lightning/tests/tuner/test_scale_batch_size.py

316 lines
10 KiB
Python

# Copyright The PyTorch Lightning team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import os
from copy import deepcopy
import pytest
import torch
from torch.utils.data import DataLoader
import tests.helpers.utils as tutils
from pytorch_lightning import Trainer
from pytorch_lightning.tuner.tuning import Tuner
from pytorch_lightning.utilities import AMPType
from pytorch_lightning.utilities.exceptions import MisconfigurationException
from tests.base import EvalModelTemplate
from tests.helpers import BoringDataModule, BoringModel, RandomDataset
from tests.helpers.datamodules import MNISTDataModule
from tests.helpers.runif import RunIf
class BatchSizeDataModule(BoringDataModule):
def __init__(self, batch_size):
super().__init__()
if batch_size is not None:
self.batch_size = batch_size
def train_dataloader(self):
return DataLoader(self.random_train, batch_size=getattr(self, "batch_size", 1))
class BatchSizeModel(BoringModel):
def __init__(self, batch_size):
super().__init__()
if batch_size is not None:
self.batch_size = batch_size
def train_dataloader(self):
return DataLoader(RandomDataset(32, 64), batch_size=getattr(self, "batch_size", 1))
@pytest.mark.parametrize(["model_bs", "dm_bs"], [
(2, -1),
(2, 2),
(2, None),
(None, 2),
(16, 16),
])
def test_scale_batch_size_method_with_model_or_datamodule(tmpdir, model_bs, dm_bs):
""" Test the tuner method `Tuner.scale_batch_size` with a datamodule. """
trainer = Trainer(
default_root_dir=tmpdir,
limit_train_batches=1,
limit_val_batches=0,
max_epochs=1,
)
tuner = Tuner(trainer)
model = BatchSizeModel(model_bs)
datamodule = BatchSizeDataModule(dm_bs) if dm_bs != -1 else None
new_batch_size = tuner.scale_batch_size(model, mode="binsearch", init_val=4, max_trials=2, datamodule=datamodule)
assert new_batch_size == 16
if model_bs is not None:
assert model.batch_size == new_batch_size
if dm_bs == -1:
# datamodule batch size takes precedence
assert trainer.train_dataloader.loaders.batch_size == new_batch_size
if dm_bs not in (-1, None):
assert datamodule.batch_size == new_batch_size
assert trainer.train_dataloader.loaders.batch_size == new_batch_size
def test_model_reset_correctly(tmpdir):
""" Check that model weights are correctly reset after scaling batch size. """
tutils.reset_seed()
model = EvalModelTemplate()
# logger file to get meta
trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
)
before_state_dict = deepcopy(model.state_dict())
trainer.tuner.scale_batch_size(model, max_trials=5)
after_state_dict = model.state_dict()
for key in before_state_dict.keys():
assert torch.all(torch.eq(before_state_dict[key], after_state_dict[key])), \
'Model was not reset correctly after scaling batch size'
def test_trainer_reset_correctly(tmpdir):
""" Check that all trainer parameters are reset correctly after scaling batch size. """
tutils.reset_seed()
model = EvalModelTemplate()
# logger file to get meta
trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
)
changed_attributes = [
'callbacks',
'checkpoint_callback',
'current_epoch',
'limit_train_batches',
'logger',
'max_steps',
'weights_summary',
]
expected = {ca: getattr(trainer, ca) for ca in changed_attributes}
trainer.tuner.scale_batch_size(model, max_trials=5)
actual = {ca: getattr(trainer, ca) for ca in changed_attributes}
assert actual == expected
@RunIf(min_gpus=1)
@pytest.mark.parametrize('scale_arg', ['power', 'binsearch', True])
def test_auto_scale_batch_size_trainer_arg(tmpdir, scale_arg):
""" Test possible values for 'batch size auto scaling' Trainer argument. """
tutils.reset_seed()
hparams = EvalModelTemplate.get_default_hparams()
model = EvalModelTemplate(**hparams)
before_batch_size = hparams.get('batch_size')
trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
auto_scale_batch_size=scale_arg,
gpus=1,
)
trainer.tune(model)
after_batch_size = model.batch_size
assert before_batch_size != after_batch_size, \
'Batch size was not altered after running auto scaling of batch size'
assert not os.path.exists(tmpdir / 'scale_batch_size_temp_model.ckpt')
@RunIf(min_gpus=1)
@pytest.mark.parametrize('use_hparams', [True, False])
def test_auto_scale_batch_size_set_model_attribute(tmpdir, use_hparams):
""" Test that new batch size gets written to the correct hyperparameter attribute. """
tutils.reset_seed()
hparams = EvalModelTemplate.get_default_hparams()
before_batch_size = hparams.get('batch_size')
class HparamsEvalModelTemplate(EvalModelTemplate):
def dataloader(self, *args, **kwargs):
# artificially set batch_size so we can get a dataloader
# remove it immediately after, because we want only self.hparams.batch_size
setattr(self, "batch_size", before_batch_size)
dataloader = super().dataloader(*args, **kwargs)
del self.batch_size
return dataloader
datamodule_model = MNISTDataModule(data_dir=tmpdir, batch_size=111) # this datamodule should get ignored!
