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Quick Start

This tutorial shows the usage of LMDeploy on:

  • Offline inference of LLM model and VLM model
  • Serve a LLM or VLM model by the OpenAI compatible server
  • Console CLI to interactively chat with LLM model

Before reading further, please ensure that you have installed lmdeploy as outlined in the installation guide

Offline batch inference

LLM inference

from lmdeploy import pipeline
pipe = pipeline('internlm/internlm2_5-7b-chat')
response = pipe(['Hi, pls intro yourself', 'Shanghai is'])
print(response)

When constructing the pipeline, if an inference engine is not designated between the TurboMind Engine and the PyTorch Engine, LMDeploy will automatically assign one based on their respective capabilities, with the TurboMind Engine taking precedence by default.

However, you have the option to manually select an engine. For instance,

from lmdeploy import pipeline, TurbomindEngineConfig
pipe = pipeline('internlm/internlm2_5-7b-chat',
                backend_config=TurbomindEngineConfig(
                    max_batch_size=32,
                    enable_prefix_caching=True,
                    cache_max_entry_count=0.8,
                    session_len=8192,
                ))

or,

from lmdeploy import pipeline, PytorchEngineConfig
pipe = pipeline('internlm/internlm2_5-7b-chat',
                backend_config=PytorchEngineConfig(
                    max_batch_size=32,
                    enable_prefix_caching=True,
                    cache_max_entry_count=0.8,
                    session_len=8192,
                ))
The parameter "cache_max_entry_count" significantly influences the GPU memory usage.
It means the proportion of FREE GPU memory occupied by the K/V cache after the model weights are loaded.

The default value is 0.8. The K/V cache memory is allocated once and reused repeatedly, which is why it is observed that the built pipeline and the "api_server" mentioned later in the next consumes a substantial amount of GPU memory.

If you encounter an Out-of-Memory(OOM) error, you may need to consider lowering the value of "cache_max_entry_count".

When use the callable pipe() to perform token generation with given prompts, you can set the sampling parameters via GenerationConfig as below:

from lmdeploy import GenerationConfig, pipeline

pipe = pipeline('internlm/internlm2_5-7b-chat')
prompts = ['Hi, pls intro yourself', 'Shanghai is']
response = pipe(prompts,
                gen_config=GenerationConfig(
                    max_new_tokens=1024,
                    top_p=0.8,
                    top_k=40,
                    temperature=0.6
                ))

In the GenerationConfig, top_k=1 or temperature=0.0 indicates greedy search.

For more information about pipeline, please read the detailed tutorial

VLM inference

The usage of VLM inference pipeline is akin to that of LLMs, with the additional capability of processing image data with the pipeline. For example, you can utilize the following code snippet to perform the inference with an InternVL model:

from lmdeploy import pipeline
from lmdeploy.vl import load_image

pipe = pipeline('OpenGVLab/InternVL2-8B')

image = load_image('https://raw.githubusercontent.com/open-mmlab/mmdeploy/main/tests/data/tiger.jpeg')
response = pipe(('describe this image', image))
print(response)

In VLM pipeline, the default image processing batch size is 1. This can be adjusted by VisionConfig. For instance, you might set it like this:

from lmdeploy import pipeline, VisionConfig
from lmdeploy.vl import load_image

pipe = pipeline('OpenGVLab/InternVL2-8B',
                vision_config=VisionConfig(
                    max_batch_size=8
                ))

image = load_image('https://raw.githubusercontent.com/open-mmlab/mmdeploy/main/tests/data/tiger.jpeg')
response = pipe(('describe this image', image))
print(response)

However, the larger the image batch size, the greater risk of an OOM error, because the LLM component within the VLM model pre-allocates a massive amount of memory in advance.

We encourage you to manually choose between the TurboMind Engine and the PyTorch Engine based on their respective capabilities, as detailed in the supported-models matrix. Additionally, follow the instructions in LLM Inference section to reduce the values of memory-related parameters

Serving

As demonstrated in the previous offline batch inference section, this part presents the respective serving methods for LLMs and VLMs.

Serve a LLM model

lmdeploy serve api_server internlm/internlm2_5-7b-chat

This command will launch an OpenAI-compatible server on the localhost at port 23333. You can specify a different server port by using the --server-port option. For more options, consult the help documentation by running lmdeploy serve api_server --help. Most of these options align with the engine configuration.

To access the service, you can utilize the official OpenAI Python package pip install openai. Below is an example demonstrating how to use the entrypoint v1/chat/completions

from openai import OpenAI
client = OpenAI(
    api_key='YOUR_API_KEY',
    base_url="http://0.0.0.0:23333/v1"
)
model_name = client.models.list().data[0].id
response = client.chat.completions.create(
  model=model_name,
  messages=[
    {"role": "system", "content": "You are a helpful assistant."},
    {"role": "user", "content": " provide three suggestions about time management"},
  ],
    temperature=0.8,
    top_p=0.8
)
print(response)

We encourage you to refer to the detailed guide for more comprehensive information about serving with Docker, function calls and other topics

Serve a VLM model

lmdeploy serve api_server OpenGVLab/InternVL2-8B
LMDeploy reuses the vision component from upstream VLM repositories. Each upstream VLM model may have different dependencies.
Consequently, LMDeploy has decided not to include the dependencies of the upstream VLM repositories in its own dependency list.
If you encounter an "ImportError" when using LMDeploy for inference with VLM models, please install the relevant dependencies yourself.

After the service is launched successfully, you can access the VLM service in a manner similar to how you would access the gptv4 service by modifying the api_key and base_url parameters:

from openai import OpenAI

client = OpenAI(api_key='YOUR_API_KEY', base_url='http://0.0.0.0:23333/v1')
model_name = client.models.list().data[0].id
response = client.chat.completions.create(
    model=model_name,
    messages=[{
        'role':
        'user',
        'content': [{
            'type': 'text',
            'text': 'Describe the image please',
        }, {
            'type': 'image_url',
            'image_url': {
                'url':
                'https://raw.githubusercontent.com/open-mmlab/mmdeploy/main/tests/data/tiger.jpeg',
            },
        }],
    }],
    temperature=0.8,
    top_p=0.8)
print(response)

Inference with Command line Interface

LMDeploy offers a very convenient CLI tool for users to chat with the LLM model locally. For example:

lmdeploy chat internlm/internlm2_5-7b-chat --backend turbomind

It is designed to assist users in checking and verifying whether LMDeploy supports their model, whether the chat template is applied correctly, and whether the inference results are delivered smoothly.

Another tool, lmdeploy check_env, aims to gather the essential environment information. It is crucial when reporting an issue to us, as it helps us diagnose and resolve the problem more effectively.

If you have any doubt about their usage, you can try using the --help option to obtain detailed information.