Files
vllm-dev/vllm/env_override.py
2025-06-11 17:29:54 +08:00

42 lines
1.7 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import os
import torch
from vllm.logger import init_logger
logger = init_logger(__name__)
# set some common config/environment variables that should be set
# for all processes created by vllm and all processes
# that interact with vllm workers.
# they are executed whenever `import vllm` is called.
if os.environ.get('NCCL_CUMEM_ENABLE', '0') != '0':
logger.warning(
"NCCL_CUMEM_ENABLE is set to %s, skipping override. "
"This may increase memory overhead with cudagraph+allreduce: "
"https://github.com/NVIDIA/nccl/issues/1234",
os.environ['NCCL_CUMEM_ENABLE'])
elif not os.path.exists('/dev/nvidia-caps-imex-channels'):
# NCCL requires NCCL_CUMEM_ENABLE to work with
# multi-node NVLink, typically on GB200-NVL72 systems.
# The ultimate way to detect multi-node NVLink is to use
# NVML APIs, which are too expensive to call here.
# As an approximation, we check the existence of
# /dev/nvidia-caps-imex-channels, used by
# multi-node NVLink to communicate across nodes.
# This will still cost some GPU memory, but it is worthwhile
# because we can get very fast cross-node bandwidth with NVLink.
os.environ['NCCL_CUMEM_ENABLE'] = '0'
# see https://github.com/vllm-project/vllm/pull/15951
# it avoids unintentional cuda initialization from torch.cuda.is_available()
os.environ['PYTORCH_NVML_BASED_CUDA_CHECK'] = '1'
# see https://github.com/vllm-project/vllm/issues/10480
os.environ['TORCHINDUCTOR_COMPILE_THREADS'] = '1'
# see https://github.com/vllm-project/vllm/issues/10619
torch._inductor.config.compile_threads = 1