[Models] Improve iteration over layers (vllm-project#19497)

Signed-off-by: Lukas Geiger <lukas.geiger94@gmail.com>

Author: lgeiger

vllm/model_executor/models/arcee.py

@@ -9,6 +9,7 @@
 # activation.
 
 from collections.abc import Iterable
+from itertools import islice
 from typing import Any, Optional, Union
 
 import torch
@@ -243,7 +244,7 @@ def forward(
 
         aux_hidden_states: list[torch.Tensor] = []
         for idx, layer in enumerate(
-                self.layers[self.start_layer:self.end_layer]):
+                islice(self.layers, self.start_layer, self.end_layer)):
             if idx in self.aux_hidden_state_layers:
                 aux_hidden_states.append(
                     hidden_states +

vllm/model_executor/models/arctic.py

@@ -2,6 +2,7 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """Inference-only Snowflake Arctic model."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -403,7 +404,7 @@ def forward(
         else:
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states = layer(positions, hidden_states)
         if not get_pp_group().is_last_rank:
             return IntermediateTensors({"hidden_states": hidden_states})

vllm/model_executor/models/baichuan.py

@@ -22,6 +22,7 @@
 """Inference-only BaiChuan model compatible with HuggingFace weights."""
 import math
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -309,7 +310,7 @@ def forward(
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 positions,
                 hidden_states,

vllm/model_executor/models/bailing_moe.py

@@ -24,6 +24,7 @@
 # limitations under the License.
 """Inference-only BailingMoE model compatible with HuggingFace weights."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -359,8 +360,7 @@ def forward(
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
 
-        for i in range(self.start_layer, self.end_layer):
-            layer = self.layers[i]
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 hidden_states,
                 position_ids,

vllm/model_executor/models/bamba.py

@@ -345,8 +345,7 @@ def forward(
 
         residual = None
         num_attn = 0
-        for i in range(len(self.layers)):
-            layer = self.layers[i]
+        for i, layer in enumerate(self.layers):
             if isinstance(layer, BambaAttentionDecoderLayer):
                 num_attn += 1
 

vllm/model_executor/models/bloom.py

@@ -20,6 +20,7 @@
 """Inference-only BLOOM model compatible with HuggingFace weights."""
 import math
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -273,7 +274,7 @@ def forward(
         else:
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
-        for layer in self.h[self.start_layer:self.end_layer]:
+        for layer in islice(self.h, self.start_layer, self.end_layer):
             hidden_states = layer(position_ids, hidden_states)
         if not get_pp_group().is_last_rank:
             return IntermediateTensors({"hidden_states": hidden_states})

vllm/model_executor/models/chameleon.py

@@ -3,6 +3,7 @@
 
 from collections.abc import Iterable, Mapping, Sequence
 from functools import cached_property
+from itertools import islice
 from typing import Annotated, Any, Literal, Optional, Union
 
 import torch
@@ -914,7 +915,7 @@ def forward(
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 positions,
                 hidden_states,

vllm/model_executor/models/chatglm.py

@@ -5,6 +5,7 @@
 """Inference-only ChatGLM model compatible with THUDM weights."""
 import json
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -281,7 +282,7 @@ def forward(
         hidden_states: torch.Tensor,
         position_ids: torch.Tensor,
     ) -> Union[torch.Tensor, IntermediateTensors]:
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states = layer(hidden_states=hidden_states,
                                   position_ids=position_ids)
 

vllm/model_executor/models/commandr.py

@@ -23,6 +23,7 @@
 # This file is based on the LLama model definition file in transformers
 """PyTorch Cohere model."""
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -322,7 +323,7 @@ def forward(
             assert intermediate_tensors is not None
             hidden_states = intermediate_tensors["hidden_states"]
             residual = intermediate_tensors["residual"]
-        for layer in self.layers[self.start_layer:self.end_layer]:
+        for layer in islice(self.layers, self.start_layer, self.end_layer):
             hidden_states, residual = layer(
                 positions,
                 hidden_states,

vllm/model_executor/models/dbrx.py

@@ -2,6 +2,7 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from collections.abc import Iterable
+from itertools import islice
 from typing import Optional, Union
 
 import torch
@@ -359,7 +360,7 @@ def forward(
         else:
             assert intermediate_tensors
             hidden_states = intermediate_tensors["hidden_states"]
-        for block in self.blocks[self.start_layer:self.end_layer]:
+        for block in islice(self.blocks, self.start_layer, self.end_layer):
             hidden_states = block(position_ids, hidden_states)
         if not get_pp_group().is_last_rank:
             return IntermediateTensors({"hidden_states": hidden_states})