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ColossalAI/colossalai/auto_parallel/tensor_shard/utils/sharding.py

121 lines
4.4 KiB

import operator
from copy import deepcopy
from functools import reduce
from typing import Dict
import torch
from colossalai.tensor.sharding_spec import ShardingSpec
__all__ = [
'transpose_partition_dim', 'update_partition_dim', 'enumerate_all_possible_1d_sharding',
'enumerate_all_possible_2d_sharding', 'generate_sharding_size'
]
def transpose_partition_dim(sharding_spec: ShardingSpec, dim1: int, dim2: int) -> ShardingSpec:
"""
Switch the sharding mesh dimensions for two tensor dimensions. This operation is in-place.
Args:
sharding_spec (ShardingSpec): the sharding spec for which partition dim are switched
dim1 (int): the tensor dimension to switch
dim2 (int): the tensor dimension to switch
"""
assert len(sharding_spec.entire_shape) >= 2, \
'The entire_shape of the sharding spec must have at least 2 dimensions'
dim_partition_dict = sharding_spec.dim_partition_dict
# transpose the dim partition
dim1_partition = dim_partition_dict.pop(dim1, None)
dim2_partition = dim_partition_dict.pop(dim2, None)
if dim1_partition:
dim_partition_dict[dim2] = dim1_partition
if dim2_partition:
dim_partition_dict[dim1] = dim2_partition
# get the transposed shape
new_shape = list(sharding_spec.entire_shape[:])
new_shape[dim2], new_shape[dim1] = new_shape[dim1], new_shape[dim2]
new_shape = torch.Size(new_shape)
# re-init the sharding spec
sharding_spec.__init__(sharding_spec.device_mesh, new_shape, dim_partition_dict)
return sharding_spec
def update_partition_dim(sharding_spec: ShardingSpec,
dim_mapping: Dict[int, int],
physical_shape: torch.Size,
inplace: bool = False):
"""
This method is used to update the partition dim dict from the logical one to the physical one.
Args:
sharding_spec (ShardingSpec): the sharding spec for which partition dims are updated
dim_mapping (Dict[int, int]): the mapping from the logical tensor dimension to the physical tensor dimension
physical_shape (torch.Size): the physical shape for the tensor
"""
if inplace:
current_sharding_spec = sharding_spec
else:
current_sharding_spec = deepcopy(sharding_spec)
old_dim_partition_dict = current_sharding_spec.dim_partition_dict
new_dim_partition_dict = {}
# assign new dim
for old_dim, new_dim in dim_mapping.items():
mesh_dims = old_dim_partition_dict.pop(old_dim)
new_dim_partition_dict[new_dim] = mesh_dims
for tensor_dim, mesh_dims in old_dim_partition_dict.items():
if tensor_dim in new_dim_partition_dict:
raise KeyError(f"There are duplicated entries for the tensor sharding dimension {tensor_dim}")
else:
new_dim_partition_dict[tensor_dim] = mesh_dims
# update sharding spec
current_sharding_spec.__init__(device_mesh=sharding_spec.device_mesh,
entire_shape=physical_shape,
dim_partition_dict=new_dim_partition_dict)
return current_sharding_spec
def enumerate_all_possible_2d_sharding(mesh_dim_0, mesh_dim_1, dim_size):
dim_partition_list = []
# enumerate all the 2D sharding cases
for i in range(dim_size):
for j in range(i + 1, dim_size):
dim_partition_dict_0 = {i: [mesh_dim_0], j: [mesh_dim_1]}
dim_partition_dict_1 = {i: [mesh_dim_1], j: [mesh_dim_0]}
dim_partition_list.append(dim_partition_dict_0)
dim_partition_list.append(dim_partition_dict_1)
for i in range(dim_size):
dim_partition_dict_flatten = {i: [mesh_dim_0, mesh_dim_1]}
dim_partition_list.append(dim_partition_dict_flatten)
return dim_partition_list
def enumerate_all_possible_1d_sharding(mesh_dim_0, dim_size):
dim_partition_list = []
# enumerate all the 1D sharding cases
for i in range(dim_size):
dim_partition_dict_0 = {i: [mesh_dim_0]}
dim_partition_list.append(dim_partition_dict_0)
return dim_partition_list
def generate_sharding_size(dim_partition_dict, device_mesh):
total_sharding_size = 1
for mesh_dim_list in dim_partition_dict.values():
mesh_dim_sharding_size = [device_mesh.shape[mesh_dim] for mesh_dim in mesh_dim_list]
sharding_size = reduce(operator.mul, mesh_dim_sharding_size)
total_sharding_size *= sharding_size
return total_sharding_size