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t/perf: avoid testing bitmaps without lookup table 

In a previous commit, the setting which controls whether or not the
pack- and MIDX-bitmap machinery writes a lookup table,
'pack.writeBitmapLookupTable' was enabled by default.

As a result, we can clean up many of our bitmap-related performance
tests. Many of the relevant performance tests look something like:

    test_it () {
      test_expect_success 'setup pack.writeBitmapLookupTable' '
        git config pack.writeBitmapLookupTable '"$1"'
      '

      # ...
    }

    test_it true
    test_it false

, where the two invocations of 'test_it' run the tests with and without
bitmap lookup tables enabled.

But now that lookup tables are enabled by default and have proven to be
a performance win, let's avoid benchmarking what is now an uncommon and
non-default scenario.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
seen
Taylor Blau 2025-04-17 17:12:20 -04:00 committed by Junio C Hamano
parent 8b0b5c7046
commit c9d41a415f
4 changed files with 92 additions and 119 deletions
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47
t/perf/p5310-pack-bitmaps.sh
View File

@ -4,37 +4,28 @@ test_description='Tests pack performance using bitmaps'
. ./perf-lib.sh . ./perf-lib.sh
. "${TEST_DIRECTORY}/perf/lib-bitmap.sh" . "${TEST_DIRECTORY}/perf/lib-bitmap.sh"


test_lookup_pack_bitmap () { test_expect_success 'start the test from scratch' '
test_expect_success 'start the test from scratch' ' rm -rf * .git
rm -rf * .git '
'


test_perf_large_repo test_perf_large_repo


# note that we do everything through config, # note that we do everything through config,
# since we want to be able to compare bitmap-aware # since we want to be able to compare bitmap-aware
# git versus non-bitmap git # git versus non-bitmap git
# #
# We intentionally use the deprecated pack.writebitmaps # We intentionally use the deprecated pack.writebitmaps
# config so that we can test against older versions of git. # config so that we can test against older versions of git.
test_expect_success 'setup bitmap config' ' test_expect_success 'setup bitmap config' '
git config pack.writebitmaps true git config pack.writebitmaps true
' '


# we need to create the tag up front such that it is covered by the repack and # we need to create the tag up front such that it is covered by the repack and
# thus by generated bitmaps. # thus by generated bitmaps.
test_expect_success 'create tags' ' test_expect_success 'create tags' '
git tag --message="tag pointing to HEAD" perf-tag HEAD git tag --message="tag pointing to HEAD" perf-tag HEAD
' '


test_perf "enable lookup table: $1" ' test_pack_bitmap
git config pack.writeBitmapLookupTable '"$1"'
'

test_pack_bitmap
}

test_lookup_pack_bitmap false
test_lookup_pack_bitmap true


test_done test_done

78
t/perf/p5311-pack-bitmaps-fetch.sh
View File

@ -3,52 +3,46 @@
test_description='performance of fetches from bitmapped packs' test_description='performance of fetches from bitmapped packs'
. ./perf-lib.sh . ./perf-lib.sh


test_fetch_bitmaps () { test_expect_success 'setup test directory' '
test_expect_success 'setup test directory' ' rm -fr * .git
rm -fr * .git '

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_perf_default_repo test_perf "server $title" '

git pack-objects --stdout --revs \
test_expect_success 'create bitmapped server repo' ' --thin --delta-base-offset \
git config pack.writebitmaps true && <revs >tmp.pack
git config pack.writeBitmapLookupTable '"$1"' &&
git repack -ad
' '


# simulate a fetch from a repository that last fetched N days ago, for test_size "size $title" '
# various values of N. We do so by following the first-parent chain, test_file_size tmp.pack
# and assume the first entry in the chain that is N days older than the current '
# HEAD is where the HEAD would have been then.
for days in 1 2 4 8 16 32 64 128; do
title=$(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 "server $title (lookup=$1)" ' test_perf "client $title" '
git pack-objects --stdout --revs \ git index-pack --stdin --fix-thin <tmp.pack
--thin --delta-base-offset \ '
<revs >tmp.pack done
'

test_size "size $title" '
test_file_size 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 test_done

85
t/perf/p5326-multi-pack-bitmaps.sh
View File

@ -4,64 +4,53 @@ test_description='Tests performance using midx bitmaps'
. ./perf-lib.sh . ./perf-lib.sh
. "${TEST_DIRECTORY}/perf/lib-bitmap.sh" . "${TEST_DIRECTORY}/perf/lib-bitmap.sh"


test_bitmap () { test_expect_success "remove existing repo" '
local enabled="$1" rm -fr * .git
'


test_expect_success "remove existing repo (lookup=$enabled)" ' test_perf_large_repo
rm -fr * .git
'


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
'


# we need to create the tag up front such that it is covered by the repack and test_expect_success "start with bitmapped pack" '
# thus by generated bitmaps. git repack -adb
test_expect_success 'create tags' ' '
git tag --message="tag pointing to HEAD" perf-tag HEAD
'


test_expect_success "use lookup table: $enabled" ' test_perf "setup multi-pack index" '
git config pack.writeBitmapLookupTable '"$enabled"' git multi-pack-index write --bitmap
' '


test_expect_success "start with bitmapped pack (lookup=$enabled)" ' test_expect_success "drop pack bitmap" '
git repack -adb rm -f .git/objects/pack/pack-*.bitmap
' '


test_perf "setup multi-pack index (lookup=$enabled)" ' test_full_bitmap
git multi-pack-index write --bitmap
'


test_expect_success "drop pack bitmap (lookup=$enabled)" ' test_expect_success "create partial bitmap state" '
rm -f .git/objects/pack/pack-*.bitmap # pick a commit to represent the repo tip in the past
' cutoff=$(git rev-list HEAD~100 -1) &&
orig_tip=$(git rev-parse HEAD) &&


test_full_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 "create partial bitmap state (lookup=$enabled)" ' # and then repack, which will leave us with a nice
# pick a commit to represent the repo tip in the past # big bitmap pack of the "old" history, and all of
cutoff=$(git rev-list HEAD~100 -1) && # the new history will be loose, as if it had been pushed
orig_tip=$(git rev-parse HEAD) && # up incrementally and exploded via unpack-objects
git repack -Ad &&
git multi-pack-index write --bitmap &&


# now pretend we have just one tip # and now restore our original tip, as if the pushes
rm -rf .git/logs .git/refs/* .git/packed-refs && # had happened
git update-ref HEAD $cutoff && git update-ref HEAD $orig_tip
'


# and then repack, which will leave us with a nice test_partial_bitmap
# 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 test_done

1
t/perf/p5333-pseudo-merge-bitmaps.sh
View File

@ -11,7 +11,6 @@ test_expect_success 'setup' '
-c bitmapPseudoMerge.all.threshold=now \ -c bitmapPseudoMerge.all.threshold=now \
-c bitmapPseudoMerge.all.stableThreshold=never \ -c bitmapPseudoMerge.all.stableThreshold=never \
-c bitmapPseudoMerge.all.maxMerges=64 \ -c bitmapPseudoMerge.all.maxMerges=64 \
-c pack.writeBitmapLookupTable=true \
repack -adb repack -adb
' '