bitmap-lookup-table: add performance tests for lookup table

Add performance tests to verify the performance of lookup table.
`p5310-pack-bitmaps.sh` contain tests with and without lookup table.
`p5312-pack-bitmaps-revs.sh` contain same tests with and without
lookup table but with `pack.writeReverseIndex` enabled.

Lookup table makes Git run faster in most of the cases. Below is the
result of `t/perf/p5310-pack-bitmaps.sh`.`perf/p5326-multi-pack-bitmaps.sh`
gives similar result. The repository used in the test is linux kernel.

Test                                                    this tree
-----------------------------------------------------------------------
5310.4: enable lookup table: false                    0.01(0.00+0.00)
5310.5: repack to disk                                320.89(230.20+23.45)
5310.6: simulated clone                               14.04(5.78+1.79)
5310.7: simulated fetch                               1.95(3.05+0.20)
5310.8: pack to file (bitmap)                         44.73(20.55+7.45)
5310.9: rev-list (commits)                            0.78(0.46+0.10)
5310.10: rev-list (objects)                           4.07(3.97+0.08)
5310.11: rev-list with tag negated via --not          0.06(0.02+0.03)
         --all (objects)
5310.12: rev-list with negative tag (objects)         0.21(0.15+0.05)
5310.13: rev-list count with blob:none                0.24(0.17+0.06)
5310.14: rev-list count with blob:limit=1k            7.07(5.92+0.48)
5310.15: rev-list count with tree:0                   0.25(0.17+0.07)
5310.16: simulated partial clone                      5.67(3.28+0.64)
5310.18: clone (partial bitmap)                       16.05(8.34+1.86)
5310.19: pack to file (partial bitmap)                59.76(27.22+7.43)
5310.20: rev-list with tree filter (partial bitmap)   0.90(0.18+0.16)
5310.24: enable lookup table: true                    0.01(0.00+0.00)
5310.25: repack to disk                               319.73(229.30+23.01)
5310.26: simulated clone                              13.69(5.72+1.78)
5310.27: simulated fetch                              1.84(3.02+0.16)
5310.28: pack to file (bitmap)                        45.63(20.67+7.50)
5310.29: rev-list (commits)                           0.56(0.39+0.8)
5310.30: rev-list (objects)                           3.77(3.74+0.08)
5310.31: rev-list with tag negated via --not          0.05(0.02+0.03)
         --all (objects)
5310.32: rev-list with negative tag (objects)         0.21(0.15+0.05)
5310.33: rev-list count with blob:none                0.23(0.17+0.05)
5310.34: rev-list count with blob:limit=1k            6.65(5.72+0.40)
5310.35: rev-list count with tree:0                   0.23(0.16+0.06)
5310.36: simulated partial clone                      5.57(3.26+0.59)
5310.38: clone (partial bitmap)                       15.89(8.39+1.84)
5310.39: pack to file (partial bitmap)                58.32(27.55+7.47)
5310.40: rev-list with tree filter (partial bitmap)   0.73(0.18+0.15)

Test 4-15 are tested without using lookup table. Same tests are
repeated in 16-30 (using lookup table).

Mentored-by: Taylor Blau <me@ttaylorr.com>
Co-Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Signed-off-by: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Abhradeep Chakraborty 2022-08-14 16:55:11 +00:00 committed by Junio C Hamano
parent 28cd730680
commit 761416ef91
5 changed files with 183 additions and 106 deletions

View File

@ -67,3 +67,34 @@ test_partial_bitmap () {
--filter=tree:0 >/dev/null
'
}
test_pack_bitmap () {
test_perf "repack to disk" '
git repack -ad
'
test_full_bitmap
test_expect_success "create partial bitmap state" '
# pick a commit to represent the repo tip in the past
cutoff=$(git rev-list HEAD~100 -1) &&
orig_tip=$(git rev-parse HEAD) &&
# now kill off all of the refs and pretend we had
# just the one tip
rm -rf .git/logs .git/refs/* .git/packed-refs &&
git update-ref HEAD $cutoff &&
# and then repack, which will leave us with a nice
# big bitmap pack of the "old" history, and all of
# the new history will be loose, as if it had been pushed
# up incrementally and exploded via unpack-objects
git repack -Ad &&
# and now restore our original tip, as if the pushes
# had happened
git update-ref HEAD $orig_tip
'
test_partial_bitmap
}

