[bugfix] 优化 reject-sampling 的 InputBatch 元数据处理

- 在 InputBatch.refresh_metadata 中为展开后的采样元数据引入 repeat_count 记录重复次数
- 完善元数据刷新逻辑以适配 reject-sampling 优化路径
- 更新 GPUModelRunnerBase，在 batch 处理阶段正确消费新的采样元数据与重复计数

vllm/v1/worker/gpu_input_batch.py

@@ -8,6 +8,7 @@ from typing import Optional, cast
 import numpy as np
 import torch
 
+from vllm import envs
 from vllm.lora.request import LoRARequest
 from vllm.multimodal.inputs import MultiModalKwargs, PlaceholderRange
 from vllm.pooling_params import PoolingParams
@@ -16,6 +17,10 @@ from vllm.utils import swap_dict_values
 from vllm.v1.outputs import LogprobsTensors
 from vllm.v1.pool.metadata import PoolingMetadata
 from vllm.v1.sample.logits_processor import (BatchUpdateBuilder,
+                                             LogitBiasLogitsProcessor,
+                                             LogitsProcessorManager,
+                                             MinPLogitsProcessor,
+                                             MinTokensLogitsProcessor,
                                              MoveDirectionality,
                                              init_builtin_logitsprocs)
 from vllm.v1.sample.metadata import SamplingMetadata
@@ -192,6 +197,10 @@ class InputBatch:
             self.repetition_penalties_cpu_tensor.numpy()
         self.repetition_penalties_reqs: set[str] = set()
 
+        # Track whether sampling metadata is currently expanded to
+        # per-token shape (spec decode reject path).
+        self._sampling_metadata_is_expanded = False
+
         # lora related
         self.request_lora_mapping = np.zeros((self.max_num_reqs, ),
                                              dtype=np.int32)
@@ -593,7 +602,7 @@ class InputBatch:
         del self._req_ids[self.num_reqs:]
         del self.req_output_token_ids[self.num_reqs:]
 
-    def refresh_metadata(self):
+    def refresh_metadata(self, repeat_counts: Optional[torch.Tensor] = None):
         """Apply batch updates, reset input batch at end of step
         
         * Apply batch add/remove/permute to logits procs' states
@@ -602,8 +611,17 @@ class InputBatch:
         batch_update = self.batch_update_builder.get_and_reset(self.num_reqs)
         for logit_proc in self.logitsprocs.all:
             logit_proc.update_state(batch_update)
-        if batch_update:
-            self.sampling_metadata = self._make_sampling_metadata()
+        needs_rebuild = (batch_update
+                         or repeat_counts is not None
+                         or self._sampling_metadata_is_expanded)
+        if needs_rebuild:
+            if repeat_counts is None:
+                self.sampling_metadata = self._make_sampling_metadata()
+            else:
+                self.sampling_metadata = self._make_sampling_metadata_expanded(
+                    repeat_counts)
+            self._sampling_metadata_is_expanded = repeat_counts is not None
+        # Expanded metadata is built on demand; do not cache a copy here.
 
     def _make_sampling_metadata(self) -> SamplingMetadata:
         num_reqs = self.num_reqs
@@ -666,6 +684,107 @@ class InputBatch:
             logitsprocs=self.logitsprocs,
         )
 
