ColossalAI/colossalai/communication/p2p.py

354 lines
16 KiB
Python

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
from typing import List, Tuple, Union
import torch
import torch.distributed as dist
from colossalai.context.parallel_mode import ParallelMode
from colossalai.core import global_context as gpc
from colossalai.utils import get_current_device
from functools import reduce
import operator
from .utils import split_tensor_into_1d_equal_chunks, gather_split_1d_tensor
TensorShape = Union[torch.Size, List[int], Tuple[int]]
def _get_tensor_shape(tensor_shape: TensorShape, chunk_tensor: bool = False) -> Tuple[TensorShape, bool]:
"""get the exact tensor shape when communicating and return whether the tensor is a chunk
Args:
tensor_shape (:class:`torch.Size`): shape of tensor
chunk_tensor (bool, optional): whether to chunk tensor, defaults to False
Returns:
Tuple[Union[:class:`torch.Size`, List[int], Tuple[int]], bool]: exact tensor shape, whether to chunk tensor
"""
if chunk_tensor:
tensor_chunk_shape = reduce(operator.mul, tensor_shape, 1)
tensor_parallel_world_size = gpc.get_world_size(ParallelMode.TENSOR)
if tensor_chunk_shape % tensor_parallel_world_size == 0:
tensor_chunk_shape = tensor_chunk_shape // tensor_parallel_world_size
else:
tensor_chunk_shape = tensor_shape
chunk_tensor = False
else:
tensor_chunk_shape = tensor_shape
return tensor_chunk_shape, chunk_tensor
def _communicate(tensor_send_next: torch.Tensor = None,
tensor_send_prev: torch.Tensor = None,
recv_prev: bool = False,
recv_next: bool = False,
recv_prev_shape: TensorShape = None,
recv_next_shape: TensorShape = None,
prev_rank: int = None,
next_rank: int = None,
dtype: torch.dtype = None,
scatter_gather_tensors: bool = False) -> Tuple[torch.Tensor]:
"""
Adapted from megatron.p2p_communication.
Communicate tensors between stages. Used as helper method in other
communication methods that are used in pipeline schedule.
Takes the following arguments:
tensor_send_next (:class:`torch.Tensor`): tensor to send to next rank (no tensor sent if
set to None).
tensor_send_prev (:class:`torch.Tensor`): tensor to send to prev rank (no tensor sent if
set to None).
recv_prev (bool): boolean for whether tensor should be received from
previous rank.
recv_next (bool): boolean for whether tensor should be received from
next rank.
recv_prev_shape (TensorShape): shape of the tensor to be received from the previous stage, defualts to None.
recv_next_shape (TensorShape): shape of the tensor to be received from the next stage, defualts to None.
prev_rank (int): the rank of the previous pipeline stage, defualts to None,
next_rank (int): the rank of the next pipeline stage, defualts to None,
dtype (torch.dtype): data type of intermediate buffers, defaults to None
scatter_gather_tensors (bool): whether to scatter and gather tensor between pipeline stages, defaults to False
Returns:
Tuple[torch.Tensor]: returns tensor_recv_prev, tensor_recv_next
"""
# Create placeholder tensors for receive in forward and backward directions
# if needed.
tensor_recv_prev = None
tensor_recv_next = None
if recv_prev:
assert recv_prev_shape is not None
recv_prev_chunk_shape, recv_prev_split = _get_tensor_shape(recv_prev_shape, scatter_gather_tensors)
tensor_recv_prev = torch.empty(recv_prev_chunk_shape,
requires_grad=True,
device=get_current_device(),
dtype=dtype)
if recv_next:
assert recv_next_shape is not None
recv_next_chunk_shape, recv_next_split = _get_tensor_shape(recv_next_shape, scatter_gather_tensors)
tensor_recv_next = torch.empty(recv_next_chunk_shape,
requires_grad=True,
device=get_current_device(),
dtype=dtype)
if tensor_send_prev is not None or recv_prev:
if prev_rank is None:
prev_rank = gpc.get_prev_global_rank(ParallelMode.PIPELINE)
if tensor_send_next is not None or recv_next:
if next_rank is None:
next_rank = gpc.get_next_global_rank(ParallelMode.PIPELINE)
if tensor_send_prev is not None:
send_prev_split = _get_tensor_shape(tensor_send_prev.shape, scatter_gather_tensors)[1]
if send_prev_split:
tensor_send_prev = split_tensor_into_1d_equal_chunks(tensor_send_prev)
if tensor_send_next is not None:
send_next_split = _get_tensor_shape(tensor_send_next.shape, scatter_gather_tensors)[1]
if send_next_split:
tensor_send_next = split_tensor_into_1d_equal_chunks(tensor_send_next)
ops = []
if tensor_send_prev is not None:
send_prev_op = dist.P2POp(dist.isend, tensor_send_prev, prev_rank)
ops.append(send_prev_op)
if tensor_recv_prev is not None:
recv_prev_op = dist.P2POp(dist.irecv, tensor_recv_prev, prev_rank)
ops.append(recv_prev_op)
if tensor_recv_next is not None:
recv_next_op = dist.P2POp(dist.irecv, tensor_recv_next, next_rank)
ops.append(recv_next_op)
if tensor_send_next is not None:
send_next_op = dist.P2POp(dist.isend, tensor_send_next, next_rank)
ops.append(send_next_op)
if len(ops) > 0:
reqs = dist.batch_isend_irecv(ops)
for req in reqs:
req.wait()
