def _create_tuple_proto(self, op):
shardings = [
xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.REPLICATED)
for _ in op.outputs
]
return xla_data_pb2.OpSharding(
type=xla_data_pb2.OpSharding.TUPLE, tuple_shardings=shardings)
def testCreateSlotWithCustomSplitXlaSharding(self):
# slot_creator is used only in optimizer V1.
# We insert our own custom split XLA sharding that overrides the SPMD
# sharding copied over by the slot_creator.
with ops.Graph().as_default(), self.cached_session():
v = variables.Variable([1.0, 2.5, 10.0, 15.1], name="var")
v = xla_sharding.mesh_split(v,
np.array([0, 1]), [0],
use_sharding_op=False)
with ops.control_dependencies(None):
slot = slot_creator.create_zeros_slot(v,
name="slot",
dtype=dtypes.float64,
copy_xla_sharding=True)
slot = xla_sharding.split(slot,
split_dimension=0,
num_devices=4,
use_sharding_op=False)
self.assertNotEqual(xla_sharding.get_tensor_sharding(v),
xla_sharding.get_tensor_sharding(slot))
slot_sharding = xla_sharding.get_tensor_sharding(slot)
slot_proto = xla_data_pb2.OpSharding()
slot_proto.ParseFromString(slot_sharding)
self.assertEqual(
slot_proto,
xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.OTHER,
tile_assignment_dimensions=[4],
tile_assignment_devices=range(4)))
def testCreateSlotWithCustomReplicatedXlaSharding(self):
# slot_creator is used only in optimizer V1.
# We insert our own custom replicated XLA sharding that overrides the SPMD
# sharding copied over by the slot_creator.
with ops.Graph().as_default(), self.cached_session():
v = variables.Variable([1.0, 2.5], name="var")
v = xla_sharding.mesh_split(v,
np.array([0, 1]), [0],
use_sharding_op=False)
with ops.control_dependencies(None):
slot = slot_creator.create_zeros_slot(v,
name="slot",
dtype=dtypes.float64,
copy_xla_sharding=True)
slot = xla_sharding.replicate(slot, use_sharding_op=False)
self.assertNotEqual(xla_sharding.get_tensor_sharding(v),
xla_sharding.get_tensor_sharding(slot))
slot_sharding = xla_sharding.get_tensor_sharding(slot)
slot_proto = xla_data_pb2.OpSharding()
slot_proto.ParseFromString(slot_sharding)
self.assertEqual(
slot_proto,
xla_data_pb2.OpSharding(
type=xla_data_pb2.OpSharding.REPLICATED))
def apply_to_tensor(self,
tensor,
assign_tuple_sharding=False,
use_sharding_op=False):
"""Applies this Sharding attribute to `tensor`.
Args:
tensor: A tf.Tensor to split.
assign_tuple_sharding: If the sharding type should be a tuple.
use_sharding_op: whether to create a sharding op on `tensor`.
Returns:
The tensor with Sharding attribute.
"""
if len(tensor.op.outputs) > 1 or assign_tuple_sharding:
proto = self._get_or_create_tuple_proto(tensor.op)
# We can't mutate an element of old_proto.tuple_shardings, so create
# a new proto.
tuple_shardings = list(proto.tuple_shardings)
tuple_shardings[tensor.value_index] = self._proto
proto = xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.TUPLE,
tuple_shardings=tuple_shardings)
else:
proto = self._proto
attr_value = proto.SerializeToString()
if use_sharding_op:
tensor = tf2xla.sharding(tensor, sharding=attr_value)
# TODO(jmolloy): This need to be seriously revisited before declaring this
# API available for public use.
# pylint: disable=protected-access
tensor.op._set_attr('_XlaSharding',
attr_value_pb2.AttrValue(s=attr_value))
return tensor
def ipu_shard(index):
"""Control sharding for a set of operations.
Provides a scope which targets operations onto a particular shard (IPU) of a
multi-IPU sharded device.
Args:
index: The index of the IPU on which to place the enclosed operations.
