diff -r 5eeb3f6704eb -r 3171372e8b5e src/cpu/testers/traffic_gen/generators.hh
--- a/src/cpu/testers/traffic_gen/generators.hh	Thu Jul 18 13:43:44 2013 +0100
+++ b/src/cpu/testers/traffic_gen/generators.hh	Thu Jul 18 13:44:52 2013 +0100
@@ -380,6 +380,12 @@
         void reset();
 
         /**
+         * Check the trace header to make sure that it is of the right
+         * format.
+         */
+        void init();
+
+        /**
          * Attempt to read a trace element from the stream,
          * and also notify the caller if the end of the file
          * was reached.
diff -r 5eeb3f6704eb -r 3171372e8b5e src/cpu/testers/traffic_gen/generators.cc
--- a/src/cpu/testers/traffic_gen/generators.cc	Thu Jul 18 13:43:44 2013 +0100
+++ b/src/cpu/testers/traffic_gen/generators.cc	Thu Jul 18 13:44:52 2013 +0100
@@ -205,13 +205,19 @@
 TraceGen::InputStream::InputStream(const std::string& filename)
     : trace(filename)
 {
+    init();
+}
+
+void
+TraceGen::InputStream::init()
+{
     // Create a protobuf message for the header and read it from the stream
     Message::PacketHeader header_msg;
     if (!trace.read(header_msg)) {
-        panic("Failed to read packet header from %s\n", filename);
+        panic("Failed to read packet header from trace\n");
 
         if (header_msg.tick_freq() != SimClock::Frequency) {
-            panic("Trace %s was recorded with a different tick frequency %d\n",
+            panic("Trace was recorded with a different tick frequency %d\n",
                   header_msg.tick_freq());
         }
     }
@@ -221,6 +227,7 @@
 TraceGen::InputStream::reset()
 {
     trace.reset();
+    init();
 }
 
 bool