To ensure that we don't regress either the size or runtime performance
of multi-pack reuse, add a performance test to measure both of these.
The test partitions the objects in GIT_TEST_PERF_LARGE_REPO into 1, 10,
and 100 packs, and then tries to perform a "clone" at each stage with
both single- and multi-pack reuse enabled.
Note that the `repack_into_n_chunks()` function in this new test script
differs from the existing `repack_into_n()`. The former partitions the
repository into N equal-sized chunks, while the latter produces N packs
of five commits each (plus their objects), and then another pack with
the remainder.
On git.git, I can produce the following results on my machine:
Test this tree
--------------------------------------------------------------------------------
5332.3: clone for 1-pack scenario (single-pack reuse) 1.57(2.99+0.15)
5332.4: clone size for 1-pack scenario (single-pack reuse) 231.8M
5332.5: clone for 1-pack scenario (multi-pack reuse) 1.79(2.96+0.21)
5332.6: clone size for 1-pack scenario (multi-pack reuse) 231.7M
5332.9: clone for 10-pack scenario (single-pack reuse) 3.89(16.75+0.35)
5332.10: clone size for 10-pack scenario (single-pack reuse) 209.9M
5332.11: clone for 10-pack scenario (multi-pack reuse) 1.56(2.99+0.17)
5332.12: clone size for 10-pack scenario (multi-pack reuse) 224.4M
5332.15: clone for 100-pack scenario (single-pack reuse) 8.24(54.31+0.59)
5332.16: clone size for 100-pack scenario (single-pack reuse) 278.3M
5332.17: clone for 100-pack scenario (multi-pack reuse) 2.13(2.44+0.33)
5332.18: clone size for 100-pack scenario (multi-pack reuse) 357.9M
Signed-off-by: Taylor Blau <me@xxxxxxxxxxxx>
---
t/perf/p5332-multi-pack-reuse.sh | 81 ++++++++++++++++++++++++++++++++
1 file changed, 81 insertions(+)
create mode 100755 t/perf/p5332-multi-pack-reuse.sh
diff --git a/t/perf/p5332-multi-pack-reuse.sh b/t/perf/p5332-multi-pack-reuse.sh
new file mode 100755
index 0000000000..5c6c575d62
--- /dev/null
+++ b/t/perf/p5332-multi-pack-reuse.sh
@@ -0,0 +1,81 @@
+#!/bin/sh
+
+test_description='tests pack performance with multi-pack reuse'
+
+. ./perf-lib.sh
+. "${TEST_DIRECTORY}/perf/lib-pack.sh"
+
+packdir=.git/objects/pack
+
+test_perf_large_repo
+
+find_pack () {
+ for idx in $packdir/pack-*.idx
+ do
+ if git show-index <$idx | grep -q "$1"
+ then
+ basename $idx
+ fi || return 1
+ done
+}
+
+repack_into_n_chunks () {
+ git repack -adk &&
+
+ test "$1" -eq 1 && return ||
+
+ find $packdir -type f | sort >packs.before &&
+
+ # partition the repository into $1 chunks of consecutive commits, and
+ # then create $1 packs with the objects reachable from each chunk
+ # (excluding any objects reachable from the previous chunks)
+ sz="$(($(git rev-list --count --all) / $1))"
+ for rev in $(git rev-list --all | awk "NR % $sz == 0" | tac)
+ do
+ pack="$(echo "$rev" | git pack-objects --revs \
+ --honor-pack-keep --delta-base-offset $packdir/pack)" &&
+ touch $packdir/pack-$pack.keep || return 1
+ done
+
+ # grab any remaining objects not packed by the previous step(s)
+ git pack-objects --revs --all --honor-pack-keep --delta-base-offset \
+ $packdir/pack &&
+
+ find $packdir -type f | sort >packs.after &&
+
+ # and install the whole thing
+ for f in $(comm -12 packs.before packs.after)
+ do
+ rm -f "$f" || return 1
+ done
+ rm -fr $packdir/*.keep
+}
+
+for nr_packs in 1 10 100
+do
+ test_expect_success "create $nr_packs-pack scenario" '
+ repack_into_n_chunks $nr_packs
+ '
+
+ test_expect_success "setup bitmaps for $nr_packs-pack scenario" '
+ find $packdir -type f -name "*.idx" | sed -e "s/.*\/\(.*\)$/+\1/g" |
+ git multi-pack-index write --stdin-packs --bitmap \
+ --preferred-pack="$(find_pack $(git rev-parse HEAD))"
+ '
+
+ for reuse in single multi
+ do
+ test_perf "clone for $nr_packs-pack scenario ($reuse-pack reuse)" "
+ git for-each-ref --format='%(objectname)' refs/heads refs/tags >in &&
+ git -c pack.allowPackReuse=$reuse pack-objects \
+ --revs --delta-base-offset --use-bitmap-index \
+ --stdout <in >result
+ "
+
+ test_size "clone size for $nr_packs-pack scenario ($reuse-pack reuse)" '
+ wc -c <result
+ '
+ done
+done
+
+test_done
--
2.43.0.102.ga31d690331.dirty
