diff --git a/apps/dsm/DSMModule.cpp b/apps/dsm/DSMModule.cpp
index 6c8003e5..1de34283 100644
--- a/apps/dsm/DSMModule.cpp
+++ b/apps/dsm/DSMModule.cpp
@@ -55,10 +55,10 @@ bool isNumber(const std::string& s) {
   return true;
 }
 
-string resolveVars(const string ts, AmSession* sess,
+string resolveVars(const string& _s, AmSession* sess,
 		   DSMSession* sc_sess, map<string,string>* event_params,
 		   bool eval_ops) {
-  string s = ts;
+  string s = _s;
   if (s.length()) {
 
     if(eval_ops) {
diff --git a/apps/dsm/DSMModule.h b/apps/dsm/DSMModule.h
index 5f541a02..df13c3a8 100644
--- a/apps/dsm/DSMModule.h
+++ b/apps/dsm/DSMModule.h
@@ -338,7 +338,7 @@ class SCStrArgAction
 #define EXEC_ACTION_STOP			\
   return false;
 
-string resolveVars(const string s, AmSession* sess,
+string resolveVars(const string &s, AmSession* sess,
 		   DSMSession* sc_sess, map<string,string>* event_params,
 		   bool eval_ops = false);