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# Copyright (c) Facebook, Inc. and its affiliates. | |
# | |
# This source code is licensed under the MIT license found in the | |
# LICENSE file in the root directory of this source tree. | |
""" | |
Train a network across multiple GPUs. | |
""" | |
import contextlib | |
import logging | |
import sys | |
import time | |
from argparse import Namespace | |
from itertools import chain | |
from typing import Any, Dict, List | |
import torch | |
from fairseq import models, optim, utils | |
from fairseq.dataclass.configs import FairseqConfig | |
from fairseq.dataclass.utils import convert_namespace_to_omegaconf | |
from fairseq.distributed import utils as distributed_utils | |
from fairseq.file_io import PathManager | |
from fairseq.logging import meters, metrics | |
from fairseq.models.ema import build_ema | |
from fairseq.nan_detector import NanDetector | |
from fairseq.optim import lr_scheduler | |
from omegaconf import OmegaConf | |
from utils import checkpoint_utils | |
logger = logging.getLogger(__name__) | |
class Trainer(object): | |
"""Main class for data parallel training. | |
This class supports synchronous distributed data parallel training, | |
where multiple workers each have a full model replica and gradients | |
are accumulated across workers before each update. We use | |
:class:`~torch.nn.parallel.DistributedDataParallel` to handle | |
communication of the gradients across workers. | |
""" | |
def __init__(self, cfg: FairseqConfig, task, model, criterion, quantizer=None): | |
if isinstance(cfg, Namespace): | |
logger.warning( | |
"argparse.Namespace configuration is deprecated! Automatically converting to OmegaConf" | |
) | |
cfg = convert_namespace_to_omegaconf(cfg) | |
self.cfg = cfg | |
self.task = task | |
# catalog shared parameters | |
shared_params = _catalog_shared_params(model) | |
self.tpu = cfg.common.tpu | |
self.cuda = torch.cuda.is_available() and not cfg.common.cpu and not self.tpu | |
if self.cuda: | |
self.device = torch.device("cuda") | |
elif self.tpu: | |
self.device = utils.get_tpu_device() | |
else: | |
self.device = torch.device("cpu") | |
if self.is_fsdp: | |
import fairscale | |
if self.cfg.common.bf16: | |
raise ValueError( | |
"FullyShardedDataParallel is not compatible with --bf16 or " | |
"--memory-efficient-bf16" | |
) | |
if self.cfg.distributed_training.zero_sharding != "none": | |
raise ValueError( | |
"FullyShardedDataParallel is not compatible with --zero-sharding " | |
"option (it's already built in)" | |
) | |
if max(self.cfg.optimization.update_freq) > 1 and fairscale.__version__ < "0.4.0": | |
raise RuntimeError( | |
"Please update to fairscale 0.4.0 or newer when combining " | |
"--update-freq with FullyShardedDataParallel" | |
) | |
else: | |
if ( | |
hasattr(self.cfg.distributed_training, "cpu_offload") | |
and self.cfg.distributed_training.cpu_offload | |
): | |
raise ValueError("--cpu-offload requires --ddp-backend=fully_sharded") | |
# copy model and criterion to current device/dtype | |
self._criterion = criterion | |
self._model = model | |
if not self.is_fsdp: | |
if cfg.common.fp16: | |
assert not cfg.common.amp, "Cannot use fp16 and AMP together" | |
self._criterion = self._criterion.half() | |
self._model = self._model.half() | |
elif cfg.common.bf16: | |
self._criterion = self._criterion.to(dtype=torch.bfloat16) | |
self._model = self._model.to(dtype=torch.bfloat16) | |
elif cfg.common.amp: | |
self._amp_retries = 0 | |
if ( | |
not cfg.distributed_training.pipeline_model_parallel | |
# the DistributedFairseqModel wrapper will handle moving to device, | |
# so only handle cases which don't use the wrapper | |
and not self.use_distributed_wrapper | |
): | |
self._criterion = self._criterion.to(device=self.device) | |
self._model = self._model.to(device=self.device) | |
self.pipeline_model_parallel = cfg.distributed_training.pipeline_model_parallel | |
self.last_device = None | |
if self.cuda and self.pipeline_model_parallel: | |
self.last_device = torch.device( | |
cfg.distributed_training.pipeline_devices[-1] | |
) | |
# check that shared parameters are preserved after device transfer | |
for shared_param in shared_params: | |
ref = _get_module_by_path(self._model, shared_param[0]) | |
for path in shared_param[1:]: | |
logger.info( | |
"detected shared parameter: {} <- {}".format(shared_param[0], path) | |
) | |
_set_module_by_path(self._model, path, ref) | |
self._dummy_batch = None # indicates we don't have a dummy batch at first | |
self._lr_scheduler = None | |
self._num_updates = 0 | |
self._num_xla_compiles = 0 # for TPUs | |
self._optim_history = None | |
self._optimizer = None | |
self._warn_once = set() | |
self._wrapped_criterion = None | |
self._wrapped_model = None | |
self._ema = None | |
# TODO(myleott): support tpu | |
if self.cuda and self.data_parallel_world_size > 1: | |
self._grad_norm_buf = torch.cuda.DoubleTensor(self.data_parallel_world_size) | |
else: | |
self._grad_norm_buf = None | |
self.quantizer = quantizer | |
if self.quantizer is not None: | |
self.quantizer.set_trainer(self) | |
# get detailed cuda environment | |
if self.cuda: | |
self.cuda_env = utils.CudaEnvironment() | |
if self.data_parallel_world_size > 1: | |
self.cuda_env_arr = distributed_utils.all_gather_list( | |
self.cuda_env, group=distributed_utils.get_global_group() | |
) | |
else: | |
self.cuda_env_arr = [self.cuda_env] | |
if self.data_parallel_rank == 0: | |
utils.CudaEnvironment.pretty_print_cuda_env_list(self.cuda_env_arr) | |
else: | |
self.cuda_env = None | |
self.cuda_env_arr = None | |
metrics.log_start_time("wall", priority=790, round=0) | |
self._start_time = time.time() | |
self._previous_training_time = 0 | |
self._cumulative_training_time = None | |
def reinitialize(self): | |
"""Reinitialize the Trainer, typically after model params change.""" | |
self._lr_scheduler = None | |
self._optimizer = None | |
self._wrapped_criterion = None | |
self._wrapped_model = None | |
def data_parallel_world_size(self): | |
if self.cfg.distributed_training.distributed_world_size == 1: | |
return 1 | |
return distributed_utils.get_data_parallel_world_size() | |
def data_parallel_process_group(self): | |
return distributed_utils.get_data_parallel_group() | |
