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From: Taylor Blau <me@ttaylorr.com>
To: git@vger.kernel.org
Cc: dstolee@microsoft.com, gitster@pobox.com, peff@peff.net
Subject: [PATCH v2 5/8] p5303: measure time to repack with keep
Date: Wed, 3 Feb 2021 22:59:13 -0500	[thread overview]
Message-ID: <b5081c01b53beb568ef2e59956d25b36be9f24d0.1612411124.git.me@ttaylorr.com> (raw)
In-Reply-To: <cover.1612411123.git.me@ttaylorr.com>

From: Jeff King <peff@peff.net>

This is the same as the regular repack test, except that we mark the
single base pack as "kept" and use --assume-kept-packs-closed. The
theory is that this should be faster than the normal repack, because
we'll have fewer objects to traverse and process.

Here are some timings on a recent clone of the kernel. In the
single-pack case, there is nothing do since there are no non-excluded
packs:

  5303.5: repack (1)                          57.42(54.88+10.64)
  5303.6: repack with --stdin-packs (1)       0.01(0.01+0.00)

and in the 50-pack case, it is much faster to use `--stdin-packs`, since
we avoid having to consider any objects in the excluded pack:

  5303.10: repack (50)                        71.26(88.24+4.96)
  5303.11: repack with --stdin-packs (50)     3.49(11.82+0.28)

but our improvements vanish as we approach 1000 packs.

  5303.15: repack (1000)                      215.64(491.33+14.80)
  5303.16: repack with --stdin-packs (1000)   198.79(380.51+7.97)

That's because the code paths around handling .keep files are known to
scale badly; they look in every single pack file to find each object.
Our solution to that was to notice that most repos don't have keep
files, and to make that case a fast path. But as soon as you add a
single .keep, that part of pack-objects slows down again (even if we
have fewer objects total to look at).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 t/perf/p5303-many-packs.sh | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/t/perf/p5303-many-packs.sh b/t/perf/p5303-many-packs.sh
index d90d714923..b76a6efe00 100755
--- a/t/perf/p5303-many-packs.sh
+++ b/t/perf/p5303-many-packs.sh
@@ -31,8 +31,11 @@ repack_into_n () {
 	' "$1" >pushes &&
 
 	# create base packfile
-	head -n 1 pushes |
-	git pack-objects --delta-base-offset --revs staging/pack &&
+	base_pack=$(
+		head -n 1 pushes |
+		git pack-objects --delta-base-offset --revs staging/pack
+	) &&
+	test_export base_pack &&
 
 	# and then incrementals between each pair of commits
 	last= &&
@@ -49,6 +52,12 @@ repack_into_n () {
 		last=$rev
 	done <pushes &&
 
+	(
+		find staging -type f -name 'pack-*.pack' |
+			xargs -n 1 basename | grep -v "$base_pack" &&
+		printf "^pack-%s.pack\n" $base_pack
+	) >stdin.packs
+
 	# and install the whole thing
 	rm -f .git/objects/pack/* &&
 	mv staging/* .git/objects/pack/
@@ -91,6 +100,15 @@ do
 		  --reflog --indexed-objects --delta-base-offset \
 		  --stdout </dev/null >/dev/null
 	'
+
+	test_perf "repack with --stdin-packs ($nr_packs)" '
+		git pack-objects \
+		  --keep-true-parents \
+		  --stdin-packs \
+		  --non-empty \
+		  --delta-base-offset \
+		  --stdout <stdin.packs >/dev/null
+	'
 done
 
 # Measure pack loading with 10,000 packs.
-- 
2.30.0.533.g2f8b6b552f.dirty


  parent reply	other threads:[~2021-02-04  4:01 UTC|newest]

