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From caff8b73402d4b5edb2c6c755506c5a90351b69a Mon Sep 17 00:00:00 2001
Message-Id: <caff8b73402d4b5edb2c6c755506c5a90351b69a.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 15:10:06 +0200
Subject: [PATCH 14/14] fetch: avoid second connectivity check if we already
have all objects
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
When fetching refs, we are doing two connectivity checks:
- The first one is done such that we can skip fetching refs in the
case where we already have all objects referenced by the updated
set of refs.
- The second one verifies that we have all objects after we have
fetched objects.
We always execute both connectivity checks, but this is wasteful in case
the first connectivity check already notices that we have all objects
locally available.
Skip the second connectivity check in case we already had all objects
available. This gives us a nice speedup when doing a mirror-fetch in a
repository with about 2.3M refs where the fetching repo already has all
objects:
Benchmark #1: HEAD~: git-fetch
Time (mean ± σ): 30.025 s ± 0.081 s [User: 27.070 s, System: 4.933 s]
Range (min … max): 29.900 s … 30.111 s 5 runs
Benchmark #2: HEAD: git-fetch
Time (mean ± σ): 25.574 s ± 0.177 s [User: 22.855 s, System: 4.683 s]
Range (min … max): 25.399 s … 25.765 s 5 runs
Summary
'HEAD: git-fetch' ran
1.17 ± 0.01 times faster than 'HEAD~: git-fetch'
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
builtin/fetch.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/builtin/fetch.c b/builtin/fetch.c
index a1e17edd8b..e2c952ec67 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1293,7 +1293,7 @@ static int check_exist_and_connected(struct ref *ref_map)
static int fetch_and_consume_refs(struct transport *transport, struct ref *ref_map)
{
- int connectivity_checked;
+ int connectivity_checked = 1;
int ret;
/*
@@ -1307,11 +1307,10 @@ static int fetch_and_consume_refs(struct transport *transport, struct ref *ref_m
trace2_region_leave("fetch", "fetch_refs", the_repository);
if (ret)
goto out;
+ connectivity_checked = transport->smart_options ?
+ transport->smart_options->connectivity_checked : 0;
}
- connectivity_checked = transport->smart_options
- ? transport->smart_options->connectivity_checked : 0;
-
trace2_region_enter("fetch", "consume_refs", the_repository);
ret = store_updated_refs(transport->url,
transport->remote->name,
--
2.33.0
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