text-generation-inference

Text-generation-inference docker image for Pytorch/XLA

This docker image integrates into a base image:

• the Text Generation Inference launcher and scheduling front-end,
• an XLA specific inference server for text-generation.

Features

The basic features of the Text Generation Inference product are supported:

• continuous batching,
• token streaming,
• greedy search and multinomial sampling using transformers.

The main differences with the standard service for CUDA and CPU backends are that:

• the service uses a single internal static batch,
• new requests are inserted in the static batch during prefill,
• the static KV cache is rebuilt entirely during prefill.

License

This docker image is released under HFOIL 1.0.

HFOIL stands for Hugging Face Optimized Inference License, and it has been specifically designed for our optimized inference solutions. While the source code remains accessible, HFOIL is not a true open source license because we added a restriction: to sell a hosted or managed service built on top of TGI, we require a separate agreement.

Please refer to this reference documentation to see if the HFOIL 1.0 restrictions apply to your deployment.

Deploy the service

The service is launched simply by running the tpu-tgi container with two sets of parameters:

docker run <system_parameters> ghcr.io/huggingface/tpu-tgi:latest <service_parameters>

• system parameters are used to map ports, volumes and devices between the host and the service,
• service parameters are forwarded to the text-generation-launcher.

Common system parameters

Finally, you might want to export the HF_TOKEN if you want to access gated repository.

Here is an example of a service instantiation on a single host TPU:

docker run -p 8080:80 \
       --net=host --privileged \
       -v $(pwd)/data:/data \
       -e HF_TOKEN=${HF_TOKEN} \
       ghcr.io/huggingface/tpu-tgi:latest \
       <service_parameters>

Using a standard model from the 🤗 HuggingFace Hub

The snippet below shows how you can deploy a service from a hub standard model:

docker run -p 8080:80 \
       --net=host --privileged \
       -v $(pwd)/data:/data \
       -e HF_TOKEN=${HF_TOKEN} \
       -e MAX_BATCH_SIZE=4 \
       -e HF_SEQUENCE_LENGTH=1024 \
       ghcr.io/huggingface/tpu-tgi:latest \
       --model-id mistralai/Mistral-7B-v0.1 \
       --max-concurrent-requests 1 \
       --max-input-length 512 \
       --max-total-tokens 1024 \
       --max-batch-prefill-tokens 512 \
       --max-batch-total-tokens 1024

Choosing service parameters

Use the following command to list the available service parameters:

docker run ghcr.io/huggingface/tpu-tgi --help

The configuration of an inference endpoint is always a compromise between throughput and latency: serving more requests in parallel will allow a higher throughput, but it will increase the latency.

The models for now work with static input dimensions [batch_size, max_length].

It leads to a maximum number of tokens of max_tokens = batch_size * max_length.

This adds several restrictions to the following parameters:

• --max-concurrent-requests must be set to batch size,
• --max-input-length must be lower than max_length,
• --max-total-tokens must be set to max_length (it is per-request),
• --max-batch-prefill-tokens must be set to batch_size * max_input_length,
• --max-batch-total-tokens must be set to max_tokens.

Choosing the correct batch size

As seen in the previous paragraph, model static batch size has a direct influence on the endpoint latency and throughput.

Please refer to text-generation-inference for optimization hints.

Note that the main constraint is to be able to fit the model for the specified batch_size within the total device memory available on your instance.

Query the service

You can query the model using either the /generate or /generate_stream routes:

curl 127.0.0.1:8080/generate \
    -X POST \
    -d '{"inputs":"What is Deep Learning?","parameters":{"max_new_tokens":20}}' \
    -H 'Content-Type: application/json'

curl 127.0.0.1:8080/generate_stream \
    -X POST \
    -d '{"inputs":"What is Deep Learning?","parameters":{"max_new_tokens":20}}' \
    -H 'Content-Type: application/json'

Build your own image

The image must be built from the top directory

make tpu-tgi