diff --git a/daemon/fw/asf-measurements.hpp b/daemon/fw/asf-measurements.hpp
index 64f88c2..205219d 100644
--- a/daemon/fw/asf-measurements.hpp
+++ b/daemon/fw/asf-measurements.hpp
@@ -131,7 +131,7 @@
   }
 
   void
-  recordRtt(const shared_ptr<pit::Entry> pitEntry, const Face& inFace);
+  recordRtt(const shared_ptr<pit::Entry>& pitEntry, const Face& inFace);
 
   void
   recordTimeout(const ndn::Name& interestName);