Support spec v2 for Frozen-KV MTP; remove v1 worker (#27607)

Co-authored-by: Khoa Pham <khoa.pham@radixark.ai>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This commit is contained in:
Liangsheng Yin
2026-06-09 15:30:20 -07:00
committed by GitHub
co-authored by Khoa Pham Claude Opus 4.8
parent 7f730edfdc
commit decb88e0e3
13 changed files with 750 additions and 1074 deletions
@@ -256,10 +256,13 @@ def _handle_frozen_kv_mtp(server_args: "ServerArgs") -> None:
"Max running requests is reset to 48 for speculative decoding. You can override this by explicitly setting --max-running-requests."
)
server_args.disable_overlap_schedule = True
logger.warning(
"Overlap scheduler is disabled when using Frozen-KV MTP speculative decoding (spec v2 is not supported yet)."
)
# SGLANG_ENABLE_SPEC_V2=False selects the non-overlap (synchronous) spec v2
# path instead of the overlap-scheduled one; both run the V2 worker.
if (
not envs.SGLANG_ENABLE_SPEC_V2.get()
and not server_args.disable_overlap_schedule
):
server_args.disable_overlap_schedule = True
if server_args.enable_mixed_chunk:
server_args.enable_mixed_chunk = False
+4 -4
View File
@@ -1163,7 +1163,7 @@ class Scheduler(
self.device_module = torch.get_device_module(self.device)
# FutureMap is always-on: input_ids relay used in both modes.
# Workers not on BaseSpecWorker (e.g. FrozenKVMTPWorker) lack the
# Workers not on BaseSpecWorker (e.g. NGRAM / DFLASH) lack the
# override; fall back to target-only so the helper still produces a
# safe decision (no accidental opt-out for unaudited shapes).
if self.draft_worker is not None:
@@ -3120,9 +3120,9 @@ class Scheduler(
)
batch.input_ids = None
else:
# Spec_v1 (NGRAM / DFLASH / FROZEN_KV_MTP, non-overlap):
# worker shape doesn't match req_pool_indices; relay is
# unused (worker rebuilds input_ids inside verify).
# Spec_v1 (NGRAM / DFLASH, non-overlap): worker shape
# doesn't match req_pool_indices; relay is unused (worker
# rebuilds input_ids inside verify).
batch.input_ids = batch_result.next_token_ids.to(torch.int64)
self.update_cache_from_scheduler(batch, batch_result)
@@ -34,7 +34,7 @@ from sglang.srt.utils import (
)
if TYPE_CHECKING:
from sglang.srt.speculative.frozen_kv_mtp_worker import FrozenKVMTPWorker
from sglang.srt.speculative.frozen_kv_mtp_worker_v2 import FrozenKVMTPDraftWorker
@dataclass
@@ -47,7 +47,7 @@ class FrozenKVMTPInputBuffers(ForwardInputBuffers):
topk_p: torch.Tensor
topk_index: torch.Tensor
hidden_states: torch.Tensor
# Consumed by the captured seed iter; see `FrozenKVMTPWorker.draft_forward`.
# Consumed by the captured seed iter; see `FrozenKVMTPDraftWorker.draft_forward`.
bonus_tokens: torch.Tensor
global_num_tokens_gpu: Optional[torch.Tensor]
global_num_tokens_for_logprob_gpu: Optional[torch.Tensor]
@@ -56,7 +56,7 @@ class FrozenKVMTPInputBuffers(ForwardInputBuffers):
class FrozenKVMTPCudaGraphRunner:
"""CUDA graph runner for the Frozen-KV MTP recurrent draft-loop step."""
def __init__(self, frozen_kv_mtp_worker: FrozenKVMTPWorker):
def __init__(self, frozen_kv_mtp_worker: FrozenKVMTPDraftWorker):
self.frozen_kv_mtp_worker = frozen_kv_mtp_worker
self.model_runner = model_runner = frozen_kv_mtp_worker.draft_model_runner
self.graphs = {}
@@ -13,7 +13,7 @@
# ==============================================================================
from __future__ import annotations
from dataclasses import dataclass, fields
from dataclasses import dataclass
from typing import Dict
from sglang.srt.mem_cache.memory_pool import KVCache
@@ -21,7 +21,6 @@ from sglang.srt.speculative.eagle_info import (
EagleDraftExtendInput,
EagleDraftInput,
EagleVerifyInput,
EagleVerifyOutput,
)
from sglang.srt.speculative.spec_info import SpecInput, SpecInputType
@@ -68,26 +67,3 @@ class FrozenKVMTPVerifyInput(EagleVerifyInput):
def __post_init__(self):
SpecInput.__init__(self, SpecInputType.FROZEN_KV_MTP_VERIFY)
def verify(self, *args, **kwargs) -> EagleVerifyOutput:
output = super().verify(*args, **kwargs)
output.draft_extend_input = _to_frozen_kv_mtp_draft_extend_input(
output.draft_extend_input
)
return output
FrozenKVMTPVerifyOutput = EagleVerifyOutput
def _to_frozen_kv_mtp_draft_extend_input(
draft_extend_input: EagleDraftExtendInput,
) -> FrozenKVMTPDraftExtendInput:
if isinstance(draft_extend_input, FrozenKVMTPDraftExtendInput):
return draft_extend_input
return FrozenKVMTPDraftExtendInput(
**{
field.name: getattr(draft_extend_input, field.name)
for field in fields(EagleDraftExtendInput)
}
)
@@ -14,19 +14,13 @@
from __future__ import annotations
from contextlib import contextmanager
from typing import TYPE_CHECKING, Tuple
from typing import TYPE_CHECKING
import torch
from sglang.srt.layers.logits_processor import LogitsProcessorOutput
from sglang.srt.managers.schedule_batch import ScheduleBatch
from sglang.srt.model_executor.forward_batch_info import ForwardBatch
from sglang.srt.speculative.frozen_kv_mtp_info import (
FrozenKVMTPContext,
FrozenKVMTPDraftExtendInput,
FrozenKVMTPDraftInput,
)
from sglang.srt.speculative.spec_utils import fast_topk
from sglang.srt.speculative.frozen_kv_mtp_info import FrozenKVMTPContext
if TYPE_CHECKING:
from sglang.srt.layers.attention.base_attn_backend import AttentionBackend
@@ -159,22 +153,3 @@ def select_last_extend_hidden(
lens = torch.tensor(batch.extend_lens, device=hidden_states.device)
last_indices = torch.cumsum(lens, dim=0) - 1
return hidden_states[last_indices.to(torch.long)]
def select_last_verified_seed(
draft_input: FrozenKVMTPDraftExtendInput,
) -> Tuple[torch.Tensor, torch.Tensor]:
counts = draft_input.num_accept_tokens.to(torch.long)
last_indices = torch.cumsum(counts, dim=0) - 1
return (
draft_input.input_ids[last_indices],
draft_input.hidden_states[last_indices],
)
def capture_for_decode(
logits_output: LogitsProcessorOutput, draft_input: FrozenKVMTPDraftInput, topk: int
) -> None:
probs = torch.softmax(logits_output.next_token_logits, dim=-1)
draft_input.topk_p, draft_input.topk_index = fast_topk(probs, topk, dim=-1)
draft_input.hidden_states = logits_output.hidden_states
@@ -1,826 +0,0 @@
# Copyright 2026 SGLang Team
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Frozen-KV MTP draft worker.
The assistant reads target KV only. It reuses EAGLE's verify input/output
contract, but owns the seed and recurrent draft loop because there is no
assistant-side KV extension.
