StarCoder2-Instruct: Fully Transparent and Permissive Self-Alignment for Code Generation

⭐️ About | 🚀 Quick start | 📚 Data generation | 🧑‍💻 Training | 📊 Evaluation | ⚠️ Limitations

About

We introduce StarCoder2-15B-Instruct-v0.1, the very first entirely self-aligned code Large Language Model (LLM) trained with a fully permissive and transparent pipeline. Our open-source pipeline uses StarCoder2-15B to generate thousands of instruction-response pairs, which are then used to fine-tune StarCoder-15B itself without any human annotations or distilled data from huge and proprietary LLMs.

• Model: bigcode/starcoder2-15b-instruct-v0.1
• Code: bigcode-project/starcoder2-self-align
• Dataset: bigcode/self-oss-instruct-sc2-exec-filter-50k
• Authors: Yuxiang Wei, Federico Cassano, Jiawei Liu, Yifeng Ding, Naman Jain, Harm de Vries, Leandro von Werra, Arjun Guha, Lingming Zhang.

Quick start

Here is an example to get started with StarCoder2-15B-Instruct-v0.1 using the transformers library:

import transformers
import torch

pipeline = transformers.pipeline(
    model="bigcode/starcoder2-15b-instruct-v0.1",
    task="text-generation",
    torch_dtype=torch.bfloat16,
    device_map="auto",
)

def respond(instruction: str, response_prefix: str) -> str:
    messages = [{"role": "user", "content": instruction}]
    prompt = pipeline.tokenizer.apply_chat_template(messages, tokenize=False)
    prompt += response_prefix

    teminators = [
        pipeline.tokenizer.eos_token_id,
        pipeline.tokenizer.convert_tokens_to_ids("###"),
    ]

    result = pipeline(
        prompt,
        max_length=256,
        num_return_sequences=1,
        do_sample=False,
        eos_token_id=teminators,
        pad_token_id=pipeline.tokenizer.eos_token_id,
        truncation=True,
    )
    response = response_prefix + result[0]["generated_text"][len(prompt) :].split("###")[0].rstrip()
    return response


instruction = "Write a quicksort function in Python with type hints and a 'less_than' parameter for custom sorting criteria."
response_prefix = ""

print(respond(instruction, response_prefix))

Data generation pipeline

Run pip install -e . first to install the package locally. Check seed_gathering for details on how we collected the seeds.

We used vLLM's OpenAI compatible server for data generation. So, before running the following commands, make sure the vLLM server is running, and the associated openai environment variables are set.

For example, you can start an vLLM server with docker:

docker run --gpus '"device=0"' \
    -v $HF_HOME:/root/.cache/huggingface \                            
    -p 10000:8000 \
    --ipc=host \
    vllm/vllm-openai:v0.3.3 \
    --model bigcode/starcoder2-15b \
    --tensor-parallel-size 1 --dtype bfloat16

And then set the environment variables as follows:

export OPENAI_API_KEY="EMPTY"
export OPENAI_BASE_URL="http://localhost:10000/v1/"

Snippet to concepts generation

python src/star_align/self_ossinstruct.py \
    --instruct_mode "S->C" \
    --seed_data_files /path/to/seeds.jsonl \
    --max_new_data 50000 \
    --tag concept_gen \
    --temperature 0.7 \
    --seed_code_start_index 0 \
    --model bigcode/starcoder2-15b \
    --num_fewshots 8 \
    --num_batched_requests 32 \
    --num_sample_per_request 1

Concepts to instruction generation

python src/star_align/self_ossinstruct.py \
    --instruct_mode "C->I" \
    --seed_data_files /path/to/concepts.jsonl \
    --max_new_data 50000 \
    --tag instruction_gen \
    --temperature 0.7 \
    --seed_code_start_index 0 \
    --model bigcode/starcoder2-15b \
    --num_fewshots 8 \
    --num_sample_per_request 1 \
    --num_batched_request 32

Instruction to response (with self-validation code) generation

python src/star_align/self_ossinstruct.py \
    --instruct_mode "I->R" \
    --seed_data_files path/to/instructions.jsonl  \
    --max_new_data 50000 \
    --tag response_gen \
    --seed_code_start_index 0 \
    --model bigcode/starcoder2-15b \
    --num_fewshots 1 \
    --num_batched_request 8 \
    --num_sample_per_request 10 \
    --temperature 0.7

