Display total time for which item has been queued in tooltip

core/src/main/java/hudson/model/Queue.java

@@ -1211,6 +1211,8 @@ public class Queue extends ResourceController implements Saveable {
 
         private /*almost final*/ transient FutureImpl future;
         
+        private final long inQueueSince;
+
         /**
          * Build is blocked because another build is in progress,
          * required {@link Resource}s are not available, or otherwise blocked
@@ -1233,6 +1235,20 @@ public class Queue extends ResourceController implements Saveable {
         @Exported
         public boolean isStuck() { return false; }
         
+        /**
+         * Since when is this item in the queue.
+         * @return Unix timestamp
+         */
+        @Exported
+        public long getInQueueSince() {
+            return this.inQueueSince;
+        }
+        
+        public String getInQueueSinceString() {
+            long duration = System.currentTimeMillis() - this.inQueueSince;
+            return Util.getTimeSpanString(duration);
+        }
+
         /**
          * Can be used to wait for the completion (either normal, abnormal, or cancellation) of the {@link Task}.
          * <p>
@@ -1265,11 +1281,20 @@ public class Queue extends ResourceController implements Saveable {
             this.task = task;
             this.id = id;
             this.future = future;
+            this.inQueueSince = System.currentTimeMillis();
+            for (Action action: actions) addAction(action);
+        }
+        
+        protected Item(Task task, List<Action> actions, int id, FutureImpl future, long inQueueSince) {
+            this.task = task;
+            this.id = id;
+            this.future = future;
+            this.inQueueSince = inQueueSince;
             for (Action action: actions) addAction(action);
         }
         
         protected Item(Item item) {
-        	this(item.task, item.getActions(), item.id, item.future);
+        	this(item.task, item.getActions(), item.id, item.future, item.inQueueSince);
         }
 
         /**

core/src/main/resources/lib/hudson/queue.jelly

@@ -58,7 +58,7 @@ THE SOFTWARE.
       <j:otherwise>
         <j:forEach var="item" items="${items}">
           <tr>
-            <td class="pane" width="100%" tooltip="${item.why}${h.escape(item.params)}" style="white-space: normal;">
+            <td class="pane" width="100%" tooltip="${item.why}${h.escape(item.params)}&lt;br&gt;${%WaitingSince(item.inQueueSinceString)}" style="white-space: normal;">
               <j:set var="stuck" value="${item.isStuck()}"/>
               <j:choose>
                 <j:when test="${h.hasPermission(item.task,item.task.READ)}">

core/src/main/resources/lib/hudson/queue.properties

+WaitingSince=Waiting since {0}
\ No newline at end of file

core/src/main/resources/lib/hudson/queue_de.properties

@@ -25,3 +25,4 @@ No\ builds\ in\ the\ queue.=Keine Builds geplant
 Jenkins\ is\ going\ to\ shut\ down.\ No\ further\ builds\ will\ be\ performed.=Jenkins fährt gerade herunter. Es werden keine weiteren Builds ausgeführt.
 cancel=Abbrechen
 Unknown\ Task=Unbekannter Task
+WaitingSince=Wartet seit {0}
\ No newline at end of file