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# Copyright 2024 The HuggingFace Team. 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.
""":
This script is used to test training a model using Tensor Parallelism and Data Parallelism.
Usage:
export CUDA_VISIBLE_DEVICES=0,1,2,3
export CUDA_VISIBLE_DEVICES=4,5,6,7
export CUDA_VISIBLE_DEVICES=5,6,7
TP_SIZE=2 DP_SIZE=2 torchrun --nproc_per_node=4 --rdzv_endpoint=localhost:29503 examples/3D_parallel.py
CP_SIZE=2 DP_SIZE=2 torchrun --nproc_per_node=4 examples/3D_parallel.py
CP_SIZE=2 TP_SIZE=2 torchrun --nproc_per_node=4 examples/3D_parallel.py
DP_SIZE=2 CP_SIZE=2 TP_SIZE=2 torchrun --nproc_per_node=8 examples/3D_parallel.py
TP_SIZE=1 CP_SIZE=4 torchrun --nproc_per_node=4 examples/3D_parallel.py
TP_SIZE=1 DP_SIZE=4 torchrun --nproc_per_node=4 examples/3D_parallel.py
TP_SIZE=4 DP_SIZE=1 torchrun --nproc_per_node=4 --rdzv_endpoint=localhost:29503 examples/3D_parallel.py
IGNORE_SANITY=1 CP_SIZE=1 TP_SIZE=1 DP_SIZE=1 torchrun --nproc_per_node=1 --rdzv_endpoint=localhost:29504 examples/3D_parallel.py
ocalhost:29504 test_train.py
"""
import logging
import os
from collections.abc import Iterable
from contextlib import nullcontext
import torch
import torch.distributed as dist
import torch.distributed.checkpoint as dcp
import torch.optim as optim
import wandb
from datasets import load_dataset
from torch.distributed.checkpoint.state_dict import get_state_dict, set_state_dict
from torch.distributed.checkpoint.stateful import Stateful
from torch.distributed.device_mesh import DeviceMesh
from torch.distributed.fsdp import FullyShardedDataParallel as FSDP
from torch.distributed.fsdp import ShardingStrategy
from torch.distributed.tensor import DTensor
from torch.distributed.tensor.experimental import context_parallel
from torch.nn.attention import SDPBackend, sdpa_kernel
from torch.utils.data import DataLoader
from torch.utils.data.distributed import DistributedSampler
from transformers import AutoModelForCausalLM, AutoTokenizer
# torch.use_deterministic_algorithms(True)
torch.backends.cudnn.deterministic = True
# Set up logging
logging.basicConfig(
format="%(asctime)s - %(levelname)s - %(name)s - %(message)s",
datefmt="%m/%d/%Y %H:%M:%S",
level=logging.INFO,
)
logger = logging.getLogger(__name__)
# from torch.distributed.tensor.experimental._attention import set_rotate_method
# set_rotate_method("alltoall") # CP rotate shards using all-to-all
def main():
tp_size = int(os.environ.get("TP_SIZE", 1))
dp_size = int(os.environ.get("DP_SIZE", 1))
cp_size = int(os.environ.get("CP_SIZE", 1)) # Add CP size configuration
sdpa_backend = SDPBackend.FLASH_ATTENTION # For CP
# sdpa_backend = SDPBackend.MATH # For CP
global_batch_size = 8 # Desired global batch size
seq_len = 1024 # Sequence length
num_train_steps = 10000 # Number of training steps
LR = 1e-5
model_name = "HuggingFaceTB/SmolLM2-1.7B"
# model_name = "unsloth/Llama-3.2-1B"
CHECKPOINT_DIR = f"checkpoint_tp{tp_size}_dp{dp_size}_cp{cp_size}"
# Initialize distributed environment
if "RANK" in os.environ and "WORLD_SIZE" in os.environ:
dist.init_process_group("nccl")
rank = dist.get_rank()
world_size = dist.get_world_size()
local_rank = int(os.environ["LOCAL_RANK"])
torch.cuda.set_device(local_rank)
assert world_size == tp_size * dp_size * cp_size, (
f"World size ({world_size}) must equal TP size ({tp_size}) * DP size ({dp_size}) * CP size ({cp_size})"
)
mesh = torch.arange(world_size).reshape(dp_size, tp_size, cp_size)
world_mesh = DeviceMesh(device_type="cuda", mesh=mesh, mesh_dim_names=("dp", "tp", "cp"))
tp_mesh = world_mesh["tp"]
dp_mesh = world_mesh["dp"]
cp_mesh = world_mesh["cp"]
world_mesh["dp", "cp"]._flatten(mesh_dim_name="dp_cp")
logger.info(f"Created DeviceMesh: {world_mesh}")
logger.info(
f"Distributed setup - Rank: {rank}, World size: {world_size}, Local rank: {local_rank}, DP: {dp_mesh.get_local_rank()}, TP: {tp_mesh.get_local_rank()}, CP: {cp_mesh.get_local_rank()}"
)
if dist.get_rank() == 0:
wandb.init(
project="tp_dp_test",
config={
"tp_size": tp_size,
"dp_size": dp_size,
"cp_size": cp_size,
"global_batch_size": global_batch_size,
"model_name": model_name,
"dataset": "roneneldan/TinyStories-1M",
"seq_len": seq_len,
"lr": LR,
"weight_decay": 0.1,
},
name=f"llama_tp{tp_size}_dp{dp_size}_cp{cp_size}"
if model_name == "unsloth/Llama-3.2-1B"
else f"tp{tp_size}_dp{dp_size}_cp{cp_size}",
)
logger.info("Wandb initialized.")
# Log the current file to wandb
wandb.save("test_train.py")
# Load model and tokenizer
logger.info(f"Loading model and tokenizer from {model_name}")
tokenizer = AutoTokenizer.from_pretrained(model_name)
if tokenizer.pad_token is None:
tokenizer.pad_token = tokenizer.eos_token
logger.info(f"Set pad_token to eos_token: {tokenizer.pad_token}")
model = AutoModelForCausalLM.from_pretrained(
model_name,
device_mesh=tp_mesh if dist.is_initialized() else None,
tp_plan="auto",
torch_dtype=torch.bfloat16,
)
logger.info(f"Model loaded onto device mesh: {tp_mesh}")
device = torch.device(f"cuda:{local_rank}")
logger.info(f"Using device: {device} for non-model tensors")
use_ddp = False
if dist.is_initialized() and dp_mesh.size() > 1:
model = FSDP(model, device_mesh=dp_mesh, sharding_strategy=ShardingStrategy.NO_SHARD)
use_ddp = True
pass
model.train()
logger.info("Loading TinyStories dataset...")
raw_dataset = load_dataset("roneneldan/TinyStories", split="train[:1%]") # Use 1% for faster testing
def tokenize_function(examples):
# Tokenize the text without padding
tokenized_batch = tokenizer(
examples["text"], padding=False, truncation=True, max_length=seq_len, return_tensors=None
)
# Set labels to be the same as input_ids for Causal LM
tokenized_batch["labels"] = tokenized_batch["input_ids"].copy()
return tokenized_batch
tokenized_dataset = raw_dataset.map(tokenize_function, batched=True, remove_columns=["text"])
logger.info(f"Dataset loaded and tokenized. Size: {len(tokenized_dataset)}")
# Create packed sequences
def create_packed_sequences(examples):
# Flatten all sequences
all_tokens = []
for input_ids in examples["input_ids"]:
all_tokens.extend(input_ids)
# Split into sequences of seq_len + 1 (for input + label)
num_sequences = len(all_tokens) // (seq_len + 1)
packed_input_ids = []
packed_labels = []
for i in range(num_sequences):
start_idx = i * (seq_len + 1)
end_idx = start_idx + (seq_len + 1)
# Get the full sequence
full_sequence = all_tokens[start_idx:end_idx]
# For input_ids, remove the last token
packed_input_ids.append(full_sequence[:-1])
# For labels, remove the first token
packed_labels.append(full_sequence[1:])
return {"input_ids": packed_input_ids, "labels": packed_labels}
# Apply packing to the dataset
packed_dataset = tokenized_dataset.map(
create_packed_sequences,
batched=True,
remove_columns=tokenized_dataset.column_names,
batch_size=1000, # Process in batches for efficiency
num_proc=60,
)
logger.info(f"Dataset packed. New size: {len(packed_dataset)}")
# Shuffle the packed dataset
packed_dataset = packed_dataset.shuffle(seed=42)
logger.info("Packed dataset shuffled")
# Calculate local batch size
if dist.is_initialized():
assert global_batch_size % dp_mesh.size() == 0, (
f"Global batch size ({global_batch_size}) must be divisible by DP size ({dp_mesh.size()})"
)
local_batch_size = global_batch_size // dp_mesh.size()
else:
local_batch_size = global_batch_size
logger.info(
f"Global batch size: {global_batch_size}, DP size: {dp_size if dist.is_initialized() else 1}, Local batch size: {local_batch_size}"
)
# Simple collate function since sequences are already packed
def collate_fn(batch):
input_ids = torch.tensor([item["input_ids"] for item in batch], dtype=torch.long)
labels = torch.tensor([item["labels"] for item in batch], dtype=torch.long)
return {"input_ids": input_ids, "labels": labels}
if dist.is_initialized():
sampler = DistributedSampler(
packed_dataset, num_replicas=dp_mesh.size(), rank=dp_mesh.get_local_rank(), shuffle=False
)
else:
sampler = None
dataloader = DataLoader(
packed_dataset,
batch_size=local_batch_size,
sampler=sampler,
shuffle=False,
collate_fn=collate_fn,
pin_memory=True,
)
logger.info(f"DataLoader created. Distributed: {dist.is_initialized()}")
optimizer = optim.AdamW(model.parameters(), lr=LR, weight_decay=0.1)
# Training loop
logger.info(f"Starting training for {num_train_steps} steps...")
model.train()
step = 0
while step < num_train_steps:
for batch in dataloader:
if step >= num_train_steps:
break # Exit loop if max steps reached
# Move batch to appropriate device
batch = {k: v.to(device) for k, v in batch.items()}
optimizer.zero_grad()
# Add position_ids to batch before CP sharding
batch_size = batch["input_ids"].shape[0]
position_ids = torch.arange(0, seq_len, dtype=torch.long, device=device)
position_ids = position_ids.unsqueeze(0).expand(batch_size, -1)
batch["position_ids"] = position_ids
from torch.distributed.tensor.experimental._attention import _cp_options
_cp_options.enable_load_balance = False
with sdpa_kernel(sdpa_backend): # TODO: ideally move this to attention implementation
cp_context = (
nullcontext()
if cp_mesh.size() == 1
else context_parallel(
cp_mesh,
buffers=[
batch["input_ids"],
batch["labels"],
batch["position_ids"],
],
buffer_seq_dims=[1, 1, 1],
)
)
with cp_context:
# Pop labels from batch before model forward pass
labels = batch.pop("labels")
outputs = model(**batch) # [mbs, seq_len/cp]
loss = outputs.loss
logits = outputs.logits
# Compute loss with shifted labels
loss = model.loss_function(
logits=logits, labels=None, shift_labels=labels, vocab_size=model.config.vocab_size
)
loss.backward()
# all reduce grads across dp_cp if applicable
all_reduce_grads(model, world_mesh, use_ddp=use_ddp)
if hasattr(model, "clip_grad_norm_"):
gradnorm = model.clip_grad_norm_(max_norm=1.0, norm_type=2.0) # TODO: fix reported gradnorm
else:
# only works with FSDP's NO_SHARD otherwise we should use FSDP's clip_grad_norm_
assert len(list(model.parameters())) > 5, "No parameters found in model. Probably DDP bug.."
gradnorm = clip_grad_norm_(model.parameters(), max_norm=1.0, norm_type=2.0, foreach=True)
optimizer.step()
# allreduce loss across cp_dp before logging
if dist.is_initialized() and (cp_mesh.size() > 1 or dp_mesh.size() > 1):
dist.all_reduce(loss, group=world_mesh["dp_cp"].get_group(), op=dist.ReduceOp.AVG)
current_loss = loss.item()
# Log loss and gradnorm to wandb (only on rank 0 of dp group)
if not dist.is_initialized() or dist.get_rank() == 0:
logger.info(
f"Step: {step} | GBS: {global_batch_size} | DP: {dp_mesh.size()} | TP: {tp_mesh.size()} | CP: {cp_mesh.size()} | Loss: {current_loss} | Gradnorm: {gradnorm} | lr: {LR}"
)
wandb.log(
{
"train/loss": current_loss,
"train/gradnorm": gradnorm,
"step": step,
"lr": LR,
"GBS": global_batch_size,
}
)
step += 1 # Increment step count
logger.info("Training loop finished.")
# Save model using DCP (only if distributed)
if dist.is_initialized():
state_dict = {"app": AppState(model, optimizer)}
dcp.save(
state_dict=state_dict,
checkpoint_id=CHECKPOINT_DIR,
)
logger.info(f"Saved checkpoint to {CHECKPOINT_DIR}")
else:
# Fallback to regular save for non-distributed case
save_dir = "test_model_nondist"
model.save_pretrained(save_dir, safe_serialization=False)
tokenizer.save_pretrained(save_dir) # Save tokenizer too
logger.info(f"Saved model to {save_dir}")
dist.destroy_process_group()
logger.info("Cleaned up distributed process group")
# Finish wandb run on rank 0
if dist.get_rank() == 0:
wandb.finish()
logger.info("Wandb run finished.")
def all_reduce_grads(model, world_mesh, use_ddp):
"""All reduce gradients across dp_cp if applicable."""
cp_mesh = world_mesh["cp"]
if use_ddp:
# DDP/FSDP takes care of syncing grads
mesh = cp_mesh
else:
mesh = world_mesh["dp", "cp"]._flatten(mesh_dim_name="dp_cp")
if dist.is_initialized() and mesh.size() > 1:
for name, param in model.named_parameters():
if param.grad is not None:
# Workaround for cross-mesh communication limitation with DTensor gradients
if isinstance(param.grad, DTensor):
local_grad = param.grad.to_local()
# Ensure grad requires grad for inplace modification checks (might not be needed)
# local_grad = local_grad.detach().requires_grad_(True)
torch.distributed.all_reduce(local_grad, op=torch.distributed.ReduceOp.SUM, group=mesh.get_group())
local_grad = local_grad / mesh.size()
# Assign averaged grad back - need careful handling if DTensor structure is complex
# This simple assignment might work if the grad structure matches param structure
param.grad = DTensor.from_local(
local_grad, device_mesh=param.grad.device_mesh, placements=param.grad.placements
)
else:
# Handle regular tensors if any exist (e.g. buffers not converted to DTensor)
torch.distributed.all_reduce(param.grad, op=torch.distributed.ReduceOp.AVG, group=mesh.get_group())
class AppState(Stateful):
"""Wrapper for checkpointing the Application State including model and optimizer."""
def __init__(self, model, optimizer=None):
self.model = model
self.optimizer = optimizer
def state_dict(self):
model_state_dict, optimizer_state_dict = get_state_dict(self.model, self.optimizer)
return {"model": model_state_dict, "optim": optimizer_state_dict}
def load_state_dict(self, state_dict):
set_state_dict(
self.model, self.optimizer, model_state_dict=state_dict["model"], optim_state_dict=state_dict["optim"]
)
def clip_grad_norm_(
parameters: Iterable[torch.Tensor],
max_norm: float,
norm_type: float = 2.0,
error_if_nonfinite: bool = False,
foreach: bool | None = None,
) -> torch.Tensor:
"""
Clip the gradient norm of an iterable of parameters.
"""
# Filter out parameters with no gradients
parameters = [p for p in parameters if p.grad is not None]
assert len(parameters) > 0, "No parameters with gradients found"
# Calculate total norm
if norm_type == float("inf"):
total_norm = max(p.grad.detach().abs().max() for p in parameters)
else:
total_norm = torch.norm(torch.stack([torch.norm(p.grad.detach(), norm_type) for p in parameters]), norm_type)
# Convert DTensor to local tensor if needed
if isinstance(total_norm, DTensor):
total_norm = total_norm.full_tensor()
# Clip gradients
clip_coef = max_norm / (total_norm + 1e-6)
if clip_coef < 1:
for p in parameters:
p.grad.detach().mul_(clip_coef)
return total_norm
if __name__ == "__main__":
main()
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