lightllm: A Python repository from cdj0311

LightLLM is a Python-based LLM (Large Language Model) inference and serving framework, notable for its lightweight design, easy scalability, and high-speed performance. LightLLM harnesses the strengths of numerous well-regarded open-source implementations, including but not limited to FasterTransformer, TGI, vLLM, and FlashAttention.

Features

Tri-process asynchronous collaboration: tokenization, model inference, and detokenization are performed asynchronously, leading to a considerable improvement in GPU utilization.
Nopad (Unpad): offers support for nopad attention operations across multiple models to efficiently handle requests with large length disparities.
Dynamic Batch: enables dynamic batch scheduling of requests
FlashAttention: incorporates FlashAttention to improve speed and reduce GPU memory footprint during inference.
Tensor Parallelism: utilizes tensor parallelism over multiple GPUs for faster inference.
Token Attention: implements token-wise's KV cache memory management mechanism, allowing for zero memory waste during inference.
High-performance Router: collaborates with Token Attention to meticulously manage the GPU memory of each token, thereby optimizing system throughput.

Supported Model List

Get started

Requirements

The code has been tested with Pytorch>=1.3, CUDA 11.8, and Python 3.9. To install the necessary dependencies, please refer to the provided requirements.txt and follow the instructions as

pip install -r requirements.txt

A more straightforward approach is to use the official Docker container:

docker build -t image_name .
docker run -it --gpus all -p 8080:80 -v your_local_path:/data/ image_name /bin/bash

Installation

Install from the source code by

python setup.py install

The code has been tested on a range of GPUs including V100, A100, A800, 4090, and H800. If you are running the code on V100, A100, A800, etc., we recommend using triton==2.0.0.dev20221202. If you are running the code on 4090, H800, etc., it is necessary to compile and install the source code of triton==2.1.0 from the GitHub repository. If the code doesn't work on other GPUs, try modifying the triton kernel used in model inference.

RUN LLaMA

With efficient Routers and TokenAttention, LightLLM can be deployed as a service and achieve the state-of-the-art throughput performance.

Launch the server:

python -m lightllm.server.api_server --model_dir /path/llama-7B --tp 1 --max_total_token_num 120000

The parameter max_total_token_num is influenced by the GPU memory of the deployment environment. A larger value for this parameter allows for the processing of more concurrent requests, thereby increasing system concurrency. For more startup parameters, please refer to api_server.py.

To initiate a query in the shell:

curl 127.0.0.1:8000/generate \
    -X POST \
    -d '{"inputs":"What is AI?","parameters":{"max_new_tokens":17, "frequency_penalty":1}}' \
    -H 'Content-Type: application/json'

To query from Python:

    import time
    import requests
    import json

    url = 'http://localhost:8000/generate'
    headers = {'Content-Type': 'application/json'}
    data = {
        'inputs': 'What is AI?',
        "parameters": {
            'do_sample': False,
            'ignore_eos': False,
            'max_new_tokens': 1024,
        }
    }
    response = requests.post(url, headers=headers, data=json.dumps(data))
    if response.status_code == 200:
        print(response.json())
    else:
        print('Error:', response.status_code, response.text)

Performance

Service Performance

We compared the service performance of LightLLM and vLLM==0.1.2 on LLaMA-7B using an A800 with 80G GPU memory.

To begin, prepare the data as follows:

wget https://huggingface.co/datasets/anon8231489123/ShareGPT_Vicuna_unfiltered/resolve/main/ShareGPT_V3_unfiltered_cleaned_split.json

Launch the service:

python -m lightllm.server.api_server --model_dir /path/llama-7b --tp 1 --max_total_token_num 121060 --tokenizer_mode auto

Evaluation:

cd test
python benchmark_serving.py --tokenizer /path/llama-7b --dataset /path/ShareGPT_V3_unfiltered_cleaned_split.json --num-prompts 2000 --request-rate 200

The performance comparisons results are presented below:

vLLM	LightLLM
Total time: 361.79 s Throughput: 5.53 requests/s	Total time: 188.85 s Throughput: 10.59 requests/s

Static inference performance

For debugging, we offer static performance testing scripts for various models. For instance, you can evaluate the inference performance of the LLaMA model by

cd test/lightllama
python test_model_infer.py

FAQ

In case the LLaMA tokenizer fails to load, consider resolving this by running the command 'pip install protobuf==3.20.0'.

License

This repository is released under the Apache-2.0 license.

Acknowledgement

We learned a lot from the following projects when developing LightLLM.

cdj0311/lightllm