ColossalAI/colossalai/trainer/_trainer.py

457 lines
16 KiB
Python

from typing import Union, List
from colossalai.context.parallel_mode import ParallelMode
import torch
from torch import Tensor
from torch.utils.data import DataLoader
from tqdm import tqdm
from colossalai.core import global_context as gpc
from colossalai.engine import Engine
from colossalai.engine.schedule import NonPipelineSchedule, BaseSchedule
from colossalai.logging import DistributedLogger
from colossalai.utils import MultiTimer
from colossalai.utils import is_dp_rank_0, is_tp_rank_0, is_no_pp_or_last_stage
from colossalai.trainer.hooks import BaseHook
class Trainer:
r"""This is a class tending for easy deployments of users' training and evaluation instead of
writing their own scripts. It is similar with ``ignite.engine`` and ``keras.engine``, but is
called `Trainer`.
Args:
engine (:class:`Engine`): Engine responsible for the process function.
schedule (:class:`BaseSchedule`, optional): Schedule responsible for forward and backward steps.
timer (:class:`MultiTimer`, optional): Timer used to monitor the whole training.
logger (:class:`colossalai.logging.DistributedLogger`, optional): Logger used to record the whole training log.
Note:
when `schedule` is None, the ``NonPipelineSchedule`` would be used. If you would like to use pipeline,
you should choose ``PipelineSchedule`` or ``InterleavedPipelineSchedule`` for the `schedule`
Examples:
>>> # define model, criterion, optimizer, lr_scheduler, train_dataloader for your training
>>> model = ...
>>> criterion = ...
>>> optimizer = ...
>>> train_dataloader = ...
>>> # Initialize your engine, train_dataloader, test_dataloader, lr_scheduler
>>> engine, train_dataloader, _, _ = colossalai.initialize(model, optimizer, criterion)
>>> # Beginning training progress
>>> timier = ...
>>> logger = ...
>>> trainer = Trainer(engine=engine, logger=logger, schedule=schedule, timer=timier)
>>> # add hooks you would like to use here.
>>> hook_list = []
>>> trainer.fit(
>>> train_dataloader=train_dataloader,
>>> epochs=gpc.config.NUM_EPOCHS,
>>> test_interval=1,
>>> hooks=hook_list,
>>> display_progress=True,
>>> return_output_label=False
>>> )
More examples and details could be found in
`Training with engine and trainer <https://www.colossalai.org/docs/basics/engine_trainer>`_
and `ColossalAI-Examples <https://github.com/hpcaitech/ColossalAI-Examples/tree/main>`_.
"""
def __init__(
self,
engine: Engine,
schedule: BaseSchedule = None,
timer: MultiTimer = None,
logger: DistributedLogger = None,
):
# training-ralated params
self._engine = engine
self._max_epochs = 0
self._cur_epoch = 0
self._max_steps = 0
self._cur_step = 0
self._steps_per_epoch = 0
# misc params
self._logger = logger
self._verbose = logger is not None
# hooks can store states in this dict, and could be consumed by other hooks
self.states = dict()
# build hooks
self.hooks = list()
# multi-timer for time benchmarking
self._timer = timer
# set schedule which specifies the training iteration for the engine
if schedule is None:
schedule = NonPipelineSchedule()
if (gpc.is_initialized(ParallelMode.PIPELINE)
and gpc.get_world_size(ParallelMode.PIPELINE) > 1):
assert not isinstance(
schedule, NonPipelineSchedule
), "NonPipelineSchedule cannot be used for pipeline parallel training, please use PipelineSchedule instead."
self._schedule = schedule
self._schedule.pre_processing(engine)
@property
def cur_epoch(self):
"""Returns the index of the current epoch."""
return self._cur_epoch
@cur_epoch.setter
def cur_epoch(self, epoch: int):
"""Set how many epochs have been processed."""
# allow setter for training resumption
self._cur_epoch = epoch
@property
def cur_step(self):
"""Returns how many iteration steps have been processed."""
return self._cur_step
@property
def max_epochs(self):
return self._max_epochs
@property
def max_steps(self):
return self._max_steps
@property
def steps_per_epoch(self):
return self._steps_per_epoch
@property
def engine(self):
return self._engine
@property
def schedule(self):
return self._schedule
def _set_current_step(self, epoch: int):
"""Sets current step number.
Args:
epoch (int): Step number to be set.
