[just for review]Release/mt5 opt

python/oneflow/framework/check_point_v2.py

@@ -172,7 +172,8 @@ def tensor_getstate(self):
             rel_dir_name = f"global_tensor_{self.global_id()}"
             abs_dir_name = save_load_path / rel_dir_name
 
-            tensor = self.to_global(
+            # Boxing to cpu firstly to avoid extra gpu memory usage
+            tensor = self.to_global(sbp=self.sbp, placement=flow.placement("cpu", self.placement.ranks)).to_global(
                 sbp=flow.sbp.broadcast,
                 placement=flow.placement("cpu", [global_src_dsk_rank]),
             ).to_local()