MLX-Textgen

A python package for serving LLM on OpenAI-compatible API endpoints with prompt caching using MLX

MLX-Textgen is a light-weight LLM serving engine that utilize MLX and a smart KV cache management system to make your LLM generation more seamless on your Apple silicon machine. It features:

Multiple KV-cache slots to reduce the needs of prompt processing
Multiple models serving with Fastapi
Common OpenAI API endpoints: /v1/models, /v1/completions, /v1/chat/completions

Installing MLX-Textgen

MLX-textgen can be easily installed with pip

pip install mlx-textgen

Features

1. Multiple KV cache slots support

All the KV cache are stored on disk. Therefore, unlike other LLM serving engine, a newly created KV cache will not overwrite the existing KV cache. This works better for agenic workflows where different types of prompts are being used frequently without losing previous cache for a long prompt.

2. Multiple LLM serving

Only one model is loaded on ram at a time, but the engine leverage MLX fast module loading time to spin up another model when it is requested. This allows serving multiple models with one endpoint.

3. Automatic model quantisation

When configuring your model, you can specify the quantisation to increase your inference speed and lower memory usage. The original model is converted to MLX quantised model format when initialising the serving engine.

Usage

1. Serving a single model

You can quickly set up a OpenAI API server with a single command.

mlx_textgen.server --model NousResearch/Hermes-3-Llama-3.1-8B --qunatize q8 --port 5001

2. Serving a multiple models

Create a config file template and add as many model as you like.

mlx_textgen.create_config --num-models 2

It will generate a file called model_config.yaml. Edit this file for the models you want to serve.

- model_id_or_path: NousResearch/Hermes-3-Llama-3.1-8B
  tokenizer_id_or_path: null
  adapter_path: null
  quant: q8
  revision: null
  model_name: null
  model_config: null
  tokenizer_config: null
- model_id_or_path: mlx-community/Llama-3.2-3B-Instruct-4bit
  tokenizer_id_or_path: null
  adapter_path: null
  quant: q4
  revision: null
  model_name: llama-3.2-3b-instruct
  model_config: null
  tokenizer_config: null

Then start the engine:

mlx_textgen.server --config-file ./model_config.yaml --port 5001

3. More engine arguments

You can check the details of other engine arguments by running:

mlx_textgen.server --help

You can sepcify the number of cache slots for each model, minimum number of tokens to create a cache file, and API keys etc.

License

This project is licensed under the terms of the MIT license.

Goekdeniz-Guelmez/MLX-Textgen