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ColossalAI/colossalai/engine/schedule/_base_schedule.py

118 lines
4.3 KiB

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
from abc import ABC, abstractmethod
import torch
from typing import Iterable, Callable
from colossalai.logging import get_dist_logger
from colossalai.utils import get_current_device
class BaseSchedule(ABC):
"""A basic helper class to control the process of training or evaluation.
It mainly composes of forward_backward_step for gradient backward and
optimizer_step for parameters update.
For the convenience to enable FP16, we aggregate all codes that contain the
control of FP16 in class schedule.
Args:
batch_data_process_func (Callable, optional): The preprocessing function which receives a batch of data,
and it will be executed in load_batch.
"""
def __init__(self, batch_data_process_func: Callable = None):
self.logger = get_dist_logger()
self.batch_data_process_func = batch_data_process_func
@staticmethod
def _move_tensor(element):
if torch.is_tensor(element):
if not element.is_cuda:
return element.to(get_current_device()).detach()
return element
def _move_to_device(self, data):
if isinstance(data, dict):
data = {k: self._move_tensor(v) for k, v in data.items()}
else:
data = self._move_tensor(data)
return data
@staticmethod
def _check_sanity(data, tag: str):
assert isinstance(data, (torch.Tensor, dict)), \
f'{tag} must be torch.Tensor or dict'
def load_batch(self, data_iter, to_gpu=True):
"""Loads a batch from data iterator. It returns the data and labels which are
already in the same GPU as where the model's.
Args:
data_iter (Iterable): Data iterator from which get a batch of data, obtained by calling iter(dataloader).
to_gpu (bool, optional): Whether the data should be moved to GPU
Returns:
Tuple (:class:`Tensor`, :class:`torch.Tensor`): A tuple of (data, label).
"""
if data_iter is None:
raise RuntimeError('Dataloader is not defined.')
batch_data = next(data_iter)
if self.batch_data_process_func:
data, label = self.batch_data_process_func(batch_data)
else:
data, label = batch_data
self._check_sanity(data, 'data')
self._check_sanity(label, 'label')
if isinstance(data, torch.Tensor):
self.batch_size = data.size(0)
else:
self.batch_size = next(iter(data.values())).size(0)
if to_gpu:
return self._move_to_device(data), self._move_to_device(label)
return data, label
def pre_processing(self, engine):
"""To perform actions before running the schedule.
"""
pass
@abstractmethod
def forward_backward_step(self,
engine,
data_iter: Iterable,
forward_only: bool,
return_loss: bool = True,
return_output_label: bool = True):
"""The process function over a batch of dataset for training or evaluation.
Args:
engine (colossalai.engine.Engine): Colossalai engine for training and inference.
data_iter (Iterable): Data iterator from which get a batch of data, obtained by calling iter(dataloader).
forward_only (bool): If True, the process won't include backward.
return_loss (bool, optional): If False, the loss won't be returned.
return_output_label (bool, optional): If False, the output and label won't be returned.
"""
pass
@staticmethod
def _call_engine(engine, inputs):
if isinstance(inputs, torch.Tensor):
return engine(inputs)
else:
return engine(**inputs)
@staticmethod
def _call_engine_criterion(engine, outputs, labels):
assert isinstance(
outputs,
(torch.Tensor, list, tuple)), f'Expect output of model is (torch.Tensor, list, tuple), got {type(outputs)}'
if isinstance(outputs, torch.Tensor):
outputs = (outputs,)
if isinstance(labels, torch.Tensor):
return engine.criterion(*outputs, labels)
else:
return engine.criterion(*outputs, **labels)