Thread overview: 120+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-19 23:23 [PATCH 00/10] repack: support repacking into a geometric sequence Taylor Blau
2021-01-19 23:24 ` [PATCH 01/10] packfile: introduce 'find_kept_pack_entry()' Taylor Blau
2021-01-20 13:40   ` Derrick Stolee
2021-01-20 14:38     ` Taylor Blau
2021-01-29  2:33   ` Junio C Hamano
2021-01-29 18:38     ` Taylor Blau
2021-01-29 19:31     ` Jeff King
2021-01-29 20:20       ` Junio C Hamano
2021-01-19 23:24 ` [PATCH 02/10] revision: learn '--no-kept-objects' Taylor Blau
2021-01-29  3:10   ` Junio C Hamano
2021-01-29 19:13     ` Taylor Blau
2021-01-19 23:24 ` [PATCH 03/10] builtin/pack-objects.c: learn '--assume-kept-packs-closed' Taylor Blau
2021-01-29  3:21   ` Junio C Hamano
2021-01-29 19:19     ` Jeff King
2021-01-29 20:01       ` Taylor Blau
2021-01-29 20:25         ` Jeff King
2021-01-29 22:10           ` Taylor Blau
2021-01-29 22:57             ` Jeff King
2021-01-29 23:03             ` Junio C Hamano
2021-01-29 23:28               ` Taylor Blau
2021-02-02  3:04                 ` Taylor Blau
2021-01-29 23:31               ` Jeff King
2021-01-29 22:13           ` Junio C Hamano
2021-01-29 20:30       ` Junio C Hamano
2021-01-29 22:43         ` Jeff King
2021-01-29 22:53           ` Taylor Blau
2021-01-29 23:00             ` Jeff King
2021-01-29 23:10             ` Junio C Hamano
2021-01-19 23:24 ` [PATCH 04/10] p5303: add missing &&-chains Taylor Blau
2021-01-19 23:24 ` [PATCH 05/10] p5303: measure time to repack with keep Taylor Blau
2021-01-29  3:40   ` Junio C Hamano
2021-01-29 19:32     ` Jeff King
2021-01-29 20:04       ` [PATCH] p5303: avoid sed GNU-ism Jeff King
2021-01-29 20:19         ` Eric Sunshine
2021-01-29 20:27           ` Jeff King
2021-01-29 20:36             ` Eric Sunshine
2021-01-29 22:11               ` Taylor Blau
2021-01-29 20:38       ` [PATCH 05/10] p5303: measure time to repack with keep Junio C Hamano
2021-01-29 22:10         ` Jeff King
2021-01-29 23:12           ` Junio C Hamano
2021-01-19 23:24 ` [PATCH 06/10] pack-objects: rewrite honor-pack-keep logic Taylor Blau
2021-01-19 23:24 ` [PATCH 07/10] packfile: add kept-pack cache for find_kept_pack_entry() Taylor Blau
2021-01-19 23:24 ` [PATCH 08/10] builtin/pack-objects.c: teach '--keep-pack-stdin' Taylor Blau
2021-01-19 23:24 ` [PATCH 09/10] builtin/repack.c: extract loose object handling Taylor Blau
2021-01-20 13:59   ` Derrick Stolee
2021-01-20 14:34     ` Taylor Blau
2021-01-20 15:51       ` Derrick Stolee
2021-01-21  3:45     ` Junio C Hamano
2021-01-19 23:24 ` [PATCH 10/10] builtin/repack.c: add '--geometric' option Taylor Blau
2021-01-20 14:05 ` [PATCH 00/10] repack: support repacking into a geometric sequence Derrick Stolee
2021-02-04  3:58 ` [PATCH v2 0/8] " Taylor Blau
2021-02-04  3:58   ` [PATCH v2 1/8] packfile: introduce 'find_kept_pack_entry()' Taylor Blau
2021-02-16 21:42     ` Jeff King
2021-02-16 21:48       ` Taylor Blau
2021-02-04  3:58   ` [PATCH v2 2/8] revision: learn '--no-kept-objects' Taylor Blau
2021-02-16 23:17     ` Jeff King
2021-02-17 18:35       ` Taylor Blau
2021-02-04  3:59   ` [PATCH v2 3/8] builtin/pack-objects.c: add '--stdin-packs' option Taylor Blau
2021-02-16 23:46     ` Jeff King
2021-02-17 18:59       ` Taylor Blau
2021-02-17 19:21         ` Jeff King
2021-02-04  3:59   ` [PATCH v2 4/8] p5303: add missing &&-chains Taylor Blau
2021-02-04  3:59   ` Taylor Blau [this message]
