vllm/vllm/spec_decode/target_model_runner.py
Russell Bryant e489ad7a21
[Misc] Add SPDX-License-Identifier headers to python source files (#12628)
- **Add SPDX license headers to python source files**
- **Check for SPDX headers using pre-commit**

commit 9d7ef44c3cfb72ca4c32e1c677d99259d10d4745
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:18:24 2025 -0500

    Add SPDX license headers to python source files
    
This commit adds SPDX license headers to python source files as
recommended to
the project by the Linux Foundation. These headers provide a concise way
that is
both human and machine readable for communicating license information
for each
source file. It helps avoid any ambiguity about the license of the code
and can
    also be easily used by tools to help manage license compliance.
    
The Linux Foundation runs license scans against the codebase to help
ensure
    we are in compliance with the licenses of the code we use, including
dependencies. Having these headers in place helps that tool do its job.
    
    More information can be found on the SPDX site:
    
    - https://spdx.dev/learn/handling-license-info/
    
    Signed-off-by: Russell Bryant <rbryant@redhat.com>

commit 5a1cf1cb3b80759131c73f6a9dddebccac039dea
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:36:32 2025 -0500

    Check for SPDX headers using pre-commit
    
    Signed-off-by: Russell Bryant <rbryant@redhat.com>

---------

Signed-off-by: Russell Bryant <rbryant@redhat.com>
2025-02-02 11:58:18 -08:00

45 lines
2.0 KiB
Python

# SPDX-License-Identifier: Apache-2.0
from typing import List, Optional
from vllm.sequence import SequenceGroupMetadata
from vllm.worker.model_runner_base import (ModelRunnerBase,
ModelRunnerInputBase,
ModelRunnerWrapperBase)
class TargetModelRunner(ModelRunnerWrapperBase):
"""Specialized model runner for speculative decoding target model.
In speculative decoding, the log probabilities selected finally may not
be the same ones as selected by the target model sampling. This means
that the time spent in the log probability calculation of the target model
is time wasted, since we calculate log probabilities after deciding which
tokens are accepted. For this reason disabling log probabilities in the
target model will make decode faster. The model runner sets the
SamplingMetadata parameters according to whether log probabilities are
requested or not.
"""
def __init__(self, model_runner: ModelRunnerBase):
# An internal boolean member variable to indicate if token log
# probabilities are needed or not.
super().__init__(model_runner)
self.disable_logprobs = True
def prepare_model_input(
self,
seq_group_metadata_list: List[SequenceGroupMetadata],
virtual_engine: int = 0,
finished_requests_ids: Optional[List[str]] = None,
) -> ModelRunnerInputBase:
model_input: ModelRunnerInputBase =\
self.model_runner.prepare_model_input(
seq_group_metadata_list, virtual_engine, finished_requests_ids)
# If token log probabilities is disabled then skip generating sampler
# CPU output. We directly serialize the GPU sampled_token_id tensors
# as needed. If log probabilities is enabled then synchronize all the
# sampling related tensors which includes the logprobs tensors.
model_input.sampling_metadata.skip_sampler_cpu_output = (
self.disable_logprobs)
return model_input