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Download scripts/train_peft.py from YukiKaze1337/cn-sqlite-sft: direct link, hf CLI and curl.
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https://huggingface.co/datasets/YukiKaze1337/cn-sqlite-sft/resolve/main/scripts/train_peft.py
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4.71 kB
| """bf16 LoRA 训练,不依赖 unsloth 和 bitsandbytes。 | |
| python scripts/train_peft.py --data data/train.jsonl --out /workspace/out | |
| """ | |
| import argparse | |
| from pathlib import Path | |
| import torch | |
| from datasets import load_dataset | |
| from peft import LoraConfig, get_peft_model | |
| from transformers import AutoModelForCausalLM, AutoTokenizer, set_seed | |
| from trl import SFTConfig, SFTTrainer | |
| def main() -> None: | |
| ap = argparse.ArgumentParser() | |
| ap.add_argument("--model", default="Qwen/Qwen3-4B-Instruct-2507") | |
| ap.add_argument("--data", default="train.jsonl") | |
| ap.add_argument("--out", default="/workspace/out") | |
| ap.add_argument("--epochs", type=float, default=3.0) | |
| ap.add_argument("--lr", type=float, default=2e-4) | |
| # 有效 batch = bs × accum = 16。第二轮最长样本 2678 token(第一轮 827),4090 上 bs 4 会爆;还 OOM 就 --bs 1 --accum 16 | |
| ap.add_argument("--bs", type=int, default=2) | |
| ap.add_argument("--accum", type=int, default=8) | |
| ap.add_argument("--seq", type=int, default=3072) | |
| ap.add_argument("--no-group", action="store_true", | |
| help="不按长度分组。默认分组:样本从两百到两千多 token 不等,随机凑一批的话短的要补齐到长的,白算一大半") | |
| ap.add_argument("--rank", type=int, default=32) | |
| ap.add_argument("--seed", type=int, default=42) | |
| ap.add_argument("--smoke", type=int, default=0, help="只跑这么多步,用来验流程(不合并、不存 8G 的合并版)") | |
| ap.add_argument("--no-merge", action="store_true", help="只存 LoRA,不存 8G 的合并版(评测用 --adapter)") | |
| args = ap.parse_args() | |
| set_seed(args.seed) # LoRA 的初始化在 Trainer 设种子之前,不在这里设的话两次训练结果不一样 | |
| tok = AutoTokenizer.from_pretrained(args.model) | |
| model = AutoModelForCausalLM.from_pretrained( | |
| args.model, torch_dtype=torch.bfloat16, device_map="cuda" | |
| ) | |
| model.gradient_checkpointing_enable() | |
| model = get_peft_model(model, LoraConfig( | |
| r=args.rank, lora_alpha=args.rank * 2, lora_dropout=0.0, bias="none", | |
| task_type="CAUSAL_LM", | |
| target_modules=["q_proj", "k_proj", "v_proj", "o_proj", | |
| "gate_proj", "up_proj", "down_proj"], | |
| )) | |
| model.print_trainable_parameters() | |
| ds = load_dataset("json", data_files=args.data, split="train") | |
| # 超过 max_length 的样本 TRL 会从右边悄悄截断,截掉的正好是 SQL;宁可直接停下 | |
| longest = max(len(tok.apply_chat_template(r["messages"], tokenize=True)) for r in ds) | |
| assert longest <= args.seq, f"最长样本 {longest} token,超过 --seq {args.seq},会把 SQL 截掉" | |
| print(f"最长样本 {longest} token(上限 {args.seq})", flush=True) | |
| # 拆成 prompt / completion,TRL 只在 SQL 上算 loss。 | |
| # 直接喂 messages 的话 loss 算在整条序列上,85% 的 token 是系统提示和建表语句,等于在背 schema。 | |
| ds = ds.map(lambda r: {"prompt": r["messages"][:-1], "completion": r["messages"][-1:]}, | |
| remove_columns=ds.column_names) | |
| print("样本", len(ds), flush=True) | |
| cfg = SFTConfig( | |
| output_dir=args.out, | |
| per_device_train_batch_size=args.bs, | |
| gradient_accumulation_steps=args.accum, | |
| num_train_epochs=args.epochs, | |
| max_steps=args.smoke if args.smoke else -1, | |
| learning_rate=args.lr, | |
| lr_scheduler_type="cosine", | |
| warmup_ratio=0.03, | |
| logging_steps=10, | |
| # 每个 epoch 存一份 LoRA(out/checkpoint-*),评测时用 eval.py --adapter 比较几个 epoch 哪个好 | |
| save_strategy="no" if args.smoke else "epoch", | |
| save_only_model=True, | |
| bf16=True, | |
| optim="adamw_torch", | |
| max_length=args.seq, | |
| group_by_length=not args.no_group, | |
| # 不 packing:TRL 的 bfd packing 要 flash-attention,否则拼在一起的样本会互相看到;样本都短,不 packing 也不亏 | |
| packing=False, | |
| dataset_kwargs={"skip_prepare_dataset": False}, | |
| report_to="none", | |
| seed=args.seed, | |
| ) | |
| trainer = SFTTrainer(model=model, train_dataset=ds, args=cfg, processing_class=tok) | |
| trainer.train() | |
| out = Path(args.out) | |
| model.save_pretrained(str(out / "lora")) | |
| tok.save_pretrained(str(out / "lora")) | |
| print("LoRA 存好了", flush=True) | |
| if args.smoke or args.no_merge: | |
| print("不合并", flush=True) | |
| return | |
| merged = model.merge_and_unload() | |
| merged.save_pretrained(str(out / "merged"), safe_serialization=True) | |
| tok.save_pretrained(str(out / "merged")) | |
| print("合并版存好了", flush=True) | |
| if __name__ == "__main__": | |
| main() | |