"""
from __future__ import annotations
import logging
from typing import List, Optional, Tuple
import torch
from sglang.srt.layers.logits_processor import LogitsProcessorOutput
from sglang.srt.layers.moe.utils import (
speculative_moe_a2a_backend_context,
speculative_moe_backend_context,
)
from sglang.srt.layers.utils.logprob import add_output_logprobs_for_spec_v1
from sglang.srt.managers.schedule_batch import ScheduleBatch
from sglang.srt.managers.scheduler import GenerationBatchResult
from sglang.srt.managers.tp_worker import TpModelWorker
from sglang.srt.model_executor.forward_batch_info import (
CaptureHiddenMode,
ForwardBatch,
ForwardMode,
)
from sglang.srt.model_executor.forward_context import ForwardContext, forward_context
from sglang.srt.model_executor.pool_configurator import MemoryPoolConfig
from sglang.srt.observability.req_time_stats import set_time_batch
from sglang.srt.observability.trace import get_global_tracing_enabled
from sglang.srt.server_args import ServerArgs
from sglang.srt.speculative.eagle_utils import (
build_tree_kernel_efficient,
organize_draft_results,
)
from sglang.srt.speculative.frozen_kv_mtp_info import (
FrozenKVMTPContext,
FrozenKVMTPDraftExtendInput,
FrozenKVMTPDraftInput,
FrozenKVMTPVerifyInput,
FrozenKVMTPVerifyOutput,
)
from sglang.srt.speculative.frozen_kv_mtp_utils import (
capture_for_decode,
expand_for_topk_draft,
frozen_kv_target_view,
position_for_batch,
select_last_extend_hidden,
select_last_verified_seed,
set_frozen_kv_positions,
target_kv_pool_view,
)
from sglang.srt.speculative.spec_info import SpeculativeAlgorithm
from sglang.srt.speculative.spec_utils import (
draft_tp_context,
fast_topk,
generate_token_bitmask,
select_top_k_tokens,
spec_stage_span,
)
from sglang.srt.utils import empty_context
from sglang.srt.utils.async_probe import (
maybe_detect_inf,
maybe_detect_nan,
maybe_detect_oob,
)
logger = logging.getLogger(__name__)
class FrozenKVMTPWorker(TpModelWorker):
"""Frozen-KV MTP worker; same constructor shape as other TpModelWorker-based
spec workers. Entry: :meth:`forward_batch_generation` (stubs for now).
"""
def __init__(
self,
server_args: ServerArgs,
gpu_id: int,
tp_rank: int,
dp_rank: Optional[int],
moe_ep_rank: int,
attn_cp_rank: int,
moe_dp_rank: int,
nccl_port: int,
target_worker: TpModelWorker,
):
self.server_args = server_args
self.topk = server_args.speculative_eagle_topk
self.speculative_num_steps = server_args.speculative_num_steps
self.speculative_num_draft_tokens = server_args.speculative_num_draft_tokens
self.gpu_id = gpu_id
self.device = server_args.device
self.target_worker = target_worker
self.page_size = server_args.page_size
self.speculative_algorithm = SpeculativeAlgorithm.from_string(
server_args.speculative_algorithm
)
assert self.speculative_algorithm.is_frozen_kv_mtp(), (
"FrozenKVMTPWorker should only be instantiated for "
"SpeculativeAlgorithm.FROZEN_KV_MTP, got "
f"{self.speculative_algorithm.name}. The dispatch happens in "
"arg_groups.speculative_hook.handle_speculative_decoding -> "
"_resolve_speculative_algorithm_alias."
)
# Assistant reads target KV directly, so its context length must match the target.
server_args.context_length = target_worker.model_runner.model_config.context_len
# Defer cuda graph capture; we do it ourselves below.
backup_disable_cuda_graph = server_args.disable_cuda_graph
server_args.disable_cuda_graph = True
# Draft attention uses target req_to_token + KV allocator (read-only).
self.req_to_token_pool, self.token_to_kv_pool_allocator = (
target_worker.get_memory_pool()
)
target_cfg = target_worker.model_runner.memory_pool_config
draft_pool_config = MemoryPoolConfig(
max_total_num_tokens=64, # Dummy value
max_running_requests=target_cfg.max_running_requests,
)
self.hot_token_id = None
with (
empty_context()
), speculative_moe_backend_context(), speculative_moe_a2a_backend_context():
super().__init__(
server_args=server_args,
gpu_id=gpu_id,
tp_rank=tp_rank,
pp_rank=0,
dp_rank=dp_rank,
moe_ep_rank=moe_ep_rank,
attn_cp_rank=attn_cp_rank,
moe_dp_rank=moe_dp_rank,
nccl_port=nccl_port,
is_draft_worker=True,
req_to_token_pool=self.req_to_token_pool,
token_to_kv_pool_allocator=self.token_to_kv_pool_allocator,
memory_pool_config=draft_pool_config,
)
embed, head = self.target_worker.model_runner.model.get_embed_and_head()
if hasattr(self.draft_model_runner.model, "set_embed_and_head"):
self.draft_model_runner.model.set_embed_and_head(embed, head)
else:
logger.debug(
"Draft model %s does not implement set_embed_and_head; "
"skipping target-embedding bind in Frozen-KV MTP skeleton.",
type(self.draft_model_runner.model).__name__,
)
self.kv_context: Optional["FrozenKVMTPContext"] = None
if hasattr(self.draft_model_runner.model, "bind_frozen_kv_context"):
self._bind_kv_context()
self.draft_model_runner.server_args.disable_cuda_graph = (
backup_disable_cuda_graph
)
self.draft_tp_context = (
draft_tp_context if server_args.enable_dp_attention else empty_context
)
self.draft_attn_backend = self._init_draft_attn_backend()
self.draft_model_runner.draft_attn_backend = self.draft_attn_backend
self.cuda_graph_runner = None
with (
self.draft_tp_context(self.draft_model_runner.tp_group),
speculative_moe_backend_context(),
speculative_moe_a2a_backend_context(),
):
self.init_cuda_graphs()
@property
def draft_model_runner(self):
return self.model_runner
def get_attn_backend(self): # pragma: no cover - exposed for adaptive
return self.draft_attn_backend
def clear_cache_pool(self):
pass
def _resolve_draft_backend_type(self) -> str:
return (
self.server_args.speculative_draft_attention_backend
or self.server_args.decode_attention_backend
or self.server_args.attention_backend
)
def _init_draft_attn_backend(self):
if self.topk == 1:
return self.draft_model_runner.attn_backend
backend_type = self._resolve_draft_backend_type()
if backend_type != "triton":
raise ValueError(
"Frozen-KV MTP topk > 1 currently supports only the triton "
f"attention backend, got {backend_type}."
)
return self._init_triton_draft_attn_backend()
def _init_triton_draft_attn_backend(self):
from sglang.srt.layers.attention.triton_backend import TritonAttnBackend
max_bs = self.req_to_token_pool.size * self.topk
kv_indptr_buf = torch.zeros(
(max_bs + 1,), dtype=torch.int32, device=self.draft_model_runner.device
)
return TritonAttnBackend(
self.draft_model_runner,
skip_prefill=True,
kv_indptr_buf=kv_indptr_buf,
)
def _bind_kv_context(self) -> None:
draft_model = self.draft_model_runner.model
if not hasattr(draft_model, "build_frozen_kv_mtp_context") or not hasattr(
draft_model, "bind_frozen_kv_context"
):
logger.debug(
"Draft model %s does not implement Frozen-KV MTP context hooks; "
"skipping frozen-kv bind.",
type(draft_model).__name__,
)
return
ctx = draft_model.build_frozen_kv_mtp_context(
target_model=self.target_worker.model_runner.model,
target_token_to_kv_pool=self.target_worker.model_runner.token_to_kv_pool,
)
draft_model.bind_frozen_kv_context(ctx)
self.kv_context = ctx
def _frozen_kv_target_view(self, forward_batch: ForwardBatch):
return frozen_kv_target_view(
forward_batch, self.kv_context, self.draft_attn_backend
)
def _target_kv_pool_view(self, forward_batch: ForwardBatch):
return target_kv_pool_view(
forward_batch, self.kv_context, self.draft_attn_backend
)
def _set_positions(self, forward_batch: ForwardBatch) -> None:
set_frozen_kv_positions(forward_batch, self.topk)
def _expand_for_topk_draft(self, forward_batch: ForwardBatch) -> None:
expand_for_topk_draft(forward_batch, self.topk)
def _position_for_batch(self, batch: ScheduleBatch) -> torch.Tensor:
return position_for_batch(batch)
@property
def _recurrent_hidden_size(self) -> int:
return int(self.draft_model_runner.model.backbone_hidden_size)
def _init_frozen_kv_metadata(self, forward_batch: ForwardBatch) -> None:
if forward_batch.forward_mode.is_idle():
return
if forward_batch.seq_lens_cpu is not None:
forward_batch.seq_lens_sum = forward_batch.seq_lens_cpu.sum().item()
else:
forward_batch.seq_lens_sum = torch.sum(forward_batch.seq_lens).item()
with self._frozen_kv_target_view(forward_batch):
self.draft_attn_backend.init_forward_metadata(forward_batch)
forward_batch.mark_forward_metadata_ready()
def _init_frozen_kv_metadata_capture_cuda_graph(
self, forward_batch: ForwardBatch
) -> None:
with self._frozen_kv_target_view(forward_batch):
self.draft_attn_backend.init_forward_metadata_out_graph(
forward_batch, in_capture=True
)
forward_batch.mark_forward_metadata_ready()
def _init_frozen_kv_metadata_replay_cuda_graph(
self, forward_batch: ForwardBatch, bs: int, seq_lens_sum: int
) -> None:
from types import SimpleNamespace
fb_view = SimpleNamespace(
batch_size=bs,
forward_mode=ForwardMode.DECODE,
input_ids=getattr(forward_batch, "input_ids", None),
req_pool_indices=forward_batch.req_pool_indices[:bs],
seq_lens=forward_batch.seq_lens[:bs],
seq_lens_sum=seq_lens_sum,
seq_lens_cpu=(
forward_batch.seq_lens_cpu[:bs]
if forward_batch.seq_lens_cpu is not None
else None
),
encoder_lens=None,
out_cache_loc=getattr(forward_batch, "out_cache_loc", None),
spec_info=None,
)
with self._frozen_kv_target_view(forward_batch):
self.draft_attn_backend.init_forward_metadata_out_graph(fb_view)
def init_cuda_graphs(self) -> None:
if self.server_args.disable_cuda_graph or self.speculative_num_steps <= 1:
return
if self.target_worker.device != "cuda":
logger.info(
"Frozen-KV MTP draft CUDA graph is only supported on CUDA; "
"running the draft loop eagerly on %s.",
self.target_worker.device,
)
return
from sglang.srt.speculative.frozen_kv_mtp_cuda_graph_runner import (
FrozenKVMTPCudaGraphRunner,
)
logger.info("Capture Frozen-KV MTP draft cuda graph begin.")