2021-02-16 23:58     ` [PATCH v2 5/8] p5303: measure time to repack with keep Jeff King
2021-02-17  0:02       ` Jeff King
2021-02-17 19:13       ` Taylor Blau
2021-02-17 19:25         ` Jeff King
2021-02-04  3:59   ` [PATCH v2 6/8] builtin/pack-objects.c: rewrite honor-pack-keep logic Taylor Blau
2021-02-17 16:05     ` Jeff King
2021-02-17 19:23       ` Taylor Blau
2021-02-17 19:29         ` Jeff King
2021-02-04  3:59   ` [PATCH v2 7/8] packfile: add kept-pack cache for find_kept_pack_entry() Taylor Blau
2021-02-17 17:11     ` Jeff King
2021-02-17 19:54       ` Taylor Blau
2021-02-17 20:25         ` Jeff King
2021-02-17 20:29           ` Taylor Blau
2021-02-17 21:43             ` Jeff King
2021-02-04  3:59   ` [PATCH v2 8/8] builtin/repack.c: add '--geometric' option Taylor Blau
2021-02-17 18:17     ` Jeff King
2021-02-17 20:01       ` Taylor Blau
2021-02-17  0:01   ` [PATCH v2 0/8] repack: support repacking into a geometric sequence Jeff King
2021-02-17 18:18     ` Jeff King
2021-02-18  3:14 ` [PATCH v3 " Taylor Blau
2021-02-18  3:14   ` [PATCH v3 1/8] packfile: introduce 'find_kept_pack_entry()' Taylor Blau
2021-02-18  3:14   ` [PATCH v3 2/8] revision: learn '--no-kept-objects' Taylor Blau
2021-02-18  3:14   ` [PATCH v3 3/8] builtin/pack-objects.c: add '--stdin-packs' option Taylor Blau
2021-02-18  3:14   ` [PATCH v3 4/8] p5303: add missing &&-chains Taylor Blau
2021-02-18  3:14   ` [PATCH v3 5/8] p5303: measure time to repack with keep Taylor Blau
2021-02-18  3:14   ` [PATCH v3 6/8] builtin/pack-objects.c: rewrite honor-pack-keep logic Taylor Blau
2021-02-18  3:14   ` [PATCH v3 7/8] packfile: add kept-pack cache for find_kept_pack_entry() Taylor Blau
2021-02-18  3:14   ` [PATCH v3 8/8] builtin/repack.c: add '--geometric' option Taylor Blau
2021-02-23  0:31   ` [PATCH v3 0/8] repack: support repacking into a geometric sequence Jeff King
2021-02-23  1:06     ` Taylor Blau
2021-02-23  1:42       ` Jeff King
2021-02-23  2:24 ` [PATCH v4 " Taylor Blau
2021-02-23  2:25   ` [PATCH v4 1/8] packfile: introduce 'find_kept_pack_entry()' Taylor Blau
2021-02-23  2:25   ` [PATCH v4 2/8] revision: learn '--no-kept-objects' Taylor Blau
2021-02-23  2:25   ` [PATCH v4 3/8] builtin/pack-objects.c: add '--stdin-packs' option Taylor Blau
2021-02-23  8:07     ` Junio C Hamano
2021-02-23 18:51       ` Jeff King
2021-02-23  2:25   ` [PATCH v4 4/8] p5303: add missing &&-chains Taylor Blau
2021-02-23  2:25   ` [PATCH v4 5/8] p5303: measure time to repack with keep Taylor Blau
2021-02-23  2:25   ` [PATCH v4 6/8] builtin/pack-objects.c: rewrite honor-pack-keep logic Taylor Blau
2021-02-23  2:25   ` [PATCH v4 7/8] packfile: add kept-pack cache for find_kept_pack_entry() Taylor Blau
2021-02-23  2:25   ` [PATCH v4 8/8] builtin/repack.c: add '--geometric' option Taylor Blau
2021-02-24 23:19     ` Junio C Hamano
2021-02-24 23:43       ` Junio C Hamano
2021-03-04 21:40         ` Taylor Blau
2021-03-04 21:55       ` Taylor Blau
2021-02-23  3:39   ` [PATCH v4 0/8] repack: support repacking into a geometric sequence Jeff King
2021-02-23  7:43   ` Junio C Hamano
2021-02-23 18:44     ` Jeff King
2021-02-23 19:54       ` Martin Fick
2021-02-23 20:06         ` Taylor Blau
2021-02-23 21:57           ` Martin Fick
2021-02-23 20:15         ` Jeff King
2021-02-23 21:41           ` Martin Fick
2021-02-23 21:53             ` Jeff King
2021-02-24 18:13               ` Martin Fick
2021-02-26  6:23                 ` Jeff King

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