def main(_A: argparse.Namespace):
if _A.num_gpus_per_machine == 0:
# Set device as CPU if num_gpus_per_machine = 0.
device: Any = torch.device("cpu")
else:
# Get the current device as set for current distributed process.
# Check `launch` function in `virtex.utils.distributed` module.
device = torch.cuda.current_device()
# Create a config object (this will be immutable) and perform common setup
# such as logging and setting up serialization directory.
_C = Config(_A.config, _A.config_override)
common_setup(_C, _A)
# -------------------------------------------------------------------------
# INSTANTIATE DATALOADER, MODEL, OPTIMIZER, SCHEDULER
# -------------------------------------------------------------------------
train_dataset = PretrainingDatasetFactory.from_config(_C, split="train")
val_dataset = PretrainingDatasetFactory.from_config(_C,
split="val",
all_captions=True)
train_dataset_no_image = PretrainingDatasetFactory.from_config(
_C, split="train", all_captions=True, include_image=False)
val_dataset_no_image = PretrainingDatasetFactory.from_config(
_C, split="val", all_captions=True, include_image=False)
# Make `DistributedSampler`s to shard datasets across GPU processes.
# Skip this if training on CPUs.
train_sampler = (
DistributedSampler(train_dataset, shuffle=True) # type: ignore
if _A.num_gpus_per_machine > 0 else None)
val_sampler = (
DistributedSampler(val_dataset, shuffle=False) # type: ignore
if _A.num_gpus_per_machine > 0 else None)
train_dataloader = DataLoader(
train_dataset,
batch_size=_C.OPTIM.BATCH_SIZE // dist.get_world_size(),
sampler=train_sampler,
shuffle=train_sampler is None,
num_workers=_A.cpu_workers,
pin_memory=True,
drop_last=True,
collate_fn=train_dataset.collate_fn,
)
val_dataloader = DataLoader(
val_dataset,
batch_size=_C.OPTIM.BATCH_SIZE // dist.get_world_size(),
sampler=val_sampler,
shuffle=False,
num_workers=_A.cpu_workers,
pin_memory=True,
drop_last=False,
collate_fn=val_dataset.collate_fn,
)
train_dataloader_no_image = DataLoader(
train_dataset_no_image,
batch_size=_C.OPTIM.BATCH_SIZE // dist.get_world_size(),
shuffle=False,
drop_last=False,
collate_fn=val_dataset.collate_fn,
)
evaluator = CiderEvaluator(train_dataloader_no_image, prefix='train')
val_dataloader_no_image = DataLoader(
val_dataset_no_image,
batch_size=_C.OPTIM.BATCH_SIZE // dist.get_world_size(),
shuffle=False,
drop_last=False,
collate_fn=val_dataset.collate_fn,
)
evaluator_val = CiderEvaluator(val_dataloader_no_image, prefix='val')
# Load supervised trained model
model = PretrainingModelFactory.from_config(_C).to(device)
CheckpointManager(model=model).load(_A.start_checkpoint)
optimizer = OptimizerFactory.from_config(_C, model.named_parameters())
scheduler = LRSchedulerFactory.from_config(_C, optimizer)
if dist.is_master_process():
print(
'total parameters:',
sum([
np.prod(p.shape) for p in model.parameters() if p.requires_grad
]))
print(
f'train data: {len(train_dataloader)}, val data: {len(val_dataloader)}'
)
tokenizer = train_dataset.tokenizer
# -------------------------------------------------------------------------
# BEFORE TRAINING STARTS
# -------------------------------------------------------------------------
# Create a gradient scaler for automatic mixed precision.
scaler = amp.GradScaler(enabled=_C.AMP)
# Load checkpoint to resume training if specified.
if _A.resume_from is not None:
start_iteration = CheckpointManager(
model=model,
optimizer=optimizer,
scheduler=scheduler,
scaler=scaler,
).load(_A.resume_from)
else:
start_iteration = 0
# Create an iterator from dataloader to sample batches perpetually.
train_dataloader_iter = cycle(train_dataloader, device, start_iteration)
# Wrap model in DDP if using more than one processes.
if dist.get_world_size() > 1:
dist.synchronize()
model = dist.DistributedDataParallel(model,
device_ids=[device],
find_unused_parameters=False)