self.cuda_graph_runner = FrozenKVMTPCudaGraphRunner(self)
logger.info("Capture Frozen-KV MTP draft cuda graph end.")
def _select_last_extend_hidden(
self, batch: ScheduleBatch, hidden_states: torch.Tensor
) -> torch.Tensor:
return select_last_extend_hidden(batch, hidden_states)
def _select_last_verified_seed(
self, draft_input: FrozenKVMTPDraftExtendInput
) -> Tuple[torch.Tensor, torch.Tensor]:
return select_last_verified_seed(draft_input)
def _capture_for_decode(
self, logits_output: LogitsProcessorOutput, draft_input: FrozenKVMTPDraftInput
) -> None:
capture_for_decode(logits_output, draft_input, self.topk)
def _draft_preprocess_idle(self, batch: ScheduleBatch) -> None:
batch.spec_info = FrozenKVMTPDraftInput.create_idle_input(
device=self.device,
hidden_size=self._recurrent_hidden_size,
dtype=self.model_config.dtype,
topk=self.topk,
capture_hidden_mode=CaptureHiddenMode.LAST,
)
def _run_assistant_seed_step(
self,
batch: ScheduleBatch,
last_token_ids: torch.Tensor,
last_hidden_states: torch.Tensor,
seq_lens_cpu: Optional[torch.Tensor] = None,
mm_input_embeds: Optional[torch.Tensor] = None,
draft_input: Optional[FrozenKVMTPDraftInput] = None,
) -> None:
"""Stash seed inputs on ``batch.spec_info``; the forward runs inside
the captured draft graph (see ``draft_forward``'s seed iter)."""
del seq_lens_cpu, mm_input_embeds, draft_input
if batch.forward_mode.is_idle() or last_token_ids.numel() == 0:
batch.spec_info = FrozenKVMTPDraftInput.create_idle_input(
device=batch.device,
hidden_size=self._recurrent_hidden_size,
dtype=self.model_config.dtype,
topk=self.topk,
capture_hidden_mode=CaptureHiddenMode.LAST,
)
return
stashed = FrozenKVMTPDraftInput()
stashed.bonus_tokens = last_token_ids.to(torch.int64)
stashed.hidden_states = last_hidden_states
# Real-shaped zeros so inherited `filter_batch`/`merge_batch` can slice
# them between iters; overwritten by the captured seed iter.
bs = last_token_ids.shape[0]
device = last_token_ids.device
stashed.topk_p = torch.zeros(
(bs, self.topk), device=device, dtype=torch.float32
)
stashed.topk_index = torch.zeros(
(bs, self.topk), device=device, dtype=torch.int64
)
stashed.capture_hidden_mode = CaptureHiddenMode.LAST
stashed.num_tokens_per_req = 1
stashed.num_tokens_for_logprob_per_req = 1
batch.spec_info = stashed
def forward_batch_generation(self, batch: ScheduleBatch) -> GenerationBatchResult:
if batch.forward_mode.is_extend() or batch.is_extend_in_batch:
(
logits_output,
next_token_ids,
seq_lens_cpu,
can_run_cuda_graph,
) = self.forward_target_extend(batch)
with (
self.draft_tp_context(self.draft_model_runner.tp_group),
speculative_moe_backend_context(),
speculative_moe_a2a_backend_context(),
spec_stage_span("draft_extend"),
):
self.forward_draft_extend(
batch,
logits_output.hidden_states,
next_token_ids,
seq_lens_cpu,
logits_output.mm_input_embeds,
)
return GenerationBatchResult(
logits_output=logits_output,
next_token_ids=next_token_ids,
num_correct_drafts=0,
can_run_cuda_graph=can_run_cuda_graph,
)
set_time_batch(batch.reqs, "set_spec_draft_start_time", trace_only=True)
with (
self.draft_tp_context(self.draft_model_runner.tp_group),
speculative_moe_backend_context(),
speculative_moe_a2a_backend_context(),
spec_stage_span("draft"),
):
verify_input = self.draft(batch)
set_time_batch(batch.reqs, "set_spec_draft_end_time", trace_only=True)
set_time_batch(batch.reqs, "set_spec_verify_start_time", trace_only=True)
# Install verify_input as `batch.spec_info` for the verify forward.
batch.spec_info = verify_input
verify_output = self.verify(batch)
if get_global_tracing_enabled():
for idx, req in enumerate(batch.reqs):
num_correct_drafts = verify_output.num_correct_drafts_per_req_cpu[idx]
req.time_stats.set_spec_verify_end_time(
num_correct_drafts=num_correct_drafts
)
set_time_batch(batch.reqs, "set_spec_draft_extend_start_time", trace_only=True)
with (
self.draft_tp_context(self.draft_model_runner.tp_group),
speculative_moe_backend_context(),
speculative_moe_a2a_backend_context(),
):
draft_extend_input = verify_output.draft_extend_input
if (
self.server_args.enable_dp_attention
or draft_extend_input.input_ids.shape[0] > 0
):
# Install draft_extend_input as `batch.spec_info` for the seed
# step; `_run_assistant_seed_step` replaces it with a fresh
# `FrozenKVMTPDraftInput` for next iter.
batch.spec_info = draft_extend_input
with spec_stage_span("draft_extend"):
self.forward_draft_extend_after_decode(batch)
else:
# All reqs finished and dp_attention isn't forcing extend.
# Install an idle FrozenKVMTPDraftInput so next iter's scheduler
# ops (merge_batch / filter_batch) see well-typed empty
# tensors instead of None.
self._draft_preprocess_idle(batch)
set_time_batch(batch.reqs, "set_spec_draft_extend_end_time", trace_only=True)
return GenerationBatchResult(
logits_output=verify_output.logits_output,
next_token_ids=verify_output.accept_tokens,
num_correct_drafts=sum(verify_output.num_correct_drafts_per_req_cpu),
num_correct_drafts_per_req_cpu=verify_output.num_correct_drafts_per_req_cpu,
can_run_cuda_graph=verify_output.can_run_cuda_graph,
)
def forward_target_extend(
self, batch: ScheduleBatch
) -> Tuple[LogitsProcessorOutput, torch.Tensor, Optional[torch.Tensor], bool]:
batch.capture_hidden_mode = CaptureHiddenMode.FULL
batch_result = self.target_worker.forward_batch_generation(batch)
return (
batch_result.logits_output,
batch_result.next_token_ids,
batch.seq_lens_cpu,
batch_result.can_run_cuda_graph,
)
def forward_draft_extend(
self,
batch: ScheduleBatch,
hidden_states: torch.Tensor,
next_token_ids: torch.Tensor,
seq_lens_cpu: Optional[torch.Tensor],
mm_input_embeds: Optional[torch.Tensor] = None,
) -> None:
last_hidden = self._select_last_extend_hidden(batch, hidden_states)
self._run_assistant_seed_step(
batch,
next_token_ids,
last_hidden,
seq_lens_cpu=seq_lens_cpu,
mm_input_embeds=mm_input_embeds,
)
def forward_draft_extend_after_decode(self, batch: ScheduleBatch) -> None:
draft_extend_input: FrozenKVMTPDraftExtendInput = batch.spec_info
input_is_idle = batch.forward_mode.is_idle()
if not input_is_idle and draft_extend_input.input_ids.shape[0] == 0:
