Repository: Link-Li/Balanced-DataParallel
Branch: master
Commit: 347b6cc4ac81
Files: 4
Total size: 13.3 KB

Directory structure:
gitextract_7w_mbpd8/

├── README.md
├── data_parallel.py
├── data_parallel_my.py
└── data_parallel_my_v2.py

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FILE CONTENTS
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================================================
FILE: README.md
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# Balanced-DataParallel
这里是改进了pytorch的DataParallel, 用来平衡第一个GPU的显存使用量

本代码来自transformer-XL:https://github.com/kimiyoung/transformer-xl

代码不是本人写的, 但是感觉很好用, 就分享一下.

# 怎么使用:

  这个 `BalancedDataParallel` 类使用起来和 `DataParallel` 类似, 下面是一个示例代码:

```
my_net = MyNet()
my_net = BalancedDataParallel(gpu0_bsz // acc_grad, my_net, dim=0).cuda()
```

  这里包含三个参数, 第一个参数是第一个GPU要分配多大的batch_size, 但是要注意, 如果你使用了梯度累积, 那么这里传入的是每次进行运算的实际batch_size大小. 举个例子, 比如你在3个GPU上面跑代码, 但是一个GPU最大只能跑3条数据, 但是因为0号GPU还要做一些数据的整合操作, 于是0号GPU只能跑2条数据, 这样一算, 你可以跑的大小是2+3+3=8, 于是你可以设置下面的这样的参数:

```
batch_szie = 8
gpu0_bsz = 2
acc_grad = 1
my_net = MyNet()
my_net = BalancedDataParallel(gpu0_bsz // acc_grad, my_net, dim=0).cuda()
```

  这个时候突然想跑个batch size是16的怎么办呢, 那就是4+6+6=16了, 这样设置累积梯度为2就行了:


```
batch_szie = 16
gpu0_bsz = 4
acc_grad = 2
my_net = MyNet()
my_net = BalancedDataParallel(gpu0_bsz // acc_grad, my_net, dim=0).cuda()

```

### 各个版本的data_parallel

- data_parallel.py: 原作者的代码, 但是使用的时候发现, 如果batch size设置的小于GPU的数量, 会导致最后一个批次的数据分配的不足以所有的GPU分配, 然后报错.

- data_parallel_my.py: 我稍微改了一点, 然后稍微测试了一下, 应该是解决了上面的问题.

- data_parallel_my_v2.py：上面第一个版本的修改，导致无法设置gpu0_bsz=0，这个版本应该是修复这个问题了


================================================
FILE: data_parallel.py
================================================

from torch.nn.parallel import DataParallel
import torch
from torch.nn.parallel._functions import Scatter
from torch.nn.parallel.parallel_apply import parallel_apply

def scatter(inputs, target_gpus, chunk_sizes, dim=0):
    r"""
    Slices tensors into approximately equal chunks and
    distributes them across given GPUs. Duplicates
    references to objects that are not tensors.
    """
    def scatter_map(obj):
        if isinstance(obj, torch.Tensor):
            try:
                return Scatter.apply(target_gpus, chunk_sizes, dim, obj)
            except:
                print('obj', obj.size())
                print('dim', dim)
                print('chunk_sizes', chunk_sizes)
                quit()
        if isinstance(obj, tuple) and len(obj) > 0:
            return list(zip(*map(scatter_map, obj)))
        if isinstance(obj, list) and len(obj) > 0:
            return list(map(list, zip(*map(scatter_map, obj))))
        if isinstance(obj, dict) and len(obj) > 0:
            return list(map(type(obj), zip(*map(scatter_map, obj.items()))))
        return [obj for targets in target_gpus]

