device_selection.py

# Data Parallel Control (dpctl)
#
# Copyright 2021 Intel Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Examples illustrating SYCL device selection features provided by dpctl."""

import dpctl


def create_default_device():
 """
 Create default SyclDevice using `sycl::default_selector`.

 Device created can be influenced by environment variable
 ONEAPI_DEVICE_SELECTOR, which determines SYCL devices seen by the
 oneAPI DPC++ runtime.
 """
 d1 = dpctl.SyclDevice()
 d2 = dpctl.select_default_device()
 assert d1 == d2
 d1.print_device_info()
 return d1


def create_gpu_device():
 """
 Create a GPU device.

 Device created can be influenced by environment variable
 ONEAPI_DEVICE_SELECTOR, which determines SYCL devices seen by the
 oneAPI DPC++ runtime.
 """
 try:
 d1 = dpctl.SyclDevice("gpu")
 d2 = dpctl.select_gpu_device()
 assert d1 == d2
 d1.print_device_info()
 except dpctl.SyclDeviceCreationError:
 print("A GPU device is not available on the system")


def create_gpu_device_if_present():
 """
 Select from union of two selections using default_selector.
 If a GPU device is available, it will be selected, if not,
 a CPU device will be selected, if available, otherwise an error
 will be raised.

 Device created can be influenced by environment variable
 ONEAPI_DEVICE_SELECTOR, which determines SYCL devices seen by the
 oneAPI DPC++ runtime.
 """
 d = dpctl.SyclDevice("gpu,cpu")
 print("Selected " + ("GPU" if d.is_gpu else "CPU") + " device")


def custom_select_device():
 """
 Programmatically select among available devices.

 Device created can be influenced by environment variable
 ONEAPI_DEVICE_SELECTOR, which determines SYCL devices seen by the
 oneAPI DPC++ runtime.
 """
 # select devices that support half-precision computation
 devs = [d for d in dpctl.get_devices() if d.has_aspect_fp16]
 # choose the device with highest default_selector score
 max_score = 0
 selected_dev = None
 for d in devs:
 if d.default_selector_score > max_score:
 max_score = d.default_selector_score
 selected_dev = d
 if selected_dev:
 selected_dev.print_device_info()
 else:
 print("No device with half-precision support is available.")
 return selected_dev


def create_device_with_aspects():
 """
 Programmatically select a device based on specific set of aspects.

 Demonstrate the usage of :func:`dpctl.select_device_with_aspects()`.
 """
 dev = dpctl.select_device_with_aspects(
 required_aspects=["fp64", "usm_shared_allocations"]
 )
 dev.print_device_info()


def list_devices():
 """Programmatically get a list of the available devices.

 The list can be filtered based on backend or device_type.
 """
 print("Get a list of all devices:\n")

 for d in dpctl.get_devices():
 d.print_device_info()
 print("=======================================\n")

 print("Get the list of only OpenCL devices:\n")

 for d in dpctl.get_devices(backend="opencl"):
 d.print_device_info()

 print("=======================================\n")

 print("Get all OpenCL CPU devices:\n")

 for d in dpctl.get_devices(backend="opencl", device_type="cpu"):
 d.print_device_info()

 print("=======================================\n")


if __name__ == "__main__":
 import _runner as runner

 runner.run_examples("Device selection examples for dpctl.", globals())