Only measure the start and end time of an OFMessage if the processing time service is enabled.

src/main/java/net/floodlightcontroller/core/internal/Controller.java

@@ -632,7 +632,11 @@ public class Controller
                                  FloodlightContext bContext)
             throws IOException {
         Ethernet eth = null;
-        long startTime = System.nanoTime();
+        long startTime = 0;
+        
+        if (pktinProcTime.isEnabled()) {
+            startTime = System.nanoTime();
+        }
 
         switch (m.getType()) {
             case PACKET_IN:
@@ -700,11 +704,13 @@ public class Controller
                 }
                 if ((bContext == null) && (bc != null)) flcontext_free(bc);
                 
-                long processingTime = System.nanoTime() - startTime;
-                if (ptWarningThresholdInNano > 0 && processingTime > ptWarningThresholdInNano) {
-                    log.warn("Time to process packet-in: {} us", processingTime/1000.0);
-                    if (eth != null)
-                        log.warn("{}", messageFilterManager.getDataAsString(sw, m, bContext));
+                if (pktinProcTime.isEnabled()) {
+                    long processingTime = System.nanoTime() - startTime;
+                    if (ptWarningThresholdInNano > 0 && processingTime > ptWarningThresholdInNano) {
+                        log.warn("Time to process packet-in: {} us", processingTime/1000.0);
+                        if (eth != null)
+                            log.warn("{}", messageFilterManager.getDataAsString(sw, m, bContext));
+                    }
                 }
         }
     }

src/main/java/net/floodlightcontroller/perfmon/IPktInProcessingTimeService.java

@@ -6,6 +6,8 @@ import net.floodlightcontroller.perfmon.PerfMonConfigs;
 
 public interface IPktInProcessingTimeService extends IFloodlightService {
 
+    public boolean isEnabled();
+    
     public CircularTimeBucketSet getCtbs();
 
     public PerfMonConfigs getPerfMonCfgs();

src/main/java/net/floodlightcontroller/perfmon/NullPktInProcessingTime.java

@@ -92,4 +92,9 @@ public class NullPktInProcessingTime
     public void updateCumulativeTimeTotal(long onePktStartTime_ns) {
         // no-op
     }
+
+    @Override
+    public boolean isEnabled() {
+        return false;
+    }
 }

src/main/java/net/floodlightcontroller/perfmon/PerfMonConfigs.java

@@ -3,8 +3,6 @@ package net.floodlightcontroller.perfmon;
 public class PerfMonConfigs {
     /***
      * procTimeMonitoringState: true if monitoring is on, default is false
-     * this variable is controller using a cli under the controller node
-     * (config-controller)> [no] performance-monitor processing-time
      */
     protected boolean procTimeMonitoringState;
     // overall per-component performance monitoring knob; off by default

src/main/java/net/floodlightcontroller/perfmon/PktInProcessingTime.java

@@ -62,7 +62,10 @@ public class PktInProcessingTime
     private int numComponents;          // Numbert of components being monitored
     private int numBuckets;             // number of time buckets, each 10s long
 
-
+    @Override
+    public boolean isEnabled() {
+        return perfMonCfgs.isProcTimeMonitoringState();
+    }
 
     public Long getLastPktTime_ns() {
         return lastPktTime_ns;