def data_parallel_rank(self): | |
if self.cfg.distributed_training.distributed_world_size == 1: | |
return 0 | |
return distributed_utils.get_data_parallel_rank() | |
def is_data_parallel_master(self): | |
# NOTE: this returns true for all model parallel replicas with data | |
# parallel rank 0 | |
return self.data_parallel_rank == 0 | |
def use_distributed_wrapper(self) -> bool: | |
return ( | |
self.data_parallel_world_size > 1 and not self.cfg.optimization.use_bmuf | |
) or ( | |
self.is_fsdp and self.cfg.distributed_training.cpu_offload | |
) | |
def should_save_checkpoint_on_current_rank(self) -> bool: | |
"""Indicates whether to save checkpoints on the current DDP rank.""" | |
if ( | |
self.is_fsdp and self.cfg.distributed_training.use_sharded_state | |
) or getattr(self.cfg.model, "base_layers", 0) > 0: | |
return True | |
else: | |
return self.is_data_parallel_master | |
def always_call_state_dict_during_save_checkpoint(self) -> bool: | |
if self.is_fsdp and not self.cfg.distributed_training.use_sharded_state: | |
# FSDP calls communication collective when consolidating checkpoints | |
return True | |
else: | |
return False | |
def checkpoint_suffix(self) -> str: | |
"""Suffix to add to the checkpoint file name.""" | |
if self.is_fsdp and self.cfg.distributed_training.use_sharded_state: | |
return self.cfg.checkpoint.checkpoint_suffix + "-shard{0}".format( | |
self.data_parallel_rank | |
) | |
else: | |
return self.cfg.checkpoint.checkpoint_suffix or "" | |
def criterion(self): | |
if self._wrapped_criterion is None: | |
if utils.has_parameters(self._criterion) and self.use_distributed_wrapper: | |
self._wrapped_criterion = models.DistributedFairseqModel( | |
self.cfg.distributed_training, | |
self._criterion, | |
process_group=self.data_parallel_process_group, | |
device=self.device, | |
) | |
else: | |
self._wrapped_criterion = self._criterion | |
return self._wrapped_criterion | |
def model(self): | |
if self._wrapped_model is None: | |
if self.use_distributed_wrapper: | |
self._wrapped_model = models.DistributedFairseqModel( | |
self.cfg.distributed_training, | |
self._model, | |
process_group=self.data_parallel_process_group, | |
device=self.device, | |
) | |
else: | |
self._wrapped_model = self._model | |
return self._wrapped_model | |
def ema(self): | |
if self._ema is None: | |
self._build_ema() | |
return self._ema | |
def _build_ema(self): | |
if self.cfg.ema.store_ema: | |
self._ema = build_ema(self._model, self.cfg.ema, self.device) | |
logger.info( | |
"Exponential Moving Average Shadow Model is initialized." | |
) | |
def optimizer(self): | |
if self._optimizer is None: | |
self._build_optimizer() | |
return self._optimizer | |
def lr_scheduler(self): | |
if self._lr_scheduler is None: | |
self._build_optimizer() # this will initialize self._lr_scheduler | |
return self._lr_scheduler | |
def _build_optimizer(self): | |
params = list( | |
filter( | |
lambda p: p.requires_grad, | |
chain(self.model.parameters(), self.criterion.parameters()), | |
) | |
) | |
if self.is_fsdp and self.cfg.common.fp16: | |
# FullyShardedDataParallel always uses MemoryEfficientFP16 wrapper, | |
# mostly for the grad scaling. But if we don't have the | |
# --memory-efficient-fp16 flag set, then we're effectively doing | |
# regular --fp16 and can allow the use of optimizers that would | |
# otherwise be unsupported by MemoryEfficientFP16Optimizer. | |
allow_unsupported = not self.cfg.common.memory_efficient_fp16 | |
self._optimizer = optim.MemoryEfficientFP16Optimizer.build_optimizer( | |
self.cfg, params, allow_unsupported=allow_unsupported | |
) | |
elif self.cfg.common.fp16 or self.cfg.common.bf16 or self.cfg.common.amp: | |
if self.cuda and torch.cuda.get_device_capability(0)[0] < 7: | |
logger.info( | |
"NOTE: your device does NOT support faster training with --fp16 or --amp, " | |
"please switch to FP32 which is likely to be faster" | |
) | |
if ( | |
self.cfg.common.memory_efficient_fp16 | |
or self.cfg.common.memory_efficient_bf16 | |
): | |
self._optimizer = optim.MemoryEfficientFP16Optimizer.build_optimizer( | |
self.cfg, params | |
) | |
elif self.cfg.common.amp: | |
self._optimizer = optim.AMPOptimizer.build_optimizer(self.cfg, params) | |
else: | |
self._optimizer = optim.FP16Optimizer.build_optimizer(self.cfg, params) | |
else: | |
if self.cuda and torch.cuda.get_device_capability(0)[0] >= 7: | |
logger.info("NOTE: your device may support faster training with --fp16 or --amp") | |
self._optimizer = optim.build_optimizer(self.cfg.optimizer, params) | |
if self.is_fsdp: | |
assert ( | |
not self.cfg.optimization.use_bmuf | |
), "--ddp-backend=fully_sharded is not compatible with BMUF" | |
assert self._optimizer.supports_flat_params, ( | |
"--ddp-backend=fully_sharded is only compatible with pointwise " | |
"optimizers (e.g., Adam, AdamW, Adadelta, Adamax, SGD, etc.). " | |
"However, the sharding will result in slightly different results when " | |
"using non-pointwise optimizers (e.g., Adagrad, Adafactor, LAMB)" | |
) | |
if self.cfg.optimization.use_bmuf: | |
self._optimizer = optim.FairseqBMUF( | |
self.cfg.bmuf, | |
self._optimizer, | |
) | |
if self.cfg.distributed_training.zero_sharding == "os": | |
if ( | |
self.cfg.common.fp16 | |
and not self.cfg.common.memory_efficient_fp16 | |
and not self.cfg.common.memory_efficient_bf16 | |
) and not self.cfg.common.fp16_no_flatten_grads: | |
raise ValueError( | |
"ZeRO is incomptabile with fp16 and flattened grads. " | |
"Please use --fp16-no-flatten-grads" | |
) | |
else: | |
optim.shard_(self._optimizer, self.data_parallel_process_group) | |
# We should initialize the learning rate scheduler immediately after | |
# building the optimizer, so that the initial learning rate is set. | |
self._lr_scheduler = lr_scheduler.build_lr_scheduler( | |
self.cfg.lr_scheduler, | |
self.optimizer, | |
) | |
self._lr_scheduler.step_update(0) | |
def is_fsdp(self): | |
return self.cfg.distributed_training.ddp_backend == "fully_sharded" | |
def consolidate_optimizer(self): | |
"""For OSS, we need to consolidate the state dict.""" | |
if self.cfg.checkpoint.no_save_optimizer_state: | |
return | |
self._gathered_optim_state = None | |
if hasattr(self.optimizer.optimizer, "consolidate_state_dict"): | |
self.optimizer.optimizer.consolidate_state_dict() | |
