ONNX Runtime is a cross-platform inferencing and training accelerator compatible with many popular ML/DNN frameworks, including PyTorch, TensorFlow/Keras, scikit-learn, and more. aka.ms/onnxruntime
Many users can benefit from ONNX Runtime, including those looking to:
- Improve inference performance for a wide variety of ML models
- Reduce time and cost of training large models
- Train in Python but deploy into a C#/C++/Java app
- Run on different hardware and operating systems
- Support models created in several different frameworks
ONNX Runtime inferencing APIs are stable and production-ready since the 1.0 release in October 2019 and can enable faster customer experiences and lower costs.
ONNX Runtime training feature was introduced in May 2020 in preview. This feature supports acceleration of PyTorch training on multi-node NVIDIA GPUs for transformer models. Additional updates for this feature are coming soon.
Table of Contents
- Get Started
- Contributions and Feedback
Frequently Asked Questions
To use ONNX Runtime, refer to the table on aka.ms/onnxruntime for instructions for different build combinations.
- Build from source (includes additional combinations)
- Docker images
- API documentation
- Hardware accelerators
- Deploy ONNX Runtime inferencing
- High level architectural design
- Performance Tuning
- Extensibility: Add a new graph transform
- Extensibility: Add a new rewrite rule
Supporting models based on the standard ONNX format, the runtime is compatible with PyTorch, scikit-learn, TensorFlow, Keras, and all other frameworks and tools that support the interoperable format.
ONNX Runtime is up to date and backwards compatible with all operators (both DNN and traditional ML) since ONNX v1.2.1+. (ONNX compatibility details). Newer versions of ONNX Runtime support all models that worked with prior versions, so updates should not break integrations.
- Operators not supported in the current ONNX spec may be available as a Contrib Operator
- Extensibility: Add a custom operator/kernel
Official builds are available on PyPi (Python), Nuget (C#/C/C++), Maven Central (Java), and npm (node.js).
- Default CPU Provider (Eigen + MLAS)
- GPU Provider - NVIDIA CUDA
- GPU Provider - DirectML (Windows)
- On Windows, the DirectML execution provider is recommended for optimal performance and compatibility with a broad set of GPUs.
Dev builds created from the master branch are available for testing newer changes between official releases. Please use these at your own risk. We strongly advise against deploying these to production workloads as support is limited for dev builds.
|Pypi (Python)||If using pip, run
CPU: onnxruntime / ort-nightly (dev)
GPU: onnxruntime-gpu / ort-gpu-nightly (dev)
|Nuget (C#/C/C++)||CPU: Microsoft.ML.OnnxRuntime / ort-nightly (dev)
GPU: Microsoft.ML.OnnxRuntime.Gpu / ort-nightly (dev)
|Maven Central (Java)||CPU: com.microsoft.onnxruntime/onnxruntime
|npm (node.js)||CPU: onnxruntime|
|Other||Contributed non-official packages (including
Homebrew, Linuxbrew, and nixpkgs)
These are not maintained by the core ONNX Runtime team and may have limited support; use at your discretion.
The following are required for usage of the official published packages.
Visual C++ Runtime (for Windows packages)
- Requires Visual C++ 2019 runtime
- Installation of the English language package
en_US.UTF-8 localeis required, as certain operators makes use of system locales.
- For Ubuntu, install language-pack-en package
- Run the following commands:
- Follow similar procedure to configure other locales on other platforms.
- Installation of the English language package and configuring
- ONNX Runtime binaries in the CPU packages use OpenMP and depend on the library being available at runtime in the system.
- For Windows, OpenMP support comes as part of VC runtime. It is also available as redist packages: vc_redist.x64.exe and vc_redist.x86.exe
- For Linux, the system must have libgomp.so.1
which can be installed using
apt-get install libgomp1.
- For Mac OS X, the system must have
libomp.dylib which can be installed using
brew install libomp.
Default GPU (CUDA)
- The default GPU build requires CUDA runtime libraries being installed on the system:
- Version: CUDA 10.1 and cuDNN 7.6.5
- Version dependencies from older ONNX Runtime releases can be found in prior release notes.
Build from Source
For production scenarios, it's strongly recommended to build only from an official release branch.
- ONNX-Ecosystem: includes ONNX Runtime (CPU, Python), dependencies, tools to convert from various frameworks, and Jupyter notebooks to help get started
- Additional dockerfiles
|Python||3.5, 3.6, 3.7, 3.8 (3.8 excludes Win GPU and Linux ARM)
Python Dev Notes
|Ruby (external project)||2.4-2.7||Samples|
Deploying ONNX Runtime
ONNX Runtime can be deployed to any cloud for model inferencing, including Azure Machine Learning Services.
ONNX Runtime Server (beta) is a hosting application for serving ONNX models using ONNX Runtime, providing a REST API for prediction.
IoT and edge devices
The expanding focus and selection of IoT devices with sensors and consistent signal streams introduces new opportunities to move AI workloads to the edge. This is particularly important when there are massive volumes of incoming data/signals that may not be efficient or useful to push to the cloud due to storage or latency considerations. Consider: surveillance tapes where 99% of footage is uneventful, or real-time person detection scenarios where immediate action is required. In these scenarios, directly executing model inferencing on the target device is crucial for optimal assistance.
Install or build the package you need to use in your application. (sample implementations using the C++ API)
The ONNX Runtime training feature enables easy integration with existing Pytorch trainer code to accelerate the exection. With a few lines of code, you can add ONNX Runtime into your existing training scripts and start seeing acceleration. The current preview version supports training acceleration for transformer models on NVIDIA GPUs.
ONNX Runtime pre-training sample: This sample is setup to pre-train the BERT-Large model to show how ONNX Runtime training can be used to accelerate training execution.
Train PyTorch model with ONNX Runtime
ONNX Runtime (ORT) has the capability to train existing PyTorch
models through its optimized backend. For this, we have introduced
an python API for PyTorch, called ORTTrainer, which can be used to
switch the training backend for PyTorch models (instance of
requires some changes in the trainer code, such as replacing the
PyTorch optimizer, and optionally, setting flags to enable
additional features such as mixed-precision training. Here is a
sample code fragment to integrate ONNX Runtime Training in your
PyTorch pre-training script:
NOTE: The current API is experimental and expected to see significant changes in the near future. Our goal is to improve the interface to provide a seamless integration with PyTorch training that requires minimal changes in users’ training code.
import torch ... import onnxruntime from onnxruntime.capi.ort_trainer import IODescription, ModelDescription, ORTTrainer # Model definition class Net(torch.nn.Module): def __init__(self, D_in, H, D_out): ... def forward(self, x): ... model = Net(D_in, H, H_out) criterion = torch.nn.Functional.cross_entropy description = ModelDescription(...) optimizer = 'SGDOptimizer' trainer = ORTTrainer(model, criterion, description, optimizer, ...) # Training Loop for t in range(1000): # forward + backward + weight update loss, y_pred = trainer.train_step(x, y, learning_rate) ...
Build ONNX Runtime Training from source
To use ONNX Runtime training in a custom environment, like on-prem NVIDIA DGX-2 clusters, you can use these build instructions to generate the Python package to integrate into existing trainer code.
This project may collect usage data and send it to Microsoft to help improve our products and services. See the privacy statement for more details.
Contributions and Feedback
We welcome contributions! Please see the contribution guidelines.
For any feedback or to report a bug, please file a GitHub Issue.
Code of Conduct
This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact firstname.lastname@example.org with any additional questions or comments.
This project is licensed under the MIT License.