refactor(runner): add EagerRunner, own the eager path, polymorphic dispatch (#28386)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This commit is contained in:
Cheng Wan
2026-06-19 13:05:43 -07:00
committed by GitHub
co-authored by Claude Opus 4.8
parent ab0714d0ee
commit d705a91de1
5 changed files with 456 additions and 359 deletions
@@ -0,0 +1,340 @@
# Copyright 2023-2026 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.
# ==============================================================================
"""No-cuda-graph phase runner; the eager dual of BaseCudaGraphRunner."""
from __future__ import annotations
import contextlib
import logging
from dataclasses import replace
from typing import TYPE_CHECKING, Any, Tuple, Union
import torch
from sglang.srt.dllm.config import DllmConfig
from sglang.srt.environ import envs
from sglang.srt.layers.cp.utils import (
cp_gather_after_forward,
cp_split_before_forward,
is_cp_v2_active,
prepare_cp_forward,
)
from sglang.srt.layers.pooler import EmbeddingPoolerOutput
from sglang.srt.model_executor.cuda_graph_buffer_registry import (
build_eager_registry,
)
from sglang.srt.model_executor.forward_batch_info import ForwardBatch, PPProxyTensors
from sglang.srt.model_executor.forward_context import ForwardContext, forward_context
from sglang.srt.model_executor.runner.base_runner import BaseRunner
from sglang.srt.model_executor.runner_backend_utils.tc_piecewise_cuda_graph import (
enable_tc_piecewise_cuda_graph,
set_tc_piecewise_forward_context,
)
from sglang.srt.utils import is_hip
logger = logging.getLogger(__name__)
_is_hip = is_hip()
if TYPE_CHECKING:
from sglang.srt.layers.logits_processor import LogitsProcessorOutput
from sglang.srt.model_executor.model_runner import ModelRunner
class EagerRunner(BaseRunner):
def __init__(self, model_runner: ModelRunner) -> None:
super().__init__(model_runner)
mr = model_runner
sa = mr.server_args
# Built first so the cg runners coalesce onto its buffers via the shared
# input pool; size to the largest tokens/req across modes the worker hits.
num_tokens_per_bs = 1
if mr.spec_algorithm.is_speculative():
# speculative_adaptive can grow draft tokens at runtime; size to the max.
num_draft_tokens = sa.max_speculative_num_draft_tokens or 1
if mr.is_draft_worker:
num_tokens_per_bs = max(
sa.speculative_eagle_topk or 1,
num_draft_tokens,
(
2 * (sa.speculative_num_steps or 0)
if sa.enable_multi_layer_eagle
else 0
),
)
else:
num_tokens_per_bs = (
mr.spec_algorithm.get_num_tokens_per_bs_for_target_verify(
num_draft_tokens, mr.is_draft_worker
)
)
else:
dllm_config = DllmConfig.from_server_args(sa)
if dllm_config is not None:
# dLLM runs block_size tokens/request (DLLM_EXTEND).
num_tokens_per_bs = dllm_config.block_size
max_bs = mr.max_running_requests
if (
mr.is_draft_worker
and mr.spec_algorithm.is_frozen_kv_mtp()
and sa.speculative_eagle_topk > 1
):
# Frozen-KV MTP expands the draft batch by topk on the bs axis
# (expand_for_topk_draft) before the eager fallback.
max_bs *= sa.speculative_eagle_topk
prefill_ceiling = (
sa.chunked_prefill_size
if sa.chunked_prefill_size and sa.chunked_prefill_size > 0
else mr.max_total_num_tokens
)
max_num_token = max(prefill_ceiling, max_bs * num_tokens_per_bs)
is_encoder_decoder = mr.model_config.is_encoder_decoder
self._eager_registry = build_eager_registry(
device=mr.device,
max_bs=max_bs,
max_num_token=max_num_token,
cache_loc_dtype=torch.int64,
enable_mamba_track=(
sa.enable_mamba_extra_buffer() and mr.spec_algorithm.is_none()
),
is_encoder_decoder=is_encoder_decoder,
encoder_len_fill_value=(
getattr(mr.model_config.hf_config, "max_source_positions", 0)
if is_encoder_decoder
else 0
),
dp_size=sa.dp_size,
)
def can_run_graph(self, forward_batch: ForwardBatch) -> bool:
# Eager never runs a cuda graph; callers dispatch on isinstance(...,
# EagerRunner) and must not route an eager batch into a replay branch.
return False
def load_batch(
self, forward_batch: ForwardBatch, pp_proxy_tensors=None, **kwargs
) -> ForwardBatch:
"""Copy the live batch into the fixed-max eager static buffers (sliced to
this batch's shape) — the eager counterpart of the cuda-graph runners'
load_batch."""
if envs.SGLANG_EAGER_INPUT_NO_COPY.get():
return replace(forward_batch)
raw_bs = forward_batch.batch_size
raw_num_tokens = forward_batch.input_ids.shape[0]
registry = self._eager_registry
registry.fill_from(
forward_batch,
raw_bs=raw_bs,
padded_bs=raw_bs,
raw_num_tokens=raw_num_tokens,
padded_num_tokens=raw_num_tokens,
pp_proxy_tensors=pp_proxy_tensors,
)
return registry.extract_buffer(
padded_bs=raw_bs,
padded_num_tokens=raw_num_tokens,
forward_batch_template=forward_batch,
)
def execute(
self, forward_batch: ForwardBatch, pp_proxy_tensors=None, **kwargs
) -> Any:
mode = forward_batch.forward_mode
if mode.is_decode():
return self._execute_decode(forward_batch, pp_proxy_tensors)
if mode.is_idle():
return self._execute_idle(forward_batch, pp_proxy_tensors)
if mode.is_extend(include_draft_extend_v2=True):
return self._execute_extend(forward_batch, pp_proxy_tensors)
raise ValueError(f"Invalid forward mode for eager runner: {mode}")
def _resolve_decode_pdmux(
self,
) -> Tuple[Any, contextlib.AbstractContextManager]:
"""Resolve the (attn_backend, forward_context) the eager decode forward
runs under. PDmux selects a per-stream backend and publishes it via an
active ForwardContext; non-pdmux uses attn_backend + the ambient ctx."""
model_runner = self.model_runner
if model_runner.server_args.enable_pdmux:
return model_runner.decode_attn_backend, forward_context(
ForwardContext(attn_backend=model_runner.decode_attn_backend)
)
return model_runner.attn_backend, contextlib.nullcontext()
def _execute_decode(
self,
forward_batch: ForwardBatch,
pp_proxy_tensors=None,
) -> Union[LogitsProcessorOutput, PPProxyTensors]:
model_runner = self.model_runner
enable_pdmux = model_runner.server_args.enable_pdmux
attn_backend, pdmux_ctx = self._resolve_decode_pdmux()
if not enable_pdmux:
forward_batch = self.load_batch(forward_batch, pp_proxy_tensors)
if forward_batch.needs_forward_metadata_init():
if hasattr(model_runner.model, "prepare_forward_batch"):
# Prepare model-specific attention metadata before planning,
# e.g. Moss-VL's prefill cross-attention custom mask.
model_runner.model.prepare_forward_batch(forward_batch)
attn_backend.init_forward_metadata(forward_batch)
# FIXME: add pp_proxy_tensors arg to all models
kwargs = model_runner._pp_kwargs(pp_proxy_tensors)
ctx = (
model_runner.device_timer.wrap(metadata={"category": "decode"})
if model_runner.device_timer
else contextlib.nullcontext()
)
with ctx, pdmux_ctx:
return model_runner.model.forward(
forward_batch.input_ids,
forward_batch.positions,
forward_batch,
**kwargs,
)
def _execute_extend(
self,
forward_batch: ForwardBatch,
pp_proxy_tensors=None,
) -> Union[LogitsProcessorOutput, PPProxyTensors, EmbeddingPoolerOutput]:
model_runner = self.model_runner
kwargs = model_runner._extend_forward_kwargs(forward_batch, pp_proxy_tensors)
if not model_runner.server_args.enable_pdmux:
forward_batch = self.load_batch(forward_batch, pp_proxy_tensors)
if forward_batch.needs_forward_metadata_init():
if hasattr(model_runner.model, "prepare_forward_batch"):
# Prepare model-specific attention metadata before planning,
# e.g. Moss-VL's prefill cross-attention custom mask.
model_runner.model.prepare_forward_batch(forward_batch)
model_runner.attn_backend.init_forward_metadata(forward_batch)
cp_v2_active = is_cp_v2_active(forward_batch)
forward_positions = forward_batch.positions
if cp_v2_active:
prepare_cp_forward(forward_batch)
complete_hidden_states = kwargs.get("input_embeds")
if complete_hidden_states is None:
embed_layer = model_runner.model.get_input_embeddings()
complete_hidden_states = embed_layer(forward_batch.input_ids)
sharded_hidden_states, sharded_positions = cp_split_before_forward(
complete_hidden_states,
forward_batch.positions,
forward_batch,
)
kwargs["input_embeds"] = sharded_hidden_states
forward_positions = sharded_positions
ctx = (
model_runner.device_timer.wrap(metadata={"category": "extend"})
if model_runner.device_timer
else contextlib.nullcontext()
)
with ctx:
pcg_runner = model_runner.prefill_cuda_graph_runner
if (
_is_hip
and pcg_runner is not None
and not isinstance(pcg_runner, EagerRunner)
and not cp_v2_active
):
# HIP PCG eager fallback: enter the PCG context so Dynamo guards
# and PCG-specific MoE/attention paths stay consistent.
with (
enable_tc_piecewise_cuda_graph(),
set_tc_piecewise_forward_context(
forward_batch,
model_runner.attention_layers,
getattr(model_runner.model, "quant_config", None),
model_runner.moe_layers,
model_runner.moe_fusions,
dsa_indexers=model_runner.dsa_indexers,
),
):
ret = model_runner.model.forward(
forward_batch.input_ids,
forward_positions,
forward_batch,
**kwargs,
)
elif cp_v2_active:
# CP-V2: drive .model directly to gather across CP ranks before logits.
hidden_states = model_runner.model.model(
forward_batch.input_ids,
forward_positions,
forward_batch,
input_embeds=kwargs.get("input_embeds"),
pp_proxy_tensors=kwargs.get("pp_proxy_tensors"),
)
aux_hidden_states = None
capture_aux_hidden_states = getattr(
model_runner.model, "capture_aux_hidden_states", False
)
if capture_aux_hidden_states:
hidden_states, aux_hidden_states = hidden_states
if model_runner.model.pp_group.is_last_rank:
hidden_states = cp_gather_after_forward(
hidden_states,
forward_batch,
torch.cuda.current_stream(),
)
ret = model_runner.model.logits_processor(
forward_batch.input_ids,
hidden_states,
model_runner.model.lm_head,
forward_batch,
aux_hidden_states,
)
elif capture_aux_hidden_states:
ret = hidden_states, aux_hidden_states
else:
ret = hidden_states
else:
ret = model_runner.model.forward(
forward_batch.input_ids,
forward_positions,
forward_batch,
**kwargs,
)
return ret
def _execute_idle(
self, forward_batch: ForwardBatch, pp_proxy_tensors=None
) -> Union[LogitsProcessorOutput, PPProxyTensors]:
model_runner = self.model_runner
# Padded idle (DP-attn MLP sync) needs metadata reinit; unpadded must
# drop stale forward_metadata to avoid an SWA use-after-free on req_pool.
if forward_batch.batch_size > 0:
if not model_runner.server_args.enable_pdmux:
forward_batch = self.load_batch(forward_batch, pp_proxy_tensors)
model_runner.attn_backend.init_forward_metadata(forward_batch)
else:
model_runner.attn_backend.forward_metadata = None
kwargs = model_runner._pp_kwargs(pp_proxy_tensors)
ctx = (
model_runner.device_timer.wrap(metadata={"category": "idle"})
if model_runner.device_timer
else contextlib.nullcontext()
)
with ctx:
return model_runner.model.forward(
forward_batch.input_ids,
forward_batch.positions,
forward_batch,
**kwargs,
)