"""
self._cur_step = epoch * self._steps_per_epoch
def _call_timer(self, action: str, item: str, *args, **kwargs) -> None:
"""Call timer funciton with a given timer name.
Args:
action (str): Function to be called on timer.
item (str): Name of the timer.
args (list): args used for action function.
kwargs (dict): kwargs used for action function.
"""
if self._timer is not None:
getattr(self._timer, action)(item, *args, **kwargs)
def _reset_states(self) -> None:
"""Clear trainer states"""
self.states = dict()
def _call_hooks(self, func, output=None):
"""Calls specific hooks in the current time point.
Args:
func (str): A string represents the time point.
output (Any, optional): Output of the model after running an iteration or None in any other time points.
"""
# Only after iter hook will receive output
for hook in self.hooks:
if output is None:
getattr(hook, func)(self)
else:
getattr(hook, func)(self, *output)
@staticmethod
def _should_display_progress(display_progress: bool):
"""Only display progress on DP rank 0, TP rank 0 and PP last rank"""
return (display_progress and is_dp_rank_0() and is_tp_rank_0()
and is_no_pp_or_last_stage())
def _train_epoch(
self,
train_dataloader: DataLoader,
epoch: int = None,
display_progress: bool = False,
return_output_label: bool = True,
):
# set training state
self._engine.train()
data_iter = iter(train_dataloader)
progress = range(self._steps_per_epoch)
if display_progress:
if epoch is None:
progress = tqdm(progress, desc="[Train]")
else:
progress = tqdm(progress, desc=f"[Epoch {epoch} / Train]")
self._call_hooks("before_train_epoch")
self._call_timer(action="start", item="Train-epoch")
for i in progress:
self._call_hooks("before_train_iter")
self._call_timer(action="start", item="Train-step")
# run 1 training step
self.engine.zero_grad()
logits, label, loss = self.schedule.forward_backward_step(
self.engine,
data_iter,
forward_only=False,
return_loss=True,
return_output_label=return_output_label,
)
self.engine.step()
self._call_timer(action="stop",
item="Train-step",
keep_in_history=True)
self._call_hooks("after_train_iter", output=(logits, label, loss))
self._cur_step += 1
if display_progress:
if "step_metrics" in self.states:
progress.set_postfix(**self.states["step_metrics"])
# stop when max iter is reached
if self._exceed_max_step():
break
self._call_timer(action="stop",
item="Train-epoch",
keep_in_history=True)
self._call_hooks("after_train_epoch")
self._call_timer(action="reset", item="Train-epoch")
def _eval(
self,
test_dataloader: DataLoader,
epoch: int = None,
display_progress: bool = False,
return_output_label: bool = True,
):
# switch engine status
self._engine.eval()
data_iter = iter(test_dataloader)
num_steps = len(test_dataloader)
self._call_hooks("before_test")
# prepare progress bar
progress = range(num_steps)
if display_progress:
desc = "Evaluation"
if epoch is not None:
desc = "[Epoch %d / Test]" % epoch
progress = tqdm(progress, desc=desc)
self._call_hooks("before_test_epoch")
self._call_timer(action="start", item="Test-epoch")
with torch.no_grad():
for _ in progress:
self._call_hooks("before_test_iter")
self._call_timer(action="start", item="Test-step")
logits, label, loss = self.schedule.forward_backward_step(
self.engine,
data_iter,
forward_only=True,
return_loss=True,
return_output_label=return_output_label,
)
self._call_timer(action="stop",
item="Test-step",
keep_in_history=True)
self._call_hooks("after_test_iter",
output=(logits, label, loss))
if display_progress:
if "step_metrics" in self.states:
progress.set_postfix(**self.states["step_metrics"])
self._call_timer(action="stop",
item="Test-epoch",
keep_in_history=True)
self._call_hooks("after_test_epoch")
self._call_hooks("after_test")
self._call_timer(action="reset", item="Test-step")
self._call_timer(action="reset", item="Test-epoch")
def _exceed_max_step(self):
return self._max_steps is not None and self._cur_step >= self._max_steps
def fit(
self,
train_dataloader: DataLoader,
epochs: int,
max_steps: int = None,
test_dataloader: DataLoader = None,
test_interval: int = 1,
hooks: List[BaseHook] = None,
display_progress: bool = False,
return_output_label: bool = True,
):
r"""Trains the model to fit training data.