datamodule_fit = MNISTDataModule(data_dir=tmpdir, batch_size=before_batch_size)
model_class = HparamsEvalModelTemplate if use_hparams else EvalModelTemplate
model = model_class(**hparams)
model.datamodule = datamodule_model # unused when another module gets passed to .tune() / .fit()
trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
auto_scale_batch_size=True,
gpus=1,
)
trainer.tune(model, datamodule_fit)
after_batch_size = model.hparams.batch_size if use_hparams else model.batch_size
assert trainer.datamodule == datamodule_fit
assert before_batch_size != after_batch_size
assert after_batch_size <= len(trainer.train_dataloader.dataset)
assert datamodule_fit.batch_size == after_batch_size
# should be left unchanged, since it was not passed to .tune()
assert datamodule_model.batch_size == 111
def test_auto_scale_batch_size_duplicate_attribute_warning(tmpdir):
""" Test for a warning when model.batch_size and model.hparams.batch_size both present. """
class TestModel(BoringModel):
def __init__(self, batch_size=1):
super().__init__()
# now we have model.batch_size and model.hparams.batch_size
self.batch_size = 1
self.save_hyperparameters()
model = TestModel()
trainer = Trainer(default_root_dir=tmpdir, max_steps=1, max_epochs=1000, auto_scale_batch_size=True)
expected_message = "Field `model.batch_size` and `model.hparams.batch_size` are mutually exclusive!"
with pytest.warns(UserWarning, match=expected_message):
trainer.tune(model)
@pytest.mark.parametrize('scale_method', ['power', 'binsearch'])
def test_call_to_trainer_method(tmpdir, scale_method):
""" Test that calling the trainer method itself works. """
tutils.reset_seed()
hparams = EvalModelTemplate.get_default_hparams()
model = EvalModelTemplate(**hparams)
before_batch_size = hparams.get('batch_size')
# logger file to get meta
trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
)
after_batch_size = trainer.tuner.scale_batch_size(model, mode=scale_method, max_trials=5)
model.batch_size = after_batch_size
trainer.fit(model)
assert before_batch_size != after_batch_size, \
'Batch size was not altered after running auto scaling of batch size'
def test_error_on_dataloader_passed_to_fit(tmpdir):
"""Verify that when the auto scale batch size feature raises an error
if a train dataloader is passed to fit """
# only train passed to fit
model = EvalModelTemplate()
trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
limit_val_batches=0.1,
limit_train_batches=0.2,
auto_scale_batch_size='power',
)
fit_options = dict(train_dataloader=model.dataloader(train=True))
with pytest.raises(MisconfigurationException):
trainer.tune(model, **fit_options)
@RunIf(min_gpus=1, amp_native=True)
def test_auto_scale_batch_size_with_amp(tmpdir):
model = EvalModelTemplate()
batch_size_before = model.batch_size
trainer = Trainer(
default_root_dir=tmpdir,
max_steps=1,
auto_scale_batch_size=True,
gpus=1,
precision=16,
)
trainer.tune(model)
batch_size_after = model.batch_size
assert trainer.amp_backend == AMPType.NATIVE
assert trainer.scaler is not None
assert batch_size_after != batch_size_before
def test_scale_batch_size_no_trials(tmpdir):
"""Check the result is correct even when no trials are run"""
trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
limit_val_batches=1,
limit_train_batches=1,
auto_scale_batch_size='power',
)
model = BatchSizeModel(batch_size=2)
result = trainer.tuner.scale_batch_size(model, max_trials=0)
assert result == 2
def test_scale_batch_size_fails_with_unavailable_mode(tmpdir):
"""Check the tuning raises error when called with mode that does not exist."""
class TestModel(BoringModel):
def __init__(self):
super().__init__()
self.batch_size = 2
model = TestModel()
trainer = Trainer(
default_root_dir=tmpdir,
max_epochs=1,
limit_val_batches=1,
limit_train_batches=1,
auto_scale_batch_size='ThisModeDoesNotExist',
)
with pytest.raises(ValueError, match='could either be `power` or `binsearch`'):
trainer.tune(model)
with pytest.raises(ValueError, match='could either be `power` or `binsearch`'):
trainer.tuner.scale_batch_size(model, mode='ThisModeDoesNotExist')