Add extension points on SpeculativeAlgorithm for custom spec v2 (#24999)

python/sglang/srt/managers/overlap_utils.py

@@ -49,7 +49,7 @@ class FutureMap:
         chunked_prefill_size: int,
         context_len: int,
         device: torch.device,
-        spec_algo: Optional[SpeculativeAlgorithm] = None,
+        spec_algo: SpeculativeAlgorithm,
     ):
         # FIXME: the calculation of future_limit and future_buffer_len maybe too conservative
         self.future_ct = 0

python/sglang/srt/managers/scheduler.py

@@ -152,7 +152,6 @@ from sglang.srt.managers.mm_utils import (
     unwrap_shm_features,
 )
 from sglang.srt.managers.multimodal_processor import get_mm_processor, import_processors
-from sglang.srt.managers.overlap_utils import FutureMap
 from sglang.srt.managers.prefill_delayer import (
     PrefillDelayer,
     PrefillDelayerSinglePassExecutor,
@@ -1343,12 +1342,11 @@ class Scheduler(
             self.future_map = None
             return
 
-        self.future_map = FutureMap(
+        self.future_map = self.spec_algorithm.create_future_map(
             self.max_running_requests,
             self.chunked_prefill_size,
             self.model_config.context_len,
             self.device,
-            self.spec_algorithm,
         )
         self.batch_record_buf = [None] * 2
         self.batch_record_ct = 0

python/sglang/srt/model_executor/cpu_graph_runner.py

@@ -36,7 +36,6 @@ from sglang.srt.model_executor.forward_batch_info import (
     PPProxyTensors,
     enable_num_token_non_padded,
 )
-from sglang.srt.speculative.spec_info import SpeculativeAlgorithm
 from sglang.srt.utils import (
     log_info_on_rank0,
     require_attn_tp_gather,
@@ -528,7 +527,7 @@ class CPUGraphRunner:
             not self.require_gathered_buffer
         ), "CPUGraphRunner does not support gathered buffer yet."
         assert (
-            model_runner.spec_algorithm == SpeculativeAlgorithm.NONE
+            model_runner.spec_algorithm.is_none()
         ), "CPUGraphRunner does not support speculative inference yet."
         # TODO add compile support for encoder-decoder models
         assert (

python/sglang/srt/model_executor/cuda_graph_runner.py

@@ -635,8 +635,10 @@ class CudaGraphRunner:
         self.num_tokens_per_bs = 1
         if model_runner.spec_algorithm.is_speculative():
             if self.model_runner.is_draft_worker:
-                # DFLASH draft workers reuse this runner for TARGET_VERIFY mode.
-                if not self.model_runner.spec_algorithm.is_dflash():
+                # Draft workers can use TARGET_VERIFY mode.
+                if (
+                    not self.model_runner.spec_algorithm.supports_target_verify_for_draft()
+                ):
                     raise RuntimeError("This should not happen")
             self.capture_forward_mode = ForwardMode.TARGET_VERIFY
             self.num_tokens_per_bs = self.speculative_num_draft_tokens

python/sglang/srt/speculative/spec_info.py

@@ -4,6 +4,8 @@ from abc import ABC, abstractmethod
 from enum import Enum, IntEnum, auto
 from typing import TYPE_CHECKING, Callable, List, Optional, Tuple, Type, Union
 
+import torch
+
 from sglang.srt.speculative.spec_registry import (
     CustomSpecAlgo,
     ServerArgsValidator,
@@ -15,6 +17,7 @@ from sglang.srt.speculative.spec_registry import (
 )
 
 if TYPE_CHECKING:
+    from sglang.srt.managers.overlap_utils import FutureMap
     from sglang.srt.managers.schedule_batch import ModelWorkerBatch
     from sglang.srt.managers.tp_worker import TpModelWorker
     from sglang.srt.server_args import ServerArgs
@@ -109,6 +112,26 @@ class SpeculativeAlgorithm(Enum):
     def is_ngram(self) -> bool:
         return self == SpeculativeAlgorithm.NGRAM
 
+    def supports_target_verify_for_draft(self) -> bool:
+        return self.is_dflash()
+
+    def create_future_map(
+        self,
+        max_running_requests: int,
+        chunked_prefill_size: int,
+        context_len: int,
+        device: torch.device,
+    ) -> FutureMap:
+        from sglang.srt.managers.overlap_utils import FutureMap
+
+        return FutureMap(
+            max_running_requests,
+            chunked_prefill_size,
+            context_len,
+            device,
+            self,
+        )
+
     def supports_spec_v2(self) -> bool:
         return (self.is_eagle() and not self.is_frozen_kv_mtp()) or self.is_standalone()