# Keep track of time per iteration and ETA.
timer = Timer(start_from=start_iteration + 1,
total_iterations=_C.OPTIM.NUM_ITERATIONS)
# Create tensorboard writer and checkpoint manager (only in master process).
if dist.is_master_process():
tensorboard_writer = SummaryWriter(log_dir=_A.serialization_dir)
tensorboard_writer.add_text("config", f"```\n{_C}\n```")
checkpoint_manager = CheckpointManager(
_A.serialization_dir,
model=model,
optimizer=optimizer,
scheduler=scheduler,
scaler=scaler,
)
# -------------------------------------------------------------------------
# TRAINING LOOP
# -------------------------------------------------------------------------
for iteration in range(start_iteration + 1, _C.OPTIM.NUM_ITERATIONS + 1):
timer.tic()
optimizer.zero_grad()
batch = next(train_dataloader_iter)
with amp.autocast(enabled=_C.AMP):
model.sample_on()
model.eval()
with torch.no_grad():
greedy_dec = model({"image": batch["image"]},
sample_mode="greedy")['predictions']
out = model({"image": batch["image"]},
sample_mode="sample",
n_samples_per_image=5)
sample_dec, caption_lengths = out['predictions'], out[
'caption_lengths']
model.train()
model.sample_off()
sample_log_probs = -model(
{
"image": batch["image"],
"caption_tokens": sample_dec,
"caption_lengths": caption_lengths
},
loss_reduction='none')['loss']
image_ids = batch['image_id'].tolist()
reward = compute_scts_reward(image_ids, greedy_dec[:, 1:],
sample_dec[:,
1:], tokenizer, evaluator)
reward = torch.from_numpy(reward).to(device)
mask = sample_dec[:, 1:] != tokenizer.pad_id
loss = -sample_log_probs * reward * mask
loss = loss.sum() / mask.sum()
scaler.scale(loss).backward()
# First clip norm of gradients, and then perform optimizer step.
scaler.unscale_(optimizer)
torch.nn.utils.clip_grad_norm_(model.parameters(),
_C.OPTIM.CLIP_GRAD_NORM)
scaler.step(optimizer)
scaler.update()
scheduler.step()
timer.toc()
# ---------------------------------------------------------------------
# LOGGING
# ---------------------------------------------------------------------
if iteration % _A.log_every == 0:
logger.info(
f"{timer.stats} [Reward {-loss:.3f}] [GPU {dist.gpu_mem_usage()} MB]"
)
if dist.is_master_process():
tensorboard_writer.add_scalars(
"learning_rate",
{
"visual": optimizer.param_groups[0]["lr"],
"common": optimizer.param_groups[-1]["lr"],
},
iteration,
)
# ---------------------------------------------------------------------
# VALIDATION
# ---------------------------------------------------------------------
if iteration % _A.checkpoint_every == 0:
if dist.is_master_process():
checkpoint_manager.step(iteration)
# All processes will wait till master process is done serializing.
dist.synchronize()
torch.set_grad_enabled(False)
model.eval()
predictions: List[Dict[str, Any]] = []
if dist.is_master_process():
pbar = tqdm(total=len(val_dataloader))
for val_iteration, val_batch in enumerate(val_dataloader, start=1):
val_batch = {
'image_id': val_batch['image_id'].to(device),
'image': val_batch['image'].to(device)
}
output_dict = model(val_batch)
for image_id, caption in zip(val_batch['image_id'],
output_dict['predictions'][:,
1:]):
predictions.append({
'image_id':
image_id.item(),
'caption':
tokenizer.decode(caption.tolist())
})
if dist.is_master_process():
pbar.update(1)
if dist.is_master_process():
pbar.close()
metrics = evaluator_val.evaluate(predictions)
metrics = {
k: torch.tensor(v, dtype=torch.float, device=device)
for k, v in metrics.items()
}
dist.average_across_processes(metrics)
metrics = {k: v.item() for k, v in metrics.items()}
torch.set_grad_enabled(True)
model.train()
if dist.is_master_process():
logger.info(f"Iteration: {iteration} | Metrics: {metrics}")
tensorboard_writer.add_scalars("val", metrics, iteration)
if iteration % _A.checkpoint_every == 0:
torch.set_grad_enabled(False)
model.eval()
batch = next(iter(val_dataloader))
batch = {"image": batch["image"][:8].to(device)}
predictions = model(batch)["predictions"].cpu()
captions = []
for i in range(predictions.shape[0]):
caption = tokenizer.decode(predictions[i].tolist())
captions.append(caption)
mean = torch.tensor(IMAGENET_COLOR_MEAN,
dtype=torch.float).view(1, 3, 1, 1)
std = torch.tensor(IMAGENET_COLOR_STD,
dtype=torch.float).view(1, 3, 1, 1)
image = batch["image"].cpu() * std + mean
if dist.is_master_process():
logger.info(f"Sample Generated Captions:")
log_text = ""
for i, caption in enumerate(captions):
logger.info(f"\t{caption}")
log_text += f"{caption}\n\n"
tensorboard_writer.add_text(f"samples_itr{iteration}",
log_text, iteration)
tensorboard_writer.add_images(f"samples_itr{iteration}", image,
iteration)
torch.set_grad_enabled(True)
model.train()
def main(_A: argparse.Namespace):
if _A.num_gpus_per_machine == 0:
# Set device as CPU if num_gpus_per_machine = 0.
device: Any = torch.device("cpu")
else:
# Get the current device as set for current distributed process.
# Check `launch` function in `virtex.utils.distributed` module.
device = torch.cuda.current_device()
# Create a config object (this will be immutable) and perform common setup
# such as logging and setting up serialization directory.
_C = Config(_A.config, _A.config_override)
common_setup(_C, _A)
# -------------------------------------------------------------------------
# INSTANTIATE DATALOADER, MODEL, OPTIMIZER, SCHEDULER
# -------------------------------------------------------------------------
train_dataset = PretrainingDatasetFactory.from_config(_C, split="train")
val_dataset = PretrainingDatasetFactory.from_config(_C, split="val")
# Make `DistributedSampler`s to shard datasets across GPU processes.
# Skip this if training on CPUs.
train_sampler = (
DistributedSampler(train_dataset, shuffle=True) # type: ignore
if _A.num_gpus_per_machine > 0 else None)
val_sampler = (
DistributedSampler(val_dataset, shuffle=False) # type: ignore
if _A.num_gpus_per_machine > 0 else None)
train_dataloader = DataLoader(
train_dataset,
batch_size=_C.OPTIM.BATCH_SIZE // dist.get_world_size(),
sampler=train_sampler,
shuffle=train_sampler is None,
num_workers=_A.cpu_workers,
pin_memory=True,
drop_last=True,
collate_fn=train_dataset.collate_fn,
)
val_dataloader = DataLoader(
val_dataset,
batch_size=_C.OPTIM.BATCH_SIZE // dist.get_world_size(),
sampler=val_sampler,
shuffle=False,
num_workers=_A.cpu_workers,
pin_memory=True,
drop_last=False,
collate_fn=val_dataset.collate_fn,
)
model = PretrainingModelFactory.from_config(_C).to(device)
optimizer = OptimizerFactory.from_config(_C, model.named_parameters())
scheduler = LRSchedulerFactory.from_config(_C, optimizer)
# -------------------------------------------------------------------------
# BEFORE TRAINING STARTS
# -------------------------------------------------------------------------
# Create a gradient scaler for automatic mixed precision.
scaler = amp.GradScaler(enabled=_C.AMP)
# Load checkpoint to resume training if specified.
if _A.resume_from is not None:
start_iteration = CheckpointManager(
model=model,
optimizer=optimizer,
scheduler=scheduler,
scaler=scaler,
).load(_A.resume_from)
else:
start_iteration = 0
# Create an iterator from dataloader to sample batches perpetually.
train_dataloader_iter = cycle(train_dataloader, device, start_iteration)
# Wrap model in DDP if using more than one processes.
if dist.get_world_size() > 1:
dist.synchronize()
model = nn.parallel.DistributedDataParallel(
model, device_ids=[device], find_unused_parameters=True)
# Keep track of time per iteration and ETA.
timer = Timer(start_from=start_iteration + 1,
total_iterations=_C.OPTIM.NUM_ITERATIONS)
