Move sampler into CUDA graph (#1201)

Co-authored-by: Yineng Zhang <me@zhyncs.com>

python/sglang/srt/layers/logits_processor.py

@@ -29,7 +29,7 @@ from sglang.srt.model_executor.forward_batch_info import ForwardMode, InputMetad
 
 
 @dataclasses.dataclass
-class LogitProcessorOutput:
+class LogitsProcessorOutput:
     # The logits of the next tokens.       shape: [#seq, vocab_size]
     next_token_logits: torch.Tensor
     # The logprobs of the next tokens.     shape: [#seq, vocab_size]
@@ -185,7 +185,7 @@ class LogitsProcessor(nn.Module):
 
         # Return only last_logits if logprob is not requested
         if not logits_metadata.return_logprob:
-            return LogitProcessorOutput(
+            return LogitsProcessorOutput(
                 next_token_logits=last_logits,
                 next_token_logprobs=None,
                 normalized_prompt_logprobs=None,
@@ -209,7 +209,7 @@ class LogitsProcessor(nn.Module):
                 else:
                     output_top_logprobs = None
 
-                return LogitProcessorOutput(
+                return LogitsProcessorOutput(
                     next_token_logits=last_logits,
                     next_token_logprobs=last_logprobs,
                     normalized_prompt_logprobs=None,
@@ -278,7 +278,7 @@ class LogitsProcessor(nn.Module):
                 # Remove the last token logprob for the prefill tokens.
                 input_token_logprobs = input_token_logprobs[:-1]
 
-                return LogitProcessorOutput(
+                return LogitsProcessorOutput(
                     next_token_logits=last_logits,
                     next_token_logprobs=last_logprobs,
                     normalized_prompt_logprobs=normalized_prompt_logprobs,

python/sglang/srt/layers/sampler.py

+import dataclasses
 import logging
+from typing import Union
 
 import torch
 from flashinfer.sampling import (
@@ -9,6 +11,8 @@ from flashinfer.sampling import (
 )
 from vllm.model_executor.custom_op import CustomOp
 
+from sglang.srt.layers.logits_processor import LogitsProcessorOutput
+
 # TODO: move this dict to another place
 from sglang.srt.managers.schedule_batch import global_server_args_dict
 from sglang.srt.sampling.sampling_batch_info import SamplingBatchInfo
@@ -16,30 +20,71 @@ from sglang.srt.sampling.sampling_batch_info import SamplingBatchInfo
 logger = logging.getLogger(__name__)
 
 
+@dataclasses.dataclass
+class SampleOutput:
+    success: torch.Tensor
+    probs: torch.Tensor
+    batch_next_token_ids: torch.Tensor
+
+
 class Sampler(CustomOp):
     def __init__(self):
         super().__init__()
 
-    def forward_cuda(self, logits: torch.Tensor, sampling_info: SamplingBatchInfo):
+    def _apply_penalties(self, logits: torch.Tensor, sampling_info: SamplingBatchInfo):
+        # min-token, presence, frequency
+        if sampling_info.linear_penalties is not None:
+            logits += sampling_info.linear_penalties
+
+        # repetition
+        if sampling_info.scaling_penalties is not None:
+            logits = torch.where(
+                logits > 0,
+                logits / sampling_info.scaling_penalties,
+                logits * sampling_info.scaling_penalties,
+            )
+
+        return logits
+
+    def _get_probs(
+        self,
+        logits: torch.Tensor,
+        sampling_info: SamplingBatchInfo,
+        is_torch_compile: bool = False,
+    ):
         # Post process logits
         logits = logits.contiguous()
         logits.div_(sampling_info.temperatures)
+        if is_torch_compile:
+            # FIXME: Temporary workaround for unknown bugs in torch.compile
+            logits.add_(0)
+
         if sampling_info.logit_bias is not None:
             logits.add_(sampling_info.logit_bias)
 
         if sampling_info.vocab_mask is not None:
             logits = logits.masked_fill(~sampling_info.vocab_mask, float("-inf"))
 
-        logits = sampling_info.penalizer_orchestrator.apply(logits)
+        logits = self._apply_penalties(logits, sampling_info)
+
+        return torch.softmax(logits, dim=-1)
 
-        probs = torch.softmax(logits, dim=-1)
+    def forward_cuda(
+        self,
+        logits: Union[torch.Tensor, LogitsProcessorOutput],
+        sampling_info: SamplingBatchInfo,
+    ):
+        if isinstance(logits, LogitsProcessorOutput):
+            logits = logits.next_token_logits
+
+        probs = self._get_probs(logits, sampling_info)
 
         if not global_server_args_dict["disable_flashinfer_sampling"]:
             max_top_k_round, batch_size = 32, probs.shape[0]
             uniform_samples = torch.rand(
                 (max_top_k_round, batch_size), device=probs.device
             )
-            if sampling_info.min_ps.any():
+            if sampling_info.need_min_p_sampling:
                 probs = top_k_renorm_prob(probs, sampling_info.top_ks)
                 probs = top_p_renorm_prob(probs, sampling_info.top_ps)
                 batch_next_token_ids, success = min_p_sampling_from_probs(
@@ -55,18 +100,23 @@ class Sampler(CustomOp):
                 probs, sampling_info.top_ks, sampling_info.top_ps, sampling_info.min_ps
             )
 
-        if not torch.all(success):
-            logging.warning("Sampling failed, fallback to top_k=1 strategy")
-            probs = probs.masked_fill(torch.isnan(probs), 0.0)
-            argmax_ids = torch.argmax(probs, dim=-1)
-            batch_next_token_ids = torch.where(
-                success, batch_next_token_ids, argmax_ids
-            )
+        return SampleOutput(success, probs, batch_next_token_ids)
+
+    def forward_native(
+        self,
+        logits: Union[torch.Tensor, LogitsProcessorOutput],
+        sampling_info: SamplingBatchInfo,
+    ):
+        if isinstance(logits, LogitsProcessorOutput):
+            logits = logits.next_token_logits
+
+        probs = self._get_probs(logits, sampling_info, is_torch_compile=True)
 
-        return batch_next_token_ids
+        batch_next_token_ids, success = top_k_top_p_min_p_sampling_from_probs_torch(
+            probs, sampling_info.top_ks, sampling_info.top_ps, sampling_info.min_ps
+        )
 
-    def forward_native():
-        raise NotImplementedError("Native forward is not implemented yet.")
+        return SampleOutput(success, probs, batch_next_token_ids)
 
 
 def top_k_top_p_min_p_sampling_from_probs_torch(
@@ -87,7 +137,10 @@ def top_k_top_p_min_p_sampling_from_probs_torch(
     probs_sort[probs_sort < min_p_thresholds.view(-1, 1)] = 0.0
     probs_sort.div_(probs_sort.max(dim=-1, keepdim=True)[0])
     try:
-        sampled_index = torch.multinomial(probs_sort, num_samples=1)
+        # FIXME: torch.multiomial does not support num_samples = 1
+        sampled_index = torch.multinomial(probs_sort, num_samples=2, replacement=True)[
+            :, :1
+        ]
     except RuntimeError as e:
         logger.warning(f"Sampling error: {e}")
         batch_next_token_ids = torch.zeros(

python/sglang/srt/managers/schedule_batch.py

+from __future__ import annotations
+
 """
 Copyright 2023-2024 SGLang Team
 Licensed under the Apache License, Version 2.0 (the "License");
@@ -17,7 +19,7 @@ limitations under the License.
 
 import logging
 from dataclasses import dataclass
-from typing import List, Optional, Union
+from typing import TYPE_CHECKING, List, Optional, Union
 
 import torch
 
@@ -29,6 +31,10 @@ from sglang.srt.mem_cache.chunk_cache import ChunkCache
 from sglang.srt.mem_cache.memory_pool import BaseTokenToKVPool, ReqToTokenPool
 from sglang.srt.sampling.sampling_batch_info import SamplingBatchInfo
 
+if TYPE_CHECKING:
+    from sglang.srt.layers.sampler import SampleOutput
+
+
 INIT_INCREMENTAL_DETOKENIZATION_OFFSET = 5
 
 # Put some global args for easy access
@@ -671,11 +677,17 @@ class ScheduleBatch:
         self.top_logprobs_nums.extend(other.top_logprobs_nums)
         self.return_logprob = any(req.return_logprob for req in self.reqs)
 
-    def sample(self, logits: torch.Tensor):
-        from sglang.srt.layers.sampler import Sampler
-
-        sampler = Sampler()
-
-        batch_next_token_ids = sampler(logits, self.sampling_info)
+    def check_sample_results(self, sample_output: SampleOutput):
+        if not torch.all(sample_output.success):
+            probs = sample_output.probs
+            batch_next_token_ids = sample_output.batch_next_token_ids
+            logging.warning("Sampling failed, fallback to top_k=1 strategy")
+            probs = probs.masked_fill(torch.isnan(probs), 0.0)
+            argmax_ids = torch.argmax(probs, dim=-1)
+            batch_next_token_ids = torch.where(
+                sample_output.success, batch_next_token_ids, argmax_ids
+            )
+            sample_output.probs = probs
+            sample_output.batch_next_token_ids = batch_next_token_ids
 
-        return batch_next_token_ids
+        return sample_output.batch_next_token_ids

python/sglang/srt/managers/tp_worker.py

@@ -31,7 +31,7 @@ from sglang.global_config import global_config
 from sglang.srt.constrained.fsm_cache import FSMCache
 from sglang.srt.constrained.jump_forward import JumpForwardCache
 from sglang.srt.hf_transformers_utils import get_processor, get_tokenizer
-from sglang.srt.layers.logits_processor import LogitProcessorOutput
+from sglang.srt.layers.logits_processor import LogitsProcessorOutput
 from sglang.srt.managers.io_struct import (
     AbortReq,
     BatchEmbeddingOut,
@@ -486,21 +486,29 @@ class ModelTpServer:
         if self.model_runner.is_generation:
             # Forward and sample the next tokens
             if batch.extend_num_tokens != 0:
-                output = self.model_runner.forward(batch, ForwardMode.EXTEND)
-                next_token_ids = batch.sample(output.next_token_logits)
+                sample_output, logits_output = self.model_runner.forward(
+                    batch, ForwardMode.EXTEND
+                )
+                next_token_ids = batch.check_sample_results(sample_output)
                 batch.sampling_info.penalizer_orchestrator.cumulate_output_tokens(
                     next_token_ids
                 )
 
                 # Move logprobs to cpu
-                if output.next_token_logprobs is not None:
-                    output.next_token_logprobs = output.next_token_logprobs[
-                        torch.arange(len(next_token_ids), device=next_token_ids.device),
+                if logits_output.next_token_logprobs is not None:
+                    logits_output.next_token_logprobs = (
+                        logits_output.next_token_logprobs[
+                            torch.arange(
+                                len(next_token_ids), device=next_token_ids.device
+                            ),
                             next_token_ids,
                         ].tolist()
-                    output.input_token_logprobs = output.input_token_logprobs.tolist()
-                    output.normalized_prompt_logprobs = (
-                        output.normalized_prompt_logprobs.tolist()
+                    )
+                    logits_output.input_token_logprobs = (
+                        logits_output.input_token_logprobs.tolist()
+                    )
+                    logits_output.normalized_prompt_logprobs = (
+                        logits_output.normalized_prompt_logprobs.tolist()
                     )
 
                 next_token_ids = next_token_ids.tolist()
@@ -539,12 +547,14 @@ class ModelTpServer:
                     self.req_to_token_pool.free(req.req_pool_idx)
 
                 if req.return_logprob:
-                    self.add_logprob_return_values(i, req, pt, next_token_ids, output)
+                    self.add_logprob_return_values(
+                        i, req, pt, next_token_ids, logits_output
+                    )
                     pt += req.extend_input_len
         else:
             assert batch.extend_num_tokens != 0
-            output = self.model_runner.forward(batch, ForwardMode.EXTEND)
-            embeddings = output.embeddings.tolist()
+            logits_output = self.model_runner.forward(batch, ForwardMode.EXTEND)
+            embeddings = logits_output.embeddings.tolist()
 
             # Check finish conditions
             for i, req in enumerate(batch.reqs):
@@ -572,7 +582,7 @@ class ModelTpServer:
         req: Req,
         pt: int,
         next_token_ids: List[int],
-        output: LogitProcessorOutput,
+        output: LogitsProcessorOutput,
     ):
         if req.normalized_prompt_logprob is None:
             req.normalized_prompt_logprob = output.normalized_prompt_logprobs[i]
@@ -654,15 +664,17 @@ class ModelTpServer:
         batch.prepare_for_decode()
 
         # Forward and sample the next tokens
-        output = self.model_runner.forward(batch, ForwardMode.DECODE)
-        next_token_ids = batch.sample(output.next_token_logits)
+        sample_output, logits_output = self.model_runner.forward(
+            batch, ForwardMode.DECODE
+        )
+        next_token_ids = batch.check_sample_results(sample_output)
         batch.sampling_info.penalizer_orchestrator.cumulate_output_tokens(
             next_token_ids
         )
 
         # Move logprobs to cpu
-        if output.next_token_logprobs is not None:
-            next_token_logprobs = output.next_token_logprobs[
+        if logits_output.next_token_logprobs is not None:
+            next_token_logprobs = logits_output.next_token_logprobs[
                 torch.arange(len(next_token_ids), device=next_token_ids.device),
                 next_token_ids,
             ].tolist()
@@ -688,7 +700,7 @@ class ModelTpServer:
                     (next_token_logprobs[i], next_token_id)
                 )
                 if req.top_logprobs_num > 0:
-                    req.output_top_logprobs.append(output.output_top_logprobs[i])
+                    req.output_top_logprobs.append(logits_output.output_top_logprobs[i])
 
         self.handle_finished_requests(batch)
 

python/sglang/srt/model_executor/cuda_graph_runner.py

@@ -25,16 +25,18 @@ from vllm.distributed.parallel_state import graph_capture
 from vllm.model_executor.custom_op import CustomOp
 
 from sglang.srt.layers.logits_processor import (
-    LogitProcessorOutput,
     LogitsMetadata,
     LogitsProcessor,
+    LogitsProcessorOutput,
 )
+from sglang.srt.layers.sampler import SampleOutput
 from sglang.srt.managers.schedule_batch import ScheduleBatch
 from sglang.srt.model_executor.forward_batch_info import (
     ForwardMode,
     InputMetadata,
     update_flashinfer_indices,
 )
+from sglang.srt.sampling.sampling_batch_info import SamplingBatchInfo
 from sglang.srt.utils import monkey_patch_vllm_all_gather
 
 
@@ -143,6 +145,10 @@ class CudaGraphRunner:
                 self.flashinfer_kv_indices.clone(),
             ]
 
+        # Sampling inputs
+        vocab_size = model_runner.model_config.vocab_size
+        self.sampling_info = SamplingBatchInfo.dummy_one(self.max_bs, vocab_size)
+
         self.compile_bs = [1, 2, 4, 8, 16, 24, 32] if use_torch_compile else []
 
         if use_torch_compile:
@@ -234,6 +240,7 @@ class CudaGraphRunner:
         def run_once():
             input_metadata = InputMetadata(
                 forward_mode=ForwardMode.DECODE,
+                sampling_info=self.sampling_info[:bs],
                 batch_size=bs,
                 req_pool_indices=req_pool_indices,
                 seq_lens=seq_lens,
@@ -298,27 +305,35 @@ class CudaGraphRunner:
             self.flashinfer_handlers[bs],
         )
 
+        # Sampling inputs
+        self.sampling_info.inplace_assign(raw_bs, batch.sampling_info)
+
         # Replay
         torch.cuda.synchronize()
         self.graphs[bs].replay()
         torch.cuda.synchronize()
-        output = self.output_buffers[bs]
+        sample_output, logits_output = self.output_buffers[bs]
 
         # Unpad
         if bs != raw_bs:
-            output = LogitProcessorOutput(
-                next_token_logits=output.next_token_logits[:raw_bs],
+            logits_output = LogitsProcessorOutput(
+                next_token_logits=logits_output.next_token_logits[:raw_bs],
                 next_token_logprobs=None,
                 normalized_prompt_logprobs=None,
                 input_token_logprobs=None,
                 input_top_logprobs=None,
                 output_top_logprobs=None,
             )
+            sample_output = SampleOutput(
+                sample_output.success[:raw_bs],
+                sample_output.probs[:raw_bs],
+                sample_output.batch_next_token_ids[:raw_bs],
+            )
 
         # Extract logprobs
         if batch.return_logprob:
-            output.next_token_logprobs = torch.nn.functional.log_softmax(
-                output.next_token_logits, dim=-1
+            logits_output.next_token_logprobs = torch.nn.functional.log_softmax(
+                logits_output.next_token_logits, dim=-1
             )
             return_top_logprob = any(x > 0 for x in batch.top_logprobs_nums)
             if return_top_logprob:
@@ -326,8 +341,8 @@ class CudaGraphRunner:
                     forward_mode=ForwardMode.DECODE,
                     top_logprobs_nums=batch.top_logprobs_nums,
                 )
-                output.output_top_logprobs = LogitsProcessor.get_top_logprobs(
-                    output.next_token_logprobs, logits_metadata
+                logits_output.output_top_logprobs = LogitsProcessor.get_top_logprobs(
+                    logits_output.next_token_logprobs, logits_metadata
                 )[1]
 
-        return output
+        return sample_output, logits_output

python/sglang/srt/model_executor/forward_batch_info.py

+from __future__ import annotations
+
 """
 Copyright 2023-2024 SGLang Team
 Licensed under the Apache License, Version 2.0 (the "License");
@@ -16,7 +18,7 @@ limitations under the License.
 """ModelRunner runs the forward passes of the models."""
 from dataclasses import dataclass
 from enum import IntEnum, auto
-from typing import TYPE_CHECKING, List, Optional
+from typing import TYPE_CHECKING, List
 
 import numpy as np
 import torch
@@ -26,6 +28,7 @@ from sglang.srt.mem_cache.memory_pool import BaseTokenToKVPool, ReqToTokenPool
 
 if TYPE_CHECKING:
     from sglang.srt.model_executor.model_runner import ModelRunner
+    from sglang.srt.sampling.sampling_batch_info import SamplingBatchInfo
 
 
 class ForwardMode(IntEnum):
@@ -42,6 +45,7 @@ class InputMetadata:
     """Store all inforamtion of a forward pass."""
 
     forward_mode: ForwardMode
+    sampling_info: SamplingBatchInfo
     batch_size: int
     req_pool_indices: torch.Tensor
     seq_lens: torch.Tensor
@@ -179,6 +183,7 @@ class InputMetadata:
     ):
         ret = cls(
             forward_mode=forward_mode,
+            sampling_info=batch.sampling_info,
             batch_size=batch.batch_size(),
             req_pool_indices=batch.req_pool_indices,
             seq_lens=batch.seq_lens,
@@ -189,6 +194,8 @@ class InputMetadata:
             top_logprobs_nums=batch.top_logprobs_nums,
         )
 
+        ret.sampling_info.prepare_penalties()
+
         ret.compute_positions(batch)
 
         ret.compute_extend_infos(batch)

python/sglang/srt/model_executor/model_runner.py

@@ -21,7 +21,7 @@ import importlib.resources
 import logging
 import pkgutil
 from functools import lru_cache
-from typing import Optional, Type
+from typing import Optional, Tuple, Type
 
 import torch
 import torch.nn as nn
@@ -44,6 +44,8 @@ from vllm.model_executor.model_loader import get_model
 from vllm.model_executor.models import ModelRegistry
 
 from sglang.global_config import global_config
+from sglang.srt.layers.logits_processor import LogitsProcessorOutput
+from sglang.srt.layers.sampler import SampleOutput
 from sglang.srt.managers.schedule_batch import ScheduleBatch, global_server_args_dict
 from sglang.srt.mem_cache.memory_pool import (
     MHATokenToKVPool,
@@ -514,7 +516,11 @@ class ModelRunner:
 
     @torch.inference_mode()
     def forward_decode(self, batch: ScheduleBatch):
-        if self.cuda_graph_runner and self.cuda_graph_runner.can_run(len(batch.reqs)):
+        if (
+            self.cuda_graph_runner
+            and self.cuda_graph_runner.can_run(len(batch.reqs))
+            and not batch.sampling_info.has_bias()
+        ):
             return self.cuda_graph_runner.replay(batch)
 
         input_metadata = InputMetadata.from_schedule_batch(
@@ -563,7 +569,9 @@ class ModelRunner:
             input_metadata.image_offsets,
         )
 
-    def forward(self, batch: ScheduleBatch, forward_mode: ForwardMode):
+    def forward(
+        self, batch: ScheduleBatch, forward_mode: ForwardMode
+    ) -> Tuple[SampleOutput, LogitsProcessorOutput]:
         if self.is_multimodal_model and forward_mode == ForwardMode.EXTEND:
             return self.forward_extend_multi_modal(batch)
         elif forward_mode == ForwardMode.DECODE:

python/sglang/srt/models/chatglm.py

@@ -31,20 +31,18 @@ from vllm.model_executor.layers.linear import (
 )
 from vllm.model_executor.layers.quantization.base_config import QuantizationConfig
 from vllm.model_executor.layers.rotary_embedding import get_rope
-from vllm.model_executor.layers.sampler import Sampler
 from vllm.model_executor.layers.vocab_parallel_embedding import (
     ParallelLMHead,
     VocabParallelEmbedding,
 )
 from vllm.model_executor.model_loader.weight_utils import default_weight_loader
-from vllm.model_executor.sampling_metadata import SamplingMetadata
-from vllm.sequence import SamplerOutput
 from vllm.transformers_utils.configs import ChatGLMConfig
 
 from sglang.srt.layers.activation import SiluAndMul
 from sglang.srt.layers.layernorm import RMSNorm
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 LoraConfig = None
@@ -383,17 +381,11 @@ class ChatGLMForCausalLM(nn.Module):
         input_metadata: InputMetadata,
     ) -> torch.Tensor:
         hidden_states = self.transformer(input_ids, positions, input_metadata)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.lm_head.weight, input_metadata
         )
-
-    def sample(
-        self,
-        logits: torch.Tensor,
-        sampling_metadata: SamplingMetadata,
-    ) -> Optional[SamplerOutput]:
-        next_tokens = self.sampler(logits, sampling_metadata)
-        return next_tokens
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         params_dict = dict(self.named_parameters(remove_duplicate=False))

python/sglang/srt/models/commandr.py

@@ -64,6 +64,7 @@ from vllm.model_executor.utils import set_weight_attrs
 from sglang.srt.layers.activation import SiluAndMul
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -326,6 +327,7 @@ class CohereForCausalLM(nn.Module):
         self.config = config
         self.quant_config = quant_config
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
         self.model = CohereModel(config, quant_config)
 
     @torch.no_grad()
@@ -340,9 +342,11 @@ class CohereForCausalLM(nn.Module):
             positions,
             input_metadata,
         )
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.model.embed_tokens.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         stacked_params_mapping = [

python/sglang/srt/models/dbrx.py

@@ -45,6 +45,7 @@ from vllm.transformers_utils.configs.dbrx import DbrxConfig
 
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -382,6 +383,7 @@ class DbrxForCausalLM(nn.Module):
             padding_size=DEFAULT_VOCAB_PADDING_SIZE,
         )
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
     @torch.no_grad()
     def forward(
@@ -391,9 +393,11 @@ class DbrxForCausalLM(nn.Module):
         input_metadata: InputMetadata,
     ) -> torch.Tensor:
         hidden_states = self.transformer(input_ids, positions, input_metadata)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.lm_head.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         expert_params_mapping = [

python/sglang/srt/models/deepseek.py

@@ -46,6 +46,7 @@ from sglang.srt.layers.activation import SiluAndMul
 from sglang.srt.layers.layernorm import RMSNorm
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -385,6 +386,7 @@ class DeepseekForCausalLM(nn.Module):
             config.vocab_size, config.hidden_size, quant_config=quant_config
         )
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
     @torch.no_grad()
     def forward(
@@ -394,9 +396,11 @@ class DeepseekForCausalLM(nn.Module):
         input_metadata: InputMetadata,
     ) -> torch.Tensor:
         hidden_states = self.model(input_ids, positions, input_metadata)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.lm_head.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         stacked_params_mapping = [

python/sglang/srt/models/deepseek_v2.py

@@ -45,6 +45,7 @@ from sglang.srt.layers.activation import SiluAndMul
 from sglang.srt.layers.layernorm import RMSNorm
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.managers.schedule_batch import global_server_args_dict
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
@@ -632,6 +633,7 @@ class DeepseekV2ForCausalLM(nn.Module):
             config.vocab_size, config.hidden_size, quant_config=quant_config
         )
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
     def forward(
         self,
@@ -640,9 +642,11 @@ class DeepseekV2ForCausalLM(nn.Module):
         input_metadata: InputMetadata,
     ) -> torch.Tensor:
         hidden_states = self.model(input_ids, positions, input_metadata)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.lm_head.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         stacked_params_mapping = [

python/sglang/srt/models/gemma.py

@@ -37,6 +37,7 @@ from vllm.model_executor.model_loader.weight_utils import default_weight_loader
 from sglang.srt.layers.layernorm import RMSNorm
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -287,6 +288,7 @@ class GemmaForCausalLM(nn.Module):
         self.quant_config = quant_config
         self.model = GemmaModel(config, quant_config=quant_config)
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
     @torch.no_grad()
     def forward(
@@ -297,9 +299,11 @@ class GemmaForCausalLM(nn.Module):
         input_embeds: torch.Tensor = None,
     ) -> torch.Tensor:
         hidden_states = self.model(input_ids, positions, input_metadata, input_embeds)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.model.embed_tokens.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return (sample_output, logits_output)
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         stacked_params_mapping = [

python/sglang/srt/models/gemma2.py

@@ -41,6 +41,7 @@ from vllm.model_executor.model_loader.weight_utils import default_weight_loader
 from sglang.srt.layers.activation import GeluAndMul
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -396,6 +397,7 @@ class Gemma2ForCausalLM(nn.Module):
         self.quant_config = quant_config
         self.model = Gemma2Model(config, cache_config, quant_config)
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
     @torch.no_grad()
     def forward(
@@ -406,9 +408,11 @@ class Gemma2ForCausalLM(nn.Module):
         input_embeds: torch.Tensor = None,
     ) -> torch.Tensor:
         hidden_states = self.model(input_ids, positions, input_metadata, input_embeds)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.model.embed_tokens.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def get_attention_sliding_window_size(self):
         return get_attention_sliding_window_size(self.config)

python/sglang/srt/models/gpt_bigcode.py

@@ -35,6 +35,7 @@ from vllm.model_executor.model_loader.weight_utils import default_weight_loader
 
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -261,6 +262,7 @@ class GPTBigCodeForCausalLM(nn.Module):
         if lora_config:
             self.unpadded_vocab_size += lora_config.lora_extra_vocab_size
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
     @torch.no_grad()
     def forward(
@@ -270,9 +272,11 @@ class GPTBigCodeForCausalLM(nn.Module):
         input_metadata: InputMetadata,
     ) -> torch.Tensor:
         hidden_states = self.transformer(input_ids, positions, input_metadata)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.lm_head.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         params_dict = dict(self.named_parameters(remove_duplicate=False))

python/sglang/srt/models/grok.py

@@ -46,6 +46,7 @@ from sglang.srt.layers.fused_moe import FusedMoE
 from sglang.srt.layers.layernorm import RMSNorm
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -297,6 +298,7 @@ class Grok1ModelForCausalLM(nn.Module):
         self.model = Grok1Model(config, quant_config=quant_config)
         self.lm_head = ParallelLMHead(config.vocab_size, config.hidden_size)
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
         # Monkey patch _prepare_weights to load pre-sharded weights
         setattr(DefaultModelLoader, "_prepare_weights", _prepare_presharded_weights)
@@ -313,9 +315,11 @@ class Grok1ModelForCausalLM(nn.Module):
         input_embeds: torch.Tensor = None,
     ) -> torch.Tensor:
         hidden_states = self.model(input_ids, positions, input_metadata, input_embeds)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.lm_head.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         stacked_params_mapping = [

python/sglang/srt/models/internlm2.py

@@ -40,6 +40,7 @@ from sglang.srt.layers.activation import SiluAndMul
 from sglang.srt.layers.layernorm import RMSNorm
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -262,6 +263,7 @@ class InternLM2ForCausalLM(nn.Module):
         self.model = InternLM2Model(config, quant_config)
         self.output = ParallelLMHead(config.vocab_size, config.hidden_size)
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
     @torch.no_grad()
     def forward(
@@ -272,9 +274,11 @@ class InternLM2ForCausalLM(nn.Module):
         input_embeds: torch.Tensor = None,
     ) -> torch.Tensor:
         hidden_states = self.model(input_ids, positions, input_metadata, input_embeds)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.output.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         stacked_params_mapping = [

python/sglang/srt/models/llama2.py

@@ -39,8 +39,9 @@ from vllm.model_executor.model_loader.weight_utils import default_weight_loader
 
 from sglang.srt.layers.activation import SiluAndMul
 from sglang.srt.layers.layernorm import RMSNorm
-from sglang.srt.layers.logits_processor import LogitProcessorOutput, LogitsProcessor
+from sglang.srt.layers.logits_processor import LogitsProcessor, LogitsProcessorOutput
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -302,6 +303,7 @@ class LlamaForCausalLM(nn.Module):
         self.model = LlamaModel(config, quant_config=quant_config)
         self.lm_head = ParallelLMHead(config.vocab_size, config.hidden_size)
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
     @torch.no_grad()
     def forward(
@@ -310,11 +312,13 @@ class LlamaForCausalLM(nn.Module):
         positions: torch.Tensor,
         input_metadata: InputMetadata,
         input_embeds: torch.Tensor = None,
-    ) -> LogitProcessorOutput:
+    ) -> LogitsProcessorOutput:
         hidden_states = self.model(input_ids, positions, input_metadata, input_embeds)
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, self.lm_head.weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def get_module_name(self, name):
         stacked_params_mapping = [

python/sglang/srt/models/llama_classification.py

@@ -24,7 +24,7 @@ from vllm.distributed import get_tensor_model_parallel_rank
 from vllm.model_executor.layers.quantization.base_config import QuantizationConfig
 from vllm.model_executor.model_loader.weight_utils import default_weight_loader
 
-from sglang.srt.layers.logits_processor import LogitProcessorOutput
+from sglang.srt.layers.logits_processor import LogitsProcessorOutput
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 from sglang.srt.models.llama2 import LlamaModel
 
@@ -65,7 +65,7 @@ class LlamaForClassification(nn.Module):
                 (input_metadata.batch_size, self.config.classification_out_size)
             ).to(input_ids.device)
 
-        return LogitProcessorOutput(
+        return LogitsProcessorOutput(
             next_token_logits=scores,
             next_token_logprobs=scores,
             normalized_prompt_logprobs=scores,

python/sglang/srt/models/minicpm.py

@@ -39,6 +39,7 @@ from sglang.srt.layers.activation import SiluAndMul
 from sglang.srt.layers.layernorm import RMSNorm
 from sglang.srt.layers.logits_processor import LogitsProcessor
 from sglang.srt.layers.radix_attention import RadixAttention
+from sglang.srt.layers.sampler import Sampler
 from sglang.srt.model_executor.forward_batch_info import InputMetadata
 
 
@@ -297,6 +298,7 @@ class MiniCPMForCausalLM(nn.Module):
         self.scale_width = self.config.hidden_size / self.config.dim_model_base
 
         self.logits_processor = LogitsProcessor(config)
+        self.sampler = Sampler()
 
     @torch.no_grad()
     def forward(
@@ -314,9 +316,11 @@ class MiniCPMForCausalLM(nn.Module):
             lm_head_weight = self.model.embed_tokens.weight
         else:
             lm_head_weight = self.lm_head.weight
-        return self.logits_processor(
+        logits_output = self.logits_processor(
             input_ids, hidden_states, lm_head_weight, input_metadata
         )
+        sample_output = self.sampler(logits_output, input_metadata.sampling_info)
+        return sample_output, logits_output
 
     def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
         stacked_params_mapping = [