diff --git a/test/-ext-/gvl/test_last_thread.rb b/test/-ext-/gvl/test_last_thread.rb
index f63d98aab16f02..bcda0e33856c51 100644
--- a/test/-ext-/gvl/test_last_thread.rb
+++ b/test/-ext-/gvl/test_last_thread.rb
@@ -15,7 +15,7 @@ def test_last_thread
       t1 = Time.now
       t = t1 - t0
 
-      assert_in_delta(1.0, t, 0.18)
+      assert_in_delta(1.0, t, 0.8)
     end;
   end
 end