Precisely track nvme optimizer offload (#6963)

Fix #4998

deepspeed/runtime/engine.py

@@ -799,10 +799,8 @@ class DeepSpeedEngine(Module):
     def zero_elastic_checkpoint(self):
         return self._config.zero_config.elastic_checkpoint
 
-    def zero_has_nvme_offload(self):
-        if not hasattr(self.optimizer, "swap_optimizer"):
-            return False
-        return self.optimizer.swap_optimizer or self.optimizer.params_in_nvme_and_cpu
+    def zero_nvme_offload_optimizer(self):
+        return getattr(self.optimizer, "swap_optimizer", False)
 
     def zero_max_live_parameters(self):
         return self._config.zero_config.max_live_parameters
@@ -2865,7 +2863,7 @@ class DeepSpeedEngine(Module):
             if not success:
                 self.optimizer._restore_from_bit16_weights()
 
-        if self.zero_has_nvme_offload():
+        if self.zero_nvme_offload_optimizer():
             from shutil import copytree, disk_usage
             offload_dir = self.optimizer.optimizer_swapper.swap_folder
             offload_ckpt_dir = os.path.join(load_dir, tag, "offloaded_tensors")
@@ -3205,7 +3203,7 @@ class DeepSpeedEngine(Module):
             self._create_zero_checkpoint_files(save_dir, tag)
             self._save_zero_checkpoint(save_dir, tag)
 
-        if self.zero_has_nvme_offload():
+        if self.zero_nvme_offload_optimizer():
             from shutil import copytree, disk_usage
             offload_dir = self.optimizer.optimizer_swapper.swap_folder
             offload_ckpt_dir = os.path.join(save_dir, tag, "offloaded_tensors")

deepspeed/runtime/swap_tensor/optimizer_utils.py

@@ -153,6 +153,11 @@ class OptimizerSwapper(object):
             'timer_names',
         ]
 
+    def purge_state(self):
+        for swap_info in self.swap_params_info.values():
+            swap_info.tensors = [swap_info.tensors[0]]
+            swap_info.has_state_tensors = False
+
     def swappable_tensor(self, param=None, numel=None):
         assert param is not None or numel is not None, "Either param or numel must be provided"
         if param is not None:

deepspeed/runtime/zero/stage3.py

@@ -2652,11 +2652,9 @@ class DeepSpeedZeroOptimizer_Stage3(ZeROOptimizer):
             self.optimizer.load_state_dict(state_dict[OPTIMIZER_STATE_DICT])
             self._clear_fp32_optimizer_param_groups()
 
-        if self.swap_optimizer or self.params_in_nvme_and_cpu:
+        if self.swap_optimizer:
             # Purge the swapped optimizer state, it was initialized to the freshly created model and not the checkpoint
-            for swap_info in self.optimizer_swapper.swap_params_info.values():
-                swap_info.tensors = [swap_info.tensors[0]]
-                swap_info.has_state_tensors = False
+            self.optimizer_swapper.purge_state()
 
         if self.swap_optimizer:
             # Touch all parameters to synchronize all buffers
@@ -2773,11 +2771,9 @@ class DeepSpeedZeroOptimizer_Stage3(ZeROOptimizer):
             else:
                 optim_sd[OPTIMIZER_STATE_DICT]['state'][0][key] = key_tensor
 
-        if self.swap_optimizer or self.params_in_nvme_and_cpu:
+        if self.swap_optimizer:
             # Purge the swapped optimizer state, it was initialized to the freshly created model and not the checkpoint
-            for swap_info in self.optimizer_swapper.swap_params_info.values():
-                swap_info.tensors = [swap_info.tensors[0]]
-                swap_info.has_state_tensors = False
+            self.optimizer_swapper.purge_state()
 
         if self.swap_optimizer:
             # Touch all parameters to synchronize all buffers

tests/unit/runtime/zero/test_nvme_checkpointing.py

@@ -22,8 +22,10 @@ class TestNVMeCheckpointing(DistributedTest):
     world_size = 1
 
     @pytest.mark.parametrize('param_offload_device, optim_offload_device',
-                             [(OffloadDeviceEnum.cpu, OffloadDeviceEnum.cpu),
+                             [(OffloadDeviceEnum.none, OffloadDeviceEnum.nvme),
                               (OffloadDeviceEnum.cpu, OffloadDeviceEnum.nvme),
+                              (OffloadDeviceEnum.nvme, OffloadDeviceEnum.none),
+                              (OffloadDeviceEnum.nvme, OffloadDeviceEnum.cpu),
                               (OffloadDeviceEnum.nvme, OffloadDeviceEnum.nvme)])
     def test_nvme_checkpointing(self, tmpdir, param_offload_device, optim_offload_device):
         zero_dir, ckpt_dir = os.path.join(tmpdir, "zero"), os.path.join(tmpdir, "checkpoint")