elif self.is_fsdp and not self.model.use_sharded_state: | |
st = self.model.gather_full_optim_state_dict( | |
self.optimizer | |
) # only returns on rank 0 | |
self._gathered_optim_state = st | |
def state_dict(self): | |
state_dict = { | |
"args": None, # legacy | |
"cfg": ( | |
OmegaConf.to_container(self.cfg, resolve=True, enum_to_str=True) | |
if OmegaConf.is_config(self.cfg) | |
else self.cfg | |
), | |
"model": self.model.state_dict(), | |
"criterion": ( | |
self.criterion.state_dict() | |
if utils.has_parameters(self.criterion) | |
else None | |
), | |
"optimizer_history": (self._optim_history or []) | |
+ [ | |
{ | |
"criterion_name": self.get_criterion().__class__.__name__, | |
"optimizer_name": self.optimizer.__class__.__name__, | |
"lr_scheduler_state": self.lr_scheduler.state_dict(), | |
"num_updates": self.get_num_updates(), | |
} | |
], | |
"task_state": self.task.state_dict() if self.task is not None else {}, | |
"extra_state": { | |
"metrics": metrics.state_dict(), | |
"previous_training_time": self.cumulative_training_time(), | |
}, | |
} | |
if self.cfg.ema.store_ema: | |
# Save EMA model state as extra state | |
state_dict["extra_state"]["ema"] = self.ema.get_model().state_dict() | |
if self.cfg.ema.ema_fp32: | |
# Save EMA params in fp32 | |
state_dict["extra_state"]["ema_fp32_params"] = self.ema.fp32_params | |
if not self.cfg.checkpoint.no_save_optimizer_state: | |
if self._gathered_optim_state is not None: | |
state_dict["last_optimizer_state"] = self._gathered_optim_state | |
self._gathered_optim_state = None | |
else: | |
state_dict["last_optimizer_state"] = self.optimizer.state_dict() | |
if self.is_fsdp: | |
# save meta data for recombining checkpoint upon loading | |
state_dict["fsdp_metadata"] = self.model.local_metadata_dict() | |
return state_dict | |
def save_checkpoint(self, filename, extra_state): | |
"""Save all training state in a checkpoint file.""" | |
logger.info(f"Saving checkpoint to {filename}") | |
# call state_dict on all ranks in case it needs internal communication | |
state_dict = utils.move_to_cpu(self.state_dict()) | |
state_dict["extra_state"].update(extra_state) | |
if self.should_save_checkpoint_on_current_rank: | |
checkpoint_utils.torch_persistent_save( | |
state_dict, | |
filename, | |
async_write=self.cfg.checkpoint.write_checkpoints_asynchronously, | |
) | |
logger.info(f"Finished saving checkpoint to {filename}") | |
def load_checkpoint( | |
self, | |
filename, | |
reset_optimizer=False, | |
reset_lr_scheduler=False, | |
optimizer_overrides=None, | |
reset_meters=False, | |
): | |
""" | |
Load all training state from a checkpoint file. | |
rank = 0 will load the checkpoint, and then broadcast it to all | |
other ranks. | |
""" | |
extra_state, self._optim_history, last_optim_state = None, [], None | |
logger.info(f"Preparing to load checkpoint {filename}") | |
is_distributed = self.data_parallel_world_size > 1 | |
bexists = PathManager.isfile(filename) | |
if bexists: | |
load_on_all_ranks = ( | |
self.cfg.checkpoint.load_checkpoint_on_all_dp_ranks | |
# TPUs don't support broadcast yet, so load checkpoints | |
# on every worker for now | |
or self.tpu | |
# FSDP requires loading checkpoint shards on all ranks | |
or (self.is_fsdp and self.cfg.distributed_training.use_sharded_state) | |
or getattr(self.cfg.model, "base_layers", 0) > 0 | |
) | |
if load_on_all_ranks or self.data_parallel_rank == 0: | |
state = checkpoint_utils.load_checkpoint_to_cpu( | |
filename, load_on_all_ranks=load_on_all_ranks | |
) | |
last_optim_state = state.get("last_optimizer_state", None) | |
# If doing zero_sharding, do not broadcast global optimizer | |
# state. Later we will broadcast sharded states to each rank | |
# to avoid memory from exploding. | |
if ( | |
not load_on_all_ranks | |
and self.cfg.distributed_training.zero_sharding == "os" | |
and "last_optimizer_state" in state | |
and is_distributed | |
): | |
state["last_optimizer_state"] = "SHARDED" | |
else: | |
last_optim_state = None | |
state = None | |
if is_distributed and not load_on_all_ranks: | |
state = distributed_utils.broadcast_object( | |
state, | |
src_rank=0, | |
group=self.data_parallel_process_group, | |
dist_device=self.device, | |
) | |
if self.data_parallel_rank > 0: | |
last_optim_state = state.get("last_optimizer_state", None) | |
# load model parameters | |
try: | |
if self.cfg.checkpoint.use_ema_weights_to_init_param and "extra_state" in state and "ema" in state["extra_state"]: | |
logger.info("use_ema_weights_to_init_param = True, will use EMA weights in the ckpt to init the model param...") | |
ema_state_dict = state["extra_state"]["ema_fp32_params"] if "ema_fp32_params" in state["extra_state"] else state["extra_state"]["ema"] | |
self.model.load_state_dict( | |
ema_state_dict, strict=True, model_cfg=self.cfg.model | |
) | |
else: | |
self.model.load_state_dict( | |
state["model"], strict=True, model_cfg=self.cfg.model | |
) | |
# save memory for later steps | |
if not (self.cfg.ema.store_ema and (self.cfg.checkpoint.use_latest_weights_to_init_ema or not ("extra_state" in state and "ema" in state["extra_state"]))): | |
del state["model"] | |
if utils.has_parameters(self.get_criterion()): | |
self.get_criterion().load_state_dict( | |
state["criterion"], strict=True | |
) | |
del state["criterion"] | |
except Exception: | |
raise Exception( | |
"Cannot load model parameters from checkpoint {}; " | |
"please ensure that the architectures match.".format(filename) | |
) | |
extra_state = state["extra_state"] | |
self._optim_history = state["optimizer_history"] | |
if last_optim_state is not None and not reset_optimizer: | |
# rebuild optimizer after loading model, since params may have changed | |
self._build_optimizer() | |
# only reload optimizer and lr_scheduler if they match | |
last_optim = self._optim_history[-1] | |
assert ( | |
last_optim["criterion_name"] == self.get_criterion().__class__.__name__ | |
), f"Criterion does not match; please reset the optimizer (--reset-optimizer). {last_optim['criterion_name']} vs {self.get_criterion().__class__.__name__}" | |
assert ( | |
last_optim["optimizer_name"] == self.optimizer.__class__.__name__ | |
), f"Optimizer does not match; please reset the optimizer (--reset-optimizer). {last_optim['optimizer_name']} vs {self.optimizer.__class__.__name__}" | |
if not reset_lr_scheduler: | |
self.lr_scheduler.load_state_dict(last_optim["lr_scheduler_state"]) | |
if self.is_fsdp and not self.model.use_sharded_state: | |
# if use_sharded_state, the last_optim_state is already sharded, skip this | |
last_optim_state = self.model.get_shard_from_optim_state_dict( | |
last_optim_state | |
) | |
elif not load_on_all_ranks and is_distributed: | |
last_optim_state = self.optimizer.broadcast_global_state_dict( | |
last_optim_state | |
) | |
self.optimizer.load_state_dict(last_optim_state, optimizer_overrides) | |
self.set_num_updates(last_optim["num_updates"]) | |
if extra_state is not None: | |
itr_state = extra_state["train_iterator"] | |
epoch = itr_state["epoch"] | |
if "previous_training_time" in extra_state: | |
self._previous_training_time = extra_state["previous_training_time"] | |
self._start_time = time.time() | |
self.lr_step(epoch) | |
if ( | |
itr_state.get("version", 1) >= 2 | |
and itr_state["iterations_in_epoch"] == 0 | |
): | |
# reset meters at start of epoch | |
reset_meters = True | |
if "metrics" in extra_state and not reset_meters: | |
metrics.load_state_dict(extra_state["metrics"]) | |
# reset TimeMeters, since their start times don't make sense anymore | |
for meter in metrics.get_meters("default"): | |
if isinstance(meter, meters.TimeMeter): | |
meter.reset() | |
if self.cfg.ema.store_ema: | |
if self.cfg.checkpoint.use_latest_weights_to_init_ema or "ema" not in extra_state: | |
if "ema" not in extra_state: | |
logger.warn( | |
"EMA not found in checkpoint. But store_ema is True. " | |
"EMA is re-initialized from checkpoint." | |
) | |
elif self.cfg.checkpoint.use_latest_weights_to_init_ema: | |
logger.info( | |
"use_latest_weights_to_init_ema = True. EMA is re-initialized from checkpoint." | |
) | |
self.ema.restore(state["model"], build_fp32_params=self.cfg.ema.ema_fp32) | |
del state["model"] | |
else: | |
logger.info( | |
"Loading EMA from checkpoint" | |
) | |
self.ema.restore(extra_state["ema"], build_fp32_params=False) | |
if self.cfg.ema.ema_fp32: | |
if "ema_fp32_params" in extra_state: | |
logger.info( | |
"Loading EMA fp32 params from checkpoint" | |
) | |
self.ema.build_fp32_params(extra_state["ema_fp32_params"]) | |
else: | |
logger.info( | |
"Building EMA fp32 params from EMA model in checkpoint" | |
) | |
self.ema.build_fp32_params() | |
logger.info( | |
"Loaded checkpoint {} (epoch {} @ {} updates)".format( | |
filename, epoch, self.get_num_updates() | |
) | |
) | |
else: | |
logger.info("No existing checkpoint found {}".format(filename)) | |
return extra_state | |
def get_train_iterator( | |
self, | |
epoch, | |
combine=True, | |
load_dataset=True, | |
data_selector=None, | |
shard_batch_itr=True, | |
disable_iterator_cache=False, | |
): | |
"""Return an EpochBatchIterator over the training set for a given epoch.""" | |
if load_dataset: | |
logger.info("loading train data for epoch {}".format(epoch)) | |
self.task.load_dataset( | |
self.cfg.dataset.train_subset, | |
epoch=epoch, | |
combine=combine, | |
data_selector=data_selector, | |
tpu=self.tpu, | |
) | |
batch_iterator = self.task.get_batch_iterator( | |
dataset=self.task.dataset(self.cfg.dataset.train_subset), | |
max_tokens=self.cfg.dataset.max_tokens, | |
max_sentences=self.cfg.dataset.batch_size, | |
max_positions=utils.resolve_max_positions( | |
self.task.max_positions(), | |
self.model.max_positions(), | |
self.cfg.dataset.max_tokens, | |
), | |
ignore_invalid_inputs=True, | |
required_batch_size_multiple=self.cfg.dataset.required_batch_size_multiple, | |
seed=self.cfg.common.seed, | |
num_shards=self.data_parallel_world_size if shard_batch_itr else 1, | |
shard_id=self.data_parallel_rank if shard_batch_itr else 0, | |
num_workers=self.cfg.dataset.num_workers, | |
epoch=epoch, | |
data_buffer_size=self.cfg.dataset.data_buffer_size, | |
disable_iterator_cache=disable_iterator_cache, | |
) | |
self.reset_dummy_batch(batch_iterator.first_batch) | |
batch_iterator.dataset.dataset._seek() | |
return batch_iterator | |
def get_valid_iterator( | |
self, | |
subset, | |
disable_iterator_cache=False, | |
): | |
"""Return an EpochBatchIterator over given validation subset for a given epoch.""" | |
self.task.dataset(subset).dataset._seek() | |
batch_iterator = self.task.get_batch_iterator( | |
dataset=self.task.dataset(subset), | |
max_tokens=self.cfg.dataset.max_tokens_valid, | |
max_sentences=self.cfg.dataset.batch_size_valid, | |
max_positions=utils.resolve_max_positions( | |
self.task.max_positions(), | |
self.model.max_positions(), | |
), | |
ignore_invalid_inputs=self.cfg.dataset.skip_invalid_size_inputs_valid_test, | |
required_batch_size_multiple=self.cfg.dataset.required_batch_size_multiple, | |
seed=self.cfg.common.seed, | |
num_shards=self.data_parallel_world_size, | |
shard_id=self.data_parallel_rank, | |
num_workers=self.cfg.dataset.num_workers, | |
# always pass a fixed "epoch" to keep validation data consistent | |
# across training epochs | |
epoch=1, | |
data_buffer_size=self.cfg.dataset.data_buffer_size, | |
disable_iterator_cache=disable_iterator_cache, | |
) | |
self.reset_dummy_batch(batch_iterator.first_batch) | |
batch_iterator.dataset.dataset._seek() | |
return batch_iterator | |
def begin_epoch(self, epoch): | |
"""Called at the beginning of each epoch.""" | |
logger.info("begin training epoch {}".format(epoch)) | |
self.lr_step_begin_epoch(epoch) | |
if self.quantizer is not None: | |
self.quantizer.begin_epoch(epoch) | |
# task specific setup per epoch | |
self.task.begin_epoch(epoch, self.get_model()) | |
if self.tpu: | |
import torch_xla.core.xla_model as xm | |
xm.rendezvous("begin_epoch") # wait for all workers | |
xm.mark_step() | |
def begin_valid_epoch(self, epoch): | |
"""Called at the beginning of each validation epoch.""" | |
# task specific setup per validation epoch | |
self.task.begin_valid_epoch(epoch, self.get_model()) | |
def reset_dummy_batch(self, batch): | |
self._dummy_batch = batch | |
def train_step(self, samples, raise_oom=False): | |
"""Do forward, backward and parameter update.""" | |
self._set_seed() | |
self.model.train() | |
self.criterion.train() | |
self.zero_grad() | |
metrics.log_start_time("train_wall", priority=800, round=0) | |
