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ColossalAI/colossalai/engine/schedule/_non_pipeline_schedule.py

95 lines
3.8 KiB

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
from typing import Iterable
import torch
import inspect
from ._base_schedule import BaseSchedule
from colossalai.utils import conditional_context
from typing import Callable
class NonPipelineSchedule(BaseSchedule):
"""A helper schedule class for no pipeline parallelism running environment.
During one process, it loads a batch of dataset and feeds it to the model.
After getting the output and calculating the loss, it will use :meth:`step`
to update the parameters if it is in training mode.
Args:
data_process_func (Callable, optional): The preprocessing function which receives a batch of data
and returns a tuple in the form of (data, label).
and it will be executed in load_batch.
Example:
# this shows an example of customized data_process_func
def data_process_func(dataloader_output):
item1, item2, item3 = dataloader_output
data = (item1, item2)
label = item3
return data, label
"""
def __init__(self, data_process_func: Callable = None):
# check that non-pipeline schedule data process func only takes in one parameter
# which is the batch data
if data_process_func:
sig = inspect.signature(data_process_func)
assert len(sig.parameters) == 1, \
'The data_process_func only takes in one parameter for NonPipelineSchedule, ' \
'which is a tuple of tensors for the current batch, ' \
'i.e. data_process_func(dataloader_output).'
super().__init__(data_process_func)
def forward_backward_step(self,
engine,
data_iter: Iterable,
forward_only: bool = False,
return_loss: bool = True,
return_output_label: bool = True):
"""The process function that loads a batch of dataset and feeds it to the model.
The returned labels and loss will None if :attr:`return_loss` is False.
Args:
engine (colossalai.engine.Engine): Colossalai engine for training and inference.
data_iter (Iterable): Dataloader as the form of an iterator, obtained by calling iter(dataloader).
forward_only (bool, optional):
If True, the model is run for the forward pass, else back propagation will be executed.
return_loss (bool, optional): Loss will be returned if True.
return_output_label (bool, optional): Output and label will be returned if True.
Returns:
Tuple[:class:`torch.Tensor`]: A tuple of (output, label, loss), loss and label could be None.
"""
assert forward_only or return_loss, \
"The argument 'return_loss' has to be True when 'forward_only' is False, but got False."
batch_data = self.load_batch(data_iter)
if self.data_process_func:
data, label = self.data_process_func(batch_data)
else:
# if not batch data process func is given,
# then we regard the batch data as a simple tuple of (data, label)
data, label = batch_data
# forward
with conditional_context(torch.no_grad(), enable=forward_only):
output = self._call_engine(engine, data)
if return_loss:
loss = self._call_engine_criterion(engine, output, label)
if not forward_only:
engine.backward(loss)
if return_output_label:
if return_loss:
return output, label, loss
else:
return output, label, None
else:
if return_loss:
return None, None, loss
else:
return None, None, None