Files
sglang/python/sglang/srt/speculative/eagle_worker.py
Yineng Zhang fad315cb8e fix EAGLE 2 non greedy case (#3407)
Co-authored-by: Ying Sheng <sqy1415@gmail.com>
2025-02-09 07:28:34 +08:00

317 lines
12 KiB
Python

import logging
import time
from typing import List, Optional, Union
import torch
from sglang.srt.layers.logits_processor import LogitsProcessorOutput
from sglang.srt.managers.schedule_batch import Req, 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.model_runner import ModelRunner
from sglang.srt.server_args import ServerArgs
from sglang.srt.speculative.eagle_draft_cuda_graph_runner import (
EAGLEDraftCudaGraphRunner,
)
from sglang.srt.speculative.eagle_utils import (
EagleDraftInput,
EagleVerifyInput,
assign_draft_cache_locs,
fast_topk,
select_top_k_tokens,
)
logger = logging.getLogger(__name__)
class EAGLEWorker(TpModelWorker):
def __init__(
self,
server_args: ServerArgs,
gpu_id: int,
tp_rank: int,
dp_rank: Optional[int],
nccl_port: int,
target_worker: TpModelWorker,
):
# Do not capture cuda graph in `super().__init__()`
# We will capture it later
backup_disable_cuda_graph = server_args.disable_cuda_graph
server_args.disable_cuda_graph = True
super().__init__(
gpu_id=gpu_id,
tp_rank=tp_rank,
server_args=server_args,
nccl_port=nccl_port,
dp_rank=dp_rank,
is_draft_worker=True,
)
self.target_worker = target_worker
self.finish_extend_len = []
# Parse arguments
self.topk = server_args.speculative_eagle_topk
self.speculative_num_steps = server_args.speculative_num_steps
self.server_args = server_args
# Share the embedding and lm_head
embed, head = self.target_worker.model_runner.model.get_embed_and_head()
self.model_runner.model.set_embed_and_head(embed, head)
self.model_runner.server_args.disable_cuda_graph = backup_disable_cuda_graph
# Create multi-step attn backends and cuda graph runners
from sglang.srt.layers.attention.flashinfer_backend import (
FlashInferMultiStepDraftBackend,
)
self.draft_attn_backend = FlashInferMultiStepDraftBackend(
self.model_runner,
self.topk,
self.speculative_num_steps,
)
self.model_runner.draft_attn_backend = self.draft_attn_backend
self.init_cuda_graphs()
def init_cuda_graphs(self):
"""Capture cuda graphs."""
self.cuda_graph_runner = None
if self.server_args.disable_cuda_graph:
return
tic = time.time()
logger.info("Capture cuda graph begin. This can take up to several minutes.")
self.cuda_graph_runner = EAGLEDraftCudaGraphRunner(self)
logger.info(f"Capture cuda graph end. Time elapsed: {time.time() - tic:.2f} s")
def forward_batch_speculative_generation(self, batch: ScheduleBatch):
if batch.forward_mode.is_decode():
# Draft
spec_info: EagleVerifyInput = self.draft(batch)
# Verify
(
next_draft_input,
logits_output,
verified_id,
self.finish_extend_len,
accept_length_cpu,
model_worker_batch,
) = self.verify(batch, spec_info)
batch.spec_info = next_draft_input
# if it is None, means all requsets are finished
if batch.spec_info.verified_id is not None:
self.forward_draft_extend_after_decode(batch)
return (
logits_output,
verified_id,
model_worker_batch,
sum(accept_length_cpu),
)
else:
# Forward with the target model and get hidden states.
# We need the full hidden states to prefill the KV cache of the draft model.
model_worker_batch = batch.get_model_worker_batch()
model_worker_batch.capture_hidden_mode = CaptureHiddenMode.FULL
logits_output, next_token_ids = self.target_worker.forward_batch_generation(
model_worker_batch
)
