def build_global_metadata(
gathered_metadatas: Sequence[Optional[ShardedTensorMetadata]]):
global_sharded_tensor_metadata = None
global_metadata_rank = 0
for rank, rank_metadata in enumerate(gathered_metadatas):
if rank_metadata is None:
continue
if global_sharded_tensor_metadata is None:
global_sharded_tensor_metadata = rank_metadata
global_metadata_rank = rank
else:
_raise_if_mismatch(global_sharded_tensor_metadata.size,
rank_metadata.size,
"global_size", [global_metadata_rank, rank],
is_local=False)
# don't need to check layout and memory format as we already checked in local shards validation stage
_raise_if_mismatch(
global_sharded_tensor_metadata.tensor_properties.dtype,
rank_metadata.tensor_properties.dtype,
"dtype", [global_metadata_rank, rank],
is_local=False)
_raise_if_mismatch(
global_sharded_tensor_metadata.tensor_properties.requires_grad,
rank_metadata.tensor_properties.requires_grad,
"requires_grad", [global_metadata_rank, rank],
is_local=False)
_raise_if_mismatch(
global_sharded_tensor_metadata.tensor_properties.pin_memory,
rank_metadata.tensor_properties.pin_memory,
"pin_memory", [global_metadata_rank, rank],
is_local=False)
# pass all validations, extend shards metadata
global_sharded_tensor_metadata.shards_metadata.extend(
rank_metadata.shards_metadata)
if global_sharded_tensor_metadata is not None:
# check if shards_metadata have overlap shards
validate_non_overlapping_shards_metadata(
global_sharded_tensor_metadata.shards_metadata)
# check if the shards_metadata is compatible with global size of the sharded tensor.
check_tensor(global_sharded_tensor_metadata.shards_metadata,
global_sharded_tensor_metadata.size)
else:
raise ValueError("ShardedTensor have no local shards on all ranks!")
return global_sharded_tensor_metadata
def _init_from_local_shards(
cls,
local_shards: List[Shard],
sharded_tensor_metadata: ShardedTensorMetadata,
process_group=None,
init_rrefs=False,
):
shards_metadata = sharded_tensor_metadata.shards_metadata
tensor_properties = sharded_tensor_metadata.tensor_properties
if len(shards_metadata) == 0:
raise ValueError("shards_metadata must not be empty!")
if tensor_properties.layout != torch.strided:
raise ValueError('Only torch.strided layout is currently supported')
sharded_tensor = cls.__new__(cls)
# prepare initialization
sharded_tensor._prepare_init(process_group=process_group, init_rrefs=init_rrefs)
sharded_tensor._metadata = sharded_tensor_metadata
# no sharding spec for sharded tensors that initialized
# from this API.
sharded_tensor._sharding_spec = None
current_rank = dist.get_rank(sharded_tensor._process_group)
local_shard_metadatas = []
# collect local shard metadatas from the global sharded_tensor_metadata
for shard_metadata in shards_metadata: # type: ignore[attr-defined]
rank, local_device = sharded_tensor._parse_and_validate_remote_device(shard_metadata.placement)
if current_rank == rank:
local_shard_metadatas.append(shard_metadata)
if len(local_shards) != len(local_shard_metadatas):
raise RuntimeError(
f'Number of local shards ({len(local_shards)}) does not match number of local '
f'shards metadata in sharded_tensor_metadata ({len(local_shard_metadatas)}) '
f'on rank ({current_rank}) '
)
for shard in local_shards:
shard_meta = shard.metadata
local_shard_tensor = shard.tensor
rank, local_device = sharded_tensor._parse_and_validate_remote_device(shard_meta.placement)
# validate if shard_meta in the metadatas collected from sharded_tensor_metadata
assert shard_meta in local_shard_metadatas, \
"local shard metadata not in sharded_tensor_metadata!"
if local_shard_tensor.layout != tensor_properties.layout:
raise ValueError(
f'Local shard tensor layout does not match with tensor_properties! '
f'local shard tensor layout: {local_shard_tensor.dtype}, '
f'tensor_properties layout: {tensor_properties.layout}'
)
if not local_shard_tensor.is_contiguous():
raise ValueError('Only torch.contiguous_format memory_format is currently supported')
if shard_meta.shard_lengths != list(local_shard_tensor.size()):
raise ValueError(
f'Local shard tensor is incompatible with local ShardMetadata! '
f'local shard tensor size: {local_shard_tensor.size()}, '
f'local ShardMetadata shard lengths: {shard_meta.shard_lengths}'
)
if local_shard_tensor.is_pinned() != tensor_properties.pin_memory:
raise ValueError(
f'Local shard tensor pin_memory does not match with tensor_properties! '
f'local shard tensor pin_memory: {local_shard_tensor.is_pinned()}, '
f'tensor_properties pin_memory: {tensor_properties.pin_memory}'
)
if local_shard_tensor.device != local_device:
raise ValueError(
f'Local shard tensor device does not match with local Shard placement! '
f'local shard tensor device: {local_shard_tensor.device}, '
f'local shard metadata placement device: {local_device}'
)
if local_shard_tensor.dtype != tensor_properties.dtype:
raise ValueError(
f'Local shard tensor dtype does not match with tensor_properties! '
f'local shard tensor dtype: {local_shard_tensor.dtype}, '
f'tensor_properties dtype: {tensor_properties.dtype}'
)
if local_shard_tensor.requires_grad != tensor_properties.requires_grad:
raise ValueError(
f'Local shard tensor requires_grad does not match with tensor_properties! '
f'local shard tensor requires_grad: {local_shard_tensor.requires_grad}, '
f'tensor_properties requires_grad: {tensor_properties.requires_grad}'
)
# check if shards_metadata have overlap shards
validate_non_overlapping_shards_metadata(shards_metadata)
