[Core] Encoder separation for Encode-Prefill-Decode Disaggregation (#4176)

### What this PR does / why we need it?
Support Encoder separation for Encode-Prefill-Decode Disaggregation

- vLLM version: v0.11.2
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.2

Signed-off-by: amy-why-3459 <[email protected]>

Author: amy-why-3459

vllm_ascend/patch/platform/__init__.py

@@ -18,6 +18,7 @@
 
 import vllm_ascend.patch.platform.patch_config  # noqa
 import vllm_ascend.patch.platform.patch_distributed  # noqa
+import vllm_ascend.patch.platform.patch_ec_connector  # noqa
 import vllm_ascend.patch.platform.patch_mamba_config  # noqa
 import vllm_ascend.patch.platform.patch_sched_yield  # noqa
 

vllm_ascend/patch/platform/patch_ec_connector.py

@@ -0,0 +1,32 @@
+import vllm.distributed.ec_transfer.ec_connector.shared_storage_connector
+from safetensors.torch import load_file
+from vllm.distributed.ec_transfer.ec_connector.base import ECConnectorMetadata
+from vllm.distributed.ec_transfer.ec_connector.shared_storage_connector import (
+    ECSharedStorageConnector, ECSharedStorageConnectorMetadata)
+from vllm.logger import logger
+
+
+class AscendECSharedStorageConnector(ECSharedStorageConnector):
+
+    def start_load_caches(self, encoder_cache, **kwargs) -> None:
+        metadata: ECConnectorMetadata = self._get_connector_metadata()
+        assert isinstance(metadata, ECSharedStorageConnectorMetadata)
+        assert encoder_cache is not None
+        if metadata is None:
+            logger.warning((
+                "In connector.start_load_caches, ",
+                "but the connector metadata is None",
+            ))
+            return
+        # Load the EC for each mm data
+        for mm_data in metadata.mm_datas:
+            if mm_data.mm_hash in encoder_cache:
+                continue
+            filename = self._generate_filename_debug(mm_data.mm_hash)
+            ec_cache = load_file(filename)["ec_cache"].npu()
+            encoder_cache[mm_data.mm_hash] = ec_cache
+            logger.debug("Success load encoder cache for hash %s",
+                         mm_data.mm_hash)
+
+
+vllm.distributed.ec_transfer.ec_connector.shared_storage_connector.ECSharedStorageConnector = AscendECSharedStorageConnector

vllm_ascend/worker/model_runner_v1.py

@@ -47,6 +47,7 @@
 from vllm.config import (CompilationMode, CUDAGraphMode, VllmConfig,
                          get_layers_from_vllm_config)
 from vllm.distributed import tensor_model_parallel_all_gather
+from vllm.distributed.ec_transfer import get_ec_transfer, has_ec_transfer
 from vllm.distributed.kv_transfer import (get_kv_transfer_group,
                                           has_kv_transfer_group)
 from vllm.distributed.kv_transfer.kv_connector.v1 import KVConnectorBase_V1
@@ -91,13 +92,16 @@
                                         UniformTypeKVCacheSpecs)
 from vllm.v1.outputs import (EMPTY_MODEL_RUNNER_OUTPUT, AsyncModelRunnerOutput,
                              DraftTokenIds, LogprobsTensors, ModelRunnerOutput,
-                             PoolerOutput)
+                             PoolerOutput,
+                             make_empty_encoder_model_runner_output)
 from vllm.v1.pool.metadata import PoolingMetadata
 from vllm.v1.sample.metadata import SamplingMetadata
 from vllm.v1.spec_decode.metadata import SpecDecodeMetadata
 from vllm.v1.spec_decode.ngram_proposer import NgramProposer
 from vllm.v1.spec_decode.suffix_decoding import SuffixDecodingProposer
 from vllm.v1.utils import CpuGpuBuffer
+from vllm.v1.worker.ec_connector_model_runner_mixin import \
+    ECConnectorModelRunnerMixin
 from vllm.v1.worker.kv_connector_model_runner_mixin import KVConnectorOutput
 from vllm.v1.worker.lora_model_runner_mixin import LoRAModelRunnerMixin
 from vllm.v1.worker.utils import (AttentionGroup, bind_kv_cache,
@@ -268,7 +272,7 @@ class ExecuteModelState(NamedTuple):
     positions: torch.Tensor
 
