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ColossalAI/colossalai/communication/collective.py

136 lines
4.5 KiB

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
import torch
import torch.distributed as dist
from torch.distributed import ReduceOp
from torch import Tensor
from colossalai.context import ParallelMode
from colossalai.core import global_context as gpc
from colossalai.utils import get_current_device
def all_gather(tensor: Tensor, dim: int, parallel_mode: ParallelMode, async_op: bool = False) -> Tensor:
"""Gathers all tensors from the parallel group and concatenates them in a
specific dimension.
:param tensor: Tensor to be gathered
:param dim: The dimension concatenating in
:param parallel_mode: Parallel group mode used in this communication
:param async_op: Whether operations are asynchronous
:type tensor: :class:`torch.Tensor`
:type dim: int
:type parallel_mode: :class:`colossalai.context.ParallelMode`
:type async_op: bool, optional
:return: The tensor generated by all-gather
:rtype: :class:`torch.Tensor`
"""
depth = gpc.get_world_size(parallel_mode)
if depth == 1:
out = tensor
work = None
else:
shape = list(tensor.shape)
shape[0], shape[dim] = shape[dim], shape[0]
shape[0] *= depth
out = torch.empty(shape, dtype=tensor.dtype, device=get_current_device())
temp = list(torch.chunk(out, depth, dim=0))
work = dist.all_gather(tensor_list=temp,
tensor=tensor.transpose(0, dim).contiguous(),
group=gpc.get_group(parallel_mode),
async_op=async_op)
out = torch.transpose(out, 0, dim)
if async_op:
return out, work
else:
return out
def reduce_scatter(tensor: Tensor,
dim: int,
parallel_mode: ParallelMode,
op: ReduceOp = ReduceOp.SUM,
async_op: bool = False) -> Tensor:
"""Reduces all tensors then scatters it in a specific dimension to all
members in the parallel group.
:param tensor: Tensor to be reduced and scattered
:param dim: The dimension scattering in
:param parallel_mode: Parallel group mode used in this communication
:param op: The type of reduce operation
:param async_op: Whether operations are asynchronous
:type tensor: :class:`torch.Tensor`
:type dim: int
:type parallel_mode: :class:`colossalai.context.ParallelMode`
:type op: ReduceOp, optional
:type async_op: bool, optional
:return: The tensor generated by reduce-scatter
:rtype: :class:`Tensor`
"""
depth = gpc.get_world_size(parallel_mode)
if depth == 1:
out = tensor
work = None
else:
temp = list(map(lambda x: x.contiguous(), torch.chunk(tensor, depth, dim=dim)))
out = torch.empty(temp[0].shape, dtype=tensor.dtype, device=get_current_device())
work = dist.reduce_scatter(output=out,
input_list=temp,
op=op,
group=gpc.get_group(parallel_mode),
async_op=async_op)
if async_op:
return out, work
else:
return out
def all_reduce(tensor: Tensor,
parallel_mode: ParallelMode,
op: ReduceOp = ReduceOp.SUM,
async_op: bool = False) -> Tensor:
depth = gpc.get_world_size(parallel_mode)
if depth == 1:
out = tensor
work = None
else:
out = tensor.contiguous()
work = dist.all_reduce(out, op=op, group=gpc.get_group(parallel_mode), async_op=async_op)
if async_op:
return out, work
else:
return out
def broadcast(tensor: Tensor, src: int, parallel_mode: ParallelMode, async_op: bool = False):
depth = gpc.get_world_size(parallel_mode)
if depth == 1:
out = tensor
work = None
else:
out = tensor.contiguous()
work = dist.broadcast(out, src=src, group=gpc.get_group(parallel_mode), async_op=async_op)
if async_op:
return out, work
else:
return out
def reduce(tensor: Tensor, dst: int, parallel_mode: ParallelMode, op: ReduceOp = ReduceOp.SUM, async_op: bool = False):
depth = gpc.get_world_size(parallel_mode)
if depth == 1:
out = tensor
work = None
else:
out = tensor.contiguous()
work = dist.reduce(out, dst=dst, op=op, group=gpc.get_group(parallel_mode), async_op=async_op)
if async_op:
return out, work
else:
return out