lightning/tests/accelerators/test_tpu_backend.py

263 lines
8.0 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 collections
from copy import deepcopy
import pytest
import torch
from torch import nn
from pytorch_lightning import Trainer
from pytorch_lightning.accelerators.cpu import CPUAccelerator
from pytorch_lightning.accelerators.tpu import TPUAccelerator
from pytorch_lightning.callbacks import Callback
from pytorch_lightning.plugins import TPUSpawnPlugin
from pytorch_lightning.utilities.exceptions import MisconfigurationException
from tests.helpers.boring_model import BoringModel
from tests.helpers.runif import RunIf
from tests.helpers.utils import pl_multi_process_test
class WeightSharingModule(BoringModel):
def __init__(self):
super().__init__()
self.layer_1 = nn.Linear(32, 10, bias=False)
self.layer_2 = nn.Linear(10, 32, bias=False)
self.layer_3 = nn.Linear(32, 10, bias=False)
self.layer_3.weight = self.layer_1.weight
def forward(self, x):
x = self.layer_1(x)
x = self.layer_2(x)
x = self.layer_3(x)
return x
@RunIf(tpu=True)
@pl_multi_process_test
def test_resume_training_on_cpu(tmpdir):
"""Checks if training can be resumed from a saved checkpoint on CPU"""
# Train a model on TPU
model = BoringModel()
trainer = Trainer(checkpoint_callback=True, max_epochs=1, tpu_cores=8)
trainer.fit(model)
model_path = trainer.checkpoint_callback.best_model_path
# Verify saved Tensors are on CPU
ckpt = torch.load(model_path)
weight_tensor = list(ckpt["state_dict"].values())[0]
assert weight_tensor.device == torch.device("cpu")
# Verify that training is resumed on CPU
trainer = Trainer(
resume_from_checkpoint=model_path, checkpoint_callback=True, max_epochs=1, default_root_dir=tmpdir
)
trainer.fit(model)
assert trainer.state.finished, f"Training failed with {trainer.state}"
@RunIf(tpu=True)
@pl_multi_process_test
def test_if_test_works_after_train(tmpdir):
"""Ensure that .test() works after .fit()"""
# Train a model on TPU
model = BoringModel()
trainer = Trainer(max_epochs=1, tpu_cores=8, default_root_dir=tmpdir, fast_dev_run=True)
trainer.fit(model)
assert len(trainer.test(model)) == 1
@RunIf(tpu=True)
@pl_multi_process_test
def test_weight_tying_warning(tmpdir, capsys=None):
"""
Ensure a warning is thrown if model parameter lengths do not match
post moving to device.
"""
model = WeightSharingModule()
trainer = Trainer(checkpoint_callback=True, max_epochs=1, tpu_cores=1)
with pytest.warns(UserWarning, match=r"The model layers do not match after moving to the target device."):
trainer.fit(model)
@RunIf(tpu=True)
@pl_multi_process_test
def test_if_weights_tied(tmpdir, capsys=None):
"""
Test if weights are properly tied on `on_post_move_to_device`.
Ensure no warning for parameter mismatch is thrown.
