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2026-02-04 17:22:39 +08:00

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3.9 KiB
Python

"""A Neuron worker class."""
from typing import List, Optional, Tuple
import torch
import torch.distributed
from vllm.config import VllmConfig
from vllm.distributed import (ensure_model_parallel_initialized,
init_distributed_environment)
from vllm.model_executor import set_random_seed
from vllm.sequence import ExecuteModelRequest
from vllm.worker.neuron_model_runner import NeuronModelRunner
from vllm.worker.worker_base import (LocalOrDistributedWorkerBase,
LoraNotSupportedWorkerBase, WorkerBase,
WorkerInput)
class NeuronWorker(LoraNotSupportedWorkerBase, LocalOrDistributedWorkerBase):
"""A worker class that executes the model on a group of neuron cores.
"""
def __init__(
self,
vllm_config: VllmConfig,
local_rank: int,
rank: int,
distributed_init_method: str,
) -> None:
WorkerBase.__init__(self, vllm_config=vllm_config)
self.local_rank = local_rank
self.rank = rank
self.distributed_init_method = distributed_init_method
if self.model_config.trust_remote_code:
# note: lazy import to avoid importing torch before initializing
from vllm.utils import init_cached_hf_modules
init_cached_hf_modules()
self.model_runner: NeuronModelRunner = NeuronModelRunner(
vllm_config=vllm_config)
self.is_driver_worker = True
def init_device(self) -> None:
self.init_distributed_environment()
# Set random seed.
set_random_seed(self.model_config.seed)
def load_model(self):
self.model_runner.load_model()
def determine_num_available_blocks(self) -> Tuple[int, int]:
"""Determine the number of available KV blocks.
Swapping is not yet supported, so always return num_cpu_blocks=0.
We configure num_gpu_blocks to be equal to max_num_seqs.
"""
# Set the number of GPU blocks to be the same as the maximum number of
# sequences that can be processed in a single batch. This is equivalent
# to schedule without PagedAttention.
num_gpu_blocks = self.scheduler_config.max_num_seqs
# Swap not yet supported with Neuron backend.
num_cpu_blocks = 0
return num_gpu_blocks, num_cpu_blocks
def initialize_cache(self, num_gpu_blocks: int,
num_cpu_blocks: int) -> None:
"""Initialize the KV cache.
"""
# Different values are not tested.
assert num_cpu_blocks == 0
assert num_gpu_blocks == self.scheduler_config.max_num_seqs
self.cache_config.num_gpu_blocks = num_gpu_blocks
self.cache_config.num_cpu_blocks = num_cpu_blocks
@property
def do_metadata_broadcast(self) -> bool:
return False
@property
def kv_cache(self) -> Optional[List[List[torch.Tensor]]]:
return None
@torch.inference_mode()
def prepare_worker_input(
self, execute_model_req: ExecuteModelRequest) -> WorkerInput:
return WorkerInput(num_seq_groups=len(
execute_model_req.seq_group_metadata_list), )
def execute_worker(self, worker_input: WorkerInput) -> None:
pass
def get_cache_block_size_bytes(self) -> int:
"""Determine the size in bytes of a cache block.
This is required for speculative decoding; it is not yet implemented.
"""
raise NotImplementedError
def init_distributed_environment(self):
"""Neuron uses transformers-neuronx for tensor parallelism.
vLLM still needs the environment inited when TP/PP > 1
"""
init_distributed_environment(
world_size=1,
rank=self.rank,
local_rank=self.local_rank,
distributed_init_method=self.distributed_init_method,
backend="gloo",
)
ensure_model_parallel_initialized(
1,
1,
)