/TensorRT-LLM

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TensorRT-LLM

A TensorRT Toolbox for Optimized Large Language Model Inference

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H200 TPS

H200 FP8 achieves 11,819 tok/s on Llama2-13B on a single GPU, and is up to 1.9x faster than H100.

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Table of Contents

TensorRT-LLM Overview

TensorRT-LLM provides users with an easy-to-use Python API to define Large Language Models (LLMs) and build TensorRT engines that contain state-of-the-art optimizations to perform inference efficiently on NVIDIA GPUs. TensorRT-LLM also contains components to create Python and C++ runtimes that execute those TensorRT engines. It also includes a backend for integration with the NVIDIA Triton Inference Server; a production-quality system to serve LLMs. Models built with TensorRT-LLM can be executed on a wide range of configurations going from a single GPU to multiple nodes with multiple GPUs (using Tensor Parallelism and/or Pipeline Parallelism).

The Python API of TensorRT-LLM is architectured to look similar to the PyTorch API. It provides users with a functional module containing functions like einsum, softmax, matmul or view. The layers module bundles useful building blocks to assemble LLMs; like an Attention block, a MLP or the entire Transformer layer. Model-specific components, like GPTAttention or BertAttention, can be found in the models module.

TensorRT-LLM comes with several popular models pre-defined. They can easily be modified and extended to fit custom needs. See below for a list of supported models.

To maximize performance and reduce memory footprint, TensorRT-LLM allows the models to be executed using different quantization modes (see examples/gpt for concrete examples). TensorRT-LLM supports INT4 or INT8 weights (and FP16 activations; a.k.a. INT4/INT8 weight-only) as well as a complete implementation of the SmoothQuant technique.

For a more detailed presentation of the software architecture and the key concepts used in TensorRT-LLM, we recommend you to read the following document.

Installation

For Windows installation, see Windows.

TensorRT-LLM must be built from source, instructions can be found here. An image of a Docker container with TensorRT-LLM and its Triton Inference Server Backend will be made available soon.

The remaining commands in that document must be executed from the TensorRT-LLM container.

Quick Start

To create a TensorRT engine for an existing model, there are 3 steps:

  1. Download pre-trained weights,
  2. Build a fully-optimized engine of the model,
  3. Deploy the engine.

The following sections show how to use TensorRT-LLM to run the BLOOM-560m model.

0. In the BLOOM folder

Inside the Docker container, you have to install the requirements:

pip install -r examples/bloom/requirements.txt
git lfs install

1. Download the model weights from HuggingFace

From the BLOOM example folder, you must download the weights of the model.

cd examples/bloom
rm -rf ./bloom/560M
mkdir -p ./bloom/560M && git clone https://huggingface.co/bigscience/bloom-560m ./bloom/560M

2. Build the engine

# Single GPU on BLOOM 560M
python build.py --model_dir ./bloom/560M/ \
                --dtype float16 \
                --use_gemm_plugin float16 \
                --use_gpt_attention_plugin float16 \
                --output_dir ./bloom/560M/trt_engines/fp16/1-gpu/

See the BLOOM example for more details and options regarding the build.py script.

3. Run

The ../summarize.py script can be used to perform the summarization of articles from the CNN Daily dataset:

python ../summarize.py --test_trt_llm \
                       --hf_model_dir ./bloom/560M/ \
                       --data_type fp16 \
                       --engine_dir ./bloom/560M/trt_engines/fp16/1-gpu/

More details about the script and how to run the BLOOM model can be found in the example folder. Many more models than BLOOM are implemented in TensorRT-LLM. They can be found in the examples directory.

Support Matrix

TensorRT-LLM optimizes the performance of a range of well-known models on NVIDIA GPUs. The following sections provide a list of supported GPU architectures as well as important features implemented in TensorRT-LLM.

Devices

TensorRT-LLM is rigorously tested on the following GPUs:

If a GPU is not listed above, it is important to note that TensorRT-LLM is expected to work on GPUs based on the Volta, Turing, Ampere, Hopper and Ada Lovelace architectures. Certain limitations may, however, apply.

Precision

Various numerical precisions are supported in TensorRT-LLM. The support for some of those numerical features require specific architectures:

FP32 FP16 BF16 FP8 INT8 INT4
Volta (SM70) Y Y N N Y Y
Turing (SM75) Y Y N N Y Y
Ampere (SM80, SM86) Y Y Y N Y Y
Ada-Lovelace (SM89) Y Y Y Y Y Y
Hopper (SM90) Y Y Y Y Y Y

In this release of TensorRT-LLM, the support for FP8 and quantized data types (INT8 or INT4) is not implemented for all the models. See the precision document and the examples folder for additional details.

