77 lines
2.8 KiB
Python

from abc import ABC, abstractmethod
from typing import Callable, List
from transformers import PreTrainedTokenizer
from vllm.config import SchedulerConfig
from vllm.core.scheduler import Scheduler
from vllm.engine.output_processor.stop_checker import StopChecker
from vllm.sequence import Sequence, SequenceGroup, SequenceGroupOutput
from vllm.transformers_utils.detokenizer import Detokenizer
from vllm.utils import Counter
class SequenceGroupOutputProcessor(ABC):
"""Interface for logic that processes new token ids in sequence groups,
managing detokenization, stop checking, and freeing/forking sequences with
the scheduler.
This is highly coupled with the LLMEngine and should be seen as an extension
of it. The logic is separated to simplify the LLMEngine class and allow
separate implementations for single-step decoding (which supports beam
search sequence forking) and multi-step decoding (which does not support
beam search, but does support speculative decoding).
"""
@staticmethod
def create_output_processor(
scheduler_config: SchedulerConfig,
detokenizer: Detokenizer,
scheduler: Scheduler,
seq_counter: Counter,
get_tokenizer_for_seq: Callable[[Sequence], PreTrainedTokenizer],
stop_checker: "StopChecker",
):
"""Create an output processor.
This returns a single-step output processor if num_lookahead_slots is
zero, else returns a multi-step output processor.
"""
if scheduler_config.num_lookahead_slots == 0:
# Importing here to avoid cycle.
from vllm.engine.output_processor.single_step import (
SingleStepOutputProcessor)
return SingleStepOutputProcessor(
scheduler_config,
detokenizer,
scheduler,
seq_counter,
stop_checker,
)
else:
# Importing here to avoid cycle.
from vllm.engine.output_processor.multi_step import (
MultiStepOutputProcessor)
return MultiStepOutputProcessor(
detokenizer,
scheduler,
seq_counter,
get_tokenizer_for_seq,
stop_checker,
)
@abstractmethod
def process_outputs(self, sequence_group: SequenceGroup,
outputs: List[SequenceGroupOutput]) -> None:
"""Process new token ids for the sequence group. Handles logic such as
detokenization, stop checking, and freeing/forking sequences in the
scheduler.
"""
pass
@abstractmethod
def process_prompt_logprob(self, seq_group: SequenceGroup,
outputs: List[SequenceGroupOutput]) -> None:
"""Update prompt logprobs received from outputs to seq_group."""
pass