+    def _make_sampling_metadata_expanded(
+        self, repeat_counts: torch.Tensor
+    ) -> SamplingMetadata:
+        num_reqs = self.num_reqs
+        repeat_counts_cpu = repeat_counts
+        all_greedy = self.all_greedy
+        all_random = self.all_random
+        # For reject-sampling optimization, force greedy sampling to keep
+        # rejection sampler assumptions (per-request shapes) intact.
+
+        def _expand_cpu_to_gpu(
+            t: Optional[torch.Tensor],
+            *,
+            dtype: Optional[torch.dtype] = None,
+        ) -> Optional[torch.Tensor]:
+            if t is None:
+                return None
+            base = t[:num_reqs]
+            if repeat_counts_cpu is not None:
+                base = base.repeat_interleave(repeat_counts_cpu, dim=0)
+            return base.to(device=self.device,
+                           dtype=dtype if dtype is not None else None,
+                           non_blocking=True)
+
+        needs_prompt_token_ids = (not self.no_penalties or
+                                  (self.num_reqs > 0
+                                   and self.logits_processing_needs_token_ids))
+        if needs_prompt_token_ids:
+            # The prompt tokens are used only for applying penalties or
+            # step pooling during the sampling/pooling process.
+            # Hence copy these tensors only when there are requests which
+            # need penalties/step_pooler to be applied.
+            prompt_token_ids = self._make_prompt_token_ids_tensor(
+                repeat_counts_cpu)
+        else:
+            prompt_token_ids = None
+
+        allowed_token_ids_mask: Optional[torch.Tensor] = None
+        if not self.no_allowed_token_ids:
+            assert self.allowed_token_ids_mask is not None
+            allowed_token_ids_mask = self.allowed_token_ids_mask_cpu_tensor
+        # Expand per-request metadata to per-token shape when repeat_counts
+        # is provided (spec decode reject-sampling path).
+        top_p_cpu = None if self.no_top_p else self.top_p_cpu_tensor
+        top_k_cpu = None if self.no_top_k else self.top_k_cpu_tensor
+
+        repeat_list = repeat_counts_cpu.tolist()
+        row_offsets: list[int] = []
+        total_rows = 0
+        for repeat in repeat_list:
+            row_offsets.append(total_rows)
+            total_rows += int(repeat)
+        expanded_logitsprocs = self._expand_logitsprocs(
+            repeat_list, row_offsets, total_rows)
+        expanded_output_token_ids: list[list[int]] = []
+        expanded_bad_words_token_ids: dict[int, list[list[int]]] = {}
+        expanded_generators: dict[int, torch.Generator] = {}
+        row_idx = 0
+        for req_idx in range(num_reqs):
+            repeat = int(repeat_list[req_idx])
+            if repeat <= 0:
+                continue
+            output_tokens = self.req_output_token_ids[req_idx]
+            assert output_tokens is not None
+            bad_words = self.bad_words_token_ids.get(req_idx)
+            generator = self.generators.get(req_idx)
+            for _ in range(repeat):
+                expanded_output_token_ids.append(output_tokens)
+                if bad_words is not None:
+                    expanded_bad_words_token_ids[row_idx] = bad_words
+                if generator is not None:
+                    expanded_generators[row_idx] = generator
+                row_idx += 1
+
+        return SamplingMetadata(
+            temperature=_expand_cpu_to_gpu(
+                None if all_greedy else self.temperature_cpu_tensor),
+            all_greedy=all_greedy,
+            all_random=all_random,
+            top_p=_expand_cpu_to_gpu(top_p_cpu),
+            top_k=_expand_cpu_to_gpu(top_k_cpu, dtype=torch.int32),
+            generators=expanded_generators,
+            max_num_logprobs=self.max_num_logprobs,
+            prompt_token_ids=prompt_token_ids,
+            frequency_penalties=(
+                None if self.no_penalties else _expand_cpu_to_gpu(
+                    self.frequency_penalties_cpu_tensor)),
+            presence_penalties=(
+                None if self.no_penalties else _expand_cpu_to_gpu(
+                    self.presence_penalties_cpu_tensor)),
+            repetition_penalties=(
+                None if self.no_penalties else _expand_cpu_to_gpu(
+                    self.repetition_penalties_cpu_tensor)),
+            output_token_ids=expanded_output_token_ids,
+            no_penalties=self.no_penalties,
+            allowed_token_ids_mask=_expand_cpu_to_gpu(
+                allowed_token_ids_mask, dtype=torch.bool),
+            bad_words_token_ids=expanded_bad_words_token_ids,
+            logitsprocs=expanded_logitsprocs,
+        )
+
     @property
     def pooling_metadata(self) -> PoolingMetadata:
         if len(self.pooling_params) == 0:
@@ -685,7 +804,9 @@ class InputBatch:
             pooling_params=pooling_params,
         )
 
-    def _make_prompt_token_ids_tensor(self) -> torch.Tensor:
+    def _make_prompt_token_ids_tensor(
+        self, repeat_counts_cpu: Optional[torch.Tensor] = None
+    ) -> torch.Tensor:
         max_prompt_len = self.num_prompt_tokens[:self.num_reqs].max()
         prompt_token_ids_cpu_tensor = torch.empty(
             (self.num_reqs, max_prompt_len),
@@ -700,9 +821,116 @@ class InputBatch:
         # token_id of this value.
         for i in range(self.num_reqs):
             prompt_token_ids[i, self.num_prompt_tokens[i]:] = self.vocab_size
+        if repeat_counts_cpu is not None:
+            prompt_token_ids_cpu_tensor = prompt_token_ids_cpu_tensor \
+                .repeat_interleave(repeat_counts_cpu, dim=0)
         return prompt_token_ids_cpu_tensor.to(device=self.device,
                                               non_blocking=True)
 
+    def _expand_logitsprocs(
+        self, repeat_list: list[int], row_offsets: list[int], total_rows: int
+    ) -> LogitsProcessorManager:
+        """Expand per-request logits processors to per-token shape for
+        repeat_counts-expanded batches."""
+
+        def _expand_min_p(proc: MinPLogitsProcessor) -> MinPLogitsProcessor:
+            expanded = MinPLogitsProcessor(
+                max_num_reqs=total_rows,
+                pin_memory=self.pin_memory,
+                device=self.device)
+            if total_rows == 0:
+                expanded.min_p_count = 0
+                expanded.min_p = expanded.min_p_device[:0]
+                expanded.min_p.unsqueeze_(1)
+                return expanded
+            base_min_p_cpu = torch.from_numpy(proc.min_p_cpu[:self.num_reqs])
+            repeats = torch.tensor(repeat_list, dtype=torch.int64)
+            expanded_min_p_cpu = base_min_p_cpu.repeat_interleave(repeats)
+            expanded.min_p_cpu_tensor[:total_rows].copy_(expanded_min_p_cpu)
+            expanded.min_p = expanded.min_p_device[:total_rows]
+            expanded.min_p.copy_(expanded.min_p_cpu_tensor[:total_rows],
+                                 non_blocking=True)
+            expanded.min_p.unsqueeze_(1)
+            expanded.min_p_count = int((expanded_min_p_cpu != 0).sum().item())
+            return expanded
+
+        def _expand_logit_bias(
+                proc: LogitBiasLogitsProcessor) -> LogitBiasLogitsProcessor:
+            expanded = LogitBiasLogitsProcessor(pin_memory=self.pin_memory,
+                                                device=self.device)
+            # Preserve biases dict for truthiness and reuse.
+            expanded.biases = proc.biases
+            if not proc.biases or total_rows == 0:
+                return expanded
+            req_indices: list[int] = []
+            tok_indices: list[int] = []
+            bias_vals: list[float] = []
+            for req_idx, lb in proc.biases.items():
+                repeat = repeat_list[req_idx]
+                if repeat <= 0:
+                    continue
+                start = row_offsets[req_idx]
+                tok_ids = list(lb.keys())
+                biases = list(lb.values())
+                for row in range(start, start + repeat):
+                    req_indices.extend([row] * len(tok_ids))
+                    tok_indices.extend(tok_ids)
+                    bias_vals.extend(biases)
+            if bias_vals:
+                expanded.bias_tensor = expanded._device_tensor(
+                    bias_vals, torch.float32)
+                expanded.logits_slice = (
+                    expanded._device_tensor(req_indices, torch.int32),
+                    expanded._device_tensor(tok_indices, torch.int32),
+                )
+            return expanded
+
+        def _expand_min_tokens(
+                proc: MinTokensLogitsProcessor) -> MinTokensLogitsProcessor:
+            expanded = MinTokensLogitsProcessor(pin_memory=self.pin_memory,
+                                                device=self.device)
+            expanded.min_toks = proc.min_toks
+            if not proc.min_toks or total_rows == 0:
+                return expanded
+            req_indices: list[int] = []
+            tok_indices: list[int] = []
+            for req_idx, (_, _, stop_tok_ids) in proc.min_toks.items():
+                repeat = repeat_list[req_idx]
+                if repeat <= 0:
+                    continue
+                start = row_offsets[req_idx]
+                stop_ids = list(stop_tok_ids)
+                for row in range(start, start + repeat):
+                    req_indices.extend([row] * len(stop_ids))
+                    tok_indices.extend(stop_ids)
+            if tok_indices:
+                expanded.logits_slice = (
+                    expanded._device_tensor(req_indices, torch.int32),
+                    expanded._device_tensor(tok_indices, torch.int32),
+                )
+            return expanded
+
+        expanded_argmax: list = []
+        for proc in self.logitsprocs.argmax_invariant:
+            if isinstance(proc, MinPLogitsProcessor):
+                expanded_argmax.append(_expand_min_p(proc))
+            else:
+                expanded_argmax.append(proc)
+
+        expanded_non_argmax: list = []
+        for proc in self.logitsprocs.non_argmax_invariant:
+            if isinstance(proc, LogitBiasLogitsProcessor):
+                expanded_non_argmax.append(_expand_logit_bias(proc))
+            elif isinstance(proc, MinTokensLogitsProcessor):
+                expanded_non_argmax.append(_expand_min_tokens(proc))
+            else:
+                expanded_non_argmax.append(proc)
+
+        return LogitsProcessorManager(
+            argmax_invariant=expanded_argmax,
+            non_argmax_invariant=expanded_non_argmax,
+        )
+
     def make_lora_inputs(
         self, num_scheduled_tokens: np.ndarray
     ) -> tuple[tuple[int, ...], tuple[int, ...], set[LoRARequest]]:

