ColossalAI/colossalai/trainer/_trainer.py

442 lines
15 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:
"""This 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`.
:param engine: Engine responsible for the process function
:type engine: :class:`Engine`
:param schedule: Schedule responsible for forward and backward steps
:type schedule: :class:`BaseSchedule`, optional
:param timer: Timer used to monitor the whole training
:type timer: :class:`MultiTimer`, optional
:param logger: Logger used to record the whole training
:type logger: :class:`colossalai.logging.DistributedLogger`, optional
"""
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.
:param epoch: Step number to be set
:type epoch: int
"""
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.
:param action: Function to be called on timer
:type action: str
:param item: Name of the timer
:type item: str
:param args: args used for action function
:param kwargs: 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.
:param func: A string represents the time point
:param output: Output of the model after running a iteration or None in any other time points
:type func: str
:type output: optional
"""
# 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,
):
"""Trains the model to fit training data.
:param train_dataloader: DataLoader in training
:param epochs: Maximum number of epoches
:param max_steps: Maximum number of running iterations
:param test_dataloader: DataLoader in testing
:param test_interval: Interval of testing
:param hooks: A list of hooks used in training
:param display_progress: If True, the training progress will be printed
:param return_output_label: If True, the output of model and the label will be returned
:type train_dataloader: DataLoader
:type epochs: int
:type max_steps: int, optional
:type test_dataloader: DataLoader, optional
:type test_interval: int, optional
:type hooks: list, optional
:type display_progress: bool, optional
:type return_output_label: bool, optional
"""
# 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.
:param test_dataloader: DataLoader in testing
:param hooks: A list of hooks used in evaluation
:param display_progress: If True, the evaluation progress will be printed
:param return_output_label: If True, the output of model and the label will be returned
:type test_dataloader: DataLoader
:type hooks: list, optional
:type display_progress: bool, optional
:type return_output_label: bool
"""
# 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.
:param data: Data as the input
:type data: Union[Tensor, List[Tensor]
:return: The output of model as the prediction
:rtype: Tensor
"""
# 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