"""
class Model(WeightSharingModule):
def on_post_move_to_device(self):
self.layer_3.weight = self.layer_1.weight
model = Model()
trainer = Trainer(checkpoint_callback=True, max_epochs=1, tpu_cores=1)
with pytest.warns(UserWarning, match="The model layers do not match"):
trainer.fit(model)
@RunIf(tpu=True)
def test_accelerator_tpu():
trainer = Trainer(accelerator="tpu", tpu_cores=8)
assert trainer._device_type == "tpu"
assert isinstance(trainer.accelerator, TPUAccelerator)
with pytest.raises(
MisconfigurationException, match="You passed `accelerator='tpu'`, but you didn't pass `tpu_cores` to `Trainer`"
):
trainer = Trainer(accelerator="tpu")
@RunIf(tpu=True)
def test_accelerator_cpu_with_tpu_cores_flag():
trainer = Trainer(accelerator="cpu", tpu_cores=8)
assert trainer._device_type == "cpu"
assert isinstance(trainer.accelerator, CPUAccelerator)
@RunIf(tpu=True)
def test_accelerator_tpu_with_auto():
trainer = Trainer(accelerator="auto", tpu_cores=8)
assert trainer._device_type == "tpu"
assert isinstance(trainer.accelerator, TPUAccelerator)
@RunIf(tpu=True)
def test_accelerator_tpu_with_devices():
trainer = Trainer(accelerator="tpu", devices=8)
assert trainer.tpu_cores == 8
assert isinstance(trainer.training_type_plugin, TPUSpawnPlugin)
assert isinstance(trainer.accelerator, TPUAccelerator)
@RunIf(tpu=True)
def test_accelerator_auto_with_devices_tpu():
trainer = Trainer(accelerator="auto", devices=8)
assert trainer._device_type == "tpu"
assert trainer.tpu_cores == 8
@RunIf(tpu=True)
def test_accelerator_tpu_with_tpu_cores_priority():
"""Test for checking `tpu_cores` flag takes priority over `devices`."""
tpu_cores = 8
with pytest.warns(UserWarning, match="The flag `devices=1` will be ignored,"):
trainer = Trainer(accelerator="tpu", devices=1, tpu_cores=tpu_cores)
assert trainer.tpu_cores == tpu_cores
@RunIf(tpu=True)
def test_set_devices_if_none_tpu():
trainer = Trainer(accelerator="tpu", tpu_cores=8)
assert trainer.devices == 8
@RunIf(tpu=True)
def test_manual_optimization_tpus(tmpdir):
class ManualOptimizationModel(BoringModel):
count = 0
called = collections.defaultdict(int)
def __init__(self):
super().__init__()
self.automatic_optimization = False
@property
def should_update(self):
return self.count % 2 == 0
def on_train_batch_start(self, batch, batch_idx, dataloader_idx):
self.called["on_train_batch_start"] += 1
self.weight_before = self.layer.weight.clone()
def training_step(self, batch, batch_idx):
self.called["training_step"] += 1
opt = self.optimizers()
output = self.layer(batch)
loss = self.loss(batch, output)
if self.should_update:
self.manual_backward(loss)
opt.step()
opt.zero_grad()
return loss
def on_train_batch_end(self, outputs, batch, batch_idx, dataloader_idx):
self.called["on_train_batch_end"] += 1
after_before = self.layer.weight.clone()
if self.should_update:
assert not torch.equal(self.weight_before, after_before), self.count
else:
assert torch.equal(self.weight_before, after_before)
assert torch.all(self.layer.weight.grad == 0)
self.count += 1
def on_train_end(self):
assert self.called["training_step"] == 5
assert self.called["on_train_batch_start"] == 5
assert self.called["on_train_batch_end"] == 5
class TestManualOptimizationCallack(Callback):
def on_train_end(self, trainer, pl_module):
opt = pl_module.optimizers()
assert opt._total_optimizer_step_calls == 3
model = ManualOptimizationModel()
model_copy = deepcopy(model)
model.training_step_end = None
model.training_epoch_end = None
trainer = Trainer(
max_epochs=1,
default_root_dir=tmpdir,
limit_train_batches=5,
limit_test_batches=0,
limit_val_batches=0,
tpu_cores=8,
callbacks=[TestManualOptimizationCallack()],
)
trainer.fit(model)
for param, param_copy in zip(model.parameters(), model_copy.parameters()):
assert not torch.equal(param.cpu().data, param_copy.data)
@RunIf(tpu=True)
def test_ddp_cpu_not_supported_on_tpus():
with pytest.raises(MisconfigurationException, match="`accelerator='ddp_cpu'` is not supported on TPU machines"):
Trainer(accelerator="ddp_cpu")