# To protect against race condition when using batch_isend_irecv().
torch.cuda.synchronize()
if recv_prev and recv_prev_split:
tensor_recv_prev = gather_split_1d_tensor(tensor_recv_prev).view(recv_prev_shape).requires_grad_()
if recv_next and recv_next_split:
tensor_recv_next = gather_split_1d_tensor(tensor_recv_next).view(recv_next_shape).requires_grad_()
return tensor_recv_prev, tensor_recv_next
def recv_forward(input_tensor_shape, prev_rank=None, dtype=torch.float, scatter_gather_tensors=False) -> torch.Tensor:
"""Copy the forward output from the previous stage in pipeline as the input tensor of this stage.
Args:
input_tensor_shape (:class:`torch.Size`): The shape of the tensor to be received.
prev_rank (int, optional): The rank of the source of the tensor.
Returns:
:class:`torch.Tensor`: The input tensor.
"""
if gpc.is_pipeline_first_stage():
input_tensor = None
else:
input_tensor, _ = _communicate(recv_prev=True,
recv_prev_shape=input_tensor_shape,
prev_rank=prev_rank,
dtype=dtype,
scatter_gather_tensors=scatter_gather_tensors)
return input_tensor
def recv_backward(output_grad_shape, next_rank=None, dtype=torch.float, scatter_gather_tensors=False) -> torch.Tensor:
"""Copy the gradient tensor from the next stage in pipeline as the input gradient of this stage.
Args:
output_grad_shape (:class:`torch.Size`): The shape of the tensor to be received.
next_rank (int, optional): The rank of the source of the tensor.
Returns:
:class:`torch.Tensor`: The input gradient tensor.
"""
if gpc.is_pipeline_last_stage():
output_tensor_grad = None
else:
_, output_tensor_grad = _communicate(recv_next=True,
recv_next_shape=output_grad_shape,
next_rank=next_rank,
dtype=dtype,
scatter_gather_tensors=scatter_gather_tensors)
return output_tensor_grad
def send_forward(output_tensor, next_rank=None, scatter_gather_tensors=False) -> None:
"""Sends the input tensor to the next stage in pipeline.
Args:
output_tensor (:class:`torch.Tensor`): Tensor to be sent.
next_rank (int, optional): The rank of the recipient of the tensor.
"""
if not gpc.is_pipeline_last_stage():
_communicate(tensor_send_next=output_tensor, next_rank=next_rank, scatter_gather_tensors=scatter_gather_tensors)
def send_backward(input_tensor_grad, prev_rank=None, scatter_gather_tensors=False) -> None:
"""Sends the gradient tensor to the previous stage in pipeline.
Args:
input_tensor_grad (:class:`torch.Tensor`): Tensor to be sent
prev_rank (int, optional): The rank of the recipient of the tensor
"""
if not gpc.is_pipeline_first_stage():
_communicate(tensor_send_prev=input_tensor_grad,
prev_rank=prev_rank,
scatter_gather_tensors=scatter_gather_tensors)
def send_forward_recv_backward(output_tensor,
output_grad_shape,
recv_next=True,
next_rank=None,
dtype=torch.float,
scatter_gather_tensors=False) -> torch.Tensor:
"""Batched communication operation. Sends the input tensor to the
next stage in pipeline, while receives the gradient tensor from the
next stage in pipeline as the input gradient tensor of this stage.
Args:
output_tensor (:class:`torch.Tensor`): Tensor to be sent.
output_grad_shape (:class:`torch.Size`): The shape of the tensor to be received.
Returns:
:class:`torch.Tensor`: The input gradient tensor.
