diff --git a/src/monitoring_experiments.ml b/src/monitoring_experiments.ml
index 7555890..a683b5d 100644
--- a/src/monitoring_experiments.ml
+++ b/src/monitoring_experiments.ml
@@ -91,7 +91,7 @@ module Make (T : Mirage_time.S) (S : Tcpip.Stack.V4V6) = struct
     Metrics.set_reporter reporter;
     Metrics.enable_all ();
     Metrics_lwt.init_periodic (fun () -> T.sleep_ns (Duration.of_sec interval));
-    Metrics_lwt.periodically (OS.MM.malloc_metrics ~tags:Metrics.Tags.[]);
+    Metrics_lwt.periodically (OS.MM.malloc_metrics ~tags:Metrics.Tags.[])[@warning "-3"];
     Metrics_lwt.periodically (memory_metrics ~tags:Metrics.Tags.[]);
     let host = match hostname with None -> [] | Some host -> [vmname host] in
     Lwt.async (timer_loop get_cache host interval stack (dst, port))