Fine-tune MiniCPM5-1B with xtuner

mmengine config-driven SFT. Uses Python config files (not YAML) and integrates with mmengine's runner / hook system.

Required input

Var	Example	Default
BASE_MODEL	openbmb/MiniCPM5-1B	required
DATA	path to messages-format jsonl	required
WORK_DIR	./runs/minicpm5_xtuner	required

Steps

1. Install (once)

pip install "xtuner==0.2.0"
# Replace opencv-python with the headless variant (avoids libGL linkage)
pip install --force-reinstall opencv-python-headless
pip uninstall -y opencv-python

2. Save the config, ${WORK_DIR}/minicpm5_lora.py

import torch
from datasets import load_dataset
from mmengine.dataset import DefaultSampler
from mmengine.hooks import (CheckpointHook, DistSamplerSeedHook, IterTimerHook,
                            LoggerHook, ParamSchedulerHook)
from mmengine.optim import AmpOptimWrapper, CosineAnnealingLR, LinearLR
from peft import LoraConfig
from torch.optim import AdamW
from transformers import AutoModelForCausalLM, AutoTokenizer

from xtuner.dataset import process_hf_dataset
from xtuner.dataset.collate_fns import default_collate_fn
from xtuner.dataset.map_fns import openai_map_fn, template_map_fn_factory
from xtuner.engine.hooks import DatasetInfoHook
from xtuner.engine.runner import TrainLoop
from xtuner.model import SupervisedFinetune
from xtuner.utils import PROMPT_TEMPLATE

pretrained_model_name_or_path = "${BASE_MODEL}"      # ← replace
data_path = "${DATA}"                                # ← replace
prompt_template = PROMPT_TEMPLATE.qwen_chat          # 🔑 ChatML, DO NOT use llama3_chat
max_length = 2048

batch_size = 4
accumulative_counts = 4
max_epochs = 2
lr = 2e-4
warmup_ratio = 0.03

tokenizer = dict(type=AutoTokenizer.from_pretrained,
                 pretrained_model_name_or_path=pretrained_model_name_or_path,
                 trust_remote_code=False, padding_side="right")