# If EMA is enabled through store_ema=True | |
# and task.uses_ema is True, pass the EMA model as a keyword | |
# argument to the task. | |
extra_kwargs = {} | |
if self.cfg.ema.store_ema and getattr(self.task, "uses_ema", False): | |
extra_kwargs["ema_model"] = self.ema.get_model() | |
# forward and backward pass | |
logging_outputs, sample_size, ooms = [], 0, 0 | |
for i, sample in enumerate(samples): # delayed update loop | |
sample, is_dummy_batch = self._prepare_sample(sample) | |
def maybe_no_sync(): | |
""" | |
Whenever *samples* contains more than one mini-batch, we | |
want to accumulate gradients locally and only call | |
all-reduce in the last backwards pass. | |
""" | |
if ( | |
self.data_parallel_world_size > 1 | |
and hasattr(self.model, "no_sync") | |
and i < len(samples) - 1 | |
# The no_sync context manager results in increased memory | |
# usage with FSDP, since full-size gradients will be | |
# accumulated on each GPU. It's typically a better tradeoff | |
# to do the extra communication with FSDP. | |
and not self.is_fsdp | |
): | |
return self.model.no_sync() | |
else: | |
return contextlib.ExitStack() # dummy contextmanager | |
try: | |
with maybe_no_sync(): | |
# forward and backward | |
loss, sample_size_i, logging_output = self.task.train_step( | |
sample=sample, | |
model=self.model, | |
criterion=self.criterion, | |
optimizer=self.optimizer, | |
update_num=self.get_num_updates(), | |
ignore_grad=is_dummy_batch, | |
**extra_kwargs, | |
) | |
del loss | |
logging_outputs.append(logging_output) | |
sample_size += sample_size_i | |
# emptying the CUDA cache after the first step can | |
# reduce the chance of OOM | |
if self.cuda and self.get_num_updates() == 0: | |
torch.cuda.empty_cache() | |
except RuntimeError as e: | |
if "out of memory" in str(e): | |
self._log_oom(e) | |
if raise_oom: | |
raise e | |
logger.warning( | |
"attempting to recover from OOM in forward/backward pass" | |
) | |
ooms += 1 | |
self.zero_grad() | |
if self.cuda: | |
torch.cuda.empty_cache() | |
if self.cfg.distributed_training.distributed_world_size == 1: | |
return None | |
else: | |
raise e | |
if self.tpu and i < len(samples) - 1: | |
# tpu-comment: every XLA operation before marking step is | |
# appended to the IR graph, and processing too many batches | |
# before marking step can lead to OOM errors. | |
# To handle gradient accumulation use case, we explicitly | |
# mark step here for every forward pass without a backward pass | |
self._xla_markstep_and_send_to_cpu() | |
if is_dummy_batch: | |
if torch.is_tensor(sample_size): | |
sample_size.zero_() | |
else: | |
sample_size *= 0.0 | |
if torch.is_tensor(sample_size): | |
sample_size = sample_size.float() | |
else: | |
sample_size = float(sample_size) | |
# gather logging outputs from all replicas | |
if self._sync_stats(): | |
train_time = self._local_cumulative_training_time() | |
logging_outputs, ( | |
sample_size, | |
ooms, | |
total_train_time, | |
) = self._aggregate_logging_outputs( | |
logging_outputs, sample_size, ooms, train_time, ignore=is_dummy_batch | |
) | |
self._cumulative_training_time = ( | |
total_train_time / self.data_parallel_world_size | |
) | |
overflow = False | |
try: | |
with torch.autograd.profiler.record_function("reduce-grads"): | |
# reduce gradients across workers | |
self.optimizer.all_reduce_grads(self.model) | |
if utils.has_parameters(self.criterion): | |
self.optimizer.all_reduce_grads(self.criterion) | |
with torch.autograd.profiler.record_function("multiply-grads"): | |
# multiply gradients by (data_parallel_size / sample_size) since | |
# DDP normalizes by the number of data parallel workers for | |
# improved fp16 precision. | |
# Thus we get (sum_of_gradients / sample_size) at the end. | |
# In case of fp16, this step also undoes loss scaling. | |
# (Debugging note: Some optimizers perform this scaling on the | |
# fly, so inspecting model.parameters() or optimizer.params may | |
# still show the original, unscaled gradients.) | |
numer = ( | |
self.data_parallel_world_size | |
if not self.cfg.optimization.use_bmuf or self._sync_stats() | |
else 1 | |
) | |
self.optimizer.multiply_grads(numer / (sample_size or 1.0)) | |
# Note: (sample_size or 1.0) handles the case of a zero gradient, in a | |
# way that avoids CPU/device transfers in case sample_size is a GPU or | |
# TPU object. The assumption is that the gradient itself is also 0. | |
with torch.autograd.profiler.record_function("clip-grads"): | |
# clip grads | |
grad_norm = self.clip_grad_norm(self.cfg.optimization.clip_norm) | |
# check that grad norms are consistent across workers | |
# on tpu check tensor is slow | |
if not self.tpu: | |
if ( | |
not self.cfg.optimization.use_bmuf | |
and self.cfg.distributed_training.ddp_backend != "slow_mo" | |
): | |
self._check_grad_norms(grad_norm) | |
if not torch.isfinite(grad_norm).all(): | |
# in case of AMP, if gradients are Nan/Inf then | |
# optimizer step is still required | |
if self.cfg.common.amp: | |
overflow = True | |
else: | |
# check local gradnorm single GPU case, trigger NanDetector | |
raise FloatingPointError("gradients are Nan/Inf") | |
with torch.autograd.profiler.record_function("optimizer"): | |
# take an optimization step | |
self.task.optimizer_step( | |
self.optimizer, model=self.model, update_num=self.get_num_updates() | |
) | |
if self.cfg.common.amp and overflow: | |
if self._amp_retries == self.cfg.common.amp_batch_retries: | |
logger.info("AMP: skipping this batch.") | |
self._amp_retries = 0 | |
else: | |
self._amp_retries += 1 | |
return self.train_step(samples, raise_oom) # recursion to feed in same batch | |
except FloatingPointError: | |
# re-run the forward and backward pass with hooks attached to print | |
# out where it fails | |
self.zero_grad() | |
with NanDetector(self.get_model()): | |
for _, sample in enumerate(samples): | |
sample, _ = self._prepare_sample(sample) | |
self.task.train_step( | |
sample, | |
self.model, | |
self.criterion, | |
self.optimizer, | |
self.get_num_updates(), | |
ignore_grad=False, | |
**extra_kwargs, | |
) | |
raise | |
except OverflowError as e: | |
overflow = True | |
logger.info( | |
f"NOTE: gradient overflow detected, ignoring gradient, {str(e)}" | |
) | |
grad_norm = torch.tensor(0.0).cuda() | |
