3 files changed, 115 insertions, 62 deletions
diff --git a/t/perf/lib-bitmap.sh b/t/perf/lib-bitmap.sh
new file mode 100644
index 0000000000..63d3bc7cec
--- /dev/null
+++ b/t/perf/lib-bitmap.sh
@@ -0,0 +1,69 @@
+# Helper functions for testing bitmap performance; see p5310.
+
+test_full_bitmap () {
+	test_perf 'simulated clone' '
+		git pack-objects --stdout --all </dev/null >/dev/null
+	'
+
+	test_perf 'simulated fetch' '
+		have=$(git rev-list HEAD~100 -1) &&
+		{
+			echo HEAD &&
+			echo ^$have
+		} | git pack-objects --revs --stdout >/dev/null
+	'
+
+	test_perf 'pack to file (bitmap)' '
+		git pack-objects --use-bitmap-index --all pack1b </dev/null >/dev/null
+	'
+
+	test_perf 'rev-list (commits)' '
+		git rev-list --all --use-bitmap-index >/dev/null
+	'
+
+	test_perf 'rev-list (objects)' '
+		git rev-list --all --use-bitmap-index --objects >/dev/null
+	'
+
+	test_perf 'rev-list with tag negated via --not --all (objects)' '
+		git rev-list perf-tag --not --all --use-bitmap-index --objects >/dev/null
+	'
+
+	test_perf 'rev-list with negative tag (objects)' '
+		git rev-list HEAD --not perf-tag --use-bitmap-index --objects >/dev/null
+	'
+
+	test_perf 'rev-list count with blob:none' '
+		git rev-list --use-bitmap-index --count --objects --all \
+			--filter=blob:none >/dev/null
+	'
+
+	test_perf 'rev-list count with blob:limit=1k' '
+		git rev-list --use-bitmap-index --count --objects --all \
+			--filter=blob:limit=1k >/dev/null
+	'
+
+	test_perf 'rev-list count with tree:0' '
+		git rev-list --use-bitmap-index --count --objects --all \
+			--filter=tree:0 >/dev/null
+	'
+
+	test_perf 'simulated partial clone' '
+		git pack-objects --stdout --all --filter=blob:none </dev/null >/dev/null
+	'
+}
+
+test_partial_bitmap () {
+	test_perf 'clone (partial bitmap)' '
+		git pack-objects --stdout --all </dev/null >/dev/null
+	'
+
+	test_perf 'pack to file (partial bitmap)' '
+		git pack-objects --use-bitmap-index --all pack2b </dev/null >/dev/null
+	'
+
+	test_perf 'rev-list with tree filter (partial bitmap)' '
+		git rev-list --use-bitmap-index --count --objects --all \
+			--filter=tree:0 >/dev/null
+	'
+}
diff --git a/t/perf/p5310-pack-bitmaps.sh b/t/perf/p5310-pack-bitmaps.sh
index 452be01056..7ad4f237bc 100755
--- a/t/perf/p5310-pack-bitmaps.sh
+++ b/t/perf/p5310-pack-bitmaps.sh
@@ -2,6 +2,7 @@
 
 test_description='Tests pack performance using bitmaps'
 . ./perf-lib.sh
+. "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
 
 test_perf_large_repo
 
@@ -25,56 +26,7 @@ test_perf 'repack to disk' '
 	git repack -ad
 '
 
-test_perf 'simulated clone' '
-	git pack-objects --stdout --all </dev/null >/dev/null
-'
-
-test_perf 'simulated fetch' '
-	have=$(git rev-list HEAD~100 -1) &&
-	{
-		echo HEAD &&
-		echo ^$have
-	} | git pack-objects --revs --stdout >/dev/null
-'
-
-test_perf 'pack to file (bitmap)' '
-	git pack-objects --use-bitmap-index --all pack1b </dev/null >/dev/null
-'
-
-test_perf 'rev-list (commits)' '
-	git rev-list --all --use-bitmap-index >/dev/null
-'
-
-test_perf 'rev-list (objects)' '
-	git rev-list --all --use-bitmap-index --objects >/dev/null
-'
-
-test_perf 'rev-list with tag negated via --not --all (objects)' '
-	git rev-list perf-tag --not --all --use-bitmap-index --objects >/dev/null
-'
-
-test_perf 'rev-list with negative tag (objects)' '
-	git rev-list HEAD --not perf-tag --use-bitmap-index --objects >/dev/null
-'
-
-test_perf 'rev-list count with blob:none' '
-	git rev-list --use-bitmap-index --count --objects --all \
-		--filter=blob:none >/dev/null
-'
-
-test_perf 'rev-list count with blob:limit=1k' '
-	git rev-list --use-bitmap-index --count --objects --all \
-		--filter=blob:limit=1k >/dev/null
-'
-
-test_perf 'rev-list count with tree:0' '
-	git rev-list --use-bitmap-index --count --objects --all \
-		--filter=tree:0 >/dev/null
-'
-
-test_perf 'simulated partial clone' '
-	git pack-objects --stdout --all --filter=blob:none </dev/null >/dev/null
-'
+test_full_bitmap
 
 test_expect_success 'create partial bitmap state' '
 	# pick a commit to represent the repo tip in the past
@@ -97,17 +49,6 @@ test_expect_success 'create partial bitmap state' '
 	git update-ref HEAD $orig_tip
 '
 
-test_perf 'clone (partial bitmap)' '
-	git pack-objects --stdout --all </dev/null >/dev/null
-'
-
-test_perf 'pack to file (partial bitmap)' '
-	git pack-objects --use-bitmap-index --all pack2b </dev/null >/dev/null
-'
-
-test_perf 'rev-list with tree filter (partial bitmap)' '
-	git rev-list --use-bitmap-index --count --objects --all \
-		--filter=tree:0 >/dev/null
-'
+test_partial_bitmap
 
 test_done
diff --git a/t/perf/p5326-multi-pack-bitmaps.sh b/t/perf/p5326-multi-pack-bitmaps.sh
new file mode 100755
index 0000000000..5845109ac7
--- /dev/null
+++ b/t/perf/p5326-multi-pack-bitmaps.sh
@@ -0,0 +1,43 @@
+#!/bin/sh
+
+test_description='Tests performance using midx bitmaps'
+. ./perf-lib.sh
+. "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
+
+test_perf_large_repo
+
+test_expect_success 'enable multi-pack index' '
+	git config core.multiPackIndex true
+'
+
+test_perf 'setup multi-pack index' '
+	git repack -ad &&
+	git multi-pack-index write --bitmap
+'
+
+test_full_bitmap
+
+test_expect_success 'create partial bitmap state' '
+	# pick a commit to represent the repo tip in the past
+	cutoff=$(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_done