fix mobilenet model time print (#4867)

test=develop

dygraph/mobilenet/train.py

@@ -38,6 +38,19 @@ args = parse_args()
 if int(os.getenv("PADDLE_TRAINER_ID", 0)) == 0:
     print_arguments(args)
 
+class TimeCostAverage(object):
+    def __init__(self):
+        self.reset()
+    def reset(self):
+        self.cnt = 0
+        self.total_time = 0
+    def record(self, usetime):
+        self.cnt += 1
+        self.total_time += usetime
+    def get_average(self):
+        if self.cnt == 0:
+            return 0
+        return self.total_time / self.cnt
 
 def eval(net, test_data_loader, eop):
     total_loss = 0.0
@@ -170,6 +183,10 @@ def train_mobilenet():
             t_last = 0
 
             # 4.1 for each batch, call net() , backward(), and minimize()
+            batch_cost_avg = TimeCostAverage()
+            batch_reader_avg = TimeCostAverage()
+            batch_net_avg = TimeCostAverage()
+            batch_backward_avg = TimeCostAverage()
             batch_start = time.time()
             for img, label in train_data_loader():
                 if args.max_iter and total_batch_num == args.max_iter:
@@ -208,16 +225,25 @@ def train_mobilenet():
 
                 # NOTE: used for benchmark
                 train_batch_cost = time.time() - batch_start
+                batch_cost_avg.record(train_batch_cost)
+                batch_reader_avg.record(batch_reader_end - batch_start)
+                batch_net_avg.record(batch_net_end - batch_reader_end)
+                batch_backward_avg.record(batch_backward_end - batch_net_end)
+
                 total_batch_num = total_batch_num + 1
                 if batch_id % args.print_step == 0:
                     print(
                         "[Epoch %d, batch %d], avg_loss %.5f, acc_top1 %.5f, acc_top5 %.5f, batch_cost: %.5f s, net_t: %.5f s, backward_t: %.5f s, reader_t: %.5f s"
                         % (eop, batch_id, avg_loss.numpy(), acc_top1.numpy(),
-                           acc_top5.numpy(), train_batch_cost,
-                           batch_net_end - batch_reader_end,
-                           batch_backward_end - batch_net_end,
-                           batch_reader_end - batch_start))
+                           acc_top5.numpy(), batch_cost_avg.get_average(),
+                           batch_net_avg.get_average(),
+                           batch_backward_avg.get_average(),
+                           batch_reader_avg.get_average()))
                     sys.stdout.flush()
+                    batch_cost_avg.reset()
+                    batch_net_avg.reset()
+                    batch_backward_avg.reset()
+                    batch_reader_avg.reset()
                 batch_start = time.time()
 
             if args.ce: