1. Pytorch释放显存占用方式
Pytorch是常用的机器学习框架之一,但是在训练深度学习模型时,经常会受到显存不足的问题的困扰。本文将介绍Pytorch释放显存占用的方式。
1.1 使用`torch.cuda.empty_cache()`释放显存空间
在Pytorch中,可以使用`torch.cuda.empty_cache()`手动释放显存。该函数会清空当前Pytorch分配的所有未释放显存空间。代码如下:
import torch
model = MyModel()
optimizer = torch.optim.Adam(model.parameters(), lr=1e-3)
criterion = nn.CrossEntropyLoss()
for epoch in range(10):
train_loss = 0.0
model.train()
for i, (inputs, labels) in enumerate(train_loader):
inputs = inputs.cuda()
labels = labels.cuda()
optimizer.zero_grad()
outputs = model(inputs)
loss = criterion(outputs, labels)
loss.backward()
optimizer.step()
train_loss += loss.item()
print('Epoch: {}, Train Loss: {}'.format(epoch+1, train_loss/len(train_loader)))
torch.cuda.empty_cache() # 释放显存空间
然而,这种方式的效果并不是很明显。因此,需要使用其他更为有效的方式。
1.2 使用`torch.cuda.memory_allocated()`和`torch.cuda.memory_cached()`查看显存占用情况
在使用Pytorch训练深度学习模型时,经常需要查看显存的占用情况,以便及时释放占用的显存空间。可以使用`torch.cuda.memory_allocated()`和`torch.cuda.memory_cached()`函数查看当前Pytorch分配的显存占用情况,代码如下:
import torch
model = MyModel()
optimizer = torch.optim.Adam(model.parameters(), lr=1e-3)
criterion = nn.CrossEntropyLoss()
print('Before Training: {} MB'.format(torch.cuda.memory_allocated()/1024/1024))
print('Before Training: {} MB'.format(torch.cuda.memory_cached()/1024/1024))
for epoch in range(10):
train_loss = 0.0
model.train()
for i, (inputs, labels) in enumerate(train_loader):
inputs = inputs.cuda()
labels = labels.cuda()
optimizer.zero_grad()
outputs = model(inputs)
loss = criterion(outputs, labels)
loss.backward()
optimizer.step()
train_loss += loss.item()
print('Epoch: {}, Train Loss: {}'.format(epoch+1, train_loss/len(train_loader)))
print('During Training: {} MB'.format(torch.cuda.memory_allocated()/1024/1024))
print('During Training: {} MB'.format(torch.cuda.memory_cached()/1024/1024))
torch.cuda.empty_cache() # 释放显存空间
print('After Training: {} MB'.format(torch.cuda.memory_allocated()/1024/1024))
print('After Training: {} MB'.format(torch.cuda.memory_cached()/1024/1024))
1.3 使用`with torch.cuda.device()`设置显存设备
可以使用`with torch.cuda.device()`函数手动设置使用哪个显卡设备,并释放掉没有使用的显存空间,以提高显存利用效率。代码如下:
import torch
device = torch.device('cuda:0')
model = MyModel()
model.to(device)
optimizer = torch.optim.Adam(model.parameters(), lr=1e-3)
criterion = nn.CrossEntropyLoss()
print('Before Training: {} MB'.format(torch.cuda.memory_allocated(device)/1024/1024))
print('Before Training: {} MB'.format(torch.cuda.memory_cached(device)/1024/1024))
for epoch in range(10):
train_loss = 0.0
model.train()
with torch.cuda.device(device):
for i, (inputs, labels) in enumerate(train_loader):
inputs = inputs.to(device)
labels = labels.to(device)
optimizer.zero_grad()
outputs = model(inputs)
loss = criterion(outputs, labels)
loss.backward()
optimizer.step()
train_loss += loss.item()
print('Epoch: {}, Train Loss: {}'.format(epoch+1, train_loss/len(train_loader)))
print('During Training: {} MB'.format(torch.cuda.memory_allocated(device)/1024/1024))
print('During Training: {} MB'.format(torch.cuda.memory_cached(device)/1024/1024))
torch.cuda.empty_cache() # 释放显存空间
print('After Training: {} MB'.format(torch.cuda.memory_allocated(device)/1024/1024))
print('After Training: {} MB'.format(torch.cuda.memory_cached(device)/1024/1024))
需要注意的是,在`with torch.cuda.device()`中设置的显存设备,一定要与`model.to(device)`中设置的设备一致,否则会报错。
综上所述,释放显存占用的方式主要有以下三种:手动释放显存空间、查看显存占用情况、手动设置使用哪个显卡设备。需要根据实际情况选择合适的释放方式。