20 files changed, 606 insertions, 135 deletions
diff --git a/t/perf/README b/t/perf/README
index fb9127a..8f217d7 100644
--- a/t/perf/README
+++ b/t/perf/README
@@ -95,6 +95,10 @@ You can set the following variables (also in your config.mak):
 	Git (e.g., performance of index-pack as the number of threads
 	changes). These can be enabled with GIT_PERF_EXTRA.
 
+    GIT_PERF_USE_SCALAR
+	Boolean indicating whether to register test repo(s) with Scalar
+	before executing tests.
+
 You can also pass the options taken by ordinary git tests; the most
 useful one is:
 
diff --git a/t/perf/lib-bitmap.sh b/t/perf/lib-bitmap.sh
index 63d3bc7..55a8feb 100644
--- a/t/perf/lib-bitmap.sh
+++ b/t/perf/lib-bitmap.sh
@@ -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
+}
diff --git a/t/perf/p0004-lazy-init-name-hash.sh b/t/perf/p0004-lazy-init-name-hash.sh
index 1afc08f..85be14e 100755
--- a/t/perf/p0004-lazy-init-name-hash.sh
+++ b/t/perf/p0004-lazy-init-name-hash.sh
@@ -49,7 +49,7 @@ test_perf "single-threaded, $desc" "
 	test-tool lazy-init-name-hash --single --count=$count
 "
 
-test_perf REPO_BIG_ENOUGH_FOR_MULTI "multi-threaded, $desc" "
+test_perf "multi-threaded, $desc" --prereq REPO_BIG_ENOUGH_FOR_MULTI "
 	test-tool lazy-init-name-hash --multi --count=$count
 "
 
diff --git a/t/perf/p0006-read-tree-checkout.sh b/t/perf/p0006-read-tree-checkout.sh
index 900b385..325566e 100755
--- a/t/perf/p0006-read-tree-checkout.sh
+++ b/t/perf/p0006-read-tree-checkout.sh
@@ -46,7 +46,15 @@ test_expect_success "setup repo" '
 '
 
 test_perf "read-tree br_base br_ballast ($nr_files)" '
-	git read-tree -m br_base br_ballast -n
+	git read-tree -n -m br_base br_ballast
+'
+
+test_perf "read-tree br_ballast_plus_1 ($nr_files)" '
+	# Run read-tree 100 times for clearer performance results & comparisons
+	for i in  $(test_seq 100)
+	do
+		git read-tree -n -m br_ballast_plus_1 || return 1
+	done
 '
 
