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.
And indeed, it is much faster in the single-pack case (all timings
measured on the kernel):
5303.5: repack (1) 57.29(54.88+10.39)
5303.6: repack with keep (1) 1.25(1.19+0.05)
and in the 50-pack case:
5303.10: repack (50) 89.71(132.78+6.14)
5303.11: repack with keep (50) 6.92(26.93+0.58)
but our improvements vanish as we approach 1000 packs.
5303.15: repack (1000) 217.14(493.76+15.29)
5303.16: repack with keep (1000) 209.46(387.83+8.42)
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 | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/t/perf/p5303-many-packs.sh b/t/perf/p5303-many-packs.sh
index 277d22ec4b..85b077b72b 100755
--- a/t/perf/p5303-many-packs.sh
+++ b/t/perf/p5303-many-packs.sh
@@ -27,8 +27,11 @@ repack_into_n () {
>pushes &&
# create base packfile
- head -n 1 pushes |
- git pack-objects --delta-base-offset --revs staging/pack &&
+ base_pack=$(
+ head -n 1 pushes |
+ git pack-objects --delta-base-offset --revs staging/pack
+ ) &&
+ test_export base_pack &&
# and then incrementals between each pair of commits
last= &&
@@ -87,6 +90,15 @@ do
--reflog --indexed-objects --delta-base-offset \
--stdout </dev/null >/dev/null
'
+
+ test_perf "repack with keep ($nr_packs)" '
+ git pack-objects --keep-true-parents \
+ --honor-pack-keep --assume-kept-packs-closed \
+ --keep-pack=pack-$base_pack.pack \
+ --non-empty --all \
+ --reflog --indexed-objects --delta-base-offset \
+ --stdout </dev/null >/dev/null
+ '
done
# Measure pack loading with 10,000 packs.
--
2.30.0.138.g6d7191ea01
