tf.config.set_logical_device_configuration

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Set the logical device configuration for a tf.config.PhysicalDevice.

Aliases:

tf.config.set_logical_device_configuration(
    device,
    logical_devices
)

A visible tf.config.PhysicalDevice will by default have a single tf.config.LogicalDevice associated with it once the runtime is initialized. Specifying a list of tf.config.LogicalDeviceConfiguration objects allows multiple devices to be created on the same tf.config.PhysicalDevice.

The following example splits the CPU into 2 logical devices:

physical_devices = tf.config.list_physical_devices('CPU')
assert len(physical_devices) == 1, "No CPUs found"
# Specify 2 virtual CPUs. Note currently memory limit is not supported.
try:
tf.config.set_logical_device_configuration(
physical_devices[0],
[tf.config.LogicalDeviceConfiguration(),
tf.config.LogicalDeviceConfiguration()])
logical_devices = tf.config.list_logical_devices('CPU')
assert len(logical_devices) == 2

tf.config.set_logical_device_configuration(
physical_devices[0],
[tf.config.LogicalDeviceConfiguration(),
tf.config.LogicalDeviceConfiguration(),
tf.config.LogicalDeviceConfiguration(),
tf.config.LogicalDeviceConfiguration()])
except:
# Cannot modify logical devices once initialized
pass

The following example splits the GPU into 2 logical devices with 100 MB each:

physical_devices = tf.config.list_physical_devices('GPU')
try:
tf.config.set_logical_device_configuration(
physical_devices[0],
[tf.config.LogicalDeviceConfiguration(memory_limit=100),
tf.config.LogicalDeviceConfiguration(memory_limit=100)])

logical_devices = tf.config.list_logical_devices('GPU')
assert len(logical_devices) == len(physical_devices) + 1

tf.config.set_logical_device_configuration(
physical_devices[0],
[tf.config.LogicalDeviceConfiguration(memory_limit=10),
tf.config.LogicalDeviceConfiguration(memory_limit=10)])
except:
# Invalid device or cannot modify logical devices once initialized
pass

Args:

  • device: The PhysicalDevice to configure.
  • logical_devices: (optional) List of tf.config.LogicalDeviceConfiguration objects to allocate for the specified PhysicalDevice. If None, the default configuration will be used.

Raises:

  • ValueError: If argument validation fails.
  • RuntimeError: Runtime is already initialized.