[OMNIML-3232] Support full TE spec for NemotronH HF-to-Megatron import

modelopt/torch/export/plugins/mcore_nemotron.py

@@ -58,16 +58,25 @@
     "D": NameRemapping("backbone.layers.{}.mixer.D", REPLICATE),
     "dt_bias": NameRemapping("backbone.layers.{}.mixer.dt_bias", REPLICATE),
     "conv1d": NameRemapping("backbone.layers.{}.mixer.conv1d.", REPLICATE),
-    "in_proj": NameRemapping("backbone.layers.{}.mixer.in_proj.", COL_TP),
+    # mapping layer_norm_weight to None tells _name_remapping to skip it;
+    # the fused layer_norm_weight is loaded separately via the "fused_norm" rule.
+    "in_proj": NameRemapping(
+        "backbone.layers.{}.mixer.in_proj.", COL_TP | {"mapping": {"layer_norm_weight": None}}
+    ),
     "out_proj": NameRemapping("backbone.layers.{}.mixer.out_proj.", ROW_TP),
     # Attention
     "input_layernorm": NameRemapping("backbone.layers.{}.norm.", REPLICATE),
     "linear_qkv": QKVMerging("backbone.layers.{}.mixer.", COL_TP),
     "linear_proj": NameRemapping("backbone.layers.{}.mixer.o_proj.", ROW_TP),
     # MLP
     "pre_mlp_layernorm": NameRemapping("backbone.layers.{}.norm.", REPLICATE),
-    "linear_fc1": NameRemapping("backbone.layers.{}.mixer.up_proj.", COL_TP),
+    "linear_fc1": NameRemapping(
+        "backbone.layers.{}.mixer.up_proj.", COL_TP | {"mapping": {"layer_norm_weight": None}}
+    ),
     "linear_fc2": NameRemapping("backbone.layers.{}.mixer.down_proj.", ROW_TP),
+    # Fused layer norm: loads the HF norm weight into fused TELayerNormColumnParallelLinear
+    # modules (in_proj, linear_qkv, linear_fc1) when using TE spec.
+    "fused_norm": NameRemapping("backbone.layers.{}.norm.weight"),
     # MoE
     "router": NameRemapping(
         "backbone.layers.{}.mixer.gate.", {"mapping": {"expert_bias": "e_score_correction_bias"}}
@@ -92,12 +101,14 @@
     "mtp.hnorm": NameRemapping("mtp.layers.{}.hnorm.", {"is_mtp": True}),
     "mtp.eh_proj": NameRemapping("mtp.layers.{}.eh_proj.", {"is_mtp": True}),
     "mtp.final_layernorm": NameRemapping("mtp.layers.{}.final_layernorm.", {"is_mtp": True}),
-    # Grouped local experts in MTP
+    # Grouped local experts (used for TEGroupedMLP in both decoder and MTP layers).
+    # The prefix uses "backbone" for regular decoder layers; when called from MTP
+    # context (is_mtp=True), _grouped_mlp_merging replaces "backbone" with "mtp".
     "experts.linear_fc1": GroupedMLPMerging(
-        "mtp.layers.{}.mixer.experts.{{}}.up_proj", COL_ETP | {"is_mtp": True}
+        "backbone.layers.{}.mixer.experts.{{}}.up_proj", COL_ETP
     ),
     "experts.linear_fc2": GroupedMLPMerging(
-        "mtp.layers.{}.mixer.experts.{{}}.down_proj", ROW_ETP | {"is_mtp": True}
+        "backbone.layers.{}.mixer.experts.{{}}.down_proj", ROW_ETP
     ),
 }
 

modelopt/torch/export/plugins/megatron_importer.py

@@ -200,6 +200,12 @@ def _name_remapping(
                 state_dict[key] = val
             else:
                 source_key = mapping.get(key, key)
+                # A mapping value of None means "skip this key" (keep existing value).
+                # This is used for fused TE modules where layer_norm_weight is loaded
+                # separately from a different HF path.
+                if source_key is None:
+                    state_dict[key] = val
+                    continue
                 # For bias tensors in ROW_TP layers, don't use parallel config to avoid sharding
                 # since bias should always be replicated, not sharded
                 if (
@@ -537,6 +543,15 @@ def _import_mamba_layer(self, layer, layer_id, layer_pbar):
         self.rules["in_proj"](layer.mixer.in_proj, layer_id)
         self.rules["out_proj"](layer.mixer.out_proj, layer_id)
 
+        # TE spec: layer norm is fused into in_proj (TELayerNormColumnParallelLinear).
+        # Load the fused layer_norm_weight from the HF norm path.
+        if (
+            isinstance(layer.norm, IdentityOp)
+            and hasattr(layer.mixer.in_proj, "layer_norm_weight")
+            and "fused_norm" in self.rules
+        ):
+            self.rules["fused_norm"](layer.mixer.in_proj.layer_norm_weight, layer_id)
+
     def _import_transformer_layer(self, layer, layer_id, layer_pbar, is_mtp: bool = False):
         if not isinstance(layer.input_layernorm, IdentityOp):
             self.rules["input_layernorm"](layer.input_layernorm, layer_id, is_mtp=is_mtp)
@@ -578,6 +593,18 @@ def _import_transformer_layer(self, layer, layer_id, layer_pbar, is_mtp: bool =
                         attention.core_attention.softmax_offset, layer_id, is_mtp=is_mtp
                     )
 
+            # TE spec: input_layernorm is fused into linear_qkv (TELayerNormColumnParallelLinear).
+            # Load the fused layer_norm_weight from the HF norm path.
+            if (
+                isinstance(layer.input_layernorm, IdentityOp)
+                and hasattr(attention, "linear_qkv")
+                and hasattr(attention.linear_qkv, "layer_norm_weight")
+                and "fused_norm" in self.rules
+            ):
+                self.rules["fused_norm"](
+                    attention.linear_qkv.layer_norm_weight, layer_id, is_mtp=is_mtp
+                )
+
         if not isinstance(layer.pre_mlp_layernorm, IdentityOp):
             self.rules["pre_mlp_layernorm"](layer.pre_mlp_layernorm, layer_id, is_mtp=is_mtp)
 
@@ -671,6 +698,18 @@ def _import_transformer_layer(self, layer, layer_id, layer_pbar, is_mtp: bool =
                 self.rules["linear_fc1"](layer.mlp.linear_fc1, layer_id, is_mtp=is_mtp)
                 self.rules["linear_fc2"](layer.mlp.linear_fc2, layer_id, is_mtp=is_mtp)
 
+                # TE spec: pre_mlp_layernorm is fused into linear_fc1
+                # (TELayerNormColumnParallelLinear).
+                # Load the fused layer_norm_weight from the HF norm path.
+                if (
+                    isinstance(layer.pre_mlp_layernorm, IdentityOp)
+                    and hasattr(layer.mlp.linear_fc1, "layer_norm_weight")
+                    and "fused_norm" in self.rules
+                ):
+                    self.rules["fused_norm"](
+                        layer.mlp.linear_fc1.layer_norm_weight, layer_id, is_mtp=is_mtp
+                    )
+
     def _import_state_dict(self):
         model = self.model
         layer_pbar = tqdm(model.decoder.layers, disable=self.disable_tqdm)