File size: 12,510 Bytes
b6af722
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
# SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0
#
# 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 signal

import torch
import torch.distributed as dist
import torch.utils.data
from megatron.core import parallel_state

from cosmos_predict1.checkpointer.tp import Checkpointer as TensorParallelCheckpointer
from cosmos_predict1.utils import distributed, ema, log, misc
from cosmos_predict1.utils.checkpointer import Checkpointer
from cosmos_predict1.utils.fsdp_checkpointer import FSDPCheckpointer
from cosmos_predict1.utils.model import Model
from cosmos_predict1.utils.trainer import Trainer


class Trainer(Trainer):
    def __init__(self, config):
        super(Trainer, self).__init__(config)
        if config.trainer.distributed_parallelism == "ddp":
            if parallel_state.get_tensor_model_parallel_world_size() > 1:
                self.checkpointer = TensorParallelCheckpointer(config.checkpoint, config.job, callbacks=self.callbacks)
                log.critical("Using Tensor Parallelism Checkpointer")
            else:
                self.checkpointer = Checkpointer(config.checkpoint, config.job, callbacks=self.callbacks)

        elif config.trainer.distributed_parallelism == "fsdp":
            self.checkpointer = FSDPCheckpointer(config.checkpoint, config.job, callbacks=self.callbacks)
        else:
            raise ValueError(f"Unsupported distributed parallelism: {config.trainer.distributed_parallelism}")

    """
    Modify the original trainer to log average loss (averaging across all devices and gradient accumulation)
    """

    def train(
        self,
        model: Model,
        dataloader_train: torch.utils.data.DataLoader,
        dataloader_val: torch.utils.data.DataLoader,
    ) -> None:
        """The training function.

        Args:
            model (Model): The PyTorch model.
            dataloader_train (torch.utils.data.DataLoader): The training data loader.
            dataloader_val (torch.utils.data.DataLoader): The validation data loader.
        """
        # Leaving this for backward compability for now, but we can think about moving this to model.on_train_start for all models.
        model = model.to("cuda", memory_format=self.config.trainer.memory_format)  # type: ignore
        log.info(f"Model Architecture:\n {model}")
        model.on_train_start(self.config.trainer.memory_format)
        # Initialize the optimizer and scheduler.
        self.callbacks.on_optimizer_init_start()

        optimizer, scheduler = model.init_optimizer_scheduler(self.config.optimizer, self.config.scheduler)

        grad_scaler = torch.amp.GradScaler("cuda", **self.config.trainer.grad_scaler_args)
        self.callbacks.on_optimizer_init_end()
        # Load the model checkpoint and get the starting iteration number.
        iteration = self.checkpointer.load(model, optimizer, scheduler, grad_scaler)
        # Set the scheduler to the current iteration.
        scheduler.last_epoch = iteration
        scheduler._step_count = iteration + 1

        grad_accum_iter = 0
        log.critical(f"Distributed parallelism mode: {self.config.trainer.distributed_parallelism}")
        if self.config.trainer.distributed_parallelism == "ddp":
            # Create a DDP model wrapper.
            model_ddp = distributed.parallel_model_wrapper(self.config.trainer.ddp, model)
        elif self.config.trainer.distributed_parallelism == "fsdp":
            model_ddp = model
        else:
            raise ValueError(f"Unknown distributed parallelism mode: {self.config.trainer.distributed_parallelism}")
        log.info("Starting training...")
        self.callbacks.on_train_start(model, iteration=iteration)
        # Initial validation.
        if self.config.trainer.run_validation and iteration == 0:
            self.validate(model, dataloader_val, iteration=iteration)
        _end_training = False
        self.callbacks.on_before_dataloading(iteration)
        accumulated_loss = 0.0

        while True:
            dataloader_train_iter = iter(dataloader_train)
            while True:
                self.callbacks.on_before_dataloading(iteration)
                try:
                    data_batch = next(dataloader_train_iter)
                except StopIteration:
                    break
                self.callbacks.on_after_dataloading(iteration)
                # If max_iter is reached, exit the training loop.
                if iteration >= self.config.trainer.max_iter:
                    _end_training = True
                    break
                # Move all tensors in the data batch to GPU device.

                data_batch = misc.to(data_batch, device="cuda")
                # The actual training step.
                self.callbacks.on_training_step_start(model, data_batch, iteration=iteration)
                model_ddp.train()
                output_batch, loss, grad_accum_iter = self.training_step(
                    model_ddp,
                    optimizer,
                    scheduler,
                    grad_scaler,
                    data_batch,
                    iteration=iteration,
                    grad_accum_iter=grad_accum_iter,
                )

                # Accumulate loss
                accumulated_loss += loss.detach()

                # If the gradients are still being accumulated, continue to load the next training batch.
                if grad_accum_iter != 0:
                    if self.enable_one_logger:
                        # Callback for skipped OneLoggerCallback.on_training_step_end()
                        self.one_logger.on_train_batch_end(set_barrier=False)
                    continue
                # Do the following when an actual optimizer (update) step has been made.
                iteration += 1