 
-class NPUModelRunner(LoRAModelRunnerMixin):
+class NPUModelRunner(LoRAModelRunnerMixin, ECConnectorModelRunnerMixin):
 
     def __init__(self, vllm_config: VllmConfig, device: torch.device):
         self.vllm_config = vllm_config
@@ -791,6 +795,11 @@ def _update_states(self, scheduler_output: "SchedulerOutput") -> None:
 
             req_ids_to_add.append(req_id)
 
+        # If this rank is an EC transfer producer,
+        # skip updating the states of KV cache blocks.
+        if has_ec_transfer() and get_ec_transfer().is_producer:
+            return
+
         # Update the states of the running/resumed requests.
         is_last_rank = get_pp_group().is_last_rank
         req_data = scheduler_output.scheduled_cached_reqs
@@ -1072,6 +1081,7 @@ def _execute_mm_encoder(self, scheduler_output: "SchedulerOutput"):
                 output,
                 is_embed=pos_info.is_embed,
             )
+            self.maybe_save_ec_to_connector(self.encoder_cache, mm_hash)
 
     def _batch_mm_kwargs_from_scheduler(
         self,
@@ -1597,15 +1607,19 @@ def _prepare_inputs(
         # _prepare_inputs may reorder the batch, so we must gather
         # multi-modal outputs after that to ensure the correct order
         if self.is_multimodal_model:
-            # Run the multimodal encoder if any.
-            self._execute_mm_encoder(scheduler_output)
-
-            # NOTE(woosuk): To unify token ids and soft tokens (vision
-            # embeddings), we always use embeddings (rather than token ids)
-            # as input to the multimodal model, even when the input is text.
-            input_ids = self.input_ids[:total_num_scheduled_tokens]
-            mm_embeds, is_mm_embed = self._gather_mm_embeddings(
-                scheduler_output)
+            with self.maybe_get_ec_connector_output(
+                    scheduler_output,
+                    encoder_cache=self.encoder_cache,
+            ):
+                # Run the multimodal encoder if any.
+                self._execute_mm_encoder(scheduler_output)
+
+                # NOTE(woosuk): To unify token ids and soft tokens (vision
+                # embeddings), we always use embeddings (rather than token ids)
+                # as input to the multimodal model, even when the input is text.
+                input_ids = self.input_ids[:total_num_scheduled_tokens]
+                mm_embeds, is_mm_embed = self._gather_mm_embeddings(
+                    scheduler_output)
 
             inputs_embeds = self.model.embed_input_ids(
                 input_ids,
@@ -2248,6 +2262,15 @@ def execute_model(
 
         with ProfileExecuteDuration().capture_async("prepare input"):
             self._update_states(scheduler_output)
+            if has_ec_transfer() and get_ec_transfer().is_producer:
+                with self.maybe_get_ec_connector_output(
+                        scheduler_output,
+                        encoder_cache=self.encoder_cache,
+                ):
+                    self._execute_mm_encoder(scheduler_output)
+                    return make_empty_encoder_model_runner_output(
+                        scheduler_output)
+
             if not scheduler_output.total_num_scheduled_tokens:
                 if not has_kv_transfer_group():
                     logger.debug(
@@ -3741,6 +3764,10 @@ def get_kv_cache_spec(self) -> dict[str, KVCacheSpec]:
             KVCacheSpec: A dictionary mapping layer names to their KV cache
             format. Layers that do not need KV cache are not included.
         """
+
+        if has_ec_transfer() and get_ec_transfer().is_producer:
+            return {}
+
         block_size = self.vllm_config.cache_config.block_size
         use_mla = self.vllm_config.model_config.use_mla
         kv_cache_spec: dict[str, KVCacheSpec] = {}

vllm_ascend/worker/worker_v1.py

@@ -30,6 +30,7 @@
 from vllm.config import VllmConfig
 from vllm.distributed import (ensure_model_parallel_initialized,
                               init_distributed_environment)
+from vllm.distributed.ec_transfer import ensure_ec_transfer_initialized
 from vllm.distributed.kv_transfer import ensure_kv_transfer_initialized
 from vllm.distributed.parallel_state import get_pp_group, get_tp_group
 from vllm.logger import logger
@@ -417,6 +418,7 @@ def _init_worker_distributed_environment(self) -> None:
                 self.parallel_config.decode_context_parallel_size)
         init_ascend_model_parallel(self.parallel_config)
         ensure_kv_transfer_initialized(self.vllm_config)
+        ensure_ec_transfer_initialized(self.vllm_config)
 
     def _init_profiler(self):
         # Torch profiler. Enabled and configured through env vars: