Select Git revision
FindCorpus.cmake
pretrain_gpt2.py 23.99 KiB
# coding=utf-8
# Copyright (c) 2019, NVIDIA CORPORATION. All rights reserved.
#
# 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.
"""Pretrain GPT2"""
from datetime import datetime
import os
import random
import math
import numpy as np
import torch
from arguments import get_args
from configure_data import configure_data
from fp16 import FP16_Module
from fp16 import FP16_Optimizer
from learning_rates import AnnealingLR
from model import GPT2Model
from model import gpt2_get_params_for_weight_decay_optimization
from model import DistributedDataParallel as LocalDDP
import mpu
from apex.optimizers import FusedAdam as Adam
from utils import Timers
from utils import save_checkpoint
from utils import load_checkpoint
from utils import report_memory
from utils import print_args
from utils import print_params_min_max_norm
from utils import print_rank_0
from utils import enable_adlr_autoresume
from utils import check_adlr_autoresume_termination
from gpt2_data_loader import make_gpt2_dataloaders
def get_model(args):
"""Build the model."""
print_rank_0('building GPT2 model ...')
model = GPT2Model(num_layers=args.num_layers,
vocab_size=args.vocab_size,
hidden_size=args.hidden_size,
num_attention_heads=args.num_attention_heads,
embedding_dropout_prob=args.hidden_dropout,
attention_dropout_prob=args.attention_dropout,
output_dropout_prob=args.hidden_dropout,
max_sequence_length=args.max_position_embeddings,
checkpoint_activations=args.checkpoint_activations,
checkpoint_num_layers=args.checkpoint_num_layers,
parallel_output=True)
if mpu.get_data_parallel_rank() == 0:
print(' > number of parameters on model parallel rank {}: {}'.format(
mpu.get_model_parallel_rank(),
sum([p.nelement() for p in model.parameters()])), flush=True)
# GPU allocation.
model.cuda(torch.cuda.current_device())
# Fp16 conversion.
if args.fp16:
model = FP16_Module(model)
# Wrap model for distributed training.
if args.DDP_impl == 'torch':
i = torch.cuda.current_device()
args.DDP_type = torch.nn.parallel.distributed.DistributedDataParallel
model = args.DDP_type(model, device_ids=[i], output_device=i,
process_group=mpu.get_data_parallel_group())
elif args.DDP_impl == 'local':
args.DDP_type = LocalDDP
model = args.DDP_type(model)
else:
print_rank_0('Unknown DDP implementation specified: {}. '
'Exiting.'.format(args.DDP_impl))
exit()
return model
def get_optimizer(model, args):
"""Set up the optimizer."""
# Build parameter groups (weight decay and non-decay).
while isinstance(model, (args.DDP_type, FP16_Module)):
model = model.module
param_groups = gpt2_get_params_for_weight_decay_optimization(model)
# Add model parallel attribute if it is not set.
for param_group in param_groups:
for param in param_group['params']:
if not hasattr(param, 'model_parallel'):
param.model_parallel = False
# Use Adam.
optimizer = Adam(param_groups,
lr=args.lr, weight_decay=args.weight_decay)
# Wrap into fp16 optimizer.
if args.fp16:
optimizer = FP16_Optimizer(optimizer,
static_loss_scale=args.loss_scale,
dynamic_loss_scale=args.dynamic_loss_scale,
dynamic_loss_args={
'scale_window': args.loss_scale_window,
'min_scale':args.min_scale,
'delayed_shift': args.hysteresis})
return optimizer
def get_learning_rate_scheduler(optimizer, args):
"""Build the learning rate scheduler."""
# Add linear learning rate scheduler.
if args.lr_decay_iters is not None:
num_iters = args.lr_decay_iters
else:
num_iters = args.train_iters
num_iters = max(1, num_iters)
init_step = -1
warmup_iter = args.warmup * num_iters
lr_scheduler = AnnealingLR(optimizer,
start_lr=args.lr,
warmup_iter=warmup_iter,
num_iters=num_iters,
decay_style=args.lr_decay_style,
last_iter=init_step,
min_lr=args.min_lr,
use_checkpoint_lr_scheduler=args.use_checkpoint_lr_scheduler,
override_lr_scheduler=args.override_lr_scheduler)
return lr_scheduler
def setup_model_and_optimizer(args):
"""Setup model and optimizer."""
model = get_model(args)
optimizer = get_optimizer(model, args)
lr_scheduler = get_learning_rate_scheduler(optimizer, args)
if args.load is not None:
args.iteration = load_checkpoint(model, optimizer, lr_scheduler, args)
else:
args.iteration = 0
return model, optimizer, lr_scheduler
def get_masks_and_position_ids(data,
eod_token,
reset_position_ids,
reset_attention_mask,
eod_mask_loss):
# Extract batch size and sequence length.
batch_size, seq_length = data.size()
# Attention mask (lower triangular).
if reset_attention_mask:
att_mask_batch = batch_size
else:
att_mask_batch = 1
attention_mask = torch.tril(torch.ones(
(att_mask_batch, seq_length, seq_length), device=data.device)).view(
att_mask_batch, 1, seq_length, seq_length)
# Loss mask.
loss_mask = torch.ones(data.size(), dtype=torch.float, device=data.device)
if eod_mask_loss:
loss_mask[data == eod_token] = 0.0
# Position ids.
position_ids = torch.arange(seq_length, dtype=torch.long,
device=data.device)
position_ids = position_ids.unsqueeze(0).expand_as(data)
# We need to clone as the ids will be modifed based on batch index.
if reset_position_ids:
position_ids = position_ids.clone()
if reset_position_ids or reset_attention_mask:
# Loop through the batches:
for b in range(batch_size):
# Find indecies where EOD token is.
eod_index = position_ids[b, data[b] == eod_token]
# Detach indecies from positions if going to modify positions.
if reset_position_ids:
eod_index = eod_index.clone()
# Loop through EOD indecies:
prev_index = 0
for j in range(eod_index.size()[0]):
i = eod_index[j]
# Mask attention loss.
if reset_attention_mask:
attention_mask[b, 0, (i+1):, :(i+1)] = 0
# Reset positions.
if reset_position_ids:
position_ids[b, (i+1):] -= (i + 1 - prev_index)
prev_index = i + 1
return attention_mask, loss_mask, position_ids
def get_batch(data_iterator, args, timers):
''' get_batch subdivides the source data into chunks of
length args.seq_length. If source is equal to the example
output of the data loading example, with a seq_length limit
of 2, we'd get the following two Variables for i = 0:
┌ a g m s ┐ ┌ b h n t ┐
└ b h n t ┘ └ c i o u ┘
Note that despite the name of the function, the subdivison of data is not
done along the batch dimension (i.e. dimension 1), since that was handled
by the data loader. The chunks are along dimension 0, corresponding
to the seq_len dimension in the LSTM. A Variable representing an appropriate
shard reset mask of the same dimensions is also returned.
'''
# Items and their type.
keys = ['text']
datatype = torch.int64
# Broadcast data.
timers('data loader').start()
if data_iterator is not None:
data = next(data_iterator)
else:
data = None
timers('data loader').stop()
data_b = mpu.broadcast_data(keys, data, datatype)
# Unpack.
tokens_ = data_b['text'].long()
labels = tokens_[:, 1:].contiguous()
tokens = tokens_[:, :-1].contiguous()
# Get the masks and postition ids.
attention_mask, loss_mask, position_ids = get_masks_and_position_ids(
tokens,
args.eod_token,
args.reset_position_ids,
args.reset_attention_mask,
args.eod_mask_loss)
# Convert
if args.fp16:
attention_mask = attention_mask.half()
return tokens, labels, loss_mask, attention_mask, position_ids
def forward_step(data_iterator, model, args, timers):
"""Forward step."""
# Get the batch.
timers('batch generator').start()
tokens, labels, loss_mask, attention_mask, position_ids = get_batch(
data_iterator, args, timers)
timers('batch generator').stop()
# Forward model.
output = model(tokens, position_ids, attention_mask)
losses = mpu.vocab_parallel_cross_entropy(output.contiguous().float(),
labels)
loss_mask = loss_mask.view(-1)
loss = torch.sum(losses.view(-1) * loss_mask) / loss_mask.sum()
return loss
def backward_step(optimizer, model, lm_loss, args, timers):
"""Backward step."""
# Total loss.
loss = lm_loss
# Backward pass.
optimizer.zero_grad()
if args.fp16:
optimizer.backward(loss, update_master_grads=False)
else:
loss.backward()
# Reduce across processes.
lm_loss_reduced = lm_loss
reduced_losses = lm_loss.view(1)
torch.distributed.all_reduce(reduced_losses.data)
reduced_losses.data = reduced_losses.data / args.world_size
if args.DDP_impl == 'local':
timers('allreduce').start()
model.allreduce_params(reduce_after=False,
fp32_allreduce=args.fp32_allreduce)
timers('allreduce').stop()
lm_loss_reduced = reduced_losses
# Update master gradients.
if args.fp16:
optimizer.update_master_grads()
# Clipping gradients helps prevent the exploding gradient.
if args.clip_grad > 0:
if not args.fp16:
mpu.clip_grad_norm(model.parameters(), args.clip_grad)
else:
optimizer.clip_master_grads(args.clip_grad)
return lm_loss_reduced
def train_step(data_iterator, model, optimizer, lr_scheduler,
args, timers):
"""Single training step."""
# Forward model for one step.
timers('forward').start()
lm_loss = forward_step(data_iterator, model, args, timers)
timers('forward').stop()
# Calculate gradients, reduce across processes, and clip.
timers('backward').start()
lm_loss_reduced = backward_step(optimizer, model, lm_loss, args, timers)
timers('backward').stop()
# Update parameters.
timers('optimizer').start()
optimizer.step()
timers('optimizer').stop()
# Update learning rate.
skipped_iter = 0
if not (args.fp16 and optimizer.overflow):
lr_scheduler.step()
else:
skipped_iter = 1
return lm_loss_reduced, skipped_iter
def train(model, optimizer, lr_scheduler,
train_data_iterator, val_data_iterator, timers, args, writer):
"""Train the model."""
# Turn on training mode which enables dropout.
model.train()
# Tracking loss.
total_lm_loss = 0.0
# Iterations.
iteration = args.iteration
skipped_iters = 0
timers('interval time').start()
report_memory_flag = True
while iteration < args.train_iters:
lm_loss, skipped_iter = train_step(train_data_iterator,
model,
optimizer,
lr_scheduler,
args, timers)
skipped_iters += skipped_iter
iteration += 1
# Update losses.
current_lm_loss = lm_loss.data.detach().float()
total_lm_loss += current_lm_loss
# Logging.
if args.DDP_impl == 'torch':
timers_to_log = ['forward', 'backward', 'optimizer',
'batch generator', 'data loader']
else:
timers_to_log = ['forward', 'backward', 'allreduce', 'optimizer',
'batch generator', 'data loader']
learning_rate = optimizer.param_groups[0]['lr']
if writer and args.rank == 0:
writer.add_scalar('learning_rate', learning_rate, iteration)
writer.add_scalar('train_loss', current_lm_loss, iteration)
if args.fp16:
writer.add_scalar('loss_scale', optimizer.loss_scale, iteration)
normalizer = iteration % args.log_interval
if normalizer == 0:
normalizer = args.log_interval
timers.write(timers_to_log, writer, iteration,
normalizer=normalizer)
if iteration % args.log_interval == 0:
avg_lm_loss = total_lm_loss.item() / args.log_interval
elapsed_time = timers('interval time').elapsed()
if writer and args.rank == 0:
writer.add_scalar('iteration_time',
elapsed_time / args.log_interval, iteration)
log_string = ' iteration {:8d}/{:8d} |'.format(iteration,
args.train_iters)
log_string += ' elapsed time per iteration (ms): {:.1f} |'.format(
elapsed_time * 1000.0 / args.log_interval)
log_string += ' learning rate {:.3E} |'.format(learning_rate)
log_string += ' lm loss {:.6E} |'.format(avg_lm_loss)
if args.fp16:
log_string += ' loss scale {:.1f} |'.format(
optimizer.loss_scale)
print_rank_0(log_string)
total_lm_loss = 0.0
if report_memory_flag:
report_memory('after {} iterations'.format(iteration))
report_memory_flag = False
timers.log(timers_to_log, normalizer=args.log_interval)
# Autoresume
if (iteration % args.adlr_autoresume_interval == 0) and args.adlr_autoresume:
check_adlr_autoresume_termination(iteration, model, optimizer,
lr_scheduler, args)
# Checkpointing
if args.save and args.save_interval and iteration % args.save_interval == 0:
save_checkpoint(iteration, model, optimizer, lr_scheduler, args)
# Evaluation
if args.eval_interval and iteration % args.eval_interval == 0 and args.do_valid:
prefix = 'iteration {}'.format(iteration)
evaluate_and_print_results(prefix, val_data_iterator, model, args,
writer, iteration, timers, False)
if args.exit_interval and iteration % args.exit_interval == 0:
torch.distributed.barrier()
time_str = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
rank = torch.distributed.get_rank()
print('rank: {} | time: {} | exiting the program at iteration {}'.
format(rank, time_str, iteration), flush=True)
exit()
return iteration, skipped_iters
def evaluate(data_iterator, model, args, timers, verbose=False):
"""Evaluation."""
# Turn on evaluation mode which disables dropout.
model.eval()
total_lm_loss = 0
with torch.no_grad():
iteration = 0
while iteration < args.eval_iters:
iteration += 1
if verbose and iteration % args.log_interval == 0:
print_rank_0('Evaluating iter {}/{}'.format(iteration, args.eval_iters))
# Forward evaluation.
lm_loss = forward_step(data_iterator, model, args, timers)
# Reduce across processes.
if isinstance(model, args.DDP_type):
torch.distributed.all_reduce(lm_loss.data)
lm_loss.data = lm_loss.data / args.world_size
total_lm_loss += lm_loss.data.detach().float().item()
# Move model back to the train mode.
model.train()
total_lm_loss /= args.eval_iters
return total_lm_loss
def evaluate_and_print_results(prefix, data_iterator, model,
args, writer, iteration,
timers, verbose=False):
"""Helper function to evaluate and dump results on screen."""
lm_loss = evaluate(data_iterator, model, args, timers, verbose)
lm_ppl = math.exp(min(20, lm_loss))
print_rank_0('-' * 100)
string = ' validation loss at {} | '.format(prefix)
string += 'LM loss: {:.6E} | '.format(lm_loss)
string += 'LM PPL: {:.6E}'.format(lm_ppl)
length = len(string) + 1
print_rank_0('-' * length)
print_rank_0(string)
print_rank_0('-' * length)
if writer and args.rank == 0:
writer.add_scalar('val_loss', lm_loss, iteration)
writer.add_scalar('val_ppl', lm_ppl, iteration)
return lm_loss
def initialize_distributed(args):
"""Initialize torch.distributed."""
# Manually set the device ids.
device = args.rank % torch.cuda.device_count()
if args.local_rank is not None:
device = args.local_rank
torch.cuda.set_device(device)
# Call the init process
init_method = 'tcp://'
master_ip = os.getenv('MASTER_ADDR', 'localhost')
master_port = os.getenv('MASTER_PORT', '6002')
init_method += master_ip + ':' + master_port
torch.distributed.init_process_group(
backend=args.distributed_backend,
world_size=args.world_size, rank=args.rank,
init_method=init_method)
# Set the model-parallel / data-parallel communicators.
mpu.initialize_model_parallel(args.model_parallel_size)
def set_random_seed(seed):
"""Set random seed for reproducability."""
if seed is not None and seed > 0:
random.seed(seed)
np.random.seed(seed)
torch.manual_seed(seed)
mpu.model_parallel_cuda_manual_seed(seed)
def get_train_val_test_data(args):
"""Load the data on rank zero and boradcast number of tokens to all GPUS."""
(train_data, val_data, test_data) = (None, None, None)
# Data loader only on rank 0 of each model parallel group.
if mpu.get_model_parallel_rank() == 0:
if args.use_npy_data_loader:
(train_data, val_data, test_data), num_tokens, \
eod_token = make_gpt2_dataloaders(args)
else:
data_config = configure_data()
data_config.set_defaults(data_set_type='GPT2', transpose=False)
(train_data, val_data, test_data), tokenizer = data_config.apply(
args)
num_tokens = tokenizer.num_tokens
eod_token = tokenizer.get_command('eos').Id
assert eod_token == tokenizer.get_command('pad').Id
before = num_tokens
after = before
multiple = args.make_vocab_size_divisible_by * \
mpu.get_model_parallel_world_size()
while (after % multiple) != 0:
after += 1
print_rank_0('> padded vocab (size: {}) with {} dummy '
'tokens (new size: {})'.format(
before, after - before, after))
print_rank_0('> found end-of-document token: {}'.format(eod_token))
token_counts = torch.cuda.LongTensor([after, eod_token, int(args.do_train), int(args.do_valid), int(args.do_test)])
else:
token_counts = torch.cuda.LongTensor([0, 0, 0, 0, 0])
# Broadcast num tokens.
torch.distributed.broadcast(token_counts,
mpu.get_model_parallel_src_rank(),
group=mpu.get_model_parallel_group())
num_tokens = token_counts[0].item()
eod_token = token_counts[1].item()
args.do_train = token_counts[2].item()
args.do_valid = token_counts[3].item()
args.do_test = token_counts[4].item()
return train_data, val_data, test_data, num_tokens, eod_token
def main():
"""Main training program."""
# Disable CuDNN.
torch.backends.cudnn.enabled = False
# Timer.
timers = Timers()
# Arguments.
args = get_args()
writer = None
if args.tensorboard_dir and args.rank == 0:
try:
from torch.utils.tensorboard import SummaryWriter
writer = SummaryWriter(log_dir = args.tensorboard_dir)
except ModuleNotFoundError:
print_rank_0('WARNING: TensorBoard writing requested but is not '
'available (are you using PyTorch 1.1.0 or later?), '
'no TensorBoard logs will be written.')
writer = None
# Pytorch distributed.
initialize_distributed(args)
if torch.distributed.get_rank() == 0:
print('Pretrain GPT2 model')
print_args(args, writer)
# Autoresume.
torch.distributed.barrier()
if args.adlr_autoresume:
enable_adlr_autoresume(args)
# Random seeds for reproducability.
set_random_seed(args.seed)
# Data stuff.
train_data, val_data, test_data, args.vocab_size, \
args.eod_token = get_train_val_test_data(args)
# Model, optimizer, and learning rate.
model, optimizer, lr_scheduler = setup_model_and_optimizer(args)
# Resume data loader if necessary.
if args.resume_dataloader:
if train_data is not None:
train_data.batch_sampler.start_iter = args.iteration % \
len(train_data)
print_rank_0('setting training data start iteration to {}'.
format(train_data.batch_sampler.start_iter))
if val_data is not None:
start_iter_val = (args.iteration // args.eval_interval) * \
args.eval_iters
val_data.batch_sampler.start_iter = start_iter_val % \
len(val_data)
print_rank_0('setting validation data start iteration to {}'.
format(val_data.batch_sampler.start_iter))
if train_data is not None:
train_data_iterator = iter(train_data)
else:
train_data_iterator = None
if val_data is not None:
val_data_iterator = iter(val_data)
else:
val_data_iterator = None
#TODO: figure out how to properly set this especially when resuming training
iteration = 0
if args.train_iters > 0:
if args.do_train:
iteration, skipped = train(model, optimizer,
lr_scheduler,
train_data_iterator,
val_data_iterator,
timers, args, writer)
if args.do_valid:
prefix = 'the end of training for val data'
val_loss = evaluate_and_print_results(prefix, val_data_iterator,
model, args, writer, iteration,
timers, False)
if args.save and iteration != 0:
save_checkpoint(iteration, model, optimizer,
lr_scheduler, args)
if test_data is not None:
test_data_iterator = iter(test_data)
else:
test_data_iterator = None
if args.do_test:
# Run on test data.
prefix = 'the end of training for test data'
evaluate_and_print_results(prefix, test_data_iterator,
model, args, None, 0, timers, True)
if __name__ == "__main__":
main()