    # After scatter_map is called, a scatter_map cell will exist. This cell
    # has a reference to the actual function scatter_map, which has references
    # to a closure that has a reference to the scatter_map cell (because the
    # fn is recursive). To avoid this reference cycle, we set the function to
    # None, clearing the cell
    try:
        return scatter_map(inputs)
    finally:
        scatter_map = None

def scatter_kwargs(inputs, kwargs, target_gpus, chunk_sizes, dim=0):
    r"""Scatter with support for kwargs dictionary"""
    inputs = scatter(inputs, target_gpus, chunk_sizes, dim) if inputs else []
    kwargs = scatter(kwargs, target_gpus, chunk_sizes, dim) if kwargs else []
    if len(inputs) < len(kwargs):
        inputs.extend([() for _ in range(len(kwargs) - len(inputs))])
    elif len(kwargs) < len(inputs):
        kwargs.extend([{} for _ in range(len(inputs) - len(kwargs))])
    inputs = tuple(inputs)
    kwargs = tuple(kwargs)
    return inputs, kwargs

class BalancedDataParallel(DataParallel):
    def __init__(self, gpu0_bsz, *args, **kwargs):
        self.gpu0_bsz = gpu0_bsz
        super().__init__(*args, **kwargs)

    def forward(self, *inputs, **kwargs):
        if not self.device_ids:
            return self.module(*inputs, **kwargs)
        if self.gpu0_bsz == 0:
            device_ids = self.device_ids[1:]
        else:
            device_ids = self.device_ids
        inputs, kwargs = self.scatter(inputs, kwargs, device_ids)
        if len(self.device_ids) == 1:
            return self.module(*inputs[0], **kwargs[0])
        replicas = self.replicate(self.module, self.device_ids)
        if self.gpu0_bsz == 0:
            replicas = replicas[1:]
        outputs = self.parallel_apply(replicas, device_ids, inputs, kwargs)
        return self.gather(outputs, self.output_device)

    def parallel_apply(self, replicas, device_ids, inputs, kwargs):
        return parallel_apply(replicas, inputs, kwargs, device_ids)

    def scatter(self, inputs, kwargs, device_ids):
        bsz = inputs[0].size(self.dim)
        num_dev = len(self.device_ids)
        gpu0_bsz = self.gpu0_bsz
        bsz_unit = (bsz - gpu0_bsz) // (num_dev - 1)
        if gpu0_bsz < bsz_unit:
            chunk_sizes = [gpu0_bsz] + [bsz_unit] * (num_dev - 1)
            delta = bsz - sum(chunk_sizes)
            for i in range(delta):
                chunk_sizes[i + 1] += 1
            if gpu0_bsz == 0:
                chunk_sizes = chunk_sizes[1:]
        else:
            return super().scatter(inputs, kwargs, device_ids)

        # print('bsz: ', bsz)
        # print('num_dev: ', num_dev)
        # print('gpu0_bsz: ', gpu0_bsz)
        # print('bsz_unit: ', bsz_unit)
        # print('chunk_sizes: ', chunk_sizes)
        return scatter_kwargs(inputs, kwargs, device_ids, chunk_sizes, dim=self.dim)



================================================
FILE: data_parallel_my.py
================================================

from torch.nn.parallel import DataParallel
import torch
from torch.nn.parallel._functions import Scatter
from torch.nn.parallel.parallel_apply import parallel_apply

def scatter(inputs, target_gpus, chunk_sizes, dim=0):
    r"""
    Slices tensors into approximately equal chunks and
    distributes them across given GPUs. Duplicates
    references to objects that are not tensors.
    """
    def scatter_map(obj):
        if isinstance(obj, torch.Tensor):
            try:
                return Scatter.apply(target_gpus, chunk_sizes, dim, obj)
            except:
                print('obj', obj.size())
                print('dim', dim)
                print('chunk_sizes', chunk_sizes)
                quit()
        if isinstance(obj, tuple) and len(obj) > 0:
            return list(zip(*map(scatter_map, obj)))
        if isinstance(obj, list) and len(obj) > 0:
            return list(map(list, zip(*map(scatter_map, obj))))
        if isinstance(obj, dict) and len(obj) > 0:
            return list(map(type(obj), zip(*map(scatter_map, obj.items()))))
        return [obj for targets in target_gpus]