# Create tensorboard writer and checkpoint manager (only in master process).
if dist.is_master_process():
tensorboard_writer = SummaryWriter(log_dir=_A.serialization_dir)
tensorboard_writer.add_text("config", f"```\n{_C}\n```")
checkpoint_manager = CheckpointManager(
_A.serialization_dir,
model=model,
optimizer=optimizer,
scheduler=scheduler,
scaler=scaler,
)
# -------------------------------------------------------------------------
# TRAINING LOOP
# -------------------------------------------------------------------------
for iteration in range(start_iteration + 1, _C.OPTIM.NUM_ITERATIONS + 1):
timer.tic()
optimizer.zero_grad()
batch = next(train_dataloader_iter)
with amp.autocast(enabled=_C.AMP):
output_dict = model(batch)
loss = output_dict["loss"]
scaler.scale(loss).backward()
# First clip norm of gradients, and then perform optimizer step.
scaler.unscale_(optimizer)
torch.nn.utils.clip_grad_norm_(model.parameters(),
_C.OPTIM.CLIP_GRAD_NORM)
scaler.step(optimizer)
scaler.update()
scheduler.step()
timer.toc()
# ---------------------------------------------------------------------
# LOGGING
# ---------------------------------------------------------------------
if iteration % _A.log_every == 0:
logger.info(
f"{timer.stats} [Loss {loss:.3f}] [GPU {dist.gpu_mem_usage()} MB]"
)
if dist.is_master_process():
tensorboard_writer.add_scalars(
"learning_rate",
{
"visual": optimizer.param_groups[0]["lr"],
"common": optimizer.param_groups[-1]["lr"],
},
iteration,
)
tensorboard_writer.add_scalars("train",
output_dict["loss_components"],
iteration)
# ---------------------------------------------------------------------
# VALIDATION
# ---------------------------------------------------------------------
if iteration % _A.checkpoint_every == 0:
if dist.is_master_process():
checkpoint_manager.step(iteration)
# All processes will wait till master process is done serializing.
dist.synchronize()
torch.set_grad_enabled(False)
model.eval()
# Accumulate different val loss components according to the type of
# pretraining model.
val_loss_counter: Counter = Counter()
for val_iteration, val_batch in enumerate(val_dataloader, start=1):
for key in val_batch:
val_batch[key] = val_batch[key].to(device)
output_dict = model(val_batch)
val_loss_counter.update(output_dict["loss_components"])
# Divide each loss component by number of val batches per GPU.
val_loss_dict = {
k: v / val_iteration
for k, v in dict(val_loss_counter).items()
}
dist.average_across_processes(val_loss_dict)
torch.set_grad_enabled(True)
model.train()
logger.info(f"Iteration: {iteration} [Val loss: {val_loss_dict}]")
if dist.is_master_process():
tensorboard_writer.add_scalars("val", val_loss_dict, iteration)
def main(_A: argparse.Namespace):
if _A.num_gpus_per_machine == 0:
# Set device as CPU if num_gpus_per_machine = 0.
device = torch.device("cpu")
else:
# Get the current device as set for current distributed process.
# Check `launch` function in `virtex.utils.distributed` module.
device = torch.cuda.current_device()
# Create a downstream config object (this will be immutable) and perform
# common setup such as logging and setting up serialization directory.
_DOWNC = Config(_A.down_config, _A.down_config_override)
common_setup(_DOWNC, _A, job_type="downstream")
# Create a (pretraining) config object and backup in serializaion directory.
_C = Config(_A.config, _A.config_override)
_C.dump(os.path.join(_A.serialization_dir, "pretrain_config.yaml"))
