diff --git a/examples/parallelwave_gan/baker/conf/default.yaml b/examples/parallelwave_gan/baker/conf/default.yaml
index 1cb1487..29d6c0f 100644
--- a/examples/parallelwave_gan/baker/conf/default.yaml
+++ b/examples/parallelwave_gan/baker/conf/default.yaml
@@ -86,7 +86,7 @@ lambda_adv: 4.0  # Loss balancing coefficient.
 batch_size: 6              # Batch size.
 batch_max_steps: 25500     # Length of each audio in batch. Make sure dividable by hop_size.
 pin_memory: true           # Whether to pin memory in Pytorch DataLoader.
-num_workers: 0             # Number of workers in Pytorch DataLoader.
+num_workers: 4             # Number of workers in Pytorch DataLoader.
 remove_short_samples: true # Whether to remove samples the length of which are less than batch_max_steps.
 allow_cache: true          # Whether to allow cache in dataset. If true, it requires cpu memory.
 
diff --git a/parakeet/training/trainer.py b/parakeet/training/trainer.py
index 548df64..ad3661f 100644
--- a/parakeet/training/trainer.py
+++ b/parakeet/training/trainer.py
@@ -76,6 +76,8 @@ class Trainer(object):
             else:
                 max_iteration = self.stop_trigger.period
 
+        p = tqdm.tqdm()
+
         while True:
             self.observation = {}
             # set observation as the report target
@@ -84,12 +86,13 @@ class Trainer(object):
             # updating parameters and state
             with scope(self.observation):
                 update()
-            print(self.observation)
+                p.update()
+                print(self.observation)
 
-            # execute extension when necessary
-            for name, entry in extensions:
-                if entry.trigger(self):
-                    entry.extension(self)
+                # execute extension when necessary
+                for name, entry in extensions:
+                    if entry.trigger(self):
+                        entry.extension(self)
 
             if stop_trigger(self):
                 print("Training Done!")