self.zero_grad() | |
except RuntimeError as e: | |
if "out of memory" in str(e): | |
self._log_oom(e) | |
logger.error("OOM during optimization, irrecoverable") | |
raise e | |
# Some distributed wrappers (e.g., SlowMo) need access to the optimizer | |
# after the step | |
if hasattr(self.model, "perform_additional_optimizer_actions"): | |
if hasattr(self.optimizer, "fp32_params"): | |
self.model.perform_additional_optimizer_actions( | |
self.optimizer.optimizer, self.optimizer.fp32_params | |
) | |
else: | |
self.model.perform_additional_optimizer_actions( | |
self.optimizer.optimizer | |
) | |
logging_output = None | |
if not overflow or self.cfg.distributed_training.ddp_backend == "slow_mo": | |
self.set_num_updates(self.get_num_updates() + 1) | |
if self.cfg.ema.store_ema: | |
# Step EMA forward with new model. | |
self.ema.step( | |
self.get_model(), | |
self.get_num_updates(), | |
) | |
metrics.log_scalar( | |
"ema_decay", | |
self.ema.get_decay(), | |
priority=10000, | |
round=5, | |
weight=0, | |
) | |
if self.tpu: | |
import torch_xla.core.xla_model as xm | |
# mark step on TPUs | |
self._xla_markstep_and_send_to_cpu() | |
# only log stats every log_interval steps | |
# this causes wps to be misreported when log_interval > 1 | |
logging_output = {} | |
if self.get_num_updates() % self.cfg.common.log_interval == 0: | |
# log memory usage | |
mem_info = xm.get_memory_info(self.device) | |
gb_free = mem_info["kb_free"] / 1024 / 1024 | |
gb_total = mem_info["kb_total"] / 1024 / 1024 | |
metrics.log_scalar( | |
"gb_free", gb_free, priority=1500, round=1, weight=0 | |
) | |
metrics.log_scalar( | |
"gb_total", gb_total, priority=1600, round=1, weight=0 | |
) | |
logging_outputs = self._xla_markstep_and_send_to_cpu( | |
logging_outputs | |
) | |
logging_output = self._reduce_and_log_stats( | |
logging_outputs, sample_size, grad_norm | |
) | |
# log whenever there's an XLA compilation, since these | |
# slow down training and may indicate opportunities for | |
# optimization | |
self._check_xla_compilation() | |
else: | |
if self.cuda and self.cuda_env is not None: | |
# log minimum free memory over the iteration | |
gb_used = torch.cuda.max_memory_allocated() / 1024 / 1024 / 1024 | |
torch.cuda.reset_peak_memory_stats() | |
gb_free = self.cuda_env.total_memory_in_GB - gb_used | |
metrics.log_scalar( | |
"gb_free", gb_free, priority=1500, round=1, weight=0 | |
) | |
# log stats | |
logging_output = self._reduce_and_log_stats( | |
logging_outputs, sample_size, grad_norm | |
) | |
# clear CUDA cache to reduce memory fragmentation | |
if ( | |
self.cuda | |
and self.cfg.common.empty_cache_freq > 0 | |
and ( | |
(self.get_num_updates() + self.cfg.common.empty_cache_freq - 1) | |
% self.cfg.common.empty_cache_freq | |
) | |
== 0 | |
): | |
torch.cuda.empty_cache() | |
if self.cfg.common.fp16 or self.cfg.common.amp: | |
metrics.log_scalar( | |
"loss_scale", | |
( | |
self.optimizer.scaler.loss_scale | |
if self.cfg.common.fp16 | |
else self.optimizer.scaler.get_scale() | |
), | |
priority=700, | |
round=4, | |
weight=0, | |
) | |
metrics.log_stop_time("train_wall") | |
return logging_output | |
def valid_step(self, sample, raise_oom=False): | |
"""Do forward pass in evaluation mode.""" | |
if self.tpu: | |
import torch_xla.core.xla_model as xm | |
xm.rendezvous("valid_step") # wait for all workers | |
# If EMA is enabled through store_ema=True | |
# and task.uses_ema is True, pass the EMA model as a keyword | |
# argument to the task. | |
extra_kwargs = {} | |
if self.cfg.ema.store_ema and getattr(self.task, "uses_ema", False): | |
extra_kwargs["ema_model"] = self.ema.get_model() | |
with torch.no_grad(): | |
self.model.eval() | |
self.criterion.eval() | |
sample, is_dummy_batch = self._prepare_sample(sample) | |
try: | |
_loss, sample_size, logging_output = self.task.valid_step( | |
sample, self.model, self.criterion, **extra_kwargs | |
) | |
except RuntimeError as e: | |
if "out of memory" in str(e): | |
self._log_oom(e) | |
if not raise_oom: | |
logger.warning( | |
"ran out of memory in validation step, retrying batch" | |
) | |
for p in self.model.parameters(): | |
if p.grad is not None: | |
p.grad = None # free some memory | |
if self.cuda: | |
torch.cuda.empty_cache() | |
return self.valid_step(sample, raise_oom=True) | |
raise e | |
logging_outputs = [logging_output] | |
if is_dummy_batch: | |
if torch.is_tensor(sample_size): | |
sample_size.zero_() | |
else: | |
sample_size *= 0.0 | |
# gather logging outputs from all replicas | |
if self.data_parallel_world_size > 1: | |
logging_outputs, (sample_size,) = self._aggregate_logging_outputs( | |
logging_outputs, | |
sample_size, | |
ignore=is_dummy_batch, | |
) | |
# log validation stats | |
if self.tpu: | |
logging_outputs = self._xla_markstep_and_send_to_cpu(logging_outputs) | |
logging_output = self._reduce_and_log_stats(logging_outputs, sample_size) | |
return logging_output | |
def zero_grad(self): | |
self.optimizer.zero_grad() | |
def lr_step_begin_epoch(self, epoch): | |
"""Adjust the learning rate at the beginning of the epoch.""" | |
self.lr_scheduler.step_begin_epoch(epoch) | |
# prefer updating the LR based on the number of steps | |
return self.lr_step_update() | |
def lr_reinit(self, total_updates, num_updates): | |
self.lr_scheduler.reinit(total_updates, num_updates) | |
def lr_step(self, epoch, val_loss=None): | |
"""Adjust the learning rate at the end of the epoch.""" | |
self.lr_scheduler.step(epoch, val_loss) | |
# prefer updating the LR based on the number of steps | |
return self.lr_step_update() | |
def lr_step_update(self): | |
"""Update the learning rate after each update.""" | |
new_lr = self.lr_scheduler.step_update(self.get_num_updates()) | |
if isinstance(new_lr, dict): | |
for k, v in new_lr.items(): | |
metrics.log_scalar(f"lr_{k}", v, weight=0, priority=300) | |
new_lr = new_lr.get("default", next(iter(new_lr.values()))) | |
else: | |
metrics.log_scalar("lr", new_lr, weight=0, priority=300) | |
return new_lr | |
def get_lr(self): | |
"""Get the current learning rate.""" | |
return self.optimizer.get_lr() | |
def get_model(self): | |
"""Get the (non-wrapped) model instance.""" | |
return self._model | |
def get_criterion(self): | |
"""Get the (non-wrapped) criterion instance.""" | |
return self._criterion | |
