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ray-project--ray/python/ray/air/_internal/device_manager/nvidia_gpu.py
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2026-07-13 13:17:40 +08:00

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2.9 KiB
Python

import os
from typing import List, Union
import torch
import ray
from ray.air._internal.device_manager.torch_device_manager import TorchDeviceManager
class CUDATorchDeviceManager(TorchDeviceManager):
"""CUDA device manager"""
def is_available(self) -> bool():
return torch.cuda.is_available()
def get_devices(self) -> List[torch.device]:
"""Gets the correct torch device list configured for this process.
Returns a list of torch CUDA devices allocated for the current worker.
If no GPUs are assigned, then it returns a list with a single CPU device.
Assumes that `CUDA_VISIBLE_DEVICES` is set and is a
superset of the `ray.get_gpu_ids()`.
"""
# GPU IDs are assigned by Ray after you specify "use_gpu"
# GPU `ray.get_gpu_ids()` may return ints or may return strings.
# We should always convert to strings.
gpu_ids = [str(id) for id in ray.get_gpu_ids()]
device_ids = []
if len(gpu_ids) > 0:
cuda_visible_str = os.environ.get("CUDA_VISIBLE_DEVICES", "")
if cuda_visible_str and cuda_visible_str != "NoDevFiles":
cuda_visible_list = cuda_visible_str.split(",")
else:
cuda_visible_list = []
# By default, there should only be one GPU ID if `use_gpu=True`.
# If there are multiple GPUs, return a list of devices.
# If using fractional GPUs, these IDs are not guaranteed
# to be unique across different processes.
for gpu_id in gpu_ids:
try:
device_ids.append(cuda_visible_list.index(gpu_id))
except IndexError:
raise RuntimeError(
"CUDA_VISIBLE_DEVICES set incorrectly. "
f"Got {cuda_visible_str}, expected to include {gpu_id}. "
"Did you override the `CUDA_VISIBLE_DEVICES` environment"
" variable? If not, please help file an issue on Github."
)
else:
# If called on the driver or outside of Ray Train, return the
# 0th device.
device_ids.append(0)
return [torch.device(f"cuda:{device_id}") for device_id in device_ids]
def set_device(self, device: Union[torch.device, int, str, None]):
torch.cuda.set_device(device)
def supports_stream(self) -> bool:
"""Validate if the device type support create a stream"""
return True
def create_stream(self, device: torch.device) -> torch.cuda.Stream:
"""Create a stream on cuda device"""
return torch.cuda.Stream(device)
def get_stream_context(self, stream):
"""Get a stream context for cuda device"""
return torch.cuda.stream(stream)
def get_current_stream(self) -> torch.cuda.Stream:
"""Get current stream for cuda device"""
return torch.cuda.current_stream()