    # After scatter_map is called, a scatter_map cell will exist. This cell
    # has a reference to the actual function scatter_map, which has references
    # to a closure that has a reference to the scatter_map cell (because the
    # fn is recursive). To avoid this reference cycle, we set the function to
    # None, clearing the cell
    try:
        return scatter_map(inputs)
    finally:
        scatter_map = None

def scatter_kwargs(inputs, kwargs, target_gpus, chunk_sizes, dim=0):
    r"""Scatter with support for kwargs dictionary"""
    inputs = scatter(inputs, target_gpus, chunk_sizes, dim) if inputs else []
    kwargs = scatter(kwargs, target_gpus, chunk_sizes, dim) if kwargs else []
    if len(inputs) < len(kwargs):
        inputs.extend([() for _ in range(len(kwargs) - len(inputs))])
    elif len(kwargs) < len(inputs):
        kwargs.extend([{} for _ in range(len(inputs) - len(kwargs))])
    inputs = tuple(inputs)
    kwargs = tuple(kwargs)
    return inputs, kwargs

class BalancedDataParallel(DataParallel):
    def __init__(self, gpu0_bsz, *args, **kwargs):
        self.gpu0_bsz = gpu0_bsz
        super().__init__(*args, **kwargs)

    def forward(self, *inputs, **kwargs):
        if not self.device_ids:
            return self.module(*inputs, **kwargs)
        if self.gpu0_bsz == 0:
            device_ids = self.device_ids[1:]
        else:
            device_ids = self.device_ids
        inputs, kwargs = self.scatter(inputs, kwargs, device_ids)
        # print('len(inputs)1: ', str(len(inputs)))
        # print('self.device_ids[:len(inputs)]', str(self.device_ids[:len(inputs)]))
        if len(self.device_ids) == 1:
            return self.module(*inputs[0], **kwargs[0])
        replicas = self.replicate(self.module, self.device_ids[:len(inputs)])
        if self.gpu0_bsz == 0:
            replicas = replicas[1:]
        outputs = self.parallel_apply(replicas, device_ids, inputs, kwargs)
        return self.gather(outputs, self.output_device)

    def parallel_apply(self, replicas, device_ids, inputs, kwargs):
        return parallel_apply(replicas, inputs, kwargs, device_ids[:len(inputs)])

    def scatter(self, inputs, kwargs, device_ids):
        bsz = inputs[0].size(self.dim)
        num_dev = len(self.device_ids)
        gpu0_bsz = self.gpu0_bsz
        bsz_unit = (bsz - gpu0_bsz) // (num_dev - 1)
        if gpu0_bsz < bsz_unit:
            chunk_sizes = [gpu0_bsz] + [bsz_unit] * (num_dev - 1)
            delta = bsz - sum(chunk_sizes)
            for i in range(delta):
                chunk_sizes[i + 1] += 1
            if gpu0_bsz == 0:
                chunk_sizes = chunk_sizes[1:]
        else:
            return super().scatter(inputs, kwargs, device_ids)

        # print('bsz: ', bsz)
        # print('num_dev: ', num_dev)
        # print('gpu0_bsz: ', gpu0_bsz)
        # print('bsz_unit: ', bsz_unit)
        # print('chunk_sizes: ', chunk_sizes)
        return scatter_kwargs(inputs, kwargs, device_ids, chunk_sizes, dim=self.dim)



================================================
FILE: data_parallel_my_v2.py
================================================

from torch.nn.parallel import DataParallel
import torch
from torch.nn.parallel._functions import Scatter
from torch.nn.parallel.parallel_apply import parallel_apply

def scatter(inputs, target_gpus, chunk_sizes, dim=0):
    r"""
    Slices tensors into approximately equal chunks and
    distributes them across given GPUs. Duplicates
    references to objects that are not tensors.
    """
    def scatter_map(obj):
        if isinstance(obj, torch.Tensor):
            try:
                return Scatter.apply(target_gpus, chunk_sizes, dim, obj)
            except:
                print('obj', obj.size())
                print('dim', dim)
                print('chunk_sizes', chunk_sizes)
                quit()
        if isinstance(obj, tuple) and len(obj) > 0:
            return list(zip(*map(scatter_map, obj)))
        if isinstance(obj, list) and len(obj) > 0:
            return list(map(list, zip(*map(scatter_map, obj))))
        if isinstance(obj, dict) and len(obj) > 0:
            return list(map(type(obj), zip(*map(scatter_map, obj.items()))))
        return [obj for targets in target_gpus]

    # After scatter_map is called, a scatter_map cell will exist. This cell
    # has a reference to the actual function scatter_map, which has references
    # to a closure that has a reference to the scatter_map cell (because the
    # fn is recursive). To avoid this reference cycle, we set the function to
    # None, clearing the cell
    try:
        return scatter_map(inputs)
    finally:
        scatter_map = None

def scatter_kwargs(inputs, kwargs, target_gpus, chunk_sizes, dim=0):
    r"""Scatter with support for kwargs dictionary"""
    inputs = scatter(inputs, target_gpus, chunk_sizes, dim) if inputs else []
    kwargs = scatter(kwargs, target_gpus, chunk_sizes, dim) if kwargs else []
    if len(inputs) < len(kwargs):
        inputs.extend([() for _ in range(len(kwargs) - len(inputs))])
    elif len(kwargs) < len(inputs):
        kwargs.extend([{} for _ in range(len(inputs) - len(kwargs))])
    inputs = tuple(inputs)
    kwargs = tuple(kwargs)
    return inputs, kwargs

class BalancedDataParallel(DataParallel):
    def __init__(self, gpu0_bsz, *args, **kwargs):
        self.gpu0_bsz = gpu0_bsz
        super().__init__(*args, **kwargs)

    def forward(self, *inputs, **kwargs):
        if not self.device_ids:
            return self.module(*inputs, **kwargs)
        if self.gpu0_bsz == 0:
            device_ids = self.device_ids[1:]
        else:
            device_ids = self.device_ids
        inputs, kwargs = self.scatter(inputs, kwargs, device_ids)

        print('len(inputs): ', str(len(inputs)))
        print('self.device_ids[:len(inputs)]', str(self.device_ids[:len(inputs)]))

        if len(self.device_ids) == 1:
            return self.module(*inputs[0], **kwargs[0])
        if self.gpu0_bsz == 0:
            replicas = self.replicate(self.module, self.device_ids)
        else:
            replicas = self.replicate(self.module, self.device_ids[:len(inputs)])

        # replicas = self.replicate(self.module, device_ids[:len(inputs)])
        if self.gpu0_bsz == 0:
            replicas = replicas[1:]

        print('replicas:', str(len(replicas)))

        outputs = self.parallel_apply(replicas, device_ids, inputs, kwargs)
        return self.gather(outputs, self.output_device)

    def parallel_apply(self, replicas, device_ids, inputs, kwargs):
        return parallel_apply(replicas, inputs, kwargs, device_ids[:len(inputs)])

    def scatter(self, inputs, kwargs, device_ids):
        bsz = inputs[0].size(self.dim)
        num_dev = len(self.device_ids)
        gpu0_bsz = self.gpu0_bsz
        bsz_unit = (bsz - gpu0_bsz) // (num_dev - 1)
        if gpu0_bsz < bsz_unit:
            chunk_sizes = [gpu0_bsz] + [bsz_unit] * (num_dev - 1)
            delta = bsz - sum(chunk_sizes)
            for i in range(delta):
                chunk_sizes[i + 1] += 1
            if gpu0_bsz == 0:
                chunk_sizes = chunk_sizes[1:]
        else:
            return super().scatter(inputs, kwargs, device_ids)

        print('bsz: ', bsz)
        print('num_dev: ', num_dev)
        print('gpu0_bsz: ', gpu0_bsz)
        print('bsz_unit: ', bsz_unit)
        print('chunk_sizes: ', chunk_sizes)
        return scatter_kwargs(inputs, kwargs, device_ids, chunk_sizes, dim=self.dim)