!5368 fix sink_size bug for transformer

Merge pull request !5368 from yuchaojie/transformer_st

model_zoo/official/nlp/transformer/train.py

@@ -170,8 +170,14 @@ def run_transformer_train():
 
     netwithgrads.set_train(True)
     model = Model(netwithgrads)
-    model.train(args.epoch_size, dataset, callbacks=callbacks, dataset_sink_mode=(args.enable_data_sink == "true"),
-                sink_size=args.save_checkpoint_steps)
+
+    enable_sink = (args.enable_data_sink == "true")
+    if enable_sink:
+        sink_size = args.save_checkpoint_steps
+        model.train(args.epoch_size*dataset.get_dataset_size()//sink_size, dataset, callbacks=callbacks,
+                    dataset_sink_mode=enable_sink, sink_size=sink_size)
+    else:
+        model.train(args.epoch_size, dataset, callbacks=callbacks, dataset_sink_mode=enable_sink)
 
 if __name__ == '__main__':
     run_transformer_train()