#ifdef CONFIG_CONTEXT_SWITCH_TRACER
 
+void ftrace_task(struct task_struct *p, void *__tr, void *__data)
+{
+#if 0
+       /*  
+        * trace timeline tree
+        */
+       __trace_special(__tr, __data,
+                       p->pid, p->se.vruntime, p->se.sum_exec_runtime);
+#else
+       /*
+        * trace balance metrics
+        */
+       __trace_special(__tr, __data,
+                       p->pid, p->se.avg_overlap, 0);
+#endif
+}
+
 void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data)
 {
        struct task_struct *p;
        struct rb_node *curr;
        struct rq *rq = __rq;
 
-       curr = first_fair(&rq->cfs);
-       if (!curr)
-               return;
-
        if (rq->cfs.curr) {
                p = task_of(rq->cfs.curr);
-               __trace_special(__tr, __data,
-                     p->pid, p->se.vruntime, p->se.sum_exec_runtime);
+               ftrace_task(p, __tr, __data);
        }
        if (rq->cfs.next) {
                p = task_of(rq->cfs.next);
-               __trace_special(__tr, __data,
-                     p->pid, p->se.vruntime, p->se.sum_exec_runtime);
+               ftrace_task(p, __tr, __data);
        }
 
-       while (curr) {
+       for (curr = first_fair(&rq->cfs); curr; curr = rb_next(curr)) {
                se = rb_entry(curr, struct sched_entity, run_node);
                if (!entity_is_task(se))
                        continue;
 
                p = task_of(se);
-
-               __trace_special(__tr, __data,
-                             p->pid, p->se.vruntime, p->se.sum_exec_runtime);
-
-               curr = rb_next(curr);
+               ftrace_task(p, __tr, __data);
        }
 }