diff --git a/revision.c b/revision.c
index 553c0faa9b..7e73dafd96 100644
--- a/revision.c
+++ b/revision.c
@@ -3271,7 +3271,7 @@ static int mark_uninteresting(const struct object_id *oid,
 			      void *cb)
 {
 	struct rev_info *revs = cb;
-	struct object *o = parse_object(revs->repo, oid);
+	struct object *o = lookup_unknown_object(revs->repo, oid);
 	o->flags |= UNINTERESTING | SEEN;
 	return 0;
 }
diff --git a/t/perf/p5600-partial-clone.sh b/t/perf/p5600-partial-clone.sh
index 754aaec3dc..ca785a3341 100755
--- a/t/perf/p5600-partial-clone.sh
+++ b/t/perf/p5600-partial-clone.sh
@@ -27,4 +27,12 @@ test_perf 'fsck' '
 	git -C bare.git fsck
 '
 
+test_perf 'count commits' '
+	git -C bare.git rev-list --all --count
+'
+
+test_perf 'count non-promisor commits' '
+	git -C bare.git rev-list --all --count --exclude-promisor-objects
+'
+
 test_done