# check if the shards_metadata is compatible with overall size of the sharded tensor.
check_tensor(shards_metadata, list(sharded_tensor_metadata.size))
# done validation, add local_shards
sharded_tensor._local_shards = local_shards
# run post initialization, i.e. map registration, rpc initialization
sharded_tensor._post_init()
return sharded_tensor
def _init_from_local_shards_and_global_metadata(
cls,
local_shards: List[Shard],
sharded_tensor_metadata: ShardedTensorMetadata,
process_group=None,
init_rrefs=False,
):
"""
Initialize a ShardedTensor with local shards and a global
ShardedTensorMetadata built on each rank.
Warning: This API is experimental and subject to change. It does
not do cross rank validations, and fully rely on the user
for the correctness of sharded_tensor_metadata on each rank
"""
process_group = (process_group if process_group is not None else
distributed_c10d._get_default_group())
current_rank = dist.get_rank(process_group)
shards_metadata = sharded_tensor_metadata.shards_metadata
tensor_properties = sharded_tensor_metadata.tensor_properties
if len(shards_metadata) == 0:
raise ValueError("shards_metadata must not be empty!")
if tensor_properties.layout != torch.strided:
raise ValueError(
'Only torch.strided layout is currently supported')
sharded_tensor = cls.__new__(cls)
sharded_tensor._prepare_init(process_group=process_group,
init_rrefs=init_rrefs)
sharded_tensor._metadata = sharded_tensor_metadata
local_shard_metadatas = []
def _raise_if_mismatch(expected,
actual,
prop_name,
rank,
is_property=False):
tensor_property_or_metadata = "tensor property" if is_property else "local ShardMetadata"
if expected != actual:
raise ValueError(
f"Local shards' tensor {prop_name} property is incompatible with "
f"{tensor_property_or_metadata} on rank {rank}: "
f"{tensor_property_or_metadata} {prop_name}={expected}, "
f"local shard tensor {prop_name}={actual}.")
# collect local shard metadatas from the global sharded_tensor_metadata
for shard_metadata in shards_metadata: # type: ignore[attr-defined]
rank, local_device = _parse_and_validate_remote_device(
sharded_tensor._process_group, shard_metadata.placement)
if current_rank == rank:
local_shard_metadatas.append(shard_metadata)
if len(local_shards) != len(local_shard_metadatas):
raise RuntimeError(
f'Number of local shards ({len(local_shards)}) does not match number of local '
f'shards metadata in sharded_tensor_metadata ({len(local_shard_metadatas)}) '
f'on rank ({current_rank}) ')
for shard in local_shards:
shard_meta = shard.metadata
local_shard_tensor = shard.tensor
rank, local_device = _parse_and_validate_remote_device(
sharded_tensor._process_group, shard_meta.placement)
# validate if shard_meta in the metadatas collected from sharded_tensor_metadata
assert shard_meta in local_shard_metadatas, \
"local shard metadata not in sharded_tensor_metadata!"
_raise_if_mismatch(tensor_properties.layout,
local_shard_tensor.layout, "layout",
current_rank, True)
if not local_shard_tensor.is_contiguous():
raise ValueError(
'Only torch.contiguous_format memory_format is currently supported'
)
_raise_if_mismatch(shard_meta.shard_sizes,
list(local_shard_tensor.size()), "size",
current_rank)
_raise_if_mismatch(tensor_properties.pin_memory,
local_shard_tensor.is_pinned(), "pin_memory",
current_rank, True)
_raise_if_mismatch(local_device, local_shard_tensor.device,
"device", current_rank)
_raise_if_mismatch(tensor_properties.dtype,
local_shard_tensor.dtype, "dtype", current_rank,
True)
_raise_if_mismatch(tensor_properties.requires_grad,
local_shard_tensor.requires_grad,
"requires_grad", current_rank, True)
# check if shards_metadata have overlap shards
validate_non_overlapping_shards_metadata(shards_metadata)
# check if the shards_metadata is compatible with overall size of the sharded tensor.
check_tensor(shards_metadata, list(sharded_tensor_metadata.size))
# done validation, add local_shards
sharded_tensor._local_shards = local_shards
# make a EnumerableShardingSpec for sharded tensors that initialized from this API.
# TODO: make sharding spec a ChunkShardingSpec by inferring from the metadata list.
# see issue https://github.com/pytorch/pytorch/issues/67244
sharded_tensor._sharding_spec = EnumerableShardingSpec(shards_metadata)
# run post initialization, i.e. map registration, rpc initialization
sharded_tensor._post_init()
return sharded_tensor