diff --git a/examples/parallelwave_gan/baker/pwg_updater.py b/examples/parallelwave_gan/baker/pwg_updater.py
index 3ab79b8..29f313b 100644
--- a/examples/parallelwave_gan/baker/pwg_updater.py
+++ b/examples/parallelwave_gan/baker/pwg_updater.py
@@ -78,15 +78,15 @@ class PWGUpdater(UpdaterBase):
         # Generator
         noise = paddle.randn(wav.shape)
 
+        _cuda_synchronize(place)
         with timer() as t:
-            _cuda_synchronize(place)
             wav_ = self.generator(noise, mel)
             _cuda_synchronize(place)
             print(f"Generator takes {t.elapse}s")
 
         ## Multi-resolution stft loss
+        _cuda_synchronize(place)
         with timer() as t:
-            _cuda_synchronize(place)
             sc_loss, mag_loss = self.criterion_stft(
                 wav_.squeeze(1), wav.squeeze(1))
             _cuda_synchronize(place)
@@ -108,15 +108,16 @@ class PWGUpdater(UpdaterBase):
             gen_loss += self.lambda_adv * adv_loss
 
         report("train/generator_loss", float(gen_loss))
+
+        _cuda_synchronize(place)
         with timer() as t:
-            _cuda_synchronize(place)
             self.optimizer_g.clear_grad()
             gen_loss.backward()
             _cuda_synchronize(place)
             print(f"Backward takes {t.elapse}s.")
 
+        _cuda_synchronize(place)
         with timer() as t:
-            _cuda_synchronize(place)
             self.optimizer_g.step()
             self.scheduler_g.step()
             _cuda_synchronize(place)