# All reqs finished. Install an idle FrozenKVMTPDraftInput so the
# next-iter draft sees a valid spec_info.
batch = batch.copy()
batch.prepare_for_idle()
batch.spec_info = FrozenKVMTPDraftInput.create_idle_input(
device=self.device,
hidden_size=self._recurrent_hidden_size,
dtype=self.model_config.dtype,
topk=self.topk,
capture_hidden_mode=CaptureHiddenMode.LAST,
)
return
if batch.forward_mode.is_idle():
return
seq_lens_backup = batch.seq_lens.clone()
seq_lens_cpu_backup = batch.seq_lens_cpu.clone()
req_pool_indices_backup = batch.req_pool_indices
try:
# Verify may leave finished requests in ScheduleBatch; seed only
# the unfinished reqs carried by `draft_extend_input`.
batch.seq_lens = draft_extend_input.seq_lens
batch.seq_lens_cpu = draft_extend_input.seq_lens_cpu
batch.req_pool_indices = draft_extend_input.req_pool_indices
last_token_ids, last_hidden = self._select_last_verified_seed(
draft_extend_input
)
# `_run_assistant_seed_step` constructs a fresh `FrozenKVMTPDraftInput`
# and installs it on `batch.spec_info` for next iter.
self._run_assistant_seed_step(
batch,
last_token_ids,
last_hidden,
seq_lens_cpu=draft_extend_input.seq_lens_cpu,
)
finally:
batch.seq_lens = seq_lens_backup
batch.seq_lens_cpu = seq_lens_cpu_backup
batch.req_pool_indices = req_pool_indices_backup
def draft(self, batch: ScheduleBatch):
if batch.forward_mode.is_idle():
return FrozenKVMTPVerifyInput.create_idle_input(
self.topk,
self.speculative_num_steps,
self.speculative_num_draft_tokens,
)
batch.maybe_evict_swa()
for req in batch.reqs:
req.decode_batch_idx += 1
spec_info = batch.spec_info
assert isinstance(spec_info, FrozenKVMTPDraftInput)
if batch.sampling_info.penalizer_orchestrator.is_required:
batch.sampling_info.penalizer_orchestrator.cumulate_output_tokens(
spec_info.bonus_tokens.to(torch.int64)
)
spec_info.capture_hidden_mode = CaptureHiddenMode.LAST
spec_info.num_tokens_per_req = self.topk
spec_info.num_tokens_for_logprob_per_req = self.topk
spec_info.positions = self._position_for_batch(batch)
batch.seq_lens_sum = torch.sum(batch.seq_lens).item()
batch.return_hidden_states = False
forward_batch = ForwardBatch.init_new(batch, self.draft_model_runner)
assert forward_batch.capture_hidden_mode == CaptureHiddenMode.LAST
self._set_positions(forward_batch)
self._expand_for_topk_draft(forward_batch)
can_run_cuda_graph = self.cuda_graph_runner and self.cuda_graph_runner.can_run(
forward_batch
)
if can_run_cuda_graph:
parent_list, top_scores_index, draft_tokens = self.cuda_graph_runner.replay(
forward_batch
)
else:
forward_batch.can_run_dp_cuda_graph = False
parent_list, top_scores_index, draft_tokens = self.draft_forward(
forward_batch
)
(
tree_mask,
position,
retrieve_index,
retrieve_next_token,
retrieve_next_sibling,
draft_tokens,
) = build_tree_kernel_efficient(
spec_info.bonus_tokens,
parent_list,
top_scores_index,
draft_tokens,
batch.seq_lens,
batch.seq_lens_sum,
self.topk,
self.speculative_num_steps,
self.speculative_num_draft_tokens,
)
return FrozenKVMTPVerifyInput(
draft_token=draft_tokens,
custom_mask=tree_mask,
positions=position,
retrieve_index=retrieve_index,
retrieve_next_token=retrieve_next_token,
retrieve_next_sibling=retrieve_next_sibling,
retrieve_cum_len=None,
spec_steps=self.speculative_num_steps,
topk=self.topk,
draft_token_num=self.speculative_num_draft_tokens,
capture_hidden_mode=CaptureHiddenMode.FULL,
seq_lens_sum=batch.seq_lens_sum,
seq_lens_cpu=batch.seq_lens_cpu,
)
def draft_forward(self, forward_batch: ForwardBatch):
spec_info = forward_batch.spec_info
assert isinstance(spec_info, FrozenKVMTPDraftInput)
score_list: List[torch.Tensor] = []
token_list: List[torch.Tensor] = []
parents_list: List[torch.Tensor] = []
# Seed + recurrent iters share the same `seq_lens - 1` rope position,
# so one init covers the loop. Must run even at num_steps == 1.
if forward_batch.needs_forward_metadata_init():
self._init_frozen_kv_metadata(forward_batch)
# Seed iter: assistant forward on (bonus_token, target_h) to produce
# iter-0 `(topk_p, topk_index, hidden_states)`. For topk>1, replicate
# to `bs*topk` to match kernel shapes, then slice back per-req.
bonus_tokens = spec_info.bonus_tokens
target_hidden = spec_info.hidden_states
if self.topk > 1:
seed_input_ids = bonus_tokens.repeat_interleave(self.topk, dim=0)
seed_prev_hidden = target_hidden.repeat_interleave(self.topk, dim=0)
else:
seed_input_ids = bonus_tokens
seed_prev_hidden = target_hidden
forward_batch.input_ids = seed_input_ids
forward_batch.spec_info.hidden_states = seed_prev_hidden
self._set_positions(forward_batch)
with (
self._target_kv_pool_view(forward_batch),
forward_context(ForwardContext(attn_backend=self.draft_attn_backend)),
):
seed_output = self.draft_model_runner.forward(forward_batch).logits_output
maybe_detect_nan(
seed_output.next_token_logits, "frozen_kv_mtp_draft: seed iter"
)
if self.topk > 1:
seed_next_logits = seed_output.next_token_logits[:: self.topk]
seed_hidden_per_req = seed_output.hidden_states[:: self.topk]
else:
seed_next_logits = seed_output.next_token_logits
seed_hidden_per_req = seed_output.hidden_states
probs = torch.softmax(seed_next_logits, dim=-1)
topk_p, topk_index = fast_topk(probs, self.topk, dim=-1)
maybe_detect_oob(
topk_index,
0,
seed_next_logits.shape[-1],
"frozen_kv_mtp_draft: seed topk_index OOB",
)
hidden_states = seed_hidden_per_req
scores = None
for i in range(self.speculative_num_steps):
input_ids, hidden_states, scores, tree_info = select_top_k_tokens(
i, topk_p, topk_index, hidden_states, scores, self.topk
)
score_list.append(tree_info[0])
token_list.append(tree_info[1])
parents_list.append(tree_info[2])
if i == self.speculative_num_steps - 1:
break
forward_batch.input_ids = input_ids
forward_batch.spec_info.hidden_states = hidden_states
self._set_positions(forward_batch)
with (
self._target_kv_pool_view(forward_batch),
forward_context(ForwardContext(attn_backend=self.draft_attn_backend)),
):
logits_output = self.draft_model_runner.forward(
forward_batch
).logits_output
maybe_detect_nan(
logits_output.next_token_logits, f"frozen_kv_mtp_draft step {i}"
)
maybe_detect_inf(
logits_output.next_token_logits, f"frozen_kv_mtp_draft step {i}"
)
probs = torch.softmax(logits_output.next_token_logits, dim=-1)
topk_p, topk_index = fast_topk(probs, self.topk, dim=-1)
maybe_detect_oob(
topk_index,
0,
logits_output.next_token_logits.shape[-1],
"frozen_kv_mtp_draft: topk_index OOB",
)
hidden_states = logits_output.hidden_states
return organize_draft_results(
