Merge branch 'master' into fix_issue_7757

Author: tohtana

deepspeed/runtime/bf16_optimizer.py

@@ -103,6 +103,8 @@ def __init__(self,
         see_memory_usage('end bf16_ optimizer', force=True)
 
     def destroy(self):
+        if not self.using_real_optimizer:
+            return
         for i, _ in enumerate(self.optimizer.param_groups):
             for p in self.bf16_groups[i]:
                 if getattr(p, '_hp_mapping', None):