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Consistency large language models (CLLMs) is a new family of models capable of reducing inference latency by efficiently decoding $n$ tokens in parallel. This decoding method is called Jacobi decoding, which improves inference efficiency in comparison with conventional auto-regressive (AR) decoding. CLLMs are trained with the objective of performing efficient Jacobi decoding by mapping any randomly initialized $n$-token sequence to the same result as AR decoding in as few steps as possible.

Experiment results have demonstrated the effectiveness of CLLMs, showing $2.4\times$ to $3.4\times$ improvements in generation speed on a variety of tasks.

A demo of using CLLM to achieve significant improvements ($\sim3\times$) in generation speed to solve a basic math problem is shown below:

Contents

• News
• Introduction
• Installation
• Model Weights
• Usage
  • Inference
  • Training
  • Evaluation
• Citation

News 🔥

• [2024/3] CLLMs are integrated in FastChat!
• [2024/2] CLLM Paper now available on arXiv. CLLMs model checkpoints are released on Huggingface Hub.

Introduction

Consistency Large Language Models (CLLMs) is a family of efficient parallel decoders refined from pre-trained LLMs.

Compared with existing fast decoding techniques, CLLMs achieve fast parallel decoding without the need for:

• Draft models
• Architectural modifications/auxiliary model components

This introduces a number of advantages for CLLMs:

• CLLMs don't have to deal with the complexity of obtaining 'good' draft models and managing two different models in a single system.
• CLLMs share the same architecture with target LLMs and require no additional engineering efforts when adopting the technique to different models.
• CLLMs can be integrated seamlessly with other techniques for efficient LLM inference (e.g. Lookahead Decoding) to achieve even more significant speedup.

Installation

1. Environment setup:

conda create -n cllm python=3.10
conda activate cllm

2. Clone this repository and build from source:

git clone git@github.com:hao-ai-lab/Consistency_LLM.git
cd Consistency_LLM

3. Install dependency:

pip install -r requirements.txt
pip install flash-attn==2.4.1

Model Weights

Target Pre-trained Models

CLLMs

Usage

Inference

bash applications/run_chat_cllm.sh {model_path} {cllm_type}

cllm_type can take the value of spider, python, gsm8k, sharegpt.

Training

1. Collect Jacobi trajectory:

• Method 1: Directly download Jacobi trajectory to data/collected_jacobi_trajectory/ from our Huggingface Hub page.
• Method 2 (Generate trajectory suitable to your own target model and dataset): Some raw datasets that contain additional information like database dependency or cannot be directly loaded from Huggingface Hub (for example, Spider and ShareGPT are required to be installed in data/raw_data). Then run scripts/generate_trajectory.sh and the training dataset for a CLLM will be saved in data/collected_jacobi_trajectory/.

For example, for the gsm8k dataset, run:

# max_new_tokens corresponds to the size of n_token_sequence
CUDA_VISIBLE_DEVICES=0 bash scripts/generate_trajectory.sh {filename} {model_path} {n_token_seq_size} {max_new_seq_len}

Other command options

--filename: path to the raw dataset, currently supporting {data/raw_data/spider, code_search_net, data/raw_data/gsm8k_train.jsonl, data/raw_data/ShareGPT_V3_unfiltered_cleaned_split.json} \ 
--data_size: maximum number of prompts used to extract Jacobi trajectories \ 
--use_aug: use data augmentation technique \
--use_labels: add dataset's labels to the output file

2. Train a CLLM:

bash scripts/train_cllm.sh {model_path} {trajectory_file} {output_path} {n_token_seq_size}

Evaluation

We follow the same settings in human-eval, Spider, MT-bench and GSM8K evaluate CLLMs' generation quality. An example code to evaluate CLLMs' throughput measured in tokens/s, fast-forwarded token count, stationary token count can be found in eval folder. Take GSM8K dataset as an example:

To test the speedup, run:

CUDA_VISIBLE_DEVICES=0 bash eval/gsm8k/speedup.sh {model_path} {target_model_path} {max_new_tokens}

To test the accuracy, run:

CUDA_VISIBLE_DEVICES=0 python eval/gsm8k/acc.py --model_dir path_to_cllm --temperature 0.0 --top_p 1.0 --output_file_name 'cllm_generated_gsm8k.jsonl' \
--dev_set "gsm8k" --prompt_type math-single --max_new_tokens_for_consistency 16 --max_tokens 1024 --use_consistency_decoding

Citation

This is the official project repository for the following paper. If you find this repository helpful, Please kindly cite:

@misc{kou2024cllms,
      title={CLLMs: Consistency Large Language Models}, 
      author={Siqi Kou and Lanxiang Hu and Zhezhi He and Zhijie Deng and Hao Zhang},
      year={2024},
      eprint={2403.00835},
      archivePrefix={arXiv},
      primaryClass={cs.CL}
}