Args:
train_dataloader (:class:`torch.utils.data.DataLoader`): DataLoader for training.
epochs (int): Maximum number of epochs.
max_steps (int, optional): Maximum number of running iterations.
test_dataloader (:class:`torch.utils.data.DataLoader`, optional): DataLoader for validation.
test_interval (int, optional): Interval of validation
hooks (list[BaseHook], optional): A list of hooks used in training.
display_progress (bool, optional): If True, a progress bar will be displayed.
"""
# set epochs and steps, consider gradient accumulation
self._steps_per_epoch = len(train_dataloader)
self._max_steps = max_steps
self._max_epochs = epochs
# check if testing is required
should_test = False
if test_dataloader is not None:
should_test = True
display_progress = self._should_display_progress(display_progress)
# reset hooks
self._reset_states()
if hooks is not None:
assert isinstance(
hooks, list
), f"expected argument hooks be to list, but got {type(hooks)}"
else:
hooks = []
self.hooks = hooks
self.hooks.sort(key=lambda hook: hook.priority)
if self._verbose:
for hook in self.hooks:
self._logger.info(
f"Using {hook.__class__.__name__} for training, priority = {hook.priority}",
ranks=[0],
)
self._logger.info(
"Lower value means higher priority for calling hook function",
ranks=[0])
self._call_hooks("after_hook_is_attached")
self._engine.train()
self._call_hooks("before_train")
# recover step value if resuming training
last_epoch = self._cur_epoch
if self.cur_epoch != 0:
self._set_current_step(last_epoch)
for epoch in range(last_epoch, epochs):
# train for one epoch
self._train_epoch(
train_dataloader=train_dataloader,
epoch=epoch,
display_progress=display_progress,
return_output_label=return_output_label,
)
# start eval
if should_test and epoch % test_interval == 0:
self._eval(
test_dataloader=test_dataloader,
display_progress=display_progress,
epoch=epoch,
return_output_label=return_output_label,
)
self._cur_epoch += 1
# check for termination
if self._exceed_max_step():
self._logger.info(
f"Max number of steps {max_steps} has been reached, training is stopped automatically",
ranks=[0],
)
break
self._call_hooks("after_train")
self._call_timer("reset", "Train-epoch")
def evaluate(
self,
test_dataloader: DataLoader,
hooks: List[BaseHook] = None,
display_progress: bool = False,
return_output_label: bool = True,
):
"""Evaluates the model with testing data.
Args:
test_dataloader (:class:`torch.utils.data.DataLoader`, optional): Dataloader for testing.
hooks (list, optional): A list of hooks used in evaluation. Defaults to None.
display_progress (bool, optional): If True, the evaluation progress will be printed. Defaults to False.
return_output_label (bool, optional): If True, the output of model and the label
will be returned. Defaults to True.
"""
# set display
display_progress = self._should_display_progress(display_progress)
# reset hooks
self._reset_states()
if hooks is not None:
assert isinstance(
hooks, list
), f"expected argument hooks be to list, but got {type(hooks)}"
else:
hooks = []
self.hooks = hooks
self.hooks.sort(key=lambda hook: hook.priority)
if self._verbose:
for hook in self.hooks:
self._logger.info(
f"Using {hook.__class__.__name__} for training, priority = {hook.priority}",
ranks=[0],
)
self._logger.info(
"Lower value means higher priority for calling hook function",
ranks=[0])
self._call_hooks("after_hook_is_attached")
# eval
self._eval(
test_dataloader=test_dataloader,
display_progress=display_progress,
return_output_label=return_output_label,
)
def predict(self, data: Union[Tensor, List[Tensor]]):
"""Uses trained model to make a prediction for a tensor or a tensor list.
Args:
data (Union[:class:`torch.tensor`, List[:class:`torch.tensor`]]): Data as the input.
Returns:
:class:`torch.tensor`: The output of model as the prediction
"""
# predict without labels
if isinstance(data, (list, tuple)):
assert isinstance(data[0], Tensor)
else:
assert isinstance(data, Tensor)
self._engine.eval()
# prepare a list of (data, label) to make it iterable
# for compatibility with schedule
simple_dataloader = [(data, None)]
data_iter = iter(simple_dataloader)
output, _, _ = self.schedule.forward_backward_step(self.engine,
data_iter,
forward_only=True,
return_loss=False)
return output