View File

@ -4,51 +4,37 @@ test_description='Tests pack performance using bitmaps'
. ./perf-lib.sh
. "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
test_perf_large_repo
test_lookup_pack_bitmap () {
test_expect_success 'start the test from scratch' '
rm -rf * .git
'
# note that we do everything through config,
# since we want to be able to compare bitmap-aware
# git versus non-bitmap git
#
# We intentionally use the deprecated pack.writebitmaps
# config so that we can test against older versions of git.
test_expect_success 'setup bitmap config' '
git config pack.writebitmaps true
'
test_perf_large_repo
# we need to create the tag up front such that it is covered by the repack and
# thus by generated bitmaps.
test_expect_success 'create tags' '
git tag --message="tag pointing to HEAD" perf-tag HEAD
'
# note that we do everything through config,
# since we want to be able to compare bitmap-aware
# git versus non-bitmap git
#
# We intentionally use the deprecated pack.writebitmaps
# config so that we can test against older versions of git.
test_expect_success 'setup bitmap config' '
git config pack.writebitmaps true
'
test_perf 'repack to disk' '
git repack -ad
'
# we need to create the tag up front such that it is covered by the repack and
# thus by generated bitmaps.
test_expect_success 'create tags' '
git tag --message="tag pointing to HEAD" perf-tag HEAD
'
test_full_bitmap
test_perf "enable lookup table: $1" '
git config pack.writeBitmapLookupTable '"$1"'
'
test_expect_success 'create partial bitmap state' '
# pick a commit to represent the repo tip in the past
cutoff=$(git rev-list HEAD~100 -1) &&
orig_tip=$(git rev-parse HEAD) &&
test_pack_bitmap
}
# now kill off all of the refs and pretend we had
# just the one tip
rm -rf .git/logs .git/refs/* .git/packed-refs &&
git update-ref HEAD $cutoff &&
# and then repack, which will leave us with a nice
# big bitmap pack of the "old" history, and all of
# the new history will be loose, as if it had been pushed
# up incrementally and exploded via unpack-objects
git repack -Ad &&
# and now restore our original tip, as if the pushes
# had happened
git update-ref HEAD $orig_tip
'
test_partial_bitmap
test_lookup_pack_bitmap false
test_lookup_pack_bitmap true
test_done

View File

@ -3,42 +3,52 @@
test_description='performance of fetches from bitmapped packs'
. ./perf-lib.sh
test_perf_default_repo
test_expect_success 'create bitmapped server repo' '
git config pack.writebitmaps true &&
git repack -ad
'
# simulate a fetch from a repository that last fetched N days ago, for
# various values of N. We do so by following the first-parent chain,
# and assume the first entry in the chain that is N days older than the current
# HEAD is where the HEAD would have been then.
for days in 1 2 4 8 16 32 64 128; do
title=$(printf '%10s' "($days days)")
test_expect_success "setup revs from $days days ago" '
now=$(git log -1 --format=%ct HEAD) &&
then=$(($now - ($days * 86400))) &&
tip=$(git rev-list -1 --first-parent --until=$then HEAD) &&
{
echo HEAD &&
echo ^$tip
} >revs
test_fetch_bitmaps () {
test_expect_success 'setup test directory' '
rm -fr * .git
'
test_perf "server $title" '
git pack-objects --stdout --revs \
--thin --delta-base-offset \
<revs >tmp.pack
test_perf_default_repo
test_expect_success 'create bitmapped server repo' '
git config pack.writebitmaps true &&
git config pack.writeBitmapLookupTable '"$1"' &&
git repack -ad
'
test_size "size $title" '
wc -c <tmp.pack
'
# simulate a fetch from a repository that last fetched N days ago, for
# various values of N. We do so by following the first-parent chain,
# and assume the first entry in the chain that is N days older than the current
# HEAD is where the HEAD would have been then.
for days in 1 2 4 8 16 32 64 128; do
title=$(printf '%10s' "($days days)")
test_expect_success "setup revs from $days days ago" '
now=$(git log -1 --format=%ct HEAD) &&
then=$(($now - ($days * 86400))) &&
tip=$(git rev-list -1 --first-parent --until=$then HEAD) &&
{
echo HEAD &&
echo ^$tip
} >revs
'
test_perf "client $title" '
git index-pack --stdin --fix-thin <tmp.pack
'
done
test_perf "server $title (lookup=$1)" '
git pack-objects --stdout --revs \
--thin --delta-base-offset \
<revs >tmp.pack
'
test_size "size $title" '
wc -c <tmp.pack
'
test_perf "client $title (lookup=$1)" '
git index-pack --stdin --fix-thin <tmp.pack
'
done
}
test_fetch_bitmaps true
test_fetch_bitmaps false
test_done

