Inference Runtimes

Loading a model into an inference runtime

Pipeless supports some inference runtimes so you can easily load a model and run inference either in CPU or GPU.

To enable one of the inference runtimes for a stage just create a process.json file within the stage folder.

The minimum content required by process.json is the runtime key and the model URI:

    "runtime": "onnx",
    "model_uri": "",

Supported runtimes

This section contains the supported inference runtimes as well as the configuration parameters for each one. The parameters for the inference runtime are provided under the inference_params field in the process.json file.

For example:

    "runtime": "onnx",
    "model_uri": "",
    "inference_params": {
        "execution_provider": "TensorRT"

ONNX Runtime

The ONNX Runtime (opens in a new tab) is widely used. Most of the machine learning frameworks allow to export models to ONNX format.

  • Runtime key: onnx
  • Parameters:
    • execution_provider: The execution provider to use. Allowed values: cpu, CUDA (Linux and Windows only), TensorRT (Linux and Windows only), OpenVINO, CoreML (macOS only).
    • execution_mode: Either Parallel or Sequential. Check the ONNX threading docs (opens in a new tab).
    • inter_threads: A integer number. Only takes effect if execution_mode is parallel (and the model nodes can be run in parallel). Indicates the maximum number of threads to use to run them in parallel.
    • intra_threads: A integer number, Indicates the number of threads to parallelize the execution within nodes.

General Troubleshooting


You may find a message like the following when CUDA was not compiled for your target GPU architecture:

Status Message: CUDA error cudaErrorNoKernelImageForDevice:no kernel image is available for execution on the device

Consider building CUDA yourself or using a different GPU. This error has been reported in some Nvidia 940MX (Maxwell architecture).

Seems to get stuck

If running pipeless run using the ONNX inference it seems to get stuck and there is not a clear error shown, try running the worker only to see the error with pipeless run worker.

I have CUDA and Cudnn installed but ONNX Runtime is not using CUDA

In this case, you usually get a warning like:

[W:onnxruntime:Default, CreateExecutionProviderInstance] Failed to create CUDAExecutionProvider. Please reference to ensure all dependencies are met.

Ensure you have the proper CUDA and Cudnn versions installed. Check the ONNX CUDA requirements (opens in a new tab) to ensure your versions are compatible. We recommend using CUDA version 11.7 since 12.X is not properly recognized by the latest version of the ONNX Runtime.

Optionally, you can use the Pipeless CUDA container image. Find the docs here.

Segmentation fault (core dumped)

The most common error that leads to a segmentation fault is to provide wrong input data to the model. Double check that what your pre-process hook is returning follows the model input format (previous to the automatic transformations mentioned above).

Another common reason is a wrong CUDA version for your target GPU.

If you suffer a segmentation fault and you are unable to understand why, open a GitHub issue providing all the information you can, so we can help you figure it out.