# Get dataset name for tensorboard logging.
DATASET = _DOWNC.DATA.ROOT.split("/")[-1]
# Set number of output classes according to dataset:
NUM_CLASSES_MAPPING = {"imagenet": 1000, "inaturalist": 8142}
NUM_CLASSES = NUM_CLASSES_MAPPING[DATASET]
# -------------------------------------------------------------------------
# INSTANTIATE DATALOADER, MODEL, OPTIMIZER, SCHEDULER
# -------------------------------------------------------------------------
train_dataset = DownstreamDatasetFactory.from_config(_DOWNC, split="train")
train_dataloader = DataLoader(
train_dataset,
batch_size=_DOWNC.OPTIM.BATCH_SIZE // dist.get_world_size(),
num_workers=_A.cpu_workers,
sampler=DistributedSampler(
train_dataset,
num_replicas=dist.get_world_size(),
rank=dist.get_rank(),
shuffle=True,
),
drop_last=False,
pin_memory=True,
collate_fn=train_dataset.collate_fn,
)
val_dataset = DownstreamDatasetFactory.from_config(_DOWNC, split="val")
val_dataloader = DataLoader(
val_dataset,
batch_size=_DOWNC.OPTIM.BATCH_SIZE // dist.get_world_size(),
num_workers=_A.cpu_workers,
sampler=DistributedSampler(
val_dataset,
num_replicas=dist.get_world_size(),
rank=dist.get_rank(),
shuffle=False,
),
pin_memory=True,
drop_last=False,
collate_fn=val_dataset.collate_fn,
)
# Initialize model using pretraining config.
pretrained_model = PretrainingModelFactory.from_config(_C)
# Load weights according to the init method, do nothing for `random`, and
# `imagenet` is already taken care of.
if _A.weight_init == "virtex":
CheckpointManager(model=pretrained_model).load(_A.checkpoint_path)
elif _A.weight_init == "torchvision":
# Keep strict=False because this state dict may have weights for
# last fc layer.
pretrained_model.visual.cnn.load_state_dict(
torch.load(_A.checkpoint_path, map_location="cpu")["state_dict"],
strict=False,
)
# Pull out the CNN (torchvision-like) from our pretrained model and add
# back the FC layer - this is exists in torchvision models, and is set to
# `nn.Identity()` during pretraining.
model = pretrained_model.visual.cnn # type: ignore
model.fc = nn.Linear(_DOWNC.MODEL.VISUAL.FEATURE_SIZE,
NUM_CLASSES).to(device)
model = model.to(device)
# Re-initialize the FC layer.
torch.nn.init.normal_(model.fc.weight.data, mean=0.0, std=0.01)
torch.nn.init.constant_(model.fc.bias.data, 0.0)
# Freeze all layers except FC as per config param.
if _DOWNC.MODEL.VISUAL.FROZEN:
for name, param in model.named_parameters():
if "fc" not in name:
param.requires_grad = False
# Cross entropy loss and accuracy meter.
criterion = nn.CrossEntropyLoss()
top1 = TopkAccuracy(top_k=1)
optimizer = OptimizerFactory.from_config(_DOWNC, model.named_parameters())
scheduler = LRSchedulerFactory.from_config(_DOWNC, optimizer)
del pretrained_model
# -------------------------------------------------------------------------
# BEFORE TRAINING STARTS
# -------------------------------------------------------------------------
# Create an iterator from dataloader to sample batches perpetually.
train_dataloader_iter = cycle(train_dataloader, device)
# Wrap model and optimizer using NVIDIA Apex for mixed precision training.
# NOTE: Always do this before wrapping model with DistributedDataParallel.
if _DOWNC.FP16_OPT > 0:
from apex import amp
model, optimizer = amp.initialize(model,
optimizer,
opt_level=f"O{_DOWNC.FP16_OPT}")
if dist.get_world_size() > 1:
dist.synchronize()
model = nn.parallel.DistributedDataParallel(
model, device_ids=[device], find_unused_parameters=True)
if dist.is_master_process():
checkpoint_manager = CheckpointManager(
_A.serialization_dir,
model=model,
optimizer=optimizer,
scheduler=scheduler,
)
tensorboard_writer = SummaryWriter(log_dir=_A.serialization_dir)
# Keep track of time per iteration and ETA.
timer = Timer(start_from=1, total_iterations=_DOWNC.OPTIM.NUM_ITERATIONS)
# -------------------------------------------------------------------------
# TRAINING LOOP
# -------------------------------------------------------------------------
for iteration in range(1, _DOWNC.OPTIM.NUM_ITERATIONS + 1):
timer.tic()
optimizer.zero_grad()
batch = next(train_dataloader_iter)
logits = model(batch["image"])
loss = criterion(logits, batch["label"])
