From d7574c95bb74cd189950cc6e9cad762099382162 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= Date: Sat, 19 Jan 2019 21:21:12 +0100 Subject: commit-graph write: use pack order when finding commits MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Slightly optimize the "commit-graph write" step by using FOR_EACH_OBJECT_PACK_ORDER with for_each_object_in_pack(). See commit [1] and [2] for the facility and a similar optimization for "cat-file". On Linux it is around 5% slower to run: echo 1 >/proc/sys/vm/drop_caches && cat .git/objects/pack/* >/dev/null && git cat-file --batch-all-objects --batch-check --unordered Than the same thing with the "cat" omitted. This is as expected, since we're iterating in pack order and the "cat" is extra work. Before this change the opposite was true of "commit-graph write". We were 6% faster if we first ran "cat" to efficiently populate the FS cache for our sole big pack on linux.git, than if we had populated it via for_each_object_in_pack(). Now we're 3% faster without the "cat" instead. My tests were done on an unloaded Linux 3.10 system with 10 runs for each. Derrick Stolee did his own tests on Windows[3] showing a 2% improvement with a high degree of accuracy. 1. 736eb88fdc ("for_each_packed_object: support iterating in pack-order", 2018-08-10) 2. 0750bb5b51 ("cat-file: support "unordered" output for --batch-all-objects", 2018-08-10) 3. https://public-inbox.org/git/f71fa868-25e8-a9c9-46a6-611b987f1a8f@gmail.com/ Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano --- commit-graph.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/commit-graph.c b/commit-graph.c index 5c8fb4b134..981faf0465 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -816,7 +816,8 @@ void write_commit_graph(const char *obj_dir, die(_("error adding pack %s"), packname.buf); if (open_pack_index(p)) die(_("error opening index for %s"), packname.buf); - for_each_object_in_pack(p, add_packed_commits, &oids, 0); + for_each_object_in_pack(p, add_packed_commits, &oids, + FOR_EACH_OBJECT_PACK_ORDER); close_pack(p); free(p); } @@ -854,7 +855,8 @@ void write_commit_graph(const char *obj_dir, if (report_progress) oids.progress = start_delayed_progress( _("Finding commits for commit graph"), 0); - for_each_packed_object(add_packed_commits, &oids, 0); + for_each_packed_object(add_packed_commits, &oids, + FOR_EACH_OBJECT_PACK_ORDER); stop_progress(&oids.progress); } -- cgit v1.2.3