The QNN Execution Provider for ONNX Runtime enables hardware accelerated execution on Qualcomm chipsets.
It uses the Qualcomm AI Engine Direct SDK (QNN SDK) to construct a QNN graph from an ONNX model which can
be executed by a supported accelerator backend library.
## Contents
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## Install Pre-requisites
Download the Qualcomm AI Engine Direct SDK (QNN SDK) from [https://qpm.qualcomm.com/main/tools/details/qualcomm_ai_engine_direct](https://qpm.qualcomm.com/main/tools/details/qualcomm_ai_engine_direct)
See [profiling-tools](../performance/tune-performance/profiling-tools.md) for more info on profiling
Alternatively to setting profiling_level at compile time, profiling can be enabled dynamically with ETW (Windows). See [tracing](../performance/tune-performance/logging_tracing.md) for more details
Supported data types vary by operator and QNN backend. Refer to the [QNN SDK documentation](https://docs.qualcomm.com/bundle/publicresource/topics/80-63442-50/operations.html) for more information.
## Running a model