[Model Runner V2] support dp & ep for spec decoding (#35294)

Signed-off-by: Giancarlo Delfin <gdelfin@inferact.ai>
Signed-off-by: zhuhaoran <zhuhaoran.zhr@alibaba-inc.com>
Co-authored-by: Giancarlo Delfin <gdelfin@inferact.ai>

vllm/v1/worker/gpu/model_runner.py

@@ -57,10 +57,7 @@ from vllm.v1.worker.gpu.block_table import BlockTables
 from vllm.v1.worker.gpu.buffer_utils import async_copy_to_gpu
 from vllm.v1.worker.gpu.cp_utils import prepare_dcp_local_seq_lens
 from vllm.v1.worker.gpu.cudagraph_utils import CudaGraphManager
-from vllm.v1.worker.gpu.dp_utils import (
-    get_cudagraph_and_dp_padding,
-    make_num_tokens_across_dp,
-)
+from vllm.v1.worker.gpu.dp_utils import get_cudagraph_and_dp_padding
 from vllm.v1.worker.gpu.input_batch import (
     InputBatch,
     InputBuffers,
@@ -265,7 +262,7 @@ class GPUModelRunner(LoRAModelRunnerMixin):
 
         prepare_communication_buffer_for_model(self.model)
         if self.speculator is not None:
-            prepare_communication_buffer_for_model(self.speculator)
+            prepare_communication_buffer_for_model(self.speculator.model)
 
         # Initialize the components that require the model.
         self.model_state = init_model_state(
@@ -382,8 +379,41 @@ class GPUModelRunner(LoRAModelRunnerMixin):
             return None, None
 
         assert self.execute_model_state is not None
-        input_batch, _, _, _, hidden_states, _, _ = self.execute_model_state
+        (
+            input_batch,
+            model_inputs,
+            attn_metadata,
+            slot_mappings_by_layer,
+            hidden_states,
+            aux_hidden_states,
+            kv_connector_output,
+            num_tokens_across_dp,
+        ) = self.execute_model_state
         self.execute_model_state = None
+
+        # dummy run the eagle speculator's propose to ensure DP/EP sync.
+        if self.speculator is not None:
+            self.speculator.propose(
+                input_batch=input_batch,
+                attn_metadata=attn_metadata,
+                slot_mappings=slot_mappings_by_layer,
+                last_hidden_states=hidden_states,
+                aux_hidden_states=aux_hidden_states,
+                num_sampled=torch.ones(
+                    input_batch.num_reqs, dtype=torch.int32, device=self.device
+                ),
+                num_rejected=torch.zeros(
+                    input_batch.num_reqs, dtype=torch.int32, device=self.device
+                ),
+                last_sampled=self.req_states.last_sampled_tokens,
+                next_prefill_tokens=self.req_states.next_prefill_tokens,
+                temperature=self.sampler.sampling_states.temperature.gpu,
+                seeds=self.sampler.sampling_states.seeds.gpu,
+                num_tokens_across_dp=num_tokens_across_dp,
+                dummy_run=True,
+                skip_attn_for_dummy_run=skip_attn,
+            )
+
         assert hidden_states is not None  # Last PP rank always has hidden_states
         sample_hidden_states = hidden_states[input_batch.logits_indices]
         return hidden_states, sample_hidden_states
@@ -431,17 +461,6 @@ class GPUModelRunner(LoRAModelRunnerMixin):
             else:
                 self._dummy_pooler_run(hidden_states)
 
-            if self.speculator is not None:
-                num_tokens_across_dp = make_num_tokens_across_dp(
-                    self.parallel_config.data_parallel_size, self.max_num_tokens
-                )
-                self.speculator.run_model(
-                    self.max_num_tokens,
-                    attn_metadata=None,
-                    slot_mappings=None,
-                    num_tokens_across_dp=num_tokens_across_dp,
-                )
-
         torch.cuda.synchronize()
         del hidden_states, sample_hidden_states
         gc.collect()
@@ -979,6 +998,7 @@ class GPUModelRunner(LoRAModelRunnerMixin):
             hidden_states,
             aux_hidden_states,
             kv_connector_output,
+            num_tokens_across_dp,
         )
 
         if not self.is_last_pp_rank:
@@ -1005,6 +1025,7 @@ class GPUModelRunner(LoRAModelRunnerMixin):
             hidden_states,
             aux_hidden_states,
             kv_connector_output,
+            num_tokens_across_dp,
         ) = self.execute_model_state
         self.execute_model_state = None
 
