[Chore] Simplify logic of `_execute_mm_encoder` (#31222)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

vllm/v1/worker/gpu_model_runner.py

@@ -61,6 +61,7 @@ from vllm.model_executor.layers.rotary_embedding import (
 )
 from vllm.model_executor.model_loader import TensorizerLoader, get_model_loader
 from vllm.model_executor.models.interfaces import (
+    MultiModalEmbeddings,
     SupportsMRoPE,
     SupportsMultiModal,
     SupportsXDRoPE,
@@ -78,11 +79,7 @@ from vllm.model_executor.models.interfaces_base import (
     is_text_generation_model,
 )
 from vllm.multimodal import MULTIMODAL_REGISTRY
-from vllm.multimodal.inputs import (
-    BatchedTensorInputs,
-    MultiModalKwargsItem,
-    PlaceholderRange,
-)
+from vllm.multimodal.inputs import BatchedTensorInputs, MultiModalKwargsItem
 from vllm.multimodal.utils import group_mm_kwargs_by_modality
 from vllm.pooling_params import PoolingParams
 from vllm.sampling_params import SamplingType
@@ -2097,28 +2094,27 @@ class GPUModelRunner(
         ]
         return logits_indices_padded
 
-    def _batch_mm_kwargs_from_scheduler(
+    def _batch_mm_inputs_from_scheduler(
         self,
         scheduler_output: "SchedulerOutput",
-    ) -> tuple[list[MultiModalKwargsItem], list[tuple[str, PlaceholderRange]]]:
-        """Batch multimodal kwargs from scheduled encoder inputs.
+    ) -> tuple[list[str], list[MultiModalKwargsItem]]:
+        """Batch multimodal inputs from scheduled encoder inputs.
 
         Args:
             scheduler_output: The scheduler output containing scheduled encoder
                 inputs.
 
         Returns:
-            A tuple of (mm_kwargs, req_ids_pos) where:
-            - mm_kwargs: List of multimodal kwargs items to be batched
-            - mm_hashes_pos: List of (mm_hash, position_info) tuples
+            A tuple of (mm_hashes, mm_kwargs) where:
+            - mm_hashes: List of multimodal hashes for each item
+            - mm_kwargs: List of multimodal kwargs for each item
         """
         scheduled_encoder_inputs = scheduler_output.scheduled_encoder_inputs
         if not scheduled_encoder_inputs:
             return [], []
-        # Batch the multi-modal inputs.
+
+        mm_hashes = list[str]()
         mm_kwargs = list[MultiModalKwargsItem]()
-        # list of tuple (mm_hash, position_info)
-        mm_hashes_pos = list[tuple[str, PlaceholderRange]]()
         for req_id, encoder_input_ids in scheduled_encoder_inputs.items():
             req_state = self.requests[req_id]
 
@@ -2126,19 +2122,16 @@ class GPUModelRunner(
                 mm_feature = req_state.mm_features[mm_input_id]
                 if mm_feature.data is None:
                     continue
-                mm_hash = mm_feature.identifier
+
+                mm_hashes.append(mm_feature.identifier)
                 mm_kwargs.append(mm_feature.data)
-                mm_hashes_pos.append((mm_hash, mm_feature.mm_position))
 
-        return mm_kwargs, mm_hashes_pos
+        return mm_hashes, mm_kwargs
 
     def _execute_mm_encoder(
         self, scheduler_output: "SchedulerOutput"
     ) -> list[torch.Tensor]:
-        # Batch the multi-modal inputs using the helper method.
-        mm_kwargs, mm_hashes_pos = self._batch_mm_kwargs_from_scheduler(
-            scheduler_output
-        )
+        mm_hashes, mm_kwargs = self._batch_mm_inputs_from_scheduler(scheduler_output)
 
         if not mm_kwargs:
             return []
@@ -2157,7 +2150,7 @@ class GPUModelRunner(
             device=self.device,
             pin_memory=self.pin_memory,
         ):
-            curr_group_outputs: list[torch.Tensor] = []
+            curr_group_outputs: MultiModalEmbeddings
 
             # EVS-related change.
             # (ekhvedchenia): Temporary hack to limit peak memory usage when
@@ -2173,6 +2166,7 @@ class GPUModelRunner(
                 and modality == "video"
                 and num_items > 1
             ):
+                curr_group_outputs_lst = list[torch.Tensor]()
                 for video_mm_kwargs_item in filter(
                     lambda item: item.modality == "video", mm_kwargs
                 ):
@@ -2188,7 +2182,9 @@ class GPUModelRunner(
                         **micro_batch_mm_inputs
                     )
 
-                    curr_group_outputs.extend(micro_batch_outputs)
+                    curr_group_outputs_lst.extend(micro_batch_outputs)
+
+                curr_group_outputs = curr_group_outputs_lst
             else:
                 # Run the encoder.
                 # `curr_group_outputs` is either of the following:
@@ -2197,7 +2193,7 @@ class GPUModelRunner(
                 # 2. A list or tuple (length: num_items) of tensors,
                 # each of shape (feature_size, hidden_size) in case the feature
                 # size is dynamic depending on the input multimodal items.
-                curr_group_outputs = model.embed_multimodal(**mm_kwargs_group)  # type: ignore[assignment]
+                curr_group_outputs = model.embed_multimodal(**mm_kwargs_group)
 
             sanity_check_mm_encoder_outputs(
                 curr_group_outputs,
@@ -2206,7 +2202,7 @@ class GPUModelRunner(
             encoder_outputs.extend(curr_group_outputs)
 
         # Cache the encoder outputs by mm_hash
-        for (mm_hash, pos_info), output in zip(mm_hashes_pos, encoder_outputs):
+        for mm_hash, output in zip(mm_hashes, encoder_outputs):
             self.encoder_cache[mm_hash] = output
             logger.debug("Finish execute for mm hash %s", mm_hash)
             self.maybe_save_ec_to_connector(self.encoder_cache, mm_hash)