Key Features

TensorRT-LLM contains examples that implement the following features.

  • Multi-head Attention(MHA)
  • Multi-query Attention (MQA)
  • Group-query Attention(GQA)
  • In-flight Batching
  • Paged KV Cache for the Attention
  • Tensor Parallelism
  • Pipeline Parallelism
  • INT4/INT8 Weight-Only Quantization (W4A16 & W8A16)
  • SmoothQuant
  • GPTQ
  • AWQ
  • FP8
  • Greedy-search
  • Beam-search
  • RoPE

In this release of TensorRT-LLM, some of the features are not enabled for all the models listed in the examples folder.

Models

The list of supported models is:

Note: Encoder-Decoder provides general encoder-decoder support that contains many encoder-decoder models such as T5, Flan-T5, etc. We unroll the exact model names in the list above to let users find specific models easiler.

Performance

Please refer to the performance page for performance numbers. That page contains measured numbers for four variants of popular models (GPT-J, LLAMA-7B, LLAMA-70B, Falcon-180B), measured on the H100, L40S and A100 GPU(s).

Advanced Topics

Quantization

This document describes the different quantization methods implemented in TensorRT-LLM and contains a support matrix for the different models.

In-flight Batching

TensorRT-LLM supports in-flight batching of requests (also known as continuous batching or iteration-level batching). It's a technique that aims at reducing wait times in queues, eliminating the need for padding requests and allowing for higher GPU utilization.

Attention

TensorRT-LLM implements several variants of the Attention mechanism that appears in most the Large Language Models. This document summarizes those implementations and how they are optimized in TensorRT-LLM.

Graph Rewriting

TensorRT-LLM uses a declarative approach to define neural networks and contains techniques to optimize the underlying graph. For more details, please refer to doc

Benchmark

TensorRT-LLM provides C++ and Python tools to perform benchmarking. Note, however, that it is recommended to use the C++ version.

Troubleshooting

[09/23/2023-03:13:00] [TRT] [E] 9: GPTLMHeadModel/layers/0/attention/qkv/PLUGIN_V2_Gemm_0: could not find any supported formats consistent with input/output data types
[09/23/2023-03:13:00] [TRT] [E] 9: [pluginV2Builder.cpp::reportPluginError::24] Error Code 9: Internal Error (GPTLMHeadModel/layers/0/attention/qkv/PLUGIN_V2_Gemm_0: could not find any supported formats consistent with input/output data types)

may happen. One possible solution is to reduce the amount of memory needed by reducing the maximum batch size, input and output lengths. Another option is to enable plugins, for example: --use_gpt_attention_plugin.

  • MPI + Slurm

TensorRT-LLM is a MPI-aware package that uses mpi4py. If you are running scripts in a Slurm environment, you might encounter interferences:

--------------------------------------------------------------------------
PMI2_Init failed to initialize.  Return code: 14
--------------------------------------------------------------------------
--------------------------------------------------------------------------
The application appears to have been direct launched using "srun",
but OMPI was not built with SLURM's PMI support and therefore cannot
execute. There are several options for building PMI support under
SLURM, depending upon the SLURM version you are using:

  version 16.05 or later: you can use SLURM's PMIx support. This
  requires that you configure and build SLURM --with-pmix.

  Versions earlier than 16.05: you must use either SLURM's PMI-1 or
  PMI-2 support. SLURM builds PMI-1 by default, or you can manually
  install PMI-2. You must then build Open MPI using --with-pmi pointing
  to the SLURM PMI library location.

Please configure as appropriate and try again.
--------------------------------------------------------------------------

As a rule of thumb, if you are running TensorRT-LLM interactively on a Slurm node, prefix your commands with mpirun -n 1 to run TensorRT-LLM in a dedicated MPI environment, not the one provided by your Slurm allocation. For example: mpirun -n 1 python3 examples/gpt/build.py ...

Release notes

  • TensorRT-LLM requires TensorRT 9.1.0.4 and 23.08 containers.

Change Log

  • TensorRT-LLM v0.5.0 is the first public release.

Known Issues

Report Issues

You can use GitHub issues to report issues with TensorRT-LLM.