Files
xc-llm-ascend/vllm_ascend/kv_offload/npu.py
kx bc30874f8b [Feat] add native kvcache offload (#3433)
### What this PR does / why we need it?
This pr is for https://github.com/vllm-project/vllm-ascend/issues/3241 ,
which is in-house solution for offloading KV cache data from the GPU
memory to other medium (in particular, CPU memory)。Previous solutions
required reliance on third-party components, which had issues with
compatibility between different versions.

### How was this patch tested?
use the following script for testing:

export CUDA_VISIBLE_DEVICES=0
export TP=1
export MODEL_PATH=/model/Qwen3-14B
export MODEL_NAME=Qwen3-14B
export PORT=10000
#export ASCEND_LAUNCH_BLOCKING=1
#export ASCEND_SLOG_PRINT_TO_STDOUT=1

python3 -m vllm.entrypoints.openai.api_server --host 0.0.0.0 --port
${PORT} --dtype bfloat16 --model ${MODEL_PATH} --served-model-name
${MODEL_NAME} --tensor-parallel-size ${TP} --gpu-memory-utilization 0.7
--max-model-len 32768 --trust-remote-code --disable-log-requests \
    --block-size 128 \
--kv-transfer-config
'{"kv_connector":"OffloadingConnector","kv_role":"kv_both","kv_connector_extra_config":{"block_size":
128, "num_cpu_blocks": 1000, "spec_name":"NPUOffloadingSpec",
"spec_module_path": "vllm_ascend.kv_offload.npu"}}'


- vLLM version: v0.11.0rc3
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0

---------

Signed-off-by: HF-001 <1670186653@qq.com>
2025-10-22 14:15:49 +08:00

72 lines
2.8 KiB
Python

from collections.abc import Iterator
from typing import Optional
import torch
from vllm.config import VllmConfig, get_layers_from_vllm_config
from vllm.model_executor.layers.attention_layer_base import AttentionLayerBase
from vllm.v1.kv_offload.abstract import LoadStoreSpec, OffloadingManager
from vllm.v1.kv_offload.backends.cpu import CPUBackend
from vllm.v1.kv_offload.lru_manager import LRUOffloadingManager
from vllm.v1.kv_offload.mediums import CPULoadStoreSpec, GPULoadStoreSpec
from vllm.v1.kv_offload.spec import OffloadingSpec
from vllm.v1.kv_offload.worker.worker import OffloadingHandler
from vllm_ascend.kv_offload.cpu_npu import CpuNpuOffloadingHandler
class NPUOffloadingSpec(OffloadingSpec):
def __init__(self, vllm_config: VllmConfig):
super().__init__(vllm_config)
num_cpu_blocks = self.extra_config.get("num_cpu_blocks")
if not num_cpu_blocks:
raise Exception(
"num_cpu_blocks must be specified in kv_connector_extra_config"
)
self.num_cpu_blocks: int = num_cpu_blocks
# scheduler-side
self._manager: Optional[OffloadingManager] = None
# worker-side
self._handler: Optional[OffloadingHandler] = None
def get_manager(self) -> OffloadingManager:
if not self._manager:
kv_events_config = self.vllm_config.kv_events_config
enable_events = (kv_events_config is not None
and kv_events_config.enable_kv_cache_events)
self._manager = LRUOffloadingManager(
CPUBackend(block_size=self.offloaded_block_size,
num_blocks=self.num_cpu_blocks),
enable_events=enable_events,
)
return self._manager
def get_handlers(
self, kv_caches: dict[str, torch.Tensor]
) -> Iterator[tuple[type[LoadStoreSpec], type[LoadStoreSpec],
OffloadingHandler]]:
if not self._handler:
layer_names = list(kv_caches.keys())
layers = get_layers_from_vllm_config(self.vllm_config,
AttentionLayerBase,
layer_names)
attn_backends = {
layer_name: layers[layer_name].get_attn_backend()
for layer_name in layer_names
}
self._handler = CpuNpuOffloadingHandler(
attn_backends=attn_backends,
gpu_block_size=self.gpu_block_size,
cpu_block_size=self.offloaded_block_size,
num_cpu_blocks=self.num_cpu_blocks,
gpu_caches=kv_caches,
)
assert self._handler is not None
yield GPULoadStoreSpec, CPULoadStoreSpec, self._handler
yield CPULoadStoreSpec, GPULoadStoreSpec, self._handler