diff --git a/src/mem/ruby/network/garnet2.0/OutputUnit.hh b/src/mem/ruby/network/garnet2.0/OutputUnit.hh
index c720888c12..dbb35eeed6 100644
--- a/src/mem/ruby/network/garnet2.0/OutputUnit.hh
+++ b/src/mem/ruby/network/garnet2.0/OutputUnit.hh
@@ -35,6 +35,7 @@
 #include <iostream>
 #include <vector>
 
+#include "base/compiler.hh"
 #include "mem/ruby/common/Consumer.hh"
 #include "mem/ruby/network/garnet2.0/CommonTypes.hh"
 #include "mem/ruby/network/garnet2.0/NetworkLink.hh"
@@ -91,7 +92,7 @@ class OutputUnit : public Consumer
 
   private:
     Router *m_router;
-    int m_id;
+    int M5_CLASS_VAR_USED m_id;
     PortDirection m_direction;
     int m_vc_per_vnet;
     NetworkLink *m_out_link;