diff --git a/pid/builder.cpp b/pid/builder.cpp
index 1164355..afb6989 100644
--- a/pid/builder.cpp
+++ b/pid/builder.cpp
@@ -45,7 +45,7 @@
     return std::string(objectPath) + std::to_string(zone);
 }
 
-static std::string getPidControlPath(int64_t zone, std::string pidname)
+static std::string getPidControlPath(int64_t zone, const std::string& pidname)
 {
     return std::string(objectPath) + std::to_string(zone) + "/" + pidname;
 }