@@ -1078,6 +1099,7 @@ class GPUModelRunner(LoRAModelRunnerMixin):
                 self.req_states.next_prefill_tokens,
                 self.sampler.sampling_states.temperature.gpu,
                 self.sampler.sampling_states.seeds.gpu,
+                num_tokens_across_dp=num_tokens_across_dp,
             )
             self.req_states.draft_tokens[input_batch.idx_mapping] = draft_tokens
             self.draft_tokens_handler.set_draft_tokens(input_batch, draft_tokens)

vllm/v1/worker/gpu/spec_decode/eagle/cudagraph.py

@@ -55,6 +55,26 @@ class EagleCudaGraphManager:
     def get_cudagraph_size(self, num_tokens: int) -> int | None:
         return self.cudagraph_sizes.get(num_tokens)
 
+    def get_cudagraph_runtime_mode(
+        self, num_tokens: int
+    ) -> tuple[CUDAGraphMode, int | None]:
+        cudagraph_size = self.get_cudagraph_size(num_tokens)
+        if cudagraph_size is None:
+            cudagraph_mode = CUDAGraphMode.NONE
+        else:
+            cudagraph_mode = self.cudagraph_mode
+
+        if (
+            cudagraph_mode == CUDAGraphMode.FULL
+            and cudagraph_size is not None
+            and cudagraph_size not in self.graphs
+        ):
+            # If graph wasn't captured yet, fall back to eager.
+            # This might happen when the dummy run is called before capture.
+            cudagraph_mode = CUDAGraphMode.NONE
+            cudagraph_size = None
+        return cudagraph_mode, cudagraph_size
+
     def capture_graph(
         self,
         num_tokens: int,

vllm/v1/worker/gpu/spec_decode/eagle/speculator.py

@@ -16,6 +16,7 @@ from vllm.v1.worker.gpu.attn_utils import (
     build_slot_mappings_by_layer,
 )
 from vllm.v1.worker.gpu.block_table import BlockTables
+from vllm.v1.worker.gpu.dp_utils import get_cudagraph_and_dp_padding
 from vllm.v1.worker.gpu.input_batch import InputBatch, InputBuffers
 from vllm.v1.worker.gpu.model_states.interface import ModelState
 from vllm.v1.worker.gpu.sample.gumbel import gumbel_sample
@@ -48,6 +49,10 @@ class EagleSpeculator:
         self.vocab_size = self.draft_model_config.get_vocab_size()
         self.dtype = vllm_config.model_config.dtype
 