# Forward with the draft model.
batch.spec_info = EagleDraftInput(
hidden_states=logits_output.hidden_states,
verified_id=next_token_ids,
)
self.forward_draft_extend(batch)
return logits_output, next_token_ids, model_worker_batch, 0
def draft(self, batch: ScheduleBatch):
self._set_mem_pool(batch, self.model_runner)
# Parse args
num_seqs = batch.batch_size()
spec_info = batch.spec_info
# Allocate cache locations
out_cache_loc = batch.alloc_token_slots(
num_seqs * self.topk * self.speculative_num_steps
)
assign_draft_cache_locs[(num_seqs,)](
batch.req_pool_indices,
batch.req_to_token_pool.req_to_token,
batch.seq_lens,
out_cache_loc,
batch.req_to_token_pool.req_to_token.shape[1],
self.topk,
self.speculative_num_steps,
)
batch.out_cache_loc = out_cache_loc
batch.seq_lens_sum = torch.sum(batch.seq_lens).item()
spec_info.positions = batch.seq_lens.repeat_interleave(self.topk, dim=0)
# Get forward batch
spec_info.capture_hidden_mode = CaptureHiddenMode.LAST
model_worker_batch = batch.get_model_worker_batch()
forward_batch = ForwardBatch.init_new(model_worker_batch, self.model_runner)
can_cuda_graph = self.cuda_graph_runner and self.cuda_graph_runner.can_run(
forward_batch
)
if can_cuda_graph:
score_list, token_list, parents_list = self.cuda_graph_runner.replay(
forward_batch
)
else:
# Initialize attention backend
self.draft_attn_backend.init_forward_metadata(forward_batch)
# Run forward steps
score_list, token_list, parents_list = self.draft_forward(forward_batch)
ret = EagleVerifyInput.create(
spec_info.verified_id,
score_list,
token_list,
parents_list,
batch.seq_lens,
batch.seq_lens_sum,
self.topk,
self.speculative_num_steps,
self.server_args.speculative_num_draft_tokens,
batch.sampling_info.is_all_greedy,
)
# Free cache locations
batch.token_to_kv_pool.free(out_cache_loc)
self._set_mem_pool(batch, self.target_worker.model_runner)
return ret
def draft_forward(self, forward_batch: ForwardBatch):
# Parse args
spec_info = forward_batch.spec_info
out_cache_loc = forward_batch.out_cache_loc
topk_p, topk_index, hidden_states = (
spec_info.topk_p,
spec_info.topk_index,
spec_info.hidden_states,
)
# Return values
score_list: List[torch.Tensor] = []
token_list: List[torch.Tensor] = []
parents_list: List[torch.Tensor] = []
# Forward multiple steps
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])
# Set inputs
forward_batch.input_ids = input_ids
forward_batch.out_cache_loc = out_cache_loc[
forward_batch.batch_size
* self.topk
* i : forward_batch.batch_size
* self.topk
* (i + 1)
]
forward_batch.positions.add_(1)
forward_batch.attn_backend = self.draft_attn_backend.attn_backends[i]
spec_info.hidden_states = hidden_states
# Run forward
logits_output = self.model_runner.model.forward(
forward_batch.input_ids, forward_batch.positions, forward_batch
)
probs = torch.softmax(logits_output.next_token_logits, dim=-1)
topk_p, topk_index = fast_topk(probs, self.topk, dim=-1)
hidden_states = logits_output.hidden_states
return score_list, token_list, parents_list
def verify(self, batch: ScheduleBatch, spec_info: EagleVerifyInput):
spec_info.prepare_for_verify(batch)
batch.forward_mode = ForwardMode.TARGET_VERIFY
batch.spec_info = spec_info
model_worker_batch = batch.get_model_worker_batch()
logits_output, _ = self.target_worker.forward_batch_generation(
model_worker_batch, skip_sample=True
)
spec_info.hidden_states = logits_output.hidden_states
res = spec_info.verify(batch, logits_output)
batch.forward_mode = ForwardMode.DECODE
return res + (model_worker_batch,)
def forward_draft_extend(self, batch: ScheduleBatch):
self._set_mem_pool(batch, self.model_runner)
batch.spec_info.prepare_for_extend(batch)
batch.spec_info.capture_hidden_mode = CaptureHiddenMode.LAST
model_worker_batch = batch.get_model_worker_batch()
forward_batch = ForwardBatch.init_new(model_worker_batch, self.model_runner)
logits_output = self.model_runner.forward(forward_batch)
self.capture_for_decode(logits_output, forward_batch)
self._set_mem_pool(batch, self.target_worker.model_runner)
def _set_mem_pool(self, batch: ScheduleBatch, runner: ModelRunner):
batch.token_to_kv_pool = runner.token_to_kv_pool
batch.req_to_token_pool = runner.req_to_token_pool
def forward_draft_extend_after_decode(self, batch: ScheduleBatch):
seq_lens_backup = batch.seq_lens
req_pool_indices_backup = batch.req_pool_indices
self._set_mem_pool(batch, self.model_runner)
batch.forward_mode = ForwardMode.DRAFT_EXTEND
batch.spec_info.prepare_extend_after_decode(batch, self.speculative_num_steps)
batch.spec_info.capture_hidden_mode = CaptureHiddenMode.LAST
model_worker_batch = batch.get_model_worker_batch()
forward_batch = ForwardBatch.init_new(model_worker_batch, self.model_runner)
logits_output = self.model_runner.forward(forward_batch)
self.capture_for_decode(logits_output, forward_batch)
self._set_mem_pool(batch, self.target_worker.model_runner)
# Restore backup.
# This is because `seq_lens` can be modified in `prepare_extend_after_decode`
batch.forward_mode = ForwardMode.DECODE
batch.seq_lens = seq_lens_backup
batch.req_pool_indices = req_pool_indices_backup
def capture_for_decode(
self, logits_output: LogitsProcessorOutput, forward_batch: ForwardBatch
):
probs = torch.softmax(logits_output.next_token_logits, dim=-1)
spec_info = forward_batch.spec_info
spec_info.topk_p, spec_info.topk_index = fast_topk(probs, self.topk, dim=-1)
spec_info.hidden_states = logits_output.hidden_states
# Don't support prefix share now.
def finish_request(self, reqs: Union[Req, List[Req]]):
if not isinstance(reqs, List):
reqs = [reqs]
for req in reqs:
if req.rid not in self.finish_extend_len:
continue
req_len = (
len(req.origin_input_ids)
+ len(req.output_ids)
- self.finish_extend_len[req.rid]
- 1
)
kv_indices = self.model_runner.req_to_token_pool.req_to_token[
req.req_pool_idx
][:req_len]
self.model_runner.token_to_kv_pool.free(kv_indices)
self.model_runner.req_to_token_pool.free(req.req_pool_idx)