View File

@ -0,0 +1,35 @@
#!/bin/sh
test_description='Tests pack performance using bitmaps (rev index enabled)'
. ./perf-lib.sh
. "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
test_lookup_pack_bitmap () {
test_expect_success 'start the test from scratch' '
rm -rf * .git
'
test_perf_large_repo
test_expect_success 'setup bitmap config' '
git config pack.writebitmaps true &&
git config pack.writeReverseIndex true
'
# we need to create the tag up front such that it is covered by the repack and
# thus by generated bitmaps.
test_expect_success 'create tags' '
git tag --message="tag pointing to HEAD" perf-tag HEAD
'
test_perf "enable lookup table: $1" '
git config pack.writeBitmapLookupTable '"$1"'
'
test_pack_bitmap
}
test_lookup_pack_bitmap false
test_lookup_pack_bitmap true
test_done

View File

@ -4,49 +4,64 @@ test_description='Tests performance using midx bitmaps'
. ./perf-lib.sh
. "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
test_perf_large_repo
test_bitmap () {
local enabled="$1"
# we need to create the tag up front such that it is covered by the repack and
# thus by generated bitmaps.
test_expect_success 'create tags' '
git tag --message="tag pointing to HEAD" perf-tag HEAD
'
test_expect_success "remove existing repo (lookup=$enabled)" '
rm -fr * .git
'
test_expect_success 'start with bitmapped pack' '
git repack -adb
'
test_perf_large_repo
test_perf 'setup multi-pack index' '
git multi-pack-index write --bitmap
'
# we need to create the tag up front such that it is covered by the repack and
# thus by generated bitmaps.
test_expect_success 'create tags' '
git tag --message="tag pointing to HEAD" perf-tag HEAD
'
test_expect_success 'drop pack bitmap' '
rm -f .git/objects/pack/pack-*.bitmap
'
test_expect_success "use lookup table: $enabled" '
git config pack.writeBitmapLookupTable '"$enabled"'
'
test_full_bitmap
test_expect_success "start with bitmapped pack (lookup=$enabled)" '
git repack -adb
'
test_expect_success 'create partial bitmap state' '
# pick a commit to represent the repo tip in the past
cutoff=$(git rev-list HEAD~100 -1) &&
orig_tip=$(git rev-parse HEAD) &&
test_perf "setup multi-pack index (lookup=$enabled)" '
git multi-pack-index write --bitmap
'
# now pretend we have just one tip
rm -rf .git/logs .git/refs/* .git/packed-refs &&
git update-ref HEAD $cutoff &&
test_expect_success "drop pack bitmap (lookup=$enabled)" '
rm -f .git/objects/pack/pack-*.bitmap
'
# and then repack, which will leave us with a nice
# big bitmap pack of the "old" history, and all of
# the new history will be loose, as if it had been pushed
# up incrementally and exploded via unpack-objects
git repack -Ad &&
git multi-pack-index write --bitmap &&
test_full_bitmap
# and now restore our original tip, as if the pushes
# had happened
git update-ref HEAD $orig_tip
'
test_expect_success "create partial bitmap state (lookup=$enabled)" '
# pick a commit to represent the repo tip in the past
cutoff=$(git rev-list HEAD~100 -1) &&
orig_tip=$(git rev-parse HEAD) &&
test_partial_bitmap
# now pretend we have just one tip
rm -rf .git/logs .git/refs/* .git/packed-refs &&
git update-ref HEAD $cutoff &&
# and then repack, which will leave us with a nice
# big bitmap pack of the "old" history, and all of
# the new history will be loose, as if it had been pushed
# up incrementally and exploded via unpack-objects
git repack -Ad &&
git multi-pack-index write --bitmap &&
# and now restore our original tip, as if the pushes
# had happened
git update-ref HEAD $orig_tip
'
test_partial_bitmap
}
test_bitmap false
test_bitmap true
test_done