desco / maskrcnn_benchmark /engine /singlepath_trainer.py
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# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
import datetime
import logging
import time
import random
import torch
import torch.distributed as dist
from maskrcnn_benchmark.utils.comm import get_world_size, synchronize, broadcast_data
from maskrcnn_benchmark.utils.metric_logger import MetricLogger
from maskrcnn_benchmark.utils.ema import ModelEma
def reduce_loss_dict(loss_dict):
"""
Reduce the loss dictionary from all processes so that process with rank
0 has the averaged results. Returns a dict with the same fields as
loss_dict, after reduction.
"""
world_size = get_world_size()
if world_size < 2:
return loss_dict
with torch.no_grad():
loss_names = []
all_losses = []
for k in sorted(loss_dict.keys()):
loss_names.append(k)
all_losses.append(loss_dict[k])
all_losses = torch.stack(all_losses, dim=0)
dist.reduce(all_losses, dst=0)
if dist.get_rank() == 0:
# only main process gets accumulated, so only divide by
# world_size in this case
all_losses /= world_size
reduced_losses = {k: v for k, v in zip(loss_names, all_losses)}
return reduced_losses
def do_train(
cfg, model, data_loader, optimizer, scheduler, checkpointer, device, checkpoint_period, arguments, rngs=None
):
logger = logging.getLogger("maskrcnn_benchmark.trainer")
logger.info("Start training")
meters = MetricLogger(delimiter=" ")
max_iter = len(data_loader)
start_iter = arguments["iteration"]
model.train()
model_ema = None
if cfg.SOLVER.MODEL_EMA > 0:
model_ema = ModelEma(model, decay=cfg.SOLVER.MODEL_EMA)
start_training_time = time.time()
end = time.time()
for iteration, (images, targets, _) in enumerate(data_loader, start_iter):
if any(len(target) < 1 for target in targets):
logger.error(
"Iteration={iteration + 1} || Image Ids used for training {_} || targets Length={[len(target) for target in targets]}"
)
continue
data_time = time.time() - end
iteration = iteration + 1
arguments["iteration"] = iteration
images = images.to(device)
targets = [target.to(device) for target in targets]
# synchronize rngs
if rngs is None:
if isinstance(model, torch.nn.parallel.DistributedDataParallel):
mix_nums = model.module.mix_nums
else:
mix_nums = model.mix_nums
rngs = [random.randint(0, mix - 1) for mix in mix_nums]
rngs = broadcast_data(rngs)
for param in model.parameters():
param.requires_grad = False
loss_dict = model(images, targets, rngs)
losses = sum(loss for loss in loss_dict.values())
# reduce losses over all GPUs for logging purposes
loss_dict_reduced = reduce_loss_dict(loss_dict)
losses_reduced = sum(loss for loss in loss_dict_reduced.values())
meters.update(loss=losses_reduced, **loss_dict_reduced)
optimizer.zero_grad()
losses.backward()
optimizer.step()
scheduler.step()
if model_ema is not None:
model_ema.update(model)
arguments["model_ema"] = model_ema.state_dict()
batch_time = time.time() - end
end = time.time()
meters.update(time=batch_time, data=data_time)
eta_seconds = meters.time.global_avg * (max_iter - iteration)
eta_string = str(datetime.timedelta(seconds=int(eta_seconds)))
if iteration % 20 == 0 or iteration == max_iter:
logger.info(
meters.delimiter.join(
[
"eta: {eta}",
"iter: {iter}",
"{meters}",
"lr: {lr:.6f}",
"max mem: {memory:.0f}",
]
).format(
eta=eta_string,
iter=iteration,
meters=str(meters),
lr=optimizer.param_groups[0]["lr"],
memory=torch.cuda.max_memory_allocated() / 1024.0 / 1024.0,
)
)
if iteration % checkpoint_period == 0:
checkpointer.save("model_{:07d}".format(iteration), **arguments)
if iteration == max_iter:
if model_ema is not None:
model.load_state_dict(model_ema.state_dict())
checkpointer.save("model_final", **arguments)
total_training_time = time.time() - start_training_time
total_time_str = str(datetime.timedelta(seconds=total_training_time))
logger.info("Total training time: {} ({:.4f} s / it)".format(total_time_str, total_training_time / (max_iter)))