Files
xc-llm-ascend/vllm_ascend/spec_decode/medusa_proposer.py
wangxiyuan 13777bf3f0 [Spec Decode]clean up spec decode interface (#6947)
This pull request refactors the speculative decoding proposer interface
to align with upstream vLLM, removing the local `Proposer` interface and
renaming methods to `propose`.

This is the first step. In the future we should remove the class
register and just add few Ascend specified method once the arch in vLLM
is ready.

- vLLM version: v0.16.0
- vLLM main:
15d76f74e2

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>
2026-03-05 14:30:10 +08:00

74 lines
2.6 KiB
Python

import torch
from vllm.config import CUDAGraphMode
from vllm.logger import init_logger
from vllm.v1.sample.metadata import SamplingMetadata
from vllm.v1.spec_decode.medusa import MedusaProposer
from vllm.v1.spec_decode.metadata import SpecDecodeMetadata
from vllm_ascend.ascend_forward_context import set_ascend_forward_context
logger = init_logger(__name__)
class AscendMedusaProposer(MedusaProposer):
"""
Medusa proposer class for generating token sequences
"""
@torch.inference_mode()
def dummy_run(
self,
num_tokens: int,
with_prefill: bool = False,
in_graph_capturing: bool = False,
num_reqs: int = 0,
num_tokens_across_dp: torch.Tensor | None = None,
aclgraph_runtime_mode: CUDAGraphMode = CUDAGraphMode.NONE,
batch_descriptor=None,
dummy_compute_logits=lambda hidden_states: None,
is_profile=False,
):
hidden_states = torch.zeros(
(self.max_num_tokens, self.hidden_size),
dtype=self.dtype,
device=self.device,
)
with set_ascend_forward_context(
None,
self.vllm_config,
num_tokens=num_tokens,
num_actual_tokens=0,
in_profile_run=is_profile,
batch_descriptor=batch_descriptor,
aclgraph_runtime_mode=aclgraph_runtime_mode,
is_draft_model=True,
):
self.model(hidden_states)
dummy_compute_logits(hidden_states)
def propose(
self,
valid_sampled_token_ids: list[list[int]],
sampling_metadata: SamplingMetadata,
spec_decode_metadata: SpecDecodeMetadata,
sample_hidden_states: torch.Tensor,
):
if sample_hidden_states.shape[0] == len(valid_sampled_token_ids):
# The input to the target model does not include draft tokens.
hidden_states = sample_hidden_states
else:
num_accepted_tokens = torch.tensor(
[len(t) for t in valid_sampled_token_ids], device=self.device, dtype=torch.long
)
num_draft_tokens = torch.tensor(spec_decode_metadata.num_draft_tokens, device=self.device, dtype=torch.long)
offsets = torch.cumsum(num_draft_tokens + 1, dim=0) - (num_draft_tokens + 1)
indices = offsets + num_accepted_tokens - 1
hidden_states = sample_hidden_states[indices]
spec_token_ids = super().propose(
target_hidden_states=hidden_states,
sampling_metadata=sampling_metadata,
)
return spec_token_ids