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TensorRT backend for ONNX

Parses ONNX models for execution with TensorRT.

See also the TensorRT documentation.

Supported TensorRT Versions

Development on the Master branch is for the latest version of TensorRT (5.1)

For versions < 5.1, clone and build from the 5.0 branch

Supported Operators

Current supported ONNX operators are found in the operator support matrix.



Download the code

Clone the code from GitHub.

git clone --recursive


The TensorRT-ONNX executables and libraries are built with CMAKE. Note by default CMAKE will tell the CUDA compiler generate code for the latest SM version. If you are using a GPU with a lower SM version you can specify which SMs to build for by using the optional -DGPU_ARCHS flag. For example, if you have a GTX 1080, you can specify -DGPU_ARCHS="61" to generate CUDA code specifically for that card.

See here for finding what maximum compute capability your specific GPU supports.

mkdir build
cd build
cmake .. -DTENSORRT_ROOT=<tensorrt_install_dir>
cmake .. -DTENSORRT_ROOT=<tensorrt_install_dir> -DGPU_ARCHS="61"
make -j8
sudo make install

Executable usage

ONNX models can be converted to serialized TensorRT engines using the onnx2trt executable:

onnx2trt my_model.onnx -o my_engine.trt

ONNX models can also be converted to human-readable text:

onnx2trt my_model.onnx -t my_model.onnx.txt

See more usage information by running:

onnx2trt -h

ONNX Python backend usage

The TensorRT backend for ONNX can be used in Python as follows:

import onnx
import onnx_tensorrt.backend as backend
import numpy as np

model = onnx.load("/path/to/model.onnx")
engine = backend.prepare(model, device='CUDA:1')
input_data = np.random.random(size=(32, 3, 224, 224)).astype(np.float32)
output_data =[0]

C++ library usage

The model parser library,, has its C++ API declared in this header:


TensorRT engines built using this parser must use the plugin factory provided in, which has its C++ API declared in this header:


Python modules

Python bindings for the ONNX-TensorRT parser in TensorRT versions >= 5.0 are packaged in the shipped .whl files. Install them with

pip install <tensorrt_install_dir>/python/tensorrt-

For earlier versions of TensorRT, the Python wrappers are built using SWIG. Build the Python wrappers and modules by running:

python build
sudo python install

Docker image

Build the onnx_tensorrt Docker image by running:

cp /path/to/TensorRT-5.1.*.tar.gz .
docker build -t onnx_tensorrt .


After installation (or inside the Docker container), ONNX backend tests can be run as follows:

Real model tests only:

python OnnxBackendRealModelTest

All tests:


You can use -v flag to make output more verbose.

Pre-trained models

Pre-trained models in ONNX format can be found at the ONNX Model Zoo

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