From 9fec7b213045135655354e864d15894175428d5a Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Wed, 1 Sep 2021 15:09:50 +0200 Subject: connected: refactor iterator to return next object ID directly MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The object ID iterator used by the connectivity checks returns the next object ID via an out-parameter and then uses a return code to indicate whether an item was found. This is a bit roundabout: instead of a separate error code, we can just return the next object ID directly and use `NULL` pointers as indicator that the iterator got no items left. Furthermore, this avoids a copy of the object ID. Refactor the iterator and all its implementations to return object IDs directly. This brings a tiny performance improvement when doing a mirror-fetch of a repository with about 2.3M refs: Benchmark #1: 328dc58b49919c43897240f2eabfa30be2ce32a4~: git-fetch Time (mean ± σ): 30.110 s ± 0.148 s [User: 27.161 s, System: 5.075 s] Range (min … max): 29.934 s … 30.406 s 10 runs Benchmark #2: 328dc58b49919c43897240f2eabfa30be2ce32a4: git-fetch Time (mean ± σ): 29.899 s ± 0.109 s [User: 26.916 s, System: 5.104 s] Range (min … max): 29.696 s … 29.996 s 10 runs Summary '328dc58b49919c43897240f2eabfa30be2ce32a4: git-fetch' ran 1.01 ± 0.01 times faster than '328dc58b49919c43897240f2eabfa30be2ce32a4~: git-fetch' While this 1% speedup could be labelled as statistically insignificant, the speedup is consistent on my machine. Furthermore, this is an end to end test, so it is expected that the improvement in the connectivity check itself is more significant. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- builtin/clone.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'builtin/clone.c') diff --git a/builtin/clone.c b/builtin/clone.c index 66fe66679c..4a1056fcc2 100644 --- a/builtin/clone.c +++ b/builtin/clone.c @@ -657,7 +657,7 @@ static void write_followtags(const struct ref *refs, const char *msg) } } -static int iterate_ref_map(void *cb_data, struct object_id *oid) +static const struct object_id *iterate_ref_map(void *cb_data) { struct ref **rm = cb_data; struct ref *ref = *rm; @@ -668,13 +668,11 @@ static int iterate_ref_map(void *cb_data, struct object_id *oid) */ while (ref && !ref->peer_ref) ref = ref->next; - /* Returning -1 notes "end of list" to the caller. */ if (!ref) - return -1; + return NULL; - oidcpy(oid, &ref->old_oid); *rm = ref->next; - return 0; + return &ref->old_oid; } static void update_remote_refs(const struct ref *refs, -- cgit v1.3