def get_meter(self, name): | |
"""[deprecated] Get a specific meter by name.""" | |
from fairseq import meters | |
if "get_meter" not in self._warn_once: | |
self._warn_once.add("get_meter") | |
utils.deprecation_warning( | |
"Trainer.get_meter is deprecated. Please use fairseq.metrics instead." | |
) | |
train_meters = metrics.get_meters("train") | |
if train_meters is None: | |
train_meters = {} | |
if name == "train_loss" and "loss" in train_meters: | |
return train_meters["loss"] | |
elif name == "train_nll_loss": | |
# support for legacy train.py, which assumed this meter is | |
# always initialized | |
m = train_meters.get("nll_loss", None) | |
return m or meters.AverageMeter() | |
elif name == "wall": | |
# support for legacy train.py, which assumed this meter is | |
# always initialized | |
m = metrics.get_meter("default", "wall") | |
return m or meters.TimeMeter() | |
elif name == "wps": | |
m = metrics.get_meter("train", "wps") | |
return m or meters.TimeMeter() | |
elif name in {"valid_loss", "valid_nll_loss"}: | |
# support for legacy train.py, which assumed these meters | |
# are always initialized | |
k = name[len("valid_") :] | |
m = metrics.get_meter("valid", k) | |
return m or meters.AverageMeter() | |
elif name == "oom": | |
return meters.AverageMeter() | |
elif name in train_meters: | |
return train_meters[name] | |
return None | |
def get_num_updates(self): | |
"""Get the number of parameters updates.""" | |
return self._num_updates | |
def set_num_updates(self, num_updates): | |
"""Set the number of parameters updates.""" | |
self._num_updates = num_updates | |
self.lr_step_update() | |
if self.quantizer: | |
self.quantizer.step_update(self._num_updates) | |
metrics.log_scalar("num_updates", self._num_updates, weight=0, priority=200) | |
def clip_grad_norm(self, clip_norm): | |
def agg_norm_fn(total_norm): | |
total_norm = total_norm.cuda().float() ** 2 | |
total_norm = distributed_utils.all_reduce( | |
total_norm, group=self.data_parallel_process_group | |
) | |
return total_norm ** 0.5 | |
should_agg_norm = ( | |
self.is_fsdp | |
and ( | |
self.data_parallel_process_group is not None | |
or torch.distributed.is_initialized() | |
) | |
) | |
return self.optimizer.clip_grad_norm( | |
clip_norm, aggregate_norm_fn=agg_norm_fn if should_agg_norm else None | |
) | |
def cumulative_training_time(self): | |
if self._cumulative_training_time is None: | |
# single GPU | |
return self._local_cumulative_training_time() | |
else: | |
return self._cumulative_training_time | |
def _local_cumulative_training_time(self): | |
"""Aggregate training time in seconds.""" | |
return time.time() - self._start_time + self._previous_training_time | |
def _fp_convert_sample(self, sample): | |
def apply_half(t): | |
if t.dtype is torch.float32: | |
return t.to(dtype=torch.half) | |
return t | |
def apply_bfloat16(t): | |
if t.dtype is torch.float32: | |
return t.to(dtype=torch.bfloat16) | |
return t | |
if self.cfg.common.fp16: | |
sample = utils.apply_to_sample(apply_half, sample) | |
if self.cfg.common.bf16: | |
sample = utils.apply_to_sample(apply_bfloat16, sample) | |
return sample | |
def _prepare_sample(self, sample, is_dummy=False): | |
if sample == "DUMMY": | |
raise Exception( | |
"Trying to use an uninitialized 'dummy' batch. This usually indicates " | |
"that the total number of batches is smaller than the number of " | |
"participating GPUs. Try reducing the batch size or using fewer GPUs." | |
) | |
if sample is None or len(sample) == 0: | |
assert ( | |
self._dummy_batch is not None and len(self._dummy_batch) > 0 | |
), "Invalid dummy batch: {}".format(self._dummy_batch) | |
sample, _ = self._prepare_sample(self._dummy_batch, is_dummy=True) | |
return sample, True | |
# Given that PCIe/NVLink bandwidth is significantly smaller than DRAM bandwidth | |
# it makes sense to do the format conversion on the CPU and then transfer | |
# a smaller buffer to the device. This also saves GPU memory capacity. | |
if self.cfg.common.on_cpu_convert_precision: | |
sample = self._fp_convert_sample(sample) | |
if self.cuda: | |
if self.pipeline_model_parallel: | |
if 'target' in sample: | |
sample['target'] = utils.move_to_cuda(sample['target'], device=self.last_device) | |
else: | |
sample = utils.move_to_cuda(sample) | |
elif self.tpu and is_dummy: | |
# the dummy batch may not be on the appropriate device | |
sample = utils.move_to_cuda(sample, device=self.device) | |
if not self.cfg.common.on_cpu_convert_precision: | |
sample = self._fp_convert_sample(sample) | |
if self._dummy_batch == "DUMMY": | |
self._dummy_batch = sample | |
return sample, False | |
def _set_seed(self): | |
# Set seed based on args.seed and the update number so that we get | |
# reproducible results when resuming from checkpoints | |
seed = self.cfg.common.seed + self.get_num_updates() | |
utils.set_torch_seed(seed) | |
def _sync_stats(self): | |
# Return True if it's using multiple GPUs and DDP or multiple GPUs with | |
# BMUF and it's a bmuf sync with warmup iterations completed before. | |
if self.data_parallel_world_size == 1: | |
return False | |
elif self.cfg.optimization.use_bmuf: | |
return ( | |
self.get_num_updates() + 1 | |
) % self.cfg.bmuf.global_sync_iter == 0 and ( | |
self.get_num_updates() + 1 | |
) > self.cfg.bmuf.warmup_iterations | |
else: | |
return True | |
def _log_oom(self, exc): | |
msg = "OOM: Ran out of memory with exception: {}".format(exc) | |
logger.warning(msg) | |
if torch.cuda.is_available() and hasattr(torch.cuda, "memory_summary"): | |
for device_idx in range(torch.cuda.device_count()): | |
logger.warning(torch.cuda.memory_summary(device=device_idx)) | |
sys.stderr.flush() | |
def _aggregate_logging_outputs( | |
self, | |
logging_outputs: List[Dict[str, Any]], | |
*extra_stats_to_sum, | |
ignore=False, | |
): | |
if self.task.__class__.logging_outputs_can_be_summed(self.get_criterion()): | |
return self._fast_stat_sync_sum( | |
logging_outputs, *extra_stats_to_sum, ignore=ignore | |
) | |
else: | |
return self._all_gather_list_sync( | |
logging_outputs, *extra_stats_to_sum, ignore=ignore | |
) | |
def _all_gather_list_sync( | |
self, | |
logging_outputs: List[Dict[str, Any]], | |
*extra_stats_to_sum, | |
ignore=False, | |
): | |
""" | |
