From: Jeff King <peff@xxxxxxxx>
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@xxxxxxxx>
Signed-off-by: Taylor Blau <me@xxxxxxxxxxxx>
---
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