vllm/v1/worker/gpu_model_runner.py

@@ -572,8 +572,21 @@ class GPUModelRunnerBase(LoRAModelRunnerMixin):
         self.input_batch.condense()
         # Allow attention backend to reorder the batch, potentially
         self._may_reorder_batch(scheduler_output)
-        # Refresh batch metadata with any pending updates.
-        self.input_batch.refresh_metadata()
+        # Refresh batch metadata with any pending updates. If we are in spec
+        # decode + reject mode, also expand sampling metadata to token shape
+        # using per-request repeat counts.
+        repeat_counts: Optional[torch.Tensor] = None
+        if envs.VLLM_REJECT_SAMPLE_OPT and \
+                scheduler_output.scheduled_spec_decode_tokens:
+            num_reqs = self.input_batch.num_reqs
+            num_draft_tokens = np.zeros(num_reqs, dtype=np.int32)
+            for req_id, draft_token_ids in (
+                    scheduler_output.scheduled_spec_decode_tokens.items()):
+                req_idx = self.input_batch.req_id_to_index.get(req_id)
+                if req_idx is not None:
+                    num_draft_tokens[req_idx] = len(draft_token_ids)
+            repeat_counts = torch.from_numpy(num_draft_tokens).add_(1)
+        self.input_batch.refresh_metadata(repeat_counts)
 
     def _get_cumsum_and_arange(
         self,
@@ -3360,8 +3373,8 @@ class GPUModelRunnerMTP(GPUModelRunnerBase):
                 )
                 sampler_output.sampled_token_ids = output_token_ids
             else:
-                sampling_metadata.all_greedy = True
-                sampling_metadata.all_random = False
+                # sampling_metadata.all_greedy = True
+                # sampling_metadata.all_random = False
                 sampler_output = self.sampler(
                     logits=logits,
                     sampling_metadata=sampling_metadata,