basic torchao fp8 mixed precision training (#2926)

* debug

* debug

* debug

* revert unneeded change

* add accelerator config to base trainer builder

* add back accumulated_cache_size_limit setting

* lint

* accelerator constructor patch for single-GPU torch fp8

* lint

* re-using existing fp8 code

* lint

* remove accelerate patch now fix in latest release

* fix

* docs

* add fp8 + fsdp2 example

* remove unused config

* update config

* smoke tests

* add validator

* add 2.7.0 guard for fsdp2

* fix

* add config descriptions

* add FSDP doc link

* nit

* set force_recompute_fp8_weight_in_bwd with enable_fsdp_float8_all_gather

* better cfg for smoke tests

* add test for accelerate patching

* update fp8 validator
This commit is contained in:
Dan Saunders
2025-07-22 16:27:47 -04:00
committed by GitHub
parent b86a1d47b0
commit 208fb7b8e7
11 changed files with 503 additions and 10 deletions

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"""
Simple end-to-end smoke tests for FP8 mixed precision training
"""
from axolotl.common.datasets import load_datasets
from axolotl.train import train
from axolotl.utils.config import normalize_config, validate_config
from axolotl.utils.dict import DictDefault
from tests.e2e.utils import check_model_output_exists, require_torch_2_7_0
class FP8IntegrationTestCase:
"""
e2e smoke tests for FP8 mixed precision training with Axolotl
"""
@require_torch_2_7_0
def test_fp8_single_gpu_smoke(self, temp_dir):
"""Smoke test for single GPU FP8 + torch.compile training"""
# pylint: disable=duplicate-code
cfg = DictDefault(
{
"base_model": "HuggingFaceTB/SmolLM2-135M",
"tokenizer_type": "AutoTokenizer",
"trust_remote_code": True,
"sequence_len": 512,
"val_set_size": 0.05,
"special_tokens": {
"pad_token": "<|endoftext|>",
},
"datasets": [
{
"path": "mhenrichsen/alpaca_2k_test",
"type": "alpaca",
},
],
"num_epochs": 1,
"max_steps": 3, # Very short smoke test
"micro_batch_size": 1,
"gradient_accumulation_steps": 2,
"output_dir": temp_dir,
"learning_rate": 0.00001,
"optimizer": "adamw_torch_fused",
"lr_scheduler": "cosine",
"sdp_attention": True,
"pad_to_seq_len": True,
"sample_packing": True,
"fp8": True,
"torch_compile": True,
"save_safetensors": True,
"save_first_step": False,
}
)
# pylint: disable=duplicate-code
cfg = validate_config(cfg)
normalize_config(cfg)
dataset_meta = load_datasets(cfg=cfg)
train(cfg=cfg, dataset_meta=dataset_meta)
check_model_output_exists(temp_dir, cfg)

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"""Test module for FP8 mixed precision with FSDP2 multi-GPU functionality."""
# pylint: disable=duplicate-code
import os
from pathlib import Path
import torch
import yaml
from accelerate.test_utils import execute_subprocess_async
from tbparse import SummaryReader
from transformers.testing_utils import get_torch_dist_unique_port
from axolotl.utils.dict import DictDefault
from tests.e2e.utils import most_recent_subdir, require_torch_2_7_0
AXOLOTL_ROOT = Path(__file__).parent.parent.parent.parent
def verify_fp8_training_success(temp_dir):
"""Verify that FP8 training completed successfully by checking artifacts and loss."""
output_path = Path(temp_dir)
model_files = list(output_path.glob("*.bin")) + list(
output_path.glob("*.safetensors")
)
assert len(model_files) > 0, "No model files found - training may have failed"
checkpoint_files = list(output_path.glob("checkpoint-*"))
assert (
len(checkpoint_files) > 0
), "No checkpoint files found - training may have failed"
tb_log_path = most_recent_subdir(temp_dir + "/runs")
if tb_log_path:
event_files = sorted(os.listdir(tb_log_path))
if event_files:
event_file = os.path.join(tb_log_path, event_files[0])
reader = SummaryReader(event_file)
df = reader.scalars
train_loss_df = df[df.tag == "train/train_loss"]
if len(train_loss_df) > 0:
final_loss = train_loss_df.value.values[-1]
assert not torch.isnan(
torch.tensor(final_loss)
), f"Training loss is NaN: {final_loss}"
class TestFP8FSDP2:
"""Test class for FP8 mixed precision with FSDP2 functionality."""
@require_torch_2_7_0
def test_fp8_fsdp2_smoke(self, temp_dir):
"""Smoke test for 2-GPU FP8 + torch.compile + FSDP2 training"""
cfg = DictDefault(
{
"base_model": "HuggingFaceTB/SmolLM2-135M",
"tokenizer_type": "AutoTokenizer",
"trust_remote_code": True,
"sequence_len": 512,
"val_set_size": 0.05,
"special_tokens": {
"pad_token": "<|endoftext|>",
},
"datasets": [
{
"path": "mhenrichsen/alpaca_2k_test",
"type": "alpaca",
},
],
"num_epochs": 1,
"max_steps": 3, # Very short smoke test
"micro_batch_size": 1,
"gradient_accumulation_steps": 1,
"output_dir": temp_dir,
"learning_rate": 0.00001,
"optimizer": "adamw_torch_fused", # Use standard optimizer for stability
"lr_scheduler": "cosine",
"sdp_attention": True,
"pad_to_seq_len": True,
"sample_packing": True,
# FP8 configuration
"fp8": True,
"fp8_enable_fsdp_float8_all_gather": True,
"torch_compile": True,
# FSDP2 configuration
"fsdp_version": 2,
"fsdp_config": {
"offload_params": False,
"cpu_ram_efficient_loading": False,
"transformer_layer_cls_to_wrap": "LlamaDecoderLayer",
"state_dict_type": "FULL_STATE_DICT",
"auto_wrap_policy": "TRANSFORMER_BASED_WRAP",
"reshard_after_forward": True,
},
"use_tensorboard": True,
"save_safetensors": True,
"save_first_step": False,
}
)
# write cfg to yaml file
Path(temp_dir).mkdir(parents=True, exist_ok=True)
with open(Path(temp_dir) / "config.yaml", "w", encoding="utf-8") as fout:
fout.write(yaml.dump(cfg.to_dict(), Dumper=yaml.Dumper))
execute_subprocess_async(
[
"axolotl",
"train",
str(Path(temp_dir) / "config.yaml"),
"--num-processes",
"2",
"--main-process-port",
f"{get_torch_dist_unique_port()}",
]
)
verify_fp8_training_success(temp_dir)