score_list, token_list, parents_list, self.speculative_num_draft_tokens
)
def verify(self, batch: ScheduleBatch):
spec_info: FrozenKVMTPVerifyInput = batch.spec_info
seq_lens_pre_verify = batch.seq_lens.clone()
spec_info.prepare_for_verify(batch, self.page_size)
spec_info.num_tokens_per_req = self.speculative_num_steps + 1
batch.return_hidden_states = False
batch.forward_mode = (
ForwardMode.TARGET_VERIFY
if not batch.forward_mode.is_idle()
else ForwardMode.IDLE
)
if batch.has_grammar:
retrieve_next_token_cpu = spec_info.retrieve_next_token.cpu()
retrieve_next_sibling_cpu = spec_info.retrieve_next_sibling.cpu()
draft_tokens_cpu = spec_info.draft_token.view(
spec_info.retrieve_next_token.shape
).cpu()
batch.seq_lens_cpu_cache = spec_info.seq_lens_cpu
batch_result = self.target_worker.forward_batch_generation(
batch, is_verify=True
)
logits_output, can_run_cuda_graph = (
batch_result.logits_output,
batch_result.can_run_cuda_graph,
)
vocab_mask = None
if batch.has_grammar:
vocab_mask = generate_token_bitmask(
batch.reqs,
spec_info,
retrieve_next_token_cpu,
retrieve_next_sibling_cpu,
draft_tokens_cpu,
batch.sampling_info.vocab_size,
)
if vocab_mask is not None:
assert spec_info.grammar is not None
vocab_mask = vocab_mask.to(spec_info.retrieve_next_token.device)
batch.sampling_info.vocab_mask = None
maybe_detect_nan(logits_output.next_token_logits, "frozen_kv_mtp_verify")
maybe_detect_inf(logits_output.next_token_logits, "frozen_kv_mtp_verify")
spec_info.hidden_states = logits_output.hidden_states
res: FrozenKVMTPVerifyOutput = spec_info.verify(
batch,
logits_output,
self.token_to_kv_pool_allocator,
self.page_size,
vocab_mask,
)
logits_output.next_token_logits = logits_output.next_token_logits[
res.accept_indices
]
logits_output.hidden_states = logits_output.hidden_states[res.accept_indices]
if (
self.target_worker.model_runner.hybrid_gdn_config is not None
or self.target_worker.model_runner.mamba2_config is not None
or self.target_worker.model_runner.hybrid_lightning_config is not None
):
logger.warning(
"Frozen-KV MTP does not implement mamba state updates; "
"targets with recurrent state should not use this path."
)
if batch.return_logprob:
add_output_logprobs_for_spec_v1(batch, res, logits_output)
batch.forward_mode = (
ForwardMode.DECODE if not batch.forward_mode.is_idle() else ForwardMode.IDLE
)
del seq_lens_pre_verify
res.can_run_cuda_graph = can_run_cuda_graph
return res
@@ -11,18 +11,79 @@
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Overlap-scheduling placeholder for frozen-KV MTP (raises until implemented)."""
"""Spec-v2 worker for Frozen-KV MTP (two layers, like ``eagle_worker_v2``).
The frozen draft reads the target KV cache read-only and owns no KV pool, so
its "draft extend" is not a model forward: it selects the last accepted token +
target hidden state as the next-iter seed, and the seed forward runs at the
start of the next draft.
"""
from __future__ import annotations
import logging
from typing import Optional
import torch
from sglang.srt.layers.moe.utils import (
speculative_moe_a2a_backend_context,
speculative_moe_backend_context,
)
from sglang.srt.managers.schedule_batch import ScheduleBatch
from sglang.srt.managers.tp_worker import TpModelWorker
from sglang.srt.model_executor.forward_batch_info import (
CaptureHiddenMode,
ForwardBatch,
ForwardMode,
)
from sglang.srt.model_executor.forward_context import ForwardContext, forward_context
from sglang.srt.model_executor.pool_configurator import MemoryPoolConfig
from sglang.srt.server_args import ServerArgs
from sglang.srt.speculative.frozen_kv_mtp_worker import FrozenKVMTPWorker
from sglang.srt.speculative.base_spec_worker import BaseDraftWorker
from sglang.srt.speculative.eagle_utils import (
build_tree_kernel_efficient,
organize_draft_results,
)
from sglang.srt.speculative.eagle_worker_v2 import EAGLEWorkerV2, _get_plan_stream
from sglang.srt.speculative.frozen_kv_mtp_info import (
FrozenKVMTPContext,
FrozenKVMTPDraftInput,
FrozenKVMTPVerifyInput,
)
from sglang.srt.speculative.frozen_kv_mtp_utils import (
expand_for_topk_draft,
frozen_kv_target_view,
position_for_batch,
select_last_extend_hidden,
set_frozen_kv_positions,
target_kv_pool_view,
)
from sglang.srt.speculative.spec_info import SpeculativeAlgorithm
from sglang.srt.speculative.spec_utils import (
draft_tp_context,
fast_topk,
select_top_k_tokens,
spec_stage_span,
)
from sglang.srt.utils import empty_context
from sglang.srt.utils.async_probe import (
maybe_detect_inf,
maybe_detect_nan,
maybe_detect_oob,
)
logger = logging.getLogger(__name__)
class FrozenKVMTPWorkerV2(FrozenKVMTPWorker):
class FrozenKVMTPDraftWorker(BaseDraftWorker, TpModelWorker):
"""Frozen-KV MTP draft worker.
The assistant reads target KV only. It reuses EAGLE's verify input/output
contract, but owns the seed and recurrent draft loop because there is no
assistant-side KV extension.
"""
def __init__(
self,
server_args: ServerArgs,
@@ -35,8 +96,659 @@ class FrozenKVMTPWorkerV2(FrozenKVMTPWorker):
nccl_port: int,
target_worker: TpModelWorker,
):
raise NotImplementedError(
"FrozenKVMTPWorkerV2 (overlap scheduling for Frozen-KV MTP) is "
"not yet implemented. Pass --disable-overlap-schedule to use "
"FrozenKVMTPWorker."
self.server_args = server_args
self.topk = server_args.speculative_eagle_topk
self.speculative_num_steps = server_args.speculative_num_steps
self.speculative_num_draft_tokens = server_args.speculative_num_draft_tokens
self.gpu_id = gpu_id
self.device = server_args.device
self.target_worker = target_worker
self.page_size = server_args.page_size
self.speculative_algorithm = SpeculativeAlgorithm.from_string(
server_args.speculative_algorithm
)
assert self.speculative_algorithm.is_frozen_kv_mtp(), (
"FrozenKVMTPDraftWorker should only be instantiated for "
"SpeculativeAlgorithm.FROZEN_KV_MTP, got "
f"{self.speculative_algorithm.name}."
)
# Defer cuda graph capture; we do it ourselves below.
backup_disable_cuda_graph = server_args.disable_cuda_graph
server_args.disable_cuda_graph = True
# Draft attention uses target req_to_token + KV allocator (read-only).
self.req_to_token_pool, self.token_to_kv_pool_allocator = (
target_worker.get_memory_pool()
)
target_cfg = target_worker.model_runner.memory_pool_config
draft_pool_config = MemoryPoolConfig(
max_total_num_tokens=64, # Dummy value
max_running_requests=target_cfg.max_running_requests,
)
self.hot_token_id = None
with (
empty_context()
), speculative_moe_backend_context(), speculative_moe_a2a_backend_context():
# NOTE: call TpModelWorker.__init__ explicitly -- BaseDraftWorker is
# an ABC with no __init__, so cooperative super() would be ambiguous.
TpModelWorker.__init__(
self,
server_args=server_args,
gpu_id=gpu_id,
tp_rank=tp_rank,
pp_rank=0,
dp_rank=dp_rank,
moe_ep_rank=moe_ep_rank,
attn_cp_rank=attn_cp_rank,
moe_dp_rank=moe_dp_rank,
nccl_port=nccl_port,
is_draft_worker=True,
req_to_token_pool=self.req_to_token_pool,
token_to_kv_pool_allocator=self.token_to_kv_pool_allocator,
memory_pool_config=draft_pool_config,
)
embed, head = self.target_worker.model_runner.model.get_embed_and_head()
if hasattr(self.draft_model_runner.model, "set_embed_and_head"):
self.draft_model_runner.model.set_embed_and_head(embed, head)
else:
logger.debug(
"Draft model %s does not implement set_embed_and_head; "
"skipping target-embedding bind in Frozen-KV MTP skeleton.",
type(self.draft_model_runner.model).__name__,
)
self.kv_context: Optional["FrozenKVMTPContext"] = None
if hasattr(self.draft_model_runner.model, "bind_frozen_kv_context"):
self._bind_kv_context()
self.draft_model_runner.server_args.disable_cuda_graph = (
backup_disable_cuda_graph
)
self.draft_tp_context = (
draft_tp_context if server_args.enable_dp_attention else empty_context
)
self.draft_attn_backend = self._init_draft_attn_backend()
self.draft_model_runner.draft_attn_backend = self.draft_attn_backend
self.cuda_graph_runner = None
# Frozen draft has no draft-extend forward (seed-select only); keep these
# None so inherited probes (spec_v2_attn_backends, adaptive) stay typed.
self.draft_extend_attn_backend = None
self.cuda_graph_runner_for_draft_extend = None
with (
self.draft_tp_context(self.draft_model_runner.tp_group),
speculative_moe_backend_context(),
speculative_moe_a2a_backend_context(),
):
self.init_cuda_graphs()
@property
def draft_model_runner(self):
return self.model_runner
@property
def draft_runner(self):
# Alias for the inherited EAGLEWorkerV2 forward/verify skeleton, which
# reads `draft_worker.draft_runner`.
return self.model_runner
def get_attn_backend(self): # pragma: no cover - exposed for adaptive
return self.draft_attn_backend
def clear_cache_pool(self):
pass
def _resolve_draft_backend_type(self) -> str:
return (
self.server_args.speculative_draft_attention_backend
or self.server_args.decode_attention_backend
or self.server_args.attention_backend
)
def _init_draft_attn_backend(self):
if self.topk == 1:
return self.draft_model_runner.attn_backend
backend_type = self._resolve_draft_backend_type()
if backend_type != "triton":
raise ValueError(
"Frozen-KV MTP topk > 1 currently supports only the triton "
f"attention backend, got {backend_type}."
)
return self._init_triton_draft_attn_backend()
def _init_triton_draft_attn_backend(self):
from sglang.srt.layers.attention.triton_backend import TritonAttnBackend
max_bs = self.req_to_token_pool.size * self.topk
kv_indptr_buf = torch.zeros(
(max_bs + 1,), dtype=torch.int32, device=self.draft_model_runner.device
)
return TritonAttnBackend(
self.draft_model_runner,
skip_prefill=True,
kv_indptr_buf=kv_indptr_buf,
)
def _bind_kv_context(self) -> None:
draft_model = self.draft_model_runner.model
if not hasattr(draft_model, "build_frozen_kv_mtp_context") or not hasattr(
draft_model, "bind_frozen_kv_context"
):
logger.debug(
"Draft model %s does not implement Frozen-KV MTP context hooks; "
"skipping frozen-kv bind.",
type(draft_model).__name__,
)
return
ctx = draft_model.build_frozen_kv_mtp_context(
target_model=self.target_worker.model_runner.model,
target_token_to_kv_pool=self.target_worker.model_runner.token_to_kv_pool,
)
draft_model.bind_frozen_kv_context(ctx)
self.kv_context = ctx
def _frozen_kv_target_view(self, forward_batch: ForwardBatch):
return frozen_kv_target_view(
forward_batch, self.kv_context, self.draft_attn_backend
)
def _target_kv_pool_view(self, forward_batch: ForwardBatch):
return target_kv_pool_view(
forward_batch, self.kv_context, self.draft_attn_backend
)
def _set_positions(self, forward_batch: ForwardBatch) -> None:
set_frozen_kv_positions(forward_batch, self.topk)
def _expand_for_topk_draft(self, forward_batch: ForwardBatch) -> None:
expand_for_topk_draft(forward_batch, self.topk)
def _position_for_batch(self, batch: ScheduleBatch) -> torch.Tensor:
return position_for_batch(batch)
@property
def _recurrent_hidden_size(self) -> int:
return int(self.draft_model_runner.model.backbone_hidden_size)
def _init_frozen_kv_metadata(self, forward_batch: ForwardBatch) -> None:
if forward_batch.forward_mode.is_idle():
return
if forward_batch.seq_lens_cpu is not None:
forward_batch.seq_lens_sum = forward_batch.seq_lens_cpu.sum().item()
else:
forward_batch.seq_lens_sum = torch.sum(forward_batch.seq_lens).item()
with self._frozen_kv_target_view(forward_batch):
self.draft_attn_backend.init_forward_metadata(forward_batch)
forward_batch.mark_forward_metadata_ready()
def _init_frozen_kv_metadata_capture_cuda_graph(
self, forward_batch: ForwardBatch
) -> None:
with self._frozen_kv_target_view(forward_batch):
self.draft_attn_backend.init_forward_metadata_out_graph(
forward_batch, in_capture=True
)
forward_batch.mark_forward_metadata_ready()
def _init_frozen_kv_metadata_replay_cuda_graph(
self, forward_batch: ForwardBatch, bs: int, seq_lens_sum: int
) -> None:
from types import SimpleNamespace
fb_view = SimpleNamespace(
batch_size=bs,
forward_mode=ForwardMode.DECODE,
input_ids=getattr(forward_batch, "input_ids", None),
req_pool_indices=forward_batch.req_pool_indices[:bs],
seq_lens=forward_batch.seq_lens[:bs],
seq_lens_sum=seq_lens_sum,
seq_lens_cpu=(
forward_batch.seq_lens_cpu[:bs]
if forward_batch.seq_lens_cpu is not None
else None
),
encoder_lens=None,
out_cache_loc=getattr(forward_batch, "out_cache_loc", None),
spec_info=None,
)
with self._frozen_kv_target_view(forward_batch):
self.draft_attn_backend.init_forward_metadata_out_graph(fb_view)
def init_cuda_graphs(self) -> None:
if self.server_args.disable_cuda_graph or self.speculative_num_steps <= 1:
return
if self.target_worker.device != "cuda":
logger.info(
"Frozen-KV MTP draft CUDA graph is only supported on CUDA; "
"running the draft loop eagerly on %s.",
self.target_worker.device,
)
return
from sglang.srt.speculative.frozen_kv_mtp_cuda_graph_runner import (
FrozenKVMTPCudaGraphRunner,
)
logger.info("Capture Frozen-KV MTP draft cuda graph begin.")
self.cuda_graph_runner = FrozenKVMTPCudaGraphRunner(self)
logger.info("Capture Frozen-KV MTP draft cuda graph end.")
def _select_last_extend_hidden(
self, batch: ScheduleBatch, hidden_states: torch.Tensor
) -> torch.Tensor:
return select_last_extend_hidden(batch, hidden_states)
def _idle_seed(self) -> FrozenKVMTPDraftInput:
return FrozenKVMTPDraftInput.create_idle_input(
device=self.device,
hidden_size=self._recurrent_hidden_size,
dtype=self.model_config.dtype,
topk=self.topk,
capture_hidden_mode=CaptureHiddenMode.LAST,
)
def _build_seed_draft_input(
self,
last_token_ids: torch.Tensor,
last_hidden_states: torch.Tensor,
) -> FrozenKVMTPDraftInput:
"""Build the next-iter seed ``FrozenKVMTPDraftInput`` from (bonus token,
target hidden). No forward here -- the seed forward runs inside the
captured draft graph (see ``draft_forward``'s seed iter)."""
if last_token_ids.numel() == 0:
return self._idle_seed()
stashed = FrozenKVMTPDraftInput()
stashed.bonus_tokens = last_token_ids.to(torch.int64)
stashed.hidden_states = last_hidden_states
# Real-shaped zeros so inherited `filter_batch`/`merge_batch` can slice
# them between iters; overwritten by the captured seed iter.
bs = last_token_ids.shape[0]
device = last_token_ids.device
stashed.topk_p = torch.zeros(
(bs, self.topk), device=device, dtype=torch.float32
)
stashed.topk_index = torch.zeros(
(bs, self.topk), device=device, dtype=torch.int64
)
stashed.capture_hidden_mode = CaptureHiddenMode.LAST
stashed.num_tokens_per_req = 1
stashed.num_tokens_for_logprob_per_req = 1
return stashed
def draft(self, batch: ScheduleBatch):
if batch.forward_mode.is_idle():
return FrozenKVMTPVerifyInput.create_idle_input(
self.topk,
self.speculative_num_steps,
self.speculative_num_draft_tokens,
)
spec_info = batch.spec_info
assert isinstance(spec_info, FrozenKVMTPDraftInput)
# NOTE: per-iter bookkeeping (penalty cumulation, maybe_evict_swa,
# decode_batch_idx tick) is done by the inherited
# EagleDraftInputV2Mixin.prepare_for_decode (scheduler-driven, see
# ScheduleBatch.prepare_for_decode), not here -- matching EAGLE v2.
# Repeating evict/tick here would double-run them: the idx clock
# gates SWA eviction timing and the SWA prefix-lock release.
spec_info.capture_hidden_mode = CaptureHiddenMode.LAST
spec_info.num_tokens_per_req = self.topk
spec_info.num_tokens_for_logprob_per_req = self.topk
spec_info.positions = self._position_for_batch(batch)
batch.seq_lens_sum = torch.sum(batch.seq_lens).item()
batch.return_hidden_states = False
forward_batch = ForwardBatch.init_new(batch, self.draft_model_runner)
assert forward_batch.capture_hidden_mode == CaptureHiddenMode.LAST
self._set_positions(forward_batch)
self._expand_for_topk_draft(forward_batch)
can_run_cuda_graph = self.cuda_graph_runner and self.cuda_graph_runner.can_run(
forward_batch
)
if can_run_cuda_graph:
parent_list, top_scores_index, draft_tokens = self.cuda_graph_runner.replay(
forward_batch
)
else:
forward_batch.can_run_dp_cuda_graph = False
parent_list, top_scores_index, draft_tokens = self.draft_forward(
forward_batch
)
(
tree_mask,
position,
retrieve_index,
retrieve_next_token,
retrieve_next_sibling,
draft_tokens,
) = build_tree_kernel_efficient(
spec_info.bonus_tokens,
parent_list,
top_scores_index,
draft_tokens,
batch.seq_lens,
batch.seq_lens_sum,
self.topk,
self.speculative_num_steps,
self.speculative_num_draft_tokens,
)
return FrozenKVMTPVerifyInput(
draft_token=draft_tokens,
custom_mask=tree_mask,
positions=position,
retrieve_index=retrieve_index,
retrieve_next_token=retrieve_next_token,
retrieve_next_sibling=retrieve_next_sibling,
retrieve_cum_len=None,
spec_steps=self.speculative_num_steps,
topk=self.topk,
draft_token_num=self.speculative_num_draft_tokens,
capture_hidden_mode=CaptureHiddenMode.FULL,
seq_lens_sum=batch.seq_lens_sum,
seq_lens_cpu=batch.seq_lens_cpu,
)
def draft_forward(self, forward_batch: ForwardBatch):
spec_info = forward_batch.spec_info
assert isinstance(spec_info, FrozenKVMTPDraftInput)
score_list: list[torch.Tensor] = []
token_list: list[torch.Tensor] = []
parents_list: list[torch.Tensor] = []
# Seed + recurrent iters share the same `seq_lens - 1` rope position,
# so one init covers the loop. Must run even at num_steps == 1.
if forward_batch.needs_forward_metadata_init():
self._init_frozen_kv_metadata(forward_batch)
# Seed iter: assistant forward on (bonus_token, target_h) to produce
# iter-0 `(topk_p, topk_index, hidden_states)`. For topk>1, replicate
# to `bs*topk` to match kernel shapes, then slice back per-req.
bonus_tokens = spec_info.bonus_tokens
target_hidden = spec_info.hidden_states
if self.topk > 1:
seed_input_ids = bonus_tokens.repeat_interleave(self.topk, dim=0)
seed_prev_hidden = target_hidden.repeat_interleave(self.topk, dim=0)
else:
seed_input_ids = bonus_tokens
seed_prev_hidden = target_hidden
forward_batch.input_ids = seed_input_ids
forward_batch.spec_info.hidden_states = seed_prev_hidden
self._set_positions(forward_batch)
with (
self._target_kv_pool_view(forward_batch),
forward_context(ForwardContext(attn_backend=self.draft_attn_backend)),
):
seed_output = self.draft_model_runner.forward(forward_batch).logits_output
maybe_detect_nan(
seed_output.next_token_logits, "frozen_kv_mtp_draft: seed iter"
)
if self.topk > 1:
seed_next_logits = seed_output.next_token_logits[:: self.topk]
seed_hidden_per_req = seed_output.hidden_states[:: self.topk]
else:
seed_next_logits = seed_output.next_token_logits
seed_hidden_per_req = seed_output.hidden_states
probs = torch.softmax(seed_next_logits, dim=-1)
topk_p, topk_index = fast_topk(probs, self.topk, dim=-1)
maybe_detect_oob(
topk_index,
0,
seed_next_logits.shape[-1],
"frozen_kv_mtp_draft: seed topk_index OOB",
)
hidden_states = seed_hidden_per_req
scores = None
for i in range(self.speculative_num_steps):
input_ids, hidden_states, scores, tree_info = select_top_k_tokens(
i, topk_p, topk_index, hidden_states, scores, self.topk
)
score_list.append(tree_info[0])
token_list.append(tree_info[1])
parents_list.append(tree_info[2])
if i == self.speculative_num_steps - 1:
break
forward_batch.input_ids = input_ids
forward_batch.spec_info.hidden_states = hidden_states
self._set_positions(forward_batch)
with (
self._target_kv_pool_view(forward_batch),
forward_context(ForwardContext(attn_backend=self.draft_attn_backend)),
):
logits_output = self.draft_model_runner.forward(
forward_batch
).logits_output
maybe_detect_nan(
logits_output.next_token_logits, f"frozen_kv_mtp_draft step {i}"
)
maybe_detect_inf(
logits_output.next_token_logits, f"frozen_kv_mtp_draft step {i}"
)
probs = torch.softmax(logits_output.next_token_logits, dim=-1)
topk_p, topk_index = fast_topk(probs, self.topk, dim=-1)
maybe_detect_oob(
topk_index,
0,
logits_output.next_token_logits.shape[-1],
"frozen_kv_mtp_draft: topk_index OOB",
)
hidden_states = logits_output.hidden_states
return organize_draft_results(
score_list, token_list, parents_list, self.speculative_num_draft_tokens
)
def draft_extend(self):
# BaseDraftWorker contract. Frozen has no draft-KV extend forward; the
# orchestrator calls `_draft_extend_for_{prefill,decode}` directly.
pass
def _draft_extend_for_prefill(
self,
batch: ScheduleBatch,
target_hidden_states: torch.Tensor,
next_token_ids: torch.Tensor,
mm_input_embeds: Optional[torch.Tensor] = None,
) -> FrozenKVMTPDraftInput:
"""Seed for the first decode iter after prefill. Frozen draft writes no
KV (reads target KV), so unlike EAGLE there is no draft-extend forward:
just select the last prompt hidden + bonus token and stash the seed."""
del mm_input_embeds # frozen seed needs no input embeds
if batch.forward_mode.is_idle():
return self._idle_seed()
last_hidden = self._select_last_extend_hidden(batch, target_hidden_states)
return self._build_seed_draft_input(next_token_ids, last_hidden)
def _draft_extend_for_decode(self, batch: ScheduleBatch, batch_result) -> None:
"""Frozen 'draft extend': no forward. Pull the last accepted token's
target hidden from the verify output and stash it as the next-iter seed.
Replaces verify's `EagleDraftInput` with a `FrozenKVMTPDraftInput` so the
next draft passes the FROZEN_KV_MTP attn-backend assertions.
"""
if batch.forward_mode.is_idle():
batch_result.next_draft_input = self._idle_seed()
return
bs = len(batch.seq_lens)
# Same per-req select_index EAGLE uses on its draft-extend output: the
# last accepted node (accept_lens - 1) in each per-req block of width
# num_draft_tokens. Verify already compacted the accepted path to the
# front (topk > 1) / it is the front chain (topk == 1).
select_index = (
torch.arange(bs, device=self.device) * self.speculative_num_draft_tokens
+ batch_result.accept_lens
- 1
)
last_hidden = batch_result.logits_output.hidden_states[select_index]
bonus_tokens = batch_result.next_draft_input.bonus_tokens
batch_result.next_draft_input = self._build_seed_draft_input(
bonus_tokens, last_hidden
)
class FrozenKVMTPWorkerV2(EAGLEWorkerV2):
"""Spec-v2 (overlap) orchestrator for Frozen-KV MTP.