 test_perf "switch between br_base br_ballast ($nr_files)" '
diff --git a/t/perf/p0090-cache-tree.sh b/t/perf/p0090-cache-tree.sh
new file mode 100755
index 0000000..a8eabca
--- /dev/null
+++ b/t/perf/p0090-cache-tree.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+test_description="Tests performance of cache tree update operations"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+count=100
+
+test_expect_success 'setup cache tree' '
+	git write-tree
+'
+
+test_cache_tree () {
+	test_perf "$1, $3" "
+		for i in \$(test_seq $count)
+		do
+			test-tool cache-tree $4 $2
+		done
+	"
+}
+
+test_cache_tree_update_functions () {
+	test_cache_tree 'no-op' 'control' "$1" "$2"
+	test_cache_tree 'prime_cache_tree' 'prime' "$1" "$2"
+	test_cache_tree 'cache_tree_update' 'update' "$1" "$2"
+}
+
+test_cache_tree_update_functions "clean" ""
+test_cache_tree_update_functions "invalidate 2" "--invalidate 2"
+test_cache_tree_update_functions "invalidate 50" "--invalidate 50"
+test_cache_tree_update_functions "empty" "--empty"
+
+test_done
diff --git a/t/perf/p1500-graph-walks.sh b/t/perf/p1500-graph-walks.sh
new file mode 100755
index 0000000..e14e762
--- /dev/null
+++ b/t/perf/p1500-graph-walks.sh
@@ -0,0 +1,50 @@
+#!/bin/sh
+
+test_description='Commit walk performance tests'
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+test_expect_success 'setup' '
+	git for-each-ref --format="%(refname)" "refs/heads/*" "refs/tags/*" >allrefs &&
+	sort -r allrefs | head -n 50 >refs &&
+	for ref in $(cat refs)
+	do
+		git branch -f ref-$ref $ref &&
+		echo ref-$ref ||
+		return 1
+	done >branches &&
+	for ref in $(cat refs)
+	do
+		git tag -f tag-$ref $ref &&
+		echo tag-$ref ||
+		return 1
+	done >tags &&
+	git commit-graph write --reachable
+'
+
+test_perf 'ahead-behind counts: git for-each-ref' '
+	git for-each-ref --format="%(ahead-behind:HEAD)" --stdin <refs
+'
+
+test_perf 'ahead-behind counts: git branch' '
+	xargs git branch -l --format="%(ahead-behind:HEAD)" <branches
+'
+
+test_perf 'ahead-behind counts: git tag' '
+	xargs git tag -l --format="%(ahead-behind:HEAD)" <tags
+'
+
+test_perf 'contains: git for-each-ref --merged' '
+	git for-each-ref --merged=HEAD --stdin <refs
+'
+
+test_perf 'contains: git branch --merged' '
+	xargs git branch --merged=HEAD <branches
+'
+
+test_perf 'contains: git tag --merged' '
+	xargs git tag --merged=HEAD <tags
+'
+
+test_done
diff --git a/t/perf/p2000-sparse-operations.sh b/t/perf/p2000-sparse-operations.sh
index c181110..39e92b0 100755
--- a/t/perf/p2000-sparse-operations.sh
+++ b/t/perf/p2000-sparse-operations.sh
@@ -43,6 +43,7 @@ test_expect_success 'setup repo and indexes' '
 	done &&
 
 	git sparse-checkout init --cone &&
+	git tag -a v1.0 -m "Final" &&
 	git sparse-checkout set $SPARSE_CONE &&
 	git checkout -b wide $OLD_COMMIT &&
 
@@ -123,5 +124,16 @@ test_perf_on_all git blame $SPARSE_CONE/f3/a
 test_perf_on_all git read-tree -mu HEAD
 test_perf_on_all git checkout-index -f --all
 test_perf_on_all git update-index --add --remove $SPARSE_CONE/a
+test_perf_on_all "git rm -f $SPARSE_CONE/a && git checkout HEAD -- $SPARSE_CONE/a"
+test_perf_on_all git grep --cached bogus -- "f2/f1/f1/*"
+test_perf_on_all git write-tree
+test_perf_on_all git describe --dirty
+test_perf_on_all 'echo >>new && git describe --dirty'
+test_perf_on_all git diff-files
+test_perf_on_all git diff-files -- $SPARSE_CONE/a
+test_perf_on_all git diff-tree HEAD
+test_perf_on_all git diff-tree HEAD -- $SPARSE_CONE/a
+test_perf_on_all "git worktree add ../temp && git worktree remove ../temp"
+test_perf_on_all git check-attr -a -- $SPARSE_CONE/a
 
 test_done
diff --git a/t/perf/p5310-pack-bitmaps.sh b/t/perf/p5310-pack-bitmaps.sh
index 7ad4f23..b1399f1 100755
--- a/t/perf/p5310-pack-bitmaps.sh
+++ b/t/perf/p5310-pack-bitmaps.sh
@@ -4,51 +4,37 @@ test_description='Tests pack performance using bitmaps'
 . ./perf-lib.sh
 . "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
 
-test_perf_large_repo
-
-# 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
-'
-
-# 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 '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
+test_lookup_pack_bitmap () {
+	test_expect_success 'start the test from scratch' '
+		rm -rf * .git
+	'
+
+	test_perf_large_repo
+
+	# 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
+	'
+
+	# 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
diff --git a/t/perf/p5311-pack-bitmaps-fetch.sh b/t/perf/p5311-pack-bitmaps-fetch.sh
index 47c3fd7..426fab8 100755
--- a/t/perf/p5311-pack-bitmaps-fetch.sh
+++ b/t/perf/p5311-pack-bitmaps-fetch.sh
@@ -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_size "size   $title" '
-		wc -c <tmp.pack
+	test_expect_success 'create bitmapped server repo' '
+		git config pack.writebitmaps true &&
+		git config pack.writeBitmapLookupTable '"$1"' &&
+		git repack -ad
 	'
 