Sync logging outputs across workers. all_gather_list_sync is | |
suitable when logging outputs are complex types. | |
""" | |
if self.tpu: | |
raise NotImplementedError | |
if ignore: | |
logging_outputs = [] | |
results = list( | |
zip( | |
*distributed_utils.all_gather_list( | |
[logging_outputs] + list(extra_stats_to_sum), | |
max_size=getattr(self.cfg.common, "all_gather_list_size", 16384), | |
group=self.data_parallel_process_group, | |
) | |
) | |
) | |
logging_outputs, extra_stats_to_sum = results[0], results[1:] | |
logging_outputs = list(chain.from_iterable(logging_outputs)) | |
extra_stats_to_sum = [sum(s) for s in extra_stats_to_sum] | |
return logging_outputs, extra_stats_to_sum | |
def _fast_stat_sync_sum( | |
self, | |
logging_outputs: List[Dict[str, Any]], | |
*extra_stats_to_sum, | |
ignore=False, | |
): | |
""" | |
Sync logging outputs across workers. fast_stat_sync_sum is | |
faster than all_gather_list_sync, but is only suitable when | |
logging outputs are scalars and can be summed. Note that | |
*logging_outputs* cannot contain any nested dicts/lists. | |
""" | |
data = {} | |
for i, stat in enumerate(extra_stats_to_sum): | |
data["extra_stats_" + str(i)] = stat | |
if len(logging_outputs) > 0: | |
log_keys = list(logging_outputs[0].keys()) | |
for k in log_keys: | |
if not ignore: | |
v = sum(log[k] for log in logging_outputs if k in log) | |
else: | |
v = logging_outputs[0][k] | |
v = torch.zeros_like(v) if torch.is_tensor(v) else 0 | |
data["logging_outputs_" + k] = v | |
else: | |
log_keys = None | |
data = distributed_utils.all_reduce_dict( | |
data, device=self.device, group=self.data_parallel_process_group | |
) | |
extra_stats_to_sum = [ | |
data["extra_stats_" + str(i)] for i in range(len(extra_stats_to_sum)) | |
] | |
if log_keys is not None: | |
logging_outputs = [{k: data["logging_outputs_" + k] for k in log_keys}] | |
else: | |
logging_outputs = [] | |
return logging_outputs, extra_stats_to_sum | |
def _check_grad_norms(self, grad_norm): | |
"""Check that grad norms are consistent across workers.""" | |
if self._grad_norm_buf is not None: | |
self._grad_norm_buf.zero_() | |
self._grad_norm_buf[self.data_parallel_rank] = grad_norm | |
distributed_utils.all_reduce( | |
self._grad_norm_buf, group=self.data_parallel_process_group | |
) | |
def is_consistent(tensor): | |
max_abs_diff = torch.max(torch.abs(tensor - tensor[0])) | |
return ( | |
(torch.isfinite(tensor).all() | |
and (max_abs_diff / (tensor[0] + 1e-6) < 1e-6).all()) | |
or | |
(self.cfg.common.amp and not torch.isfinite(tensor).all()) | |
# in case of amp non-finite grads are fine | |
) | |
if not is_consistent(self._grad_norm_buf): | |
pretty_detail = "\n".join( | |
"rank {:3d} = {:.8f}".format(r, n) | |
for r, n in enumerate(self._grad_norm_buf.tolist()) | |
) | |
error_detail = "grad_norm across the workers:\n{}\n".format( | |
pretty_detail | |
) | |
# use FloatingPointError to trigger NanDetector | |
raise FloatingPointError( | |
"Fatal error: gradients are inconsistent between workers. " | |
"Try --ddp-backend=legacy_ddp. " | |
"Or are you mixing up different generation of GPUs in training?" | |
+ "\n" | |
+ "-" * 80 | |
+ "\n{}\n".format(error_detail) | |
+ "-" * 80 | |
) | |
def _reduce_and_log_stats(self, logging_outputs, sample_size, grad_norm=None): | |
if grad_norm is not None and ( | |
not torch.is_tensor(grad_norm) or torch.isfinite(grad_norm) | |
): | |
metrics.log_speed("ups", 1.0, priority=100, round=2) | |
metrics.log_scalar("gnorm", grad_norm, priority=400, round=3) | |
if self.cfg.optimization.clip_norm > 0: | |
metrics.log_scalar( | |
"clip", | |
torch.where( | |
grad_norm > self.cfg.optimization.clip_norm, | |
grad_norm.new_tensor(100), | |
grad_norm.new_tensor(0), | |
), | |
priority=500, | |
round=1, | |
) | |
with metrics.aggregate() as agg: | |
if logging_outputs is not None: | |
self.task.reduce_metrics(logging_outputs, self.get_criterion()) | |
del logging_outputs | |
# extra warning for criterions that don't properly log a loss value | |
if "loss" not in agg: | |
if "loss" not in self._warn_once: | |
self._warn_once.add("loss") | |
logger.warning( | |
"Criterion.reduce_metrics did not log a 'loss' value, " | |
"which may break some functionality" | |
) | |
metrics.log_scalar("loss", -1) | |
# support legacy interface | |
if self.tpu: | |
logging_output = {} | |
else: | |
logging_output = agg.get_smoothed_values() | |
logging_output["sample_size"] = sample_size | |
for key_to_delete in ["ppl", "wps", "wpb", "bsz"]: | |
if key_to_delete in logging_output: | |
del logging_output[key_to_delete] | |
return logging_output | |
def _check_xla_compilation(self): | |
import torch_xla.debug.metrics as met | |
compile_stats = met.metric_data("CompileTime") | |
if compile_stats is None: | |
return | |
num_xla_compiles = compile_stats[0] | |
if num_xla_compiles > self._num_xla_compiles: | |
logger.warning( | |
"XLA compilation detected on device #{}; too many of these can lead " | |
"to slow training, but we expect a few in the beginning".format( | |
self.cfg.distributed_training.distributed_rank | |
) | |
) | |
self._num_xla_compiles = num_xla_compiles | |
def _xla_markstep_and_send_to_cpu(self, data=None): | |
import torch_xla.core.xla_model as xm | |
xm.mark_step() | |
if data is not None: | |
from fairseq.utils import xla_device_to_cpu | |
return xla_device_to_cpu(data) | |
def _catalog_shared_params(module, memo=None, prefix=""): | |
if memo is None: | |
first_call = True | |
memo = {} | |
else: | |
first_call = False | |
for name, param in module._parameters.items(): | |
param_prefix = prefix + ("." if prefix else "") + name | |
if param not in memo: | |
memo[param] = [] | |
memo[param].append(param_prefix) | |
for name, m in module._modules.items(): | |
if m is None: | |
continue | |
submodule_prefix = prefix + ("." if prefix else "") + name | |
_catalog_shared_params(m, memo, submodule_prefix) | |
if first_call: | |
return [x for x in memo.values() if len(x) > 1] | |
def _get_module_by_path(module, path): | |
path = path.split(".") | |
for name in path: | |
module = getattr(module, name) | |
return module | |
def _set_module_by_path(module, path, value): | |
path = path.split(".") | |
for name in path[:-1]: | |
module = getattr(module, name) | |
setattr(module, path[-1], value) | |