Reuses ``EAGLEWorkerV2``'s verify / ``move_accept_tokens`` / forward
skeleton verbatim; only the draft worker and the seed-based draft-extend
are frozen-specific.
"""
def __init__(
self,
server_args: ServerArgs,
gpu_id: int,
tp_rank: int,
dp_rank: Optional[int],
moe_ep_rank: int,
attn_cp_rank: int,
moe_dp_rank: int,
nccl_port: int,
target_worker: TpModelWorker,
):
# NOTE: intentionally does NOT call EAGLEWorkerV2.__init__ -- that builds
# an EagleDraftWorker (with its own draft KV pool). The frozen draft owns
# no KV, so we mirror the relevant setup and build a FrozenKVMTPDraftWorker.
self.server_args = server_args
self.topk = server_args.speculative_eagle_topk
self.speculative_num_steps = server_args.speculative_num_steps
self.speculative_num_draft_tokens = server_args.speculative_num_draft_tokens
self.tp_rank = tp_rank
self.gpu_id = gpu_id
self.device = server_args.device
self._target_worker = target_worker
self.page_size = server_args.page_size
self.speculative_algorithm = SpeculativeAlgorithm.from_string(
server_args.speculative_algorithm
)
self.req_to_token_pool, self.token_to_kv_pool_allocator = (
target_worker.get_memory_pool()
)
# Match the draft context length to the target (assistant reads target KV).
server_args.context_length = target_worker.model_runner.model_config.context_len
self._draft_worker = FrozenKVMTPDraftWorker(
server_args,
gpu_id,
tp_rank,
dp_rank,
moe_ep_rank,
attn_cp_rank,
moe_dp_rank,
nccl_port,
target_worker,
)
# Frozen MTP does not wire the adaptive controller yet.
assert (
not server_args.speculative_adaptive
), "Frozen-KV MTP does not support adaptive speculative decoding yet."
self.adaptive_controller = None
# Some dummy tensors (parity with EAGLEWorkerV2 init).
self.num_new_pages_per_topk = torch.empty(
(), dtype=torch.int64, device=self.device
)
self.extend_lens = torch.empty((), dtype=torch.int64, device=self.device)
self.plan_stream, self.plan_stream_ctx = _get_plan_stream(self.device)
@property
def spec_v2_attn_backends(self) -> tuple:
# Frozen draft touches no draft-extend backend; only target + draft.
return (
self._target_worker.model_runner.attn_backend,
self._draft_worker.draft_attn_backend,
)
def forward_batch_generation(self, batch: ScheduleBatch, on_publish=None):
# Mirrors EAGLEWorkerV2.forward_batch_generation; the only frozen-specific
# change is the idle draft-input (FrozenKVMTPDraftInput + recurrent hidden
# size). The draft / seed-based draft-extend hooks are FrozenKVMTPDraftWorker's.
if batch.forward_mode.is_extend() or batch.is_extend_in_batch:
# Target prefill (frozen is never standalone -> capture FULL hidden).
batch.capture_hidden_mode = CaptureHiddenMode.FULL
batch_output = self.target_worker.forward_batch_generation(batch)
# Spec_v2 convention: batch.seq_lens = length BEFORE this iter's tokens.
batch_output.new_seq_lens = batch.seq_lens
# Publish before draft-extend so the fence is at target-end.
if on_publish is not None:
on_publish(batch_output.new_seq_lens)
# Draft prefill seed (no forward).
with (
self.draft_worker.draft_tp_context(
self.draft_worker.draft_runner.tp_group
),
speculative_moe_backend_context(),
speculative_moe_a2a_backend_context(),
spec_stage_span("draft_extend"),
):
batch_output.next_draft_input = (
self.draft_worker._draft_extend_for_prefill(
batch,
batch_output.logits_output.hidden_states,
batch_output.next_token_ids,
batch_output.logits_output.mm_input_embeds,
)
)
return batch_output
else:
self.activate_step_by_batch(batch.seq_lens.shape[0])
if batch.spec_info is None:
batch.spec_info = self.draft_worker._idle_seed()
with (
self.draft_worker.draft_tp_context(
self.draft_worker.draft_runner.tp_group
),
speculative_moe_backend_context(),
speculative_moe_a2a_backend_context(),
spec_stage_span("draft"),
):
verify_input = self.draft_worker.draft(batch)
assert verify_input.is_verify_input()
batch.spec_info = verify_input
batch_output = self.verify(batch)
# Publish before draft-extend so the fence is at verify-end.
if on_publish is not None:
on_publish(batch_output.new_seq_lens)
with (
self.draft_worker.draft_tp_context(
self.draft_worker.draft_runner.tp_group
),
speculative_moe_backend_context(),
speculative_moe_a2a_backend_context(),
spec_stage_span("draft_extend"),
):
self.draft_worker._draft_extend_for_decode(batch, batch_output)
return batch_output
+6 -10
View File
@@ -146,7 +146,7 @@ class SpeculativeAlgorithm(Enum):
return None
def supports_spec_v2(self) -> bool:
return (self.is_eagle() and not self.is_frozen_kv_mtp()) or self.is_standalone()
return self.is_eagle() or self.is_standalone()
def get_num_tokens_per_bs_for_target_verify(
self, num_draft_tokens: int, is_draft_worker: bool
@@ -177,17 +177,13 @@ class SpeculativeAlgorithm(Enum):
return DFlashWorker
if self.is_frozen_kv_mtp():
if enable_overlap:
raise ValueError(
"FROZEN_KV_MTP does not support spec v2. Disable overlap "
"scheduling to use FrozenKVMTPWorker."
)
from sglang.srt.speculative.frozen_kv_mtp_worker import (
FrozenKVMTPWorker,
# V2 worker drives both overlap and non-overlap (scheduler runs it
# synchronously when overlap is disabled), same as EAGLE.
from sglang.srt.speculative.frozen_kv_mtp_worker_v2 import (
FrozenKVMTPWorkerV2,
)
return FrozenKVMTPWorker
return FrozenKVMTPWorkerV2
# EAGLE / EAGLE3 / STANDALONE / MULTI_LAYER always use the V2 worker,
# even with overlap disabled (scheduler drives it synchronously).
@@ -29,7 +29,7 @@ from sglang.srt.speculative.frozen_kv_mtp_info import (
FrozenKVMTPContext,
FrozenKVMTPDraftInput,
)
from sglang.srt.speculative.frozen_kv_mtp_worker import FrozenKVMTPWorker
from sglang.srt.speculative.frozen_kv_mtp_worker_v2 import FrozenKVMTPDraftWorker
from sglang.srt.speculative.spec_info import SpeculativeAlgorithm
from ..attention_methods.dense_attention import (
@@ -226,26 +226,26 @@ class _FrozenKVMTPWorkerHarness:
)
self.model_runner.forward = model_forward
self._hidden_size = settings.hidden_size
self.draft_forward = MethodType(FrozenKVMTPWorker.draft_forward, self)
self.draft_forward = MethodType(FrozenKVMTPDraftWorker.draft_forward, self)
self._frozen_kv_target_view = MethodType(
FrozenKVMTPWorker._frozen_kv_target_view,
FrozenKVMTPDraftWorker._frozen_kv_target_view,
self,
)
self._target_kv_pool_view = MethodType(
FrozenKVMTPWorker._target_kv_pool_view,
FrozenKVMTPDraftWorker._target_kv_pool_view,
self,
)
self._set_positions = MethodType(FrozenKVMTPWorker._set_positions, self)
self._set_positions = MethodType(FrozenKVMTPDraftWorker._set_positions, self)
self._init_frozen_kv_metadata = MethodType(
FrozenKVMTPWorker._init_frozen_kv_metadata,
FrozenKVMTPDraftWorker._init_frozen_kv_metadata,
self,
)
self._init_frozen_kv_metadata_capture_cuda_graph = MethodType(
FrozenKVMTPWorker._init_frozen_kv_metadata_capture_cuda_graph,
FrozenKVMTPDraftWorker._init_frozen_kv_metadata_capture_cuda_graph,
self,
)
self._init_frozen_kv_metadata_replay_cuda_graph = MethodType(
FrozenKVMTPWorker._init_frozen_kv_metadata_replay_cuda_graph,
FrozenKVMTPDraftWorker._init_frozen_kv_metadata_replay_cuda_graph,
self,
)