112 lines
3.6 KiB
Markdown
Executable File
112 lines
3.6 KiB
Markdown
Executable File
---
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title: "DCGAN Tutorial"
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excerpt: "Train your first GAN model with DeepSpeed!"
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tags: getting-started training
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---
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If you haven't already, we advise you to first read through the [Getting Started](/getting-started/) guide before stepping through this
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tutorial.
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In this tutorial, we will port the DCGAN model to DeepSpeed using custom (user-defined) optimizers and a multi-engine setup!
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## Running Original DCGAN
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Please go through the [original tutorial](https://pytorch.org/tutorials/beginner/dcgan_faces_tutorial.html) for the Celebrities dataset first using the [original code](https://github.com/pytorch/examples/blob/master/dcgan/main.py). Then run `bash gan_baseline_run.sh`.
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## Enabling DeepSpeed
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The codes may be obtained [here](https://github.com/deepspeedai/DeepSpeedExamples/tree/master/gan).
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### Argument Parsing
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The first step to apply DeepSpeed is adding configuration arguments to DCGAN model, using the `deepspeed.add_config_arguments()` function as below.
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```python
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import deepspeed
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def main():
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parser = get_argument_parser()
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parser = deepspeed.add_config_arguments(parser)
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args = parser.parse_args()
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train(args)
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```
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### Initialization
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We use `deepspeed.initialize` to create two model engines (one for the discriminator network and one for the generator network along with their respective optimizers) as follows:
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```python
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model_engineD, optimizerD, _, _ = deepspeed.initialize(args=args, model=netD, model_parameters=netD.parameters(), optimizer=optimizerD)
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model_engineG, optimizerG, _, _ = deepspeed.initialize(args=args, model=netG, model_parameters=netG.parameters(), optimizer=optimizerG)
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```
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Note that DeepSpeed automatically takes care of the distributed training aspect, so we set ngpu=0 to disable the default data parallel mode of pytorch.
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### Discriminator Training
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We modify the backward for discriminator as follows:
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```python
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model_engineD.backward(errD_real)
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model_engineD.backward(errD_fake)
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```
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which leads to the inclusion of the gradients due to both real and fake mini-batches in the optimizer update.
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### Generator Training
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We modify the backward for generator as follows:
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```python
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model_engineG.backward(errG)
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```
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**Note:** In the case where we use gradient accumulation, backward on the generator would result in accumulation of gradients on the discriminator, due to the tensor dependencies as a result of `errG` being computed from a forward pass through the discriminator; so please set `requires_grad=False` for the `netD` parameters before doing the generator backward.
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### Configuration
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The next step to use DeepSpeed is to create a configuration JSON file (gan_deepspeed_config.json). This file provides DeepSpeed specific parameters defined by the user, e.g., batch size, optimizer, scheduler and other parameters.
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```json
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{
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"train_batch_size" : 64,
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"optimizer": {
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"type": "Adam",
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"params": {
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"lr": 0.0002,
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"betas": [
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0.5,
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0.999
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],
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"eps": 1e-8
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}
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},
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"steps_per_print" : 10
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}
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```
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### Run DCGAN Model with DeepSpeed Enabled
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To start training the DCGAN model with DeepSpeed, we execute the following command which will use all detected GPUs by default.
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```bash
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deepspeed gan_deepspeed_train.py --dataset celeba --cuda --deepspeed_config gan_deepspeed_config.json --tensorboard_path './runs/deepspeed'
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```
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## Performance Comparison
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We use a total batch size of 64 and perform the training on 16 GPUs for 1 epoch on a DGX-2 node which leads to 3x speed-up. The summary of the results is given below:
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- Baseline total wall clock time for 1 epochs is 393 secs
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- Deepspeed total wall clock time for 1 epochs is 128 secs
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###
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