Returns:
A context
"""
if hasattr(index, '__iter__'):
ipus = index
else:
ipus = [index]
proto = xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.MAXIMAL,
tile_assignment_devices=ipus)
attr_value = attr_value_pb2.AttrValue(s=proto.SerializeToString())
attrs = {"_XlaSharding": attr_value}
# pylint: disable=protected-access
with ops.get_default_graph()._attr_scope(attrs):
yield
def tile(cls, tile_assignment):
"""Returns a Tiled sharding attribute.
This causes an op to be partially computed on multiple cores in the
XLA device.
Args:
tile_assignment: An np.ndarray describing the topology of the tiling and
which device will compute which part of the topology.
Raises:
TypeError: tile_assignment was not of np.array type.
TODO(jmolloy): This concept is nefarious and is not
something we really want to expose to users (especially as the
contract for tile_assignment is very strict).
"""
if not isinstance(tile_assignment, _np.ndarray):
raise TypeError('Tile assignment must be of type np.ndarray')
dims = list(tile_assignment.shape)
flattened_devices = tile_assignment.reshape(-1, order='C')
return Sharding(
proto=xla_data_pb2.OpSharding(
type=xla_data_pb2.OpSharding.OTHER,
tile_assignment_dimensions=dims,
tile_assignment_devices=list(flattened_devices)))
def split(cls, tensor, split_dimension, num_devices, input_shape=None):
"""Returns a Sharding that splits a tensor across a dimension.
This creates a Tiled attribute, similar to tile(), but easier to use for the
common case of tiling a tensor N ways in one dimension.
Args:
tensor: A tf.Tensor to split.
split_dimension: The dimension number to split.
num_devices: The number of cores to split `tensor` over.
input_shape: The shape of the original tensor.
Raises:
ValueError: The tensor to split was smaller in the split dimension than
the number of devices to split over.
"""
if input_shape:
shape = input_shape
else:
shape = tensor.shape.as_list()
if (shape[split_dimension] is not None and
shape[split_dimension] < num_devices):
raise ValueError('Split dimension was smaller than the required number '
'of splits: shape=%r, dimension=%r, num_devices=%r' %
(shape, split_dimension, num_devices))
tile_assignment_dims = [1] * len(shape)
tile_assignment_dims[split_dimension] = num_devices
return Sharding(
proto=xla_data_pb2.OpSharding(
type=xla_data_pb2.OpSharding.OTHER,
tile_assignment_dimensions=tile_assignment_dims,
tile_assignment_devices=range(num_devices)))
def manual(cls):
"""Returns a manuall sharding attribute.
This means the op is manually partitioned by the user and XLA will not
change the shapes.
"""
return Sharding(
proto=xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.MANUAL))
def replicate(cls):
"""Returns a replicated sharding attribute.
This causes an op to be computed in its entirety independently on all
cores in the XLA device.
"""
return Sharding(
proto=xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.REPLICATED))
def _get_or_create_tuple_proto(self, op):
try:
attr = op.get_attr('_XlaSharding')
proto = xla_data_pb2.OpSharding()
proto.ParseFromString(attr)
return proto
except ValueError:
return self._create_tuple_proto(op)
def assign_device(cls, core):
"""Returns an AssignDevice sharding attribute.
This causes an op to be computed in its entirety only on one core in
the XLA device.
Args:
core: The core to assign this Op to.
"""
return Sharding(
proto=xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.MAXIMAL,
tile_assignment_dimensions=[1],
tile_assignment_devices=[core]))
def GetVarSharding(var: tf.Variable) -> TensorShardingSpec:
"""Returns the sharding directly attached to a variable."""
sharding = xla_sharding.get_op_sharding(var.op)
if not sharding:
return TensorShardingSpec.ReplicatedSpec()
proto = xla_data_pb2.OpSharding()
proto.ParseFromString(sharding)
spec_without_padding = TensorShardingSpec.FromXlaOpSharding(proto)
# Consider uneven padding.
return TensorShardingSpec.FromFullShape(
[int(d) for d in var.shape], spec_without_padding.split_dims_mapping,
spec_without_padding.device_mesh)
def set_ipu_shard(op, index):
"""Set shard index for op.
