fix eval for map dataset

paddlenlp/trainer/trainer.py

@@ -1588,20 +1588,13 @@ def _get_eval_sampler(self, eval_dataset: Dataset):
                 drop_last=False,
             )
         else:
-            drop_last = False
-            if self.args.pipeline_parallel_degree > 1:
-                drop_last = True
-                logger.warning(
-                    "In parallel mode, the batch_size is strictly checked. set DistributedBatchSampler drop_last=True."
-                )
-
             return DistributedBatchSampler(
                 eval_dataset,
                 num_replicas=self.args.dataset_world_size,
                 rank=self.args.dataset_rank,
                 batch_size=self.args.per_device_eval_batch_size,
                 shuffle=False,
-                drop_last=drop_last,
+                drop_last=False,
             )
 
     def get_eval_dataloader(self, eval_dataset: Optional[Dataset] = None) -> DataLoader: