diff --git a/benchmark/array_sample.yml b/benchmark/array_sample.yml
index 4449ffd0e0..1cd2b34794 100644
--- a/benchmark/array_sample.yml
+++ b/benchmark/array_sample.yml
@@ -1,4 +1,3 @@
-
 prelude: ary = (1..10_000).to_a
 benchmark:
   - ary.sample
diff --git a/benchmark/time_at.yml b/benchmark/time_at.yml
index 4fd082e478..3247efbe77 100644
--- a/benchmark/time_at.yml
+++ b/benchmark/time_at.yml
@@ -1,3 +1,5 @@
+prelude: |
+  # frozen_string_literal: true
 benchmark:
   - 'Time.at(0)'
   - 'Time.at(0, 500)'