-	test_perf "client $title" '
-		git index-pack --stdin --fix-thin <tmp.pack
-	'
-done
+	# simulate a fetch from a repository that last fetched N days ago, for
+	# various values of N. We do so by following the first-parent chain,
+	# and assume the first entry in the chain that is N days older than the current
+	# HEAD is where the HEAD would have been then.
+	for days in 1 2 4 8 16 32 64 128; do
+		title=$(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 "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
diff --git a/t/perf/p5312-pack-bitmaps-revs.sh b/t/perf/p5312-pack-bitmaps-revs.sh
new file mode 100755
index 0000000..ceec606
--- /dev/null
+++ b/t/perf/p5312-pack-bitmaps-revs.sh
@@ -0,0 +1,34 @@
+#!/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
+	'
+
+	# 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 '"$1"'
+	'
+
+	test_pack_bitmap
+}
+
+test_lookup_pack_bitmap false
+test_lookup_pack_bitmap true
+
+test_done
diff --git a/t/perf/p5326-multi-pack-bitmaps.sh b/t/perf/p5326-multi-pack-bitmaps.sh
index f2fa228..d082e6c 100755
--- a/t/perf/p5326-multi-pack-bitmaps.sh
+++ b/t/perf/p5326-multi-pack-bitmaps.sh
@@ -4,49 +4,64 @@ test_description='Tests performance using midx bitmaps'
 . ./perf-lib.sh
 . "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
 