Args:
op(tf.Operation): Operator
index(int): IPU index
"""
proto = xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.MAXIMAL,
tile_assignment_devices=[index])
attr_value = attr_value_pb2.AttrValue(s=proto.SerializeToString())
op._set_attr(sharding._XLA_SHARDING, attr_value)
def ipu_shard(index):
ipus = []
if hasattr(index, '__iter__'):
ipus = index
else:
ipus = [index]
proto = xla_data_pb2.OpSharding(
type=xla_data_pb2.OpSharding.MAXIMAL, tile_assignment_devices=ipus)
attr_value = attr_value_pb2.AttrValue(s=proto.SerializeToString())
attrs = {"_XlaSharding": attr_value}
# pylint: disable=protected-access
with ops.get_default_graph()._attr_scope(attrs):
yield
def subgroup_tile(cls, tile_assignment, subgroup_modes):
"""Returns a subgroup manual sharding attribute.
This is similar to tile(), but tile_assignment has one or more dimension
than the tensor, and subgroup_modes define the sharding types in the last
dimensions of tile_assignment.
Args:
tile_assignment: An np.ndarray describing the topology of the tiling and
which device will compute which part of the topology.
subgroup_modes: sharding types for the dimension more than the tensor
shape rank.
Raises:
TypeError: tile_assignment was not of np.array type or subgroup_modes
has unsupported sharding type.
"""
if not isinstance(tile_assignment, _np.ndarray):
raise TypeError(
'SubgroupTile assignment must be of type np.ndarray')
if not isinstance(subgroup_modes, list):
raise TypeError(
'subgroup_modes in subgroup manual must be of type list')
if len(tile_assignment.shape) < len(subgroup_modes):
raise TypeError(
'SubgroupTile assignment must have rank larger than'
' length of subgroup_modes')
for sharding_type in subgroup_modes:
if sharding_type not in [
xla_data_pb2.OpSharding.REPLICATED,
xla_data_pb2.OpSharding.MANUAL
]:
raise TypeError(
'Each sharding_type in subgroup_modes in subgroup manual must '
'be of type xla_data_pb2.OpSharding.REPLICATED'
' or xla_data_pb2.OpSharding.MANUAL')
dims = list(tile_assignment.shape)
flattened_devices = tile_assignment.reshape(-1, order='C')
return Sharding(proto=xla_data_pb2.OpSharding(
type=xla_data_pb2.OpSharding.OTHER,
tile_assignment_dimensions=dims,
tile_assignment_devices=list(flattened_devices),
last_tile_dims=list(subgroup_modes)))
def apply_to_tensor(self, tensor):
"""Applies this Sharding attribute to `tensor`."""
if len(tensor.op.outputs) > 1:
proto = self._get_or_create_tuple_proto(tensor.op)
# We can't mutate an element of old_proto.tuple_shardings, so create
# a new proto.
tuple_shardings = list(proto.tuple_shardings)
tuple_shardings[tensor.value_index] = self._proto
proto = xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.TUPLE,
tuple_shardings=tuple_shardings)
else:
proto = self._proto
attr_value = attr_value_pb2.AttrValue(s=proto.SerializeToString())
# TODO(jmolloy): This need to be seriously revisited before declaring this
# API available for public use.
# pylint: disable=protected-access
tensor.op._set_attr('_XlaSharding', attr_value)
def apply_to_tensor(self,
tensor,
assign_tuple_sharding=False,
use_sharding_op=False,
unspecified_dims=None):
"""Applies this Sharding attribute to `tensor`.
Args:
tensor: A tf.Tensor to split.
assign_tuple_sharding: If the sharding type should be a tuple.
use_sharding_op: Whether to create a sharding op on `tensor`.
unspecified_dims: An optional list of dimensions unspecified.
Returns:
The tensor with Sharding attribute.
"""
if unspecified_dims:
assert use_sharding_op and not assign_tuple_sharding
proto = self._proto
if use_sharding_op:
if assign_tuple_sharding:
proto = self._create_tuple_proto(num_outputs=1)
tensor = tf2xla.sharding(tensor,
sharding=proto.SerializeToString())
else:
tensor = tf2xla.sharding(tensor,
sharding=proto.SerializeToString(),
unspecified_dims=unspecified_dims
or [])
elif assign_tuple_sharding or len(tensor.op.outputs) > 1:
proto = self._get_or_create_tuple_proto(tensor.op)
# We can't mutate an element of old_proto.tuple_shardings, so create
# a new proto.
tuple_shardings = list(proto.tuple_shardings)
tuple_shardings[tensor.value_index] = self._proto
proto = xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.TUPLE,
tuple_shardings=tuple_shardings)
# TODO(jmolloy): This need to be seriously revisited before declaring this
# API available for public use.
# pylint: disable=protected-access
tensor.op._set_attr(
'_XlaSharding',
attr_value_pb2.AttrValue(s=proto.SerializeToString()))
return tensor
def get_sharding_tile_shape(sharding):
"""Returns the tile assignment shape for a sharded Tensor.
Args:
sharding: a serialized OpSharding message describing the layout of a
sharded Tensor.
Returns:
A list, for each dimension of the sharded Tensor, of the number of shards
into which it has been split. Returns None if the input indicates no tile
assignments.
"""
if sharding is None:
return None
sharding_message = xla_data_pb2.OpSharding()
sharding_message.ParseFromString(sharding)
if sharding_message.tile_assignment_dimensions:
return sharding_message.tile_assignment_dimensions
else:
return None
def split(cls, tensor, split_dimension, num_devices):
"""Returns a Sharding that splits a tensor across a dimension.
This creates a Tiled attribute, similar to tile(), but easier to use for the
common case of tiling a tensor N ways in one dimension.
Args:
tensor: A tf.Tensor to split.
split_dimension: The dimension number to split.
num_devices: The number of cores to split `tensor` over.
Raises:
ValueError: The tensor to split was smaller in the split dimension than
the number of devices to split over.
"""
tensor.shape.assert_is_fully_defined()
shape = tensor.shape.as_list()
if shape[split_dimension] < num_devices:
raise ValueError('Split dimension was smaller than the required number '
'of splits: shape=%r, dimension=%r, num_devices=%r',
shape, split_dimension, num_devices)
tile_shape = shape
tile_shape[split_dimension] = int(
math.ceil(tile_shape[split_dimension] / num_devices))
tile_shape_proto = xla_data_pb2.Shape(
element_type=xla_data_pb2.F32, dimensions=tile_shape)
tile_assignment_dims = [1] * len(shape)
tile_assignment_dims[split_dimension] = num_devices
return Sharding(
proto=xla_data_pb2.OpSharding(
type=xla_data_pb2.OpSharding.OTHER,
tile_shape=tile_shape_proto,
tile_assignment_dimensions=tile_assignment_dims,
tile_assignment_devices=range(num_devices)))
def partial_tile(cls, tile_assignment):
"""Returns a partially tiled sharding attribute.
This is similar to tile(), but tile_assignment has one more dimension than
the tensor, and tiles in the last dimension of tile_assignment are
replicated.
Args:
tile_assignment: An np.ndarray describing the topology of the tiling and
which device will compute which part of the topology.
Raises:
TypeError: tile_assignment was not of np.array type.
"""
if not isinstance(tile_assignment, _np.ndarray):
raise TypeError('PartialTile assignment must be of type np.ndarray')
dims = list(tile_assignment.shape)
flattened_devices = tile_assignment.reshape(-1, order='C')
return Sharding(
proto=xla_data_pb2.OpSharding(
type=xla_data_pb2.OpSharding.OTHER,
tile_assignment_dimensions=dims,
tile_assignment_devices=list(flattened_devices),
replicate_on_last_tile_dim=True))
def _create_tuple_proto(self, num_outputs):
shardings = [
xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.REPLICATED)
] * num_outputs
return xla_data_pb2.OpSharding(type=xla_data_pb2.OpSharding.TUPLE,
tuple_shardings=shardings)
def set_ipu_shard(op, index):
proto = xla_data_pb2.OpSharding(
type=xla_data_pb2.OpSharding.MAXIMAL, tile_assignment_devices=[index])
attr_value = attr_value_pb2.AttrValue(s=proto.SerializeToString())
op._set_attr(sharding._XLA_SHARDING, attr_value)
