lightning/tests/tests_fabric/utilities/test_init.py

118 lines
4.1 KiB
Python

# Copyright The Lightning AI 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 time
from unittest.mock import Mock
import pytest
import torch.nn
from lightning.fabric.utilities.init import (
_EmptyInit,
_has_meta_device_parameters_or_buffers,
_materialize_meta_tensors,
)
from tests_fabric.helpers.runif import RunIf
@RunIf(min_cuda_gpus=1)
def test_empty_init(monkeypatch):
"""Test that `_EmptyInit()` skips initialization and allocates uninitialized memory."""
init_mock = Mock()
monkeypatch.setattr(torch.Tensor, "uniform_", init_mock)
with _EmptyInit(enabled=True):
torch.nn.Linear(2, 2, device="cuda")
init_mock.assert_not_called()
with _EmptyInit(enabled=False):
torch.nn.Linear(2, 2, device="cuda")
init_mock.assert_called()
@RunIf(min_cuda_gpus=1)
def test_empty_init_speed():
"""Test that `_EmptyInit()` is faster than regular initialization."""
t0 = time.perf_counter()
with _EmptyInit(enabled=False):
torch.nn.Linear(10000, 10000, device="cuda")
torch.cuda.synchronize()
normal_init_time = time.perf_counter() - t0
t0 = time.perf_counter()
with _EmptyInit(enabled=True):
torch.nn.Linear(10000, 10000, device="cuda")
torch.cuda.synchronize()
empty_init_time = time.perf_counter() - t0
assert normal_init_time > 2 * empty_init_time
def test_materialize_meta_tensors():
class Submodule(torch.nn.Module):
def __init__(self):
super().__init__()
self.l = torch.nn.Linear(1, 1)
class MyModel(torch.nn.Module):
def __init__(self):
super().__init__()
self.register_buffer("buf", torch.tensor(0))
self.l = torch.nn.Linear(1, 1)
self.inner = Submodule()
with torch.device("meta"):
model = MyModel()
with pytest.raises(TypeError, match="MyModel.reset_parameters` method is implemented"):
_materialize_meta_tensors(model, torch.device("cpu"))
class MyModel2(MyModel):
def reset_parameters(self):
self.buf = torch.empty_like(self.buf)
with torch.device("meta"):
model = MyModel2()
_materialize_meta_tensors(model, torch.device("cpu"))
assert model.buf.device.type == "cpu"
assert len(list(model.parameters())) == 4
assert all(p.device.type == "cpu" for p in model.parameters())
def test_has_meta_device_parameters_or_buffers():
"""Test that the `_has_meta_device_parameters_or_buffers` function can find meta-device parameters in models and
optimizers."""
class BufferModule(torch.nn.Module):
def __init__(self):
super().__init__()
self.register_buffer("buffer", torch.ones(2, device="meta"))
# nn.Module
module = torch.nn.Linear(2, 2)
meta_module = torch.nn.Linear(2, 2, device="meta")
buffer_meta_module = BufferModule()
assert not _has_meta_device_parameters_or_buffers(module)
assert _has_meta_device_parameters_or_buffers(meta_module)
assert _has_meta_device_parameters_or_buffers(torch.nn.Sequential(module, meta_module, torch.nn.ReLU()))
assert _has_meta_device_parameters_or_buffers(buffer_meta_module)
# optim.Optimizer
optimizer = torch.optim.SGD(module.parameters(), lr=0.1)
meta_optimizer = torch.optim.SGD(meta_module.parameters(), lr=0.1)
assert not _has_meta_device_parameters_or_buffers(optimizer)
assert _has_meta_device_parameters_or_buffers(meta_optimizer)
# unsupported objects
with pytest.raises(TypeError, match="Expected `torch.nn.Module` or `torch.optim.Optimizer`"):
_has_meta_device_parameters_or_buffers(None)