+        # DP configuration
+        self.dp_size = vllm_config.parallel_config.data_parallel_size
+        self.dp_rank = vllm_config.parallel_config.data_parallel_rank
+
         self.input_buffers = InputBuffers(
             max_num_reqs=self.max_num_reqs,
             max_num_tokens=self.max_num_tokens,
@@ -122,8 +127,8 @@ class EagleSpeculator:
         self,
         num_reqs: int,
         num_tokens_padded: int,
-        attn_metadata: dict[str, Any],
-        slot_mappings: dict[str, torch.Tensor],
+        attn_metadata: dict[str, Any] | None,
+        slot_mappings: dict[str, torch.Tensor] | None,
         num_tokens_across_dp: torch.Tensor | None,
         cudagraph_runtime_mode: CUDAGraphMode = CUDAGraphMode.NONE,
     ) -> None:
@@ -164,6 +169,7 @@ class EagleSpeculator:
                     self.hidden_states,
                     self.max_model_len,
                 )
+                if attn_metadata is not None:
                     self.block_tables.compute_slot_mappings(
                         idx_mapping, query_start_loc, pos
                     )
@@ -203,6 +209,9 @@ class EagleSpeculator:
         temperature: torch.Tensor,
         # [max_num_reqs]
         seeds: torch.Tensor,
+        num_tokens_across_dp: torch.Tensor | None = None,
+        dummy_run: bool = False,
+        skip_attn_for_dummy_run: bool = False,
     ) -> torch.Tensor:
         # NOTE(woosuk): To avoid CPU-GPU synchronization without CPU knowing the
         # number of rejected tokens, we maintain the size of eagle's input_ids and
@@ -236,7 +245,7 @@ class EagleSpeculator:
             num_tokens,
             attn_metadata,
             slot_mappings,
-            num_tokens_across_dp=None,  # FIXME
+            num_tokens_across_dp=num_tokens_across_dp,
         )
         sample_hidden_states = last_hidden_states[last_token_indices]
         logits = self.model.compute_logits(sample_hidden_states)
@@ -282,27 +291,42 @@ class EagleSpeculator:
             self.max_model_len,
             self.max_num_reqs,
         )
+
+        if not (dummy_run and skip_attn_for_dummy_run):
             query_start_loc = self.input_buffers.query_start_loc[: num_reqs + 1]
             slot_mappings = self.block_tables.compute_slot_mappings(
                 idx_mapping, query_start_loc, pos
             )
 
-        cudagraph_size = self.cudagraph_manager.get_cudagraph_size(num_reqs)
-        cudagraph_mode = self.cudagraph_manager.cudagraph_mode
-        if cudagraph_size is not None and cudagraph_mode == CUDAGraphMode.FULL:
+        cudagraph_mode, cudagraph_size = (
+            self.cudagraph_manager.get_cudagraph_runtime_mode(num_reqs)
+        )
+        num_tokens_padded, num_tokens_across_dp, synced_cudagraph_mode = (
+            get_cudagraph_and_dp_padding(
+                num_reqs,
+                cudagraph_size,
+                cudagraph_mode.value,
+                self.dp_size,
+                self.dp_rank,
+            )
+        )
+        cudagraph_mode = CUDAGraphMode(synced_cudagraph_mode)
+        if cudagraph_mode == CUDAGraphMode.FULL:
             # Run full CUDA graph.
-            self.cudagraph_manager.run_fullgraph(cudagraph_size)
+            self.cudagraph_manager.run_fullgraph(num_tokens_padded)
             return self.draft_tokens[:num_reqs]
 
         # Run eager or piecewise CUDA graph.
-        num_tokens_padded = cudagraph_size if cudagraph_size is not None else num_reqs
+        attn_metadata_updated = None
+        slot_mappings_updated = None
+        if not (dummy_run and skip_attn_for_dummy_run):
             query_start_loc_cpu = torch.arange(
                 num_reqs + 1, dtype=torch.int32, device="cpu"
             )
             block_tables = [x[:num_reqs] for x in self.block_tables.input_block_tables]
 
             # FIXME(woosuk): This is UNSAFE!!
-        attn_metadata = build_attn_metadata(
+            attn_metadata_updated = build_attn_metadata(
                 attn_groups=self.attn_groups,
                 num_reqs=num_reqs,
                 num_tokens=num_reqs,
@@ -315,15 +339,16 @@ class EagleSpeculator:
                 slot_mappings=slot_mappings,
                 kv_cache_config=self.kv_cache_config,
             )
-        slot_mappings_by_layer = build_slot_mappings_by_layer(
+            slot_mappings_updated = build_slot_mappings_by_layer(
                 slot_mappings, self.kv_cache_config
             )
+
         self.generate_draft(
             num_reqs,
             num_tokens_padded,
-            attn_metadata,
-            slot_mappings_by_layer,
-            num_tokens_across_dp=None,  # FIXME
+            attn_metadata_updated,
+            slot_mappings_updated,
+            num_tokens_across_dp=num_tokens_across_dp,
             cudagraph_runtime_mode=cudagraph_mode,
         )
         return self.draft_tokens[:num_reqs]