From: Patrick Steinhardt <ps@pks.im>
To: git@vger.kernel.org
Cc: "Jeff King" <peff@peff.net>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Junio C Hamano" <gitster@pobox.com>
Subject: [PATCH 4/6] fetch-pack: optimize loading of refs via commit graph
Date: Fri, 20 Aug 2021 12:08:41 +0200 [thread overview]
Message-ID: <67917af7ceeefe41ae0f6edf69cd61e2ee8c0ea3.1629452412.git.ps@pks.im> (raw)
In-Reply-To: <cover.1629452412.git.ps@pks.im>
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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.
---
fetch-pack.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fetch-pack.c b/fetch-pack.c
index 1a6242cd71..c57faf278f 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,
@@ -139,7 +144,7 @@ static struct commit *deref_without_lazy_fetch(const struct object_id *oid,
}
if (type == OBJ_COMMIT) {
- struct commit *commit = lookup_commit(the_repository, oid);
+ commit = lookup_commit(the_repository, oid);
if (!commit || repo_parse_commit(the_repository, commit))
return NULL;
return commit;
--
2.33.0
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next prev parent reply other threads:[~2021-08-20 10:10 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-20 10:08 [PATCH 0/6] Speed up mirror-fetches with many refs Patrick Steinhardt
2021-08-20 10:08 ` [PATCH 1/6] fetch: speed up lookup of want refs via commit-graph Patrick Steinhardt
2021-08-20 14:27 ` Derrick Stolee
2021-08-20 17:18 ` Junio C Hamano
2021-08-23 6:46 ` Patrick Steinhardt
2021-08-25 14:12 ` Derrick Stolee
2021-08-20 10:08 ` [PATCH 2/6] fetch: avoid unpacking headers in object existence check Patrick Steinhardt
2021-08-25 23:44 ` Ævar Arnfjörð Bjarmason
2021-08-20 10:08 ` [PATCH 3/6] connected: refactor iterator to return next object ID directly Patrick Steinhardt
2021-08-20 14:32 ` Derrick Stolee
2021-08-20 17:43 ` Junio C Hamano
2021-08-20 17:43 ` René Scharfe
2021-08-23 6:47 ` Patrick Steinhardt
2021-08-20 10:08 ` Patrick Steinhardt [this message]
2021-08-20 14:37 ` [PATCH 4/6] fetch-pack: optimize loading of refs via commit graph Derrick Stolee
2021-08-20 10:08 ` [PATCH 5/6] fetch: refactor fetch refs to be more extendable Patrick Steinhardt
2021-08-20 14:41 ` Derrick Stolee
2021-08-20 10:08 ` [PATCH 6/6] fetch: avoid second connectivity check if we already have all objects Patrick Steinhardt
2021-08-20 14:47 ` Derrick Stolee
2021-08-23 6:52 ` Patrick Steinhardt
2021-08-20 14:50 ` [PATCH 0/6] Speed up mirror-fetches with many refs Derrick Stolee
2021-08-21 0:09 ` Junio C Hamano
2021-08-24 10:36 ` [PATCH v2 0/7] " Patrick Steinhardt
2021-08-24 10:36 ` [PATCH v2 1/7] fetch: speed up lookup of want refs via commit-graph Patrick Steinhardt
2021-08-25 14:16 ` Derrick Stolee
2021-08-24 10:37 ` [PATCH v2 2/7] fetch: avoid unpacking headers in object existence check Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 3/7] connected: refactor iterator to return next object ID directly Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 4/7] fetch-pack: optimize loading of refs via commit graph Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 5/7] fetch: refactor fetch refs to be more extendable Patrick Steinhardt
2021-08-25 14:19 ` Derrick Stolee
2021-09-01 12:48 ` Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 6/7] fetch: merge fetching and consuming refs Patrick Steinhardt
2021-08-25 14:26 ` Derrick Stolee
2021-09-01 12:49 ` Patrick Steinhardt
2021-08-24 10:37 ` [PATCH v2 7/7] fetch: avoid second connectivity check if we already have all objects Patrick Steinhardt
2021-08-24 22:48 ` [PATCH v2 0/7] Speed up mirror-fetches with many refs Junio C Hamano
2021-08-25 6:04 ` Patrick Steinhardt
2021-08-25 14:27 ` Derrick Stolee
2021-09-01 13:09 ` [PATCH v3 " Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 1/7] fetch: speed up lookup of want refs via commit-graph Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 2/7] fetch: avoid unpacking headers in object existence check Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 3/7] connected: refactor iterator to return next object ID directly Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 4/7] fetch-pack: optimize loading of refs via commit graph Patrick Steinhardt
2021-09-01 13:09 ` [PATCH v3 5/7] fetch: refactor fetch refs to be more extendable Patrick Steinhardt
2021-09-01 13:10 ` [PATCH v3 6/7] fetch: merge fetching and consuming refs Patrick Steinhardt
2021-09-01 13:10 ` [PATCH v3 7/7] fetch: avoid second connectivity check if we already have all objects Patrick Steinhardt
2021-09-01 19:58 ` [PATCH v3 0/7] Speed up mirror-fetches with many refs Junio C Hamano
2021-09-08 0:08 ` Junio C Hamano
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