# Perform dynamic scaling of loss to adjust for mixed precision.
if _DOWNC.FP16_OPT > 0:
with amp.scale_loss(loss, optimizer) as scaled_loss:
scaled_loss.backward()
else:
loss.backward()
optimizer.step()
scheduler.step(iteration)
timer.toc()
if iteration % _A.log_every == 0 and dist.is_master_process():
logger.info(
f"{timer.stats} | Loss: {loss:.3f} | GPU: {dist.gpu_mem_usage()} MB"
)
tensorboard_writer.add_scalar(f"{DATASET}/train_loss", loss,
iteration)
tensorboard_writer.add_scalar(
f"{DATASET}/learning_rate",
optimizer.param_groups[0]["lr"],
iteration,
)
# ---------------------------------------------------------------------
# VALIDATION
# ---------------------------------------------------------------------
if iteration % _A.checkpoint_every == 0:
torch.set_grad_enabled(False)
model.eval()
total_val_loss = torch.tensor(0.0).to(device)
for val_iteration, batch in enumerate(val_dataloader, start=1):
for key in batch:
batch[key] = batch[key].to(device)
logits = model(batch["image"])
loss = criterion(logits, batch["label"])
top1(logits, batch["label"])
total_val_loss += loss
# Divide each loss component by number of val batches per GPU.
total_val_loss = total_val_loss / val_iteration
dist.average_across_processes(total_val_loss)
# Get accumulated Top-1 accuracy for logging across GPUs.
acc = top1.get_metric(reset=True)
dist.average_across_processes(acc)
torch.set_grad_enabled(True)
model.train()
# Save recent checkpoint and best checkpoint based on accuracy.
if dist.is_master_process():
checkpoint_manager.step(iteration)
if iteration % _A.checkpoint_every == 0 and dist.is_master_process():
logger.info(f"Iter: {iteration} | Top-1 accuracy: {acc})")
tensorboard_writer.add_scalar(f"{DATASET}/val_loss",
total_val_loss, iteration)
# This name scoping will result in Tensorboard displaying all metrics
# (VOC07, caption, etc.) together.
tensorboard_writer.add_scalars(f"metrics/{DATASET}", {"top1": acc},
iteration)
# All processes will wait till master process is done logging.
dist.synchronize()
def main(_A: argparse.Namespace):
apex = False
is_cpu = False
if _A.num_gpus_per_machine == 0:
# Set device as CPU if num_gpus_per_machine = 0.
device = torch.device("cpu")
is_cpu = True
else:
# Get the current device as set for current distributed process.
# Check `launch` function in `virtex.utils.distributed` module.
device = torch.cuda.current_device()
# Create a config object (this will be immutable) and perform common setup
# such as logging and setting up serialization directory.
_C = Config(_A.config, _A.config_override)
common_setup(_C, _A)
# -------------------------------------------------------------------------
# INSTANTIATE DATALOADER, MODEL, OPTIMIZER
# -------------------------------------------------------------------------
tokenizer = TokenizerFactory.from_config(_C)
train_dataset = PretrainingDatasetFactory.from_config(_C,
split="train",
csv=_A.train_csv)
val_dataset = PretrainingDatasetFactory.from_config(_C,
split="val",
csv=_A.val_csv)
train_dataloader = DataLoader(
train_dataset,
batch_size=_C.OPTIM.BATCH_SIZE // dist.get_world_size(),
#sampler= Sampler(train_dataset),
sampler=DistributedSampler(train_dataset, shuffle=True),
num_workers=_A.cpu_workers,
pin_memory=True,
drop_last=True,
collate_fn=train_dataset.collate_fn,
)
val_dataloader = DataLoader(
val_dataset,
batch_size=_C.OPTIM.BATCH_SIZE // dist.get_world_size(),
# sampler = Sampler(val_dataset),
sampler=DistributedSampler(val_dataset, shuffle=False),
num_workers=_A.cpu_workers,
pin_memory=True,
drop_last=False,
collate_fn=val_dataset.collate_fn,
)
model = PretrainingModelFactory.from_config(_C).to(device)
optimizer = OptimizerFactory.from_config(_C, model.named_parameters())
scheduler = LRSchedulerFactory.from_config(_C, optimizer)
# -------------------------------------------------------------------------
# BEFORE TRAINING STARTS
# -------------------------------------------------------------------------
# Load checkpoint to resume training if specified.
if _A.resume_from is not None:
start_iteration = CheckpointManager(model=model,
optimizer=optimizer,
scheduler=scheduler).load(
_A.resume_from)
else:
start_iteration = 0
# Keep track of time per iteration and ETA.
timer = Timer(
start_from=start_iteration + 1,
total_iterations=_C.OPTIM.NUM_ITERATIONS,
)
# Create an iterator from dataloader to sample batches perpetually.
train_dataloader_iter = cycle(train_dataloader, device, start_iteration)
if (not is_cpu):