"""
if gpc.is_pipeline_last_stage():
output_tensor_grad = None
else:
_, output_tensor_grad = _communicate(tensor_send_next=output_tensor,
recv_next=recv_next,
recv_next_shape=output_grad_shape,
next_rank=next_rank,
dtype=dtype,
scatter_gather_tensors=scatter_gather_tensors)
return output_tensor_grad
def send_backward_recv_forward(input_tensor_grad,
input_tensor_shape,
recv_prev=True,
prev_rank=None,
dtype=torch.float,
scatter_gather_tensors=False) -> torch.Tensor:
"""Batched communication operation. Sends the gradient tensor to the
previous stage in pipeline, while receives the output tensor from the
previous stage in pipeline as the input of this stage.
Args:
input_tensor_grad (:class:`torch.Tensor`): Tensor to be sent.
input_tensor_shape (:class:`torch.Size`): The shape of the tensor to be received.
Returns:
:class:`torch.Tensor`: The input tensor.
"""
if gpc.is_pipeline_first_stage():
input_tensor = None
else:
input_tensor, _ = _communicate(tensor_send_prev=input_tensor_grad,
recv_prev=recv_prev,
recv_prev_shape=input_tensor_shape,
prev_rank=prev_rank,
dtype=dtype,
scatter_gather_tensors=scatter_gather_tensors)
return input_tensor
def send_forward_recv_forward(output_tensor,
input_tensor_shape,
recv_prev=True,
prev_rank=None,
next_rank=None,
dtype=torch.float,
scatter_gather_tensors=False) -> torch.Tensor:
"""Batched communication operation. Sends the input tensor to the
next stage in pipeline, while receives the output tensor from the
previous stage in pipeline as the input of this stage.
Args:
output_tensor (:class:`torch.Tensor`): Tensor to be sent.
input_tensor_shape (:class:`torch.Size`): The shape of the tensor to be received.
Returns:
:class:`torch.Tensor`: The input tensor.
"""
input_tensor, _ = _communicate(tensor_send_next=output_tensor,
recv_prev=recv_prev,
recv_prev_shape=input_tensor_shape,
prev_rank=prev_rank,
next_rank=next_rank,
dtype=dtype,
scatter_gather_tensors=scatter_gather_tensors)
return input_tensor
def send_backward_recv_backward(input_tensor_grad,
output_grad_shape,
recv_next=True,
prev_rank=None,
next_rank=None,
dtype=torch.float,
scatter_gather_tensors=False) -> torch.Tensor:
"""Batched communication operation. Sends the gradient tensor to the
previous stage in pipeline, while receives the gradient tensor from the
next member in pipeline as the input of this stage.
Args:
input_tensor_grad (:class:`torch.Tensor`): Tensor to be sent.
output_grad_shape (:class:`torch.Size`): The shape of the tensor to be received.
Returns:
:class:`torch.Tensor`: The input gradient tensor.
"""
_, output_tensor_grad = _communicate(tensor_send_prev=input_tensor_grad,
recv_next=recv_next,
recv_next_shape=output_grad_shape,
prev_rank=prev_rank,
next_rank=next_rank,
dtype=dtype,
scatter_gather_tensors=scatter_gather_tensors)
return output_tensor_grad
def send_forward_backward_recv_forward_backward(output_tensor,
input_tensor_grad,
input_tensor_shape,
output_grad_shape,
recv_prev=True,
recv_next=True,
prev_rank=None,
next_rank=None,
dtype=torch.float,
scatter_gather_tensors=False) -> Tuple[torch.Tensor]:
"""Batched communication operation. Sends the input tensor to the next stage in pipeline and
the gradient tensor to the previous stage, while receives the input gradient tensor from the
next stage and the input tensor from the previous stage.
Args:
output_tensor (:class:`torch.Tensor`): Tensor sent to the next.
input_tensor_grad (:class:`torch.Tensor`): Tensor sent to the previous.
input_tensor_shape (:class:`torch.Size`): The shape of the tensor received from the previous.
output_grad_shape (:class:`torch.Size`): The shape of the tensor received from the next.
Returns:
Tuple(Tensor, Tensor): (the input tensor, the input gradient tensor)
"""
input_tensor, output_tensor_grad = _communicate(tensor_send_next=output_tensor,
tensor_send_prev=input_tensor_grad,
recv_prev=recv_prev,
recv_next=recv_next,
recv_prev_shape=input_tensor_shape,
recv_next_shape=output_grad_shape,
prev_rank=prev_rank,
next_rank=next_rank,
dtype=dtype,
scatter_gather_tensors=scatter_gather_tensors)
return input_tensor, output_tensor_grad