fix async save hang

paddlenlp/trainer/plugins/unified_checkpoint.py

@@ -189,6 +189,7 @@ def _file_save_async_or_sync(
                         ),
                     )
                     self._process_model_weight.start()
+                process = self._process_model_weight
             elif state_dict_type == "master_weight":
                 if self._shm_master_weight is None:
                     self._meta_dict_master_weight, buffer_size = create_meta_dict(state_dict)
@@ -215,6 +216,7 @@ def _file_save_async_or_sync(
                         ),
                     )
                     self._process_master_weight.start()
+                process = self._process_master_weight
             elif state_dict_type == "optimizer_weight":
                 if self._shm_optimizer_weight is None:
                     self._meta_dict_optim, buffer_size = create_meta_dict(state_dict)
@@ -239,11 +241,14 @@ def _file_save_async_or_sync(
                         ),
                     )
                     self._process_optimizer_weight.start()
+                process = self._process_optimizer_weight
 
             while True:  # wait until no process is saving.
                 flag_value = shared_save_flag[0]
                 if flag_value == 0:
                     break
+                if not process.is_alive():
+                    raise RuntimeError(f"The process that saves {state_dict_type} has been killed unexpectedly.")
                 time.sleep(0.5)
                 logger.info(f"Wait for the previous save process to finish saving {state_dict_type}")
             # only save model weight or save master weight, we enter this loop.
@@ -771,14 +776,20 @@ def unlink_shared_memory(self):
 
         if self._shared_save_model_flag is not None:
             while self._shared_save_model_flag[0] > 0:  # async process is saving
+                if not self._process_model_weight.is_alive():
+                    raise RuntimeError("The process that saves model_weight has been killed unexpectedly.")
                 time.sleep(0.5)
             self._shared_save_model_flag[0] = -1
         if self._shared_save_master_weight_flag is not None:
             while self._shared_save_master_weight_flag[0] > 0:
+                if not self._process_master_weight.is_alive():
+                    raise RuntimeError("The process that saves master_weight has been killed unexpectedly.")
                 time.sleep(0.5)
             self._shared_save_master_weight_flag[0] = -1
         if self._shared_save_optimizer_flag is not None:
             while self._shared_save_optimizer_flag[0] > 0:
+                if not self._process_optimizer_weight.is_alive():
+                    raise RuntimeError("The process that saves optimizer_weight has been killed unexpectedly.")
                 time.sleep(0.5)
             self._shared_save_optimizer_flag[0] = -1
 
@@ -795,7 +806,8 @@ def unlink_shared_memory(self):
             self._shm_optimizer_weight.unlink()
             self._shm_optimizer_weight = None
 
-        dist.barrier()
+        if paddle.distributed.get_world_size() > 1:
+            dist.barrier()
 
 
 def load_unified_checkpoint_locally(args, model, resume_from_checkpoint: str, safe_serialization=False):