# Wrap model and optimizer using NVIDIA Apex for mixed precision training.
# NOTE: Always do this before wrapping model with DistributedDataParallel.
if apex:
if _C.FP16_OPT > 0:
from apex import amp
model, optimizer = amp.initialize(model,
optimizer,
opt_level=f"O{_C.FP16_OPT}")
# Wrap model in DDP if using more than one processes.
if dist.get_world_size() > 1:
dist.synchronize()
model = nn.parallel.DistributedDataParallel(
model, device_ids=[device], find_unused_parameters=True)
# Create checkpoint manager and tensorboard writer (only in master process).
if dist.is_master_process():
checkpoint_manager = CheckpointManager(
_A.serialization_dir,
model=model,
optimizer=optimizer,
scheduler=scheduler,
)
tensorboard_writer = SummaryWriter(log_dir=_A.serialization_dir)
tensorboard_writer.add_text("config", f"```\n{_C}\n```")
# -------------------------------------------------------------------------
# TRAINING LOOP
# -------------------------------------------------------------------------
for iteration in range(start_iteration + 1, _C.OPTIM.NUM_ITERATIONS + 1):
timer.tic()
optimizer.zero_grad()
batch_loss = torch.tensor(0.0, device=device)
batch = next(train_dataloader_iter)
output_dict = model(batch)
loss = output_dict["loss"]
batch_loss += loss.item()
# Perform dynamic scaling of loss to adjust for mixed precision.
if apex and _C.FP16_OPT > 0:
with amp.scale_loss(loss, optimizer) as scaled_loss:
scaled_loss.backward()
else:
loss.backward()
# Clip norm of gradients before optimizer step.
torch.nn.utils.clip_grad_norm_(
amp.master_params(optimizer)
if apex and _C.FP16_OPT > 0 else model.parameters(),
_C.OPTIM.CLIP_GRAD_NORM,
)
optimizer.step()
scheduler.step(iteration)
timer.toc()
# ---------------------------------------------------------------------
# TENSORBOARD LOGGING
# ---------------------------------------------------------------------
if iteration % _A.log_every == 0 and dist.is_master_process():
logger.info(f"{timer.stats} | Loss: {batch_loss:.3f} | "
f"GPU mem: {dist.gpu_mem_usage()} MB")
tensorboard_writer.add_scalars(
"learning_rate",
{
"visual": optimizer.param_groups[0]["lr"],
"common": optimizer.param_groups[-1]["lr"],
},
iteration,
)
tensorboard_writer.add_scalars("train",
output_dict["loss_components"],
iteration)
# ---------------------------------------------------------------------
# VALIDATION
# ---------------------------------------------------------------------
if iteration % _A.checkpoint_every == 0:
if dist.is_master_process():
checkpoint_manager.step(iteration)
torch.set_grad_enabled(False)
model.eval()
# Accumulate different val loss components according to the type of
# pretraining model.
val_loss_counter: Counter = Counter()
for val_iteration, val_batch in enumerate(val_dataloader, start=1):
for key in val_batch:
val_batch[key] = val_batch[key].to(device)
output_dict = model(val_batch)
val_loss_counter.update(output_dict["loss_components"])
# Divide each loss component by number of val batches per GPU.
val_loss_dict = {
k: v / val_iteration
for k, v in dict(val_loss_counter).items()
}
dist.average_across_processes(val_loss_dict)
torch.set_grad_enabled(True)
model.train()
if iteration % _A.checkpoint_every == 0 and dist.is_master_process():
logger.info(f"Iter: {iteration} | Val loss: {val_loss_dict}")
tensorboard_writer.add_scalars("val", val_loss_dict, iteration)
# All processes will wait till master process is done logging.
dist.synchronize()