-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
-'
-
-test_expect_success 'start with bitmapped pack' '
-	git repack -adb
-'
-
-test_perf 'setup multi-pack index' '
-	git multi-pack-index write --bitmap
-'
-
-test_expect_success 'drop pack bitmap' '
-	rm -f .git/objects/pack/pack-*.bitmap
-'
-
-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 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 () {
+	local enabled="$1"
+
+	test_expect_success "remove existing repo (lookup=$enabled)" '
+		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
+	'
+
+	test_expect_success "use lookup table: $enabled" '
+		git config pack.writeBitmapLookupTable '"$enabled"'
+	'
+
+	test_expect_success "start with bitmapped pack (lookup=$enabled)" '
+		git repack -adb
+	'
+
+	test_perf "setup multi-pack index (lookup=$enabled)" '
+		git multi-pack-index write --bitmap
+	'
+
+	test_expect_success "drop pack bitmap (lookup=$enabled)" '
+		rm -f .git/objects/pack/pack-*.bitmap
+	'
+
+	test_full_bitmap
+
+	test_expect_success "create partial bitmap state (lookup=$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) &&
+
+		# 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
diff --git a/t/perf/p5332-multi-pack-reuse.sh b/t/perf/p5332-multi-pack-reuse.sh
new file mode 100755
index 0000000..5c6c575
--- /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
diff --git a/t/perf/p6300-for-each-ref.sh b/t/perf/p6300-for-each-ref.sh
new file mode 100755
index 0000000..fa7289c
--- /dev/null
+++ b/t/perf/p6300-for-each-ref.sh
@@ -0,0 +1,87 @@
+#!/bin/sh
+
+test_description='performance of for-each-ref'
+. ./perf-lib.sh
+
+test_perf_fresh_repo
+
+ref_count_per_type=10000
+test_iteration_count=10
+
+test_expect_success "setup" '
+	test_commit_bulk $(( 1 + $ref_count_per_type )) &&
+
+	# Create refs
+	test_seq $ref_count_per_type |
+		sed "s,.*,update refs/heads/branch_& HEAD~&\nupdate refs/custom/special_& HEAD~&," |
+		git update-ref --stdin &&
+
+	# Create annotated tags
+	for i in $(test_seq $ref_count_per_type)
+	do
+		# Base tags
+		echo "tag tag_$i" &&
+		echo "mark :$i" &&
+		echo "from HEAD~$i" &&
+		printf "tagger %s <%s> %s\n" \
+			"$GIT_COMMITTER_NAME" \
+			"$GIT_COMMITTER_EMAIL" \
+			"$GIT_COMMITTER_DATE" &&
+		echo "data <<EOF" &&
+		echo "tag $i" &&
+		echo "EOF" &&
+
+		# Nested tags
+		echo "tag nested_$i" &&
+		echo "from :$i" &&
+		printf "tagger %s <%s> %s\n" \
+			"$GIT_COMMITTER_NAME" \
+			"$GIT_COMMITTER_EMAIL" \
+			"$GIT_COMMITTER_DATE" &&
+		echo "data <<EOF" &&
+		echo "nested tag $i" &&
+		echo "EOF" || return 1
+	done | git fast-import
+'
+
+test_for_each_ref () {
+	title="for-each-ref"
+	if test $# -gt 0; then
+		title="$title ($1)"
+		shift
+	fi
+	args="$@"
+
+	test_perf "$title" "
+		for i in \$(test_seq $test_iteration_count); do
+			git for-each-ref $args >/dev/null
+		done
+	"
+}
+
+run_tests () {
+	test_for_each_ref "$1"
+	test_for_each_ref "$1, no sort" --no-sort
+	test_for_each_ref "$1, --count=1" --count=1
+	test_for_each_ref "$1, --count=1, no sort" --no-sort --count=1
+	test_for_each_ref "$1, tags" refs/tags/
+	test_for_each_ref "$1, tags, no sort" --no-sort refs/tags/
+	test_for_each_ref "$1, tags, dereferenced" '--format="%(refname) %(objectname) %(*objectname)"' refs/tags/
+	test_for_each_ref "$1, tags, dereferenced, no sort" --no-sort '--format="%(refname) %(objectname) %(*objectname)"' refs/tags/
+
+	test_perf "for-each-ref ($1, tags) + cat-file --batch-check (dereferenced)" "
+		for i in \$(test_seq $test_iteration_count); do
+			git for-each-ref --format='%(objectname)^{} %(refname) %(objectname)' refs/tags/ | \
+				git cat-file --batch-check='%(objectname) %(rest)' >/dev/null
+		done
+	"
+}
+
+run_tests "loose"
+
+test_expect_success 'pack refs' '
+	git pack-refs --all
+'
+run_tests "packed"
+
+test_done
diff --git a/t/perf/p7102-reset.sh b/t/perf/p7102-reset.sh
new file mode 100755
index 0000000..9b039e8
--- /dev/null
+++ b/t/perf/p7102-reset.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+test_description='performance of reset'
+. ./perf-lib.sh
+
+test_perf_default_repo
+test_checkout_worktree
+
+test_perf 'reset --hard with change in tree' '
+	base=$(git rev-parse HEAD) &&
+	test_commit --no-tag A &&
+	new=$(git rev-parse HEAD) &&
+
+	for i in $(test_seq 10)
+	do
+		git reset --hard $new &&
+		git reset --hard $base || return $?
+	done
+'
+
+test_done
diff --git a/t/perf/p7527-builtin-fsmonitor.sh b/t/perf/p7527-builtin-fsmonitor.sh
index 9338b9e..c3f9a4c 100755
--- a/t/perf/p7527-builtin-fsmonitor.sh
+++ b/t/perf/p7527-builtin-fsmonitor.sh
@@ -249,7 +249,7 @@ test_expect_success "Cleanup temp and matrix branches" "
 	do
 		for fsm_val in $fsm_values
 		do
-			cleanup $uc_val $fsm_val
+			cleanup $uc_val $fsm_val || return 1
 		done
 	done
 "
diff --git a/t/perf/p7822-grep-perl-character.sh b/t/perf/p7822-grep-perl-character.sh
new file mode 100755
index 0000000..87009c6
--- /dev/null
+++ b/t/perf/p7822-grep-perl-character.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+
+test_description="git-grep's perl regex
+
+If GIT_PERF_GREP_THREADS is set to a list of threads (e.g. '1 4 8'
+etc.) we will test the patterns under those numbers of threads.
+"
+
+. ./perf-lib.sh
+
+test_perf_large_repo
+test_checkout_worktree
+
+if test -n "$GIT_PERF_GREP_THREADS"
+then
+	test_set_prereq PERF_GREP_ENGINES_THREADS
+fi
+
+for pattern in \
+	'\\bhow' \
+	'\\bÆvar' \
+	'\\d+ \\bÆvar' \
+	'\\bBelón\\b' \
+	'\\w{12}\\b'
+do
+	echo '$pattern' >pat
+	if ! test_have_prereq PERF_GREP_ENGINES_THREADS
+	then
+		test_perf "grep -P '$pattern'" --prereq PCRE "
+			git -P grep -f pat || :
+		"
+	else
+		for threads in $GIT_PERF_GREP_THREADS
+		do
+			test_perf "grep -P '$pattern' with $threads threads" --prereq PTHREADS,PCRE "
+				git -c grep.threads=$threads -P grep -f pat || :
+			"
+		done
+	fi
+done
+
+test_done
diff --git a/t/perf/p9210-scalar.sh b/t/perf/p9210-scalar.sh
new file mode 100755
index 0000000..265f7cd
--- /dev/null
+++ b/t/perf/p9210-scalar.sh
@@ -0,0 +1,39 @@
+#!/bin/sh
+
+test_description='test scalar performance'
+. ./perf-lib.sh
+
+test_perf_large_repo "$TRASH_DIRECTORY/to-clone"
+
+test_expect_success 'enable server-side partial clone' '
+	git -C to-clone config uploadpack.allowFilter true &&
+	git -C to-clone config uploadpack.allowAnySHA1InWant true
+'
+
+test_perf 'scalar clone' '
+	rm -rf scalar-clone &&
+	scalar clone "file://$(pwd)/to-clone" scalar-clone
+'
+
+test_perf 'git clone' '
+	rm -rf git-clone &&
+	git clone "file://$(pwd)/to-clone" git-clone
+'
+
+test_compare_perf () {
+	command=$1
+	shift
+	args=$*
+	test_perf "$command $args (scalar)" "
+		$command -C scalar-clone/src $args
+	"
+
+	test_perf "$command $args (non-scalar)" "
+		$command -C git-clone $args
+	"
+}
+
+test_compare_perf git status
+test_compare_perf test_commit --append --no-tag A
+
+test_done
diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
index 27c2801..ab0c763 100644
--- a/t/perf/perf-lib.sh
+++ b/t/perf/perf-lib.sh
@@ -15,7 +15,7 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this program.  If not, see http://www.gnu.org/licenses/ .
+# along with this program.  If not, see https://www.gnu.org/licenses/ .
 
 # These variables must be set before the inclusion of test-lib.sh below,
 # because it will change our working directory.
@@ -31,7 +31,7 @@ unset GIT_CONFIG_NOSYSTEM
 GIT_CONFIG_SYSTEM="$TEST_DIRECTORY/perf/config"
 export GIT_CONFIG_SYSTEM
 
-if test -n "$GIT_TEST_INSTALLED" -a -z "$PERF_SET_GIT_TEST_INSTALLED"
+if test -n "$GIT_TEST_INSTALLED" && test -z "$PERF_SET_GIT_TEST_INSTALLED"
 then
 	error "Do not use GIT_TEST_INSTALLED with the perf tests.
 
@@ -49,6 +49,9 @@ export TEST_DIRECTORY TRASH_DIRECTORY GIT_BUILD_DIR GIT_TEST_CMP
 MODERN_GIT=$GIT_BUILD_DIR/bin-wrappers/git
 export MODERN_GIT
 
+MODERN_SCALAR=$GIT_BUILD_DIR/bin-wrappers/scalar
+export MODERN_SCALAR
+
 perf_results_dir=$TEST_RESULTS_DIR
 test -n "$GIT_PERF_SUBSECTION" && perf_results_dir="$perf_results_dir/$GIT_PERF_SUBSECTION"
 mkdir -p "$perf_results_dir"
@@ -120,6 +123,10 @@ test_perf_create_repo_from () {
 			# status" due to a locked index. Since we have
 			# a copy it's fine to remove the lock.
 			rm .git/index.lock
+		fi &&
+		if test_bool_env GIT_PERF_USE_SCALAR false
+		then
+			"$MODERN_SCALAR" register
 		fi
 	) || error "failed to copy repository '$source' to '$repo'"
 }
@@ -130,7 +137,11 @@ test_perf_fresh_repo () {
 	"$MODERN_GIT" init -q "$repo" &&
 	(
 		cd "$repo" &&
-		test_perf_do_repo_symlink_config_
+		test_perf_do_repo_symlink_config_ &&
+		if test_bool_env GIT_PERF_USE_SCALAR false
+		then
+			"$MODERN_SCALAR" register
+		fi
 	)
 }
 
diff --git a/t/perf/repos/inflate-repo.sh b/t/perf/repos/inflate-repo.sh
index fcfc992..412e4b4 100755
--- a/t/perf/repos/inflate-repo.sh
+++ b/t/perf/repos/inflate-repo.sh
@@ -33,7 +33,7 @@ do
 done
 
 git ls-tree -r HEAD >GEN_src_list
-nr_src_files=$(cat GEN_src_list | wc -l)
+nr_src_files=$(wc -l <GEN_src_list)
 
 src_branch=$(git symbolic-ref --short HEAD)
 
diff --git a/t/perf/run b/t/perf/run
index 55219aa..486ead2 100755
--- a/t/perf/run
+++ b/t/perf/run
@@ -91,10 +91,10 @@ set_git_test_installed () {
 run_dirs_helper () {
 	mydir=${1%/}
 	shift
-	while test $# -gt 0 -a "$1" != -- -a ! -f "$1"; do
+	while test $# -gt 0 && test "$1" != -- && test ! -f "$1"; do
 		shift
 	done
-	if test $# -gt 0 -a "$1" = --; then
+	if test $# -gt 0 && test "$1" = --; then
 		shift
 	fi
 
@@ -124,7 +124,7 @@ run_dirs_helper () {
 }
 
 run_dirs () {
-	while test $# -gt 0 -a "$1" != -- -a ! -f "$1"; do
+	while test $# -gt 0 && test "$1" != -- && test ! -f "$1"; do
 		run_dirs_helper "$@"
 		shift
 	done
@@ -171,13 +171,17 @@ run_subsection () {
 	get_var_from_env_or_config "GIT_PERF_MAKE_COMMAND" "perf" "makeCommand"
 	get_var_from_env_or_config "GIT_PERF_MAKE_OPTS" "perf" "makeOpts"
 
+	get_var_from_env_or_config "GIT_PERF_USE_SCALAR" "perf" "useScalar" "--bool"
+	export GIT_PERF_USE_SCALAR
+
 	get_var_from_env_or_config "GIT_PERF_REPO_NAME" "perf" "repoName"
 	export GIT_PERF_REPO_NAME
 
 	GIT_PERF_AGGREGATING_LATER=t
 	export GIT_PERF_AGGREGATING_LATER
 
-	if test $# = 0 -o "$1" = -- -o -f "$1"; then
+	if test $# = 0 || test "$1" = -- || test -f "$1"
+	then
 		set -- . "$@"
 	fi
 
@@ -229,10 +233,10 @@ then
 	)
 elif test -n "$GIT_PERF_SUBSECTION"
 then
-	egrep "^$GIT_PERF_SUBSECTION\$" "$TEST_RESULTS_DIR"/run_subsections.names >/dev/null ||
+	grep -E "^$GIT_PERF_SUBSECTION\$" "$TEST_RESULTS_DIR"/run_subsections.names >/dev/null ||
 		die "subsection '$GIT_PERF_SUBSECTION' not found in '$GIT_PERF_CONFIG_FILE'"
 
-	egrep "^$GIT_PERF_SUBSECTION\$" "$TEST_RESULTS_DIR"/run_subsections.names | while read -r subsec
+	grep -E "^$GIT_PERF_SUBSECTION\$" "$TEST_RESULTS_DIR"/run_subsections.names | while read -r subsec
 	do
 		(
 			GIT_PERF_SUBSECTION="$subsec"