                # Average loss over accumulation steps
                grad_accum_avg_loss = accumulated_loss / self.config.trainer.grad_accum_iter
                # Average loss across all devices
                device_avg_loss = grad_accum_avg_loss.clone()
                dist.all_reduce(device_avg_loss, op=dist.ReduceOp.SUM)
                device_avg_loss /= dist.get_world_size()
                # Reset accumulation variables
                accumulated_loss = 0.0

                self.callbacks.on_training_step_end(
                    model, data_batch, output_batch, device_avg_loss, iteration=iteration
                )

                # self.callbacks.on_training_step_end(model, data_batch, output_batch, loss, iteration=iteration)

                # Validation.
                if self.config.trainer.run_validation and iteration % self.config.trainer.validation_iter == 0:
                    self.validate(model, dataloader_val, iteration=iteration)
                # Save checkpoint.
                if iteration % self.config.checkpoint.save_iter == 0:
                    self.checkpointer.save(model, optimizer, scheduler, grad_scaler, iteration=iteration)
                # This iteration is successful; reset the timeout signal.
                signal.alarm(self.config.trainer.timeout_period)
            if _end_training:
                break
        log.success("Done with training.")
        self.checkpointer.save(model, optimizer, scheduler, grad_scaler, iteration=iteration)
        self.callbacks.on_train_end(model, iteration=iteration)
        self.checkpointer.finalize()
        distributed.barrier()
        self.callbacks.on_app_end()

    def training_step(
        self,
        model_ddp: torch.nn.Module | distributed.DistributedDataParallel,
        optimizer: torch.optim.Optimizer,
        scheduler: torch.optim.lr_scheduler.LRScheduler,
        grad_scaler: torch.amp.GradScaler,
        data: dict[str, torch.Tensor],
        iteration: int = 0,
        grad_accum_iter: int = 0,
    ) -> tuple[dict[str, torch.Tensor], torch.Tensor, int]:
        """The training step.

        Args:
            model_ddp (torch.nn.Module | distributed.DistributedDataParallel): The model with a DDP wrapper or, the bare
              module, depending on whether distributed training is enabled or not.
            optimizer (torch.optim.Optimizer): The model optimizer.
            scheduler (torch.optim.lr_scheduler.LRScheduler): The optimization scheduler.
            grad_scaler (torch.amp.GradScaler): The gradient scaler (for mixed precision training).
            data (dict[str, torch.Tensor]): Data batch (dictionary of tensors).
            iteration (int): Current iteration number.
            grad_accum_iter (int): Number of gradient accumulation iterations.

        Returns:
            output (dict[str, torch.Tensor]): The model output from the training data batch (dictionary of tensors).
            loss (torch.Tensor): The total loss of the training data batch.
        """
        # Only let DDP sync gradient at the last iteration of the gradient accumulation window
        with distributed.ddp_sync_grad(model_ddp, grad_accum_iter == self.config.trainer.grad_accum_iter - 1):
            with self.training_timer("forward"):
                output_batch, loss = model_ddp.training_step(data, iteration)
            self.callbacks.on_before_backward(model_ddp, loss, iteration=iteration)
            with self.training_timer("backward"):
                loss_scaled = grad_scaler.scale(loss / self.config.trainer.grad_accum_iter)
                loss_scaled.backward()
                if self.config.trainer.distributed_parallelism == "ddp":
                    model_ddp.module.on_after_backward()
                else:
                    model_ddp.on_after_backward()
            self.callbacks.on_after_backward(model_ddp, iteration=iteration)
        grad_accum_iter += 1
        if grad_accum_iter == self.config.trainer.grad_accum_iter:
            with self.training_timer("optimizer_step"):
                self.callbacks.on_before_optimizer_step(
                    model_ddp, optimizer, scheduler, grad_scaler, iteration=iteration
                )
                grad_scaler.step(optimizer)
                grad_scaler.update()
                scheduler.step()
                self.callbacks.on_before_zero_grad(model_ddp, optimizer, scheduler, iteration=iteration)
                if self.config.trainer.distributed_parallelism == "ddp":
                    model_ddp.module.on_before_zero_grad(optimizer, scheduler, iteration=iteration)
                else:
                    model_ddp.on_before_zero_grad(optimizer, scheduler, iteration=iteration)
                optimizer.zero_grad(set_to_none=True)
            grad_accum_iter = 0
        return output_batch, loss, grad_accum_iter

    @torch.no_grad()
    def validate(self, model: Model, dataloader_val: torch.utils.data.DataLoader, iteration: int = 0) -> None:
        """Validate on the full validation dataset.

        Args:
            model (Model): The PyTorch model.
            dataloader_val (torch.utils.data.DataLoader): The validation data loader.
            iteration (int): Current iteration number.
        """
        self.callbacks.on_validation_start(model, dataloader_val, iteration=iteration)
        model.eval()
        # Evaluate on the full validation set.
        with ema.ema_scope(model, enabled=getattr(model.config.ema, "enabled", False)):
            for val_iter, data_batch in enumerate(dataloader_val):
                if self.config.trainer.max_val_iter is not None and val_iter >= self.config.trainer.max_val_iter:
                    break
                data_batch = misc.to(data_batch, device="cuda")
                self.callbacks.on_validation_step_start(model, data_batch, iteration=iteration)
                output_batch, loss = model.validation_step(data_batch, iteration)
                self.callbacks.on_validation_step_end(model, data_batch, output_batch, loss, iteration=iteration)
        self.callbacks.on_validation_end(model, iteration=iteration)