Execution filter

Warning: Though we implemented reliability guards, it is highly recommended to run execution in a sandbox environment. The command below doesn't provide sandboxing by default.

python src/star_align/execution_filter.py --response_path /path/to/response.jsonl --result_path /path/to/filtered.jsonl
# The current implementation may cause deadlock.
# If you encounter deadlock, manually do `ps -ef | grep execution_filter` and kill the stuck process.
# Note that filtered.jsonl may contain multiple passing samples for the same instruction which needs further selection.

For using the the Docker container for executing code, you will first need to git submodule update --init --recursive to clone the server, then run:

pushd ./src/star_align/code_exec_server
./build_and_run.sh
popd
python src/star_align/execution_filter.py --response_path /path/to/response.jsonl --result_path /path/to/filtered.jsonl --container_server http://127.0.0.1:8000

Data sanitization and selection

RAW=1 python src/star_align/sanitize_data.py /path/to/filtered.jsonl /path/to/sanitized.jsonl
python src/star_align/clean_data.py --data_files /path/to/sanitized.jsonl --output_file /path/to/sanitized.jsonl --diversify_func_names
SMART=1 python src/star_align/sanitize_data.py /path/to/sanitized.jsonl /path/to/sanitized.jsonl

Training Details

Run pip install -e . first to install the package locally. And install Flash Attention to speed up the training.

Hyperparameters

• Optimizer: Adafactor
• Learning rate: 1e-5
• Epoch: 4
• Batch size: 64
• Warmup ratio: 0.05
• Scheduler: Linear
• Sequence length: 1280
• Dropout: Not applied

Hardware

1 x NVIDIA A100 80GB. Yes, you just need one A100 to finetune StarCoder2-15B!

Script

The following script finetunes StarCoder2-15B-Instruct-v0.1 from the base StarCoder2-15B model. /path/to/dataset.jsonl is the JSONL format of the 50k dataset we generated. You can dump the dataset to JSONL to fit the training script.

Click to see the training script

NOTE: StarCoder2-15B sets dropout values to 0.1 by default. We did not apply dropout in finetuning and thus set the them to 0.0.

MODEL_KEY=bigcode/starcoder2-15b
LR=1e-5
EPOCH=4
SEQ_LEN=1280
WARMUP_RATIO=0.05
OUTPUT_DIR=/path/to/output_model
DATASET_FILE=/path/to/50k-dataset.jsonl
accelerate launch -m star_align.train \
    --model_key $MODEL_KEY \
    --model_name_or_path $MODEL_KEY \
    --use_flash_attention True \
    --datafile_paths $DATASET_FILE \
    --output_dir $OUTPUT_DIR \
    --bf16 True \
    --num_train_epochs $EPOCH \
    --max_training_seq_length $SEQ_LEN \
    --pad_to_max_length False \
    --per_device_train_batch_size 1 \
    --gradient_accumulation_steps 64 \
    --group_by_length False \
    --ddp_find_unused_parameters False \
    --logging_steps 1 \
    --log_level info \
    --optim adafactor \
    --max_grad_norm -1 \
    --warmup_ratio $WARMUP_RATIO \
    --learning_rate $LR \
    --lr_scheduler_type linear \
    --attention_dropout 0.0 \
    --residual_dropout 0.0 \
    --embedding_dropout 0.0

Evaluation on EvalPlus, LiveCodeBench, and DS-1000

Check evaluation for more details.

Bias, Risks, and Limitations

StarCoder2-15B-Instruct-v0.1 is primarily finetuned for Python code generation tasks that can be verified through execution, which may lead to certain biases and limitations. For example, the model might not adhere strictly to instructions that dictate the output format. In these situations, it's beneficial to provide a response prefix or a one-shot example to steer the model’s output. Additionally, the model may have limitations with other programming languages and out-of-domain coding tasks.

The model also inherits the bias, risks, and limitations from its base StarCoder2-15B model. For more information, please refer to the StarCoder2-15B model card.