range (min … max): 30.172 s … 31.479 s 5 runs
Summary
'HEAD: git-fetch' ran
1.02 ± 0.02 times faster than 'HEAD~: git-fetch'
In case this fails, we fall back to the old code which peels the
objects to a commit.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
fetch-pack.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/fetch-pack.c b/fetch-pack.c
index e6ec79f81a..a9604f35a3 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -119,6 +119,11 @@ static struct commit *deref_without_lazy_fetch(const struct object_id *oid,
{
enum object_type type;
struct object_info info = { .typep = &type };
+ struct commit *commit;
+
+ commit = lookup_commit_in_graph(the_repository, oid);
+ if (commit)
+ return commit;
while (1) {
if (oid_object_info_extended(the_repository, oid, &info,
--
2.33.0
|
