Files
sglang/python/sglang/srt/managers/overlap_utils.py
2025-12-16 17:09:44 -08:00

164 lines
6.3 KiB
Python

from __future__ import annotations
from dataclasses import dataclass
from typing import TYPE_CHECKING, Optional
import torch
from sglang.srt.utils import get_compiler_backend
if TYPE_CHECKING:
from sglang.srt.managers.schedule_batch import ModelWorkerBatch
from sglang.srt.managers.scheduler import GenerationBatchResult
from sglang.srt.speculative.eagle_info import EagleDraftInput
from sglang.srt.speculative.spec_info import SpeculativeAlgorithm
@torch.compile(dynamic=True, backend=get_compiler_backend())
def _resolve_future_token_ids(input_ids, future_token_ids_map):
input_ids[:] = torch.where(
input_ids < 0,
future_token_ids_map[torch.clamp(-input_ids, min=0)],
input_ids,
)
@dataclass
class FutureIndices:
indices: torch.Tensor
interval: Optional[slice] = None
class FutureMap:
def __init__(
self,
max_running_requests: int,
chunked_prefill_size: int,
context_len: int,
device: torch.device,
spec_algo: Optional[SpeculativeAlgorithm] = None,
):
# FIXME: the calculation of future_limit and future_buffer_len maybe too conservative
self.future_ct = 0
# Circular buffer layout (wraps in this order):
# Running decode batch -> Prefill chunk 1 -> ... -> Prefill chunk N
# A running decode batch's result will be resolved after all prefill chunks are done.
# reserve `max_num_chunks` extra future slots on top of `max_running_requests * 3`.
max_num_chunks = (
(context_len + chunked_prefill_size - 1) // chunked_prefill_size
if chunked_prefill_size
else 0
)
self.future_limit = max_running_requests * (3 + max_num_chunks)
# Adding 2 * max_running_requests to future_limit ensures the buffer is sufficiently large.
self.future_buffer_len = self.future_limit + 2 * max_running_requests
self.device = device
self.spec_algo = spec_algo
if self.spec_algo.is_none():
# For non-speculative decoding, we only need to store the token ids.
self.buf_initialized = True
self.token_ids_buf = torch.empty(
(self.future_buffer_len,), dtype=torch.int64, device=self.device
)
else:
# For speculative decoding, we lazily initialize the buffers
# This is to make the shape derivation easier.
self.buf_initialized = False
def _lazy_init_buf(self, draft_input: EagleDraftInput):
self.buf_initialized = True
# Get a reference for each tensor
topk_p0 = draft_input.topk_p[0]
topk_index0 = draft_input.topk_index[0]
hidden_states0 = draft_input.hidden_states[0]
verified_id0 = draft_input.verified_id[0]
new_seq_lens0 = draft_input.new_seq_lens[0]
self.topk_p_buf = torch.empty(
(self.future_buffer_len, *topk_p0.shape),
dtype=topk_p0.dtype,
device=self.device,
)
self.topk_index_buf = torch.empty(
(self.future_buffer_len, *topk_index0.shape),
dtype=topk_index0.dtype,
device=self.device,
)
self.hidden_states_buf = torch.empty(
(self.future_buffer_len, *hidden_states0.shape),
dtype=hidden_states0.dtype,
device=self.device,
)
self.verified_id_buf = torch.empty(
(self.future_buffer_len, *verified_id0.shape),
dtype=verified_id0.dtype,
device=self.device,
)
self.new_seq_lens_buf = torch.empty(
(self.future_buffer_len, *new_seq_lens0.shape),
dtype=new_seq_lens0.dtype,
device=self.device,
)
def alloc_future_indices(self, bs: int) -> FutureIndices:
"""Update the circular buffer pointer and allocate future indices."""
cur_future_ct = self.future_ct
self.future_ct = (cur_future_ct + bs) % self.future_limit
start = cur_future_ct + 1
end = cur_future_ct + 1 + bs
indices = torch.arange(start, end, dtype=torch.int64, device=self.device)
return FutureIndices(indices=indices, interval=slice(start, end))
def resolve_future(self, model_worker_batch: ModelWorkerBatch):
if self.spec_algo.is_eagle():
# TODO(lsyin): write future indices into spec_info.future_indices
draft_input: EagleDraftInput = model_worker_batch.spec_info
if draft_input is None:
# FIXME(lsyin): No future exists, only for prefill batch, not compatible with mixed mode
return
indices = draft_input.future_indices.indices
draft_input.topk_p = self.topk_p_buf[indices]
draft_input.topk_index = self.topk_index_buf[indices]
draft_input.hidden_states = self.hidden_states_buf[indices]
draft_input.verified_id = self.verified_id_buf[indices]
draft_input.new_seq_lens = self.new_seq_lens_buf[indices]
else:
_resolve_future_token_ids(model_worker_batch.input_ids, self.token_ids_buf)
def is_empty_slice(self, s: slice) -> bool:
start, stop, step = s.indices(self.future_buffer_len)
if step > 0:
return start >= stop
else:
return start <= stop
def store_to_map(
self, future_indices: FutureIndices, batch_result: GenerationBatchResult
):
if self.spec_algo.is_eagle():
draft_input: EagleDraftInput = batch_result.next_draft_input
self.store_to_map_for_new_batch(future_indices, draft_input)
else:
intv = future_indices.interval
self.token_ids_buf[intv] = batch_result.next_token_ids
def store_to_map_for_new_batch(
self, future_indices: FutureIndices, draft_input: EagleDraftInput
):
intv = future_indices.interval
if self.is_empty_slice(intv):
# idle indices in dp attention do not need store info
return
if not self.buf_initialized:
self._lazy_init_buf(draft_input)
self.topk_p_buf[intv] = draft_input.topk_p
self.topk_index_buf[intv] = draft_input.topk_index
self.hidden_states_buf[intv] = draft_input.hidden_states
self.verified_id_buf[intv] = draft_input.verified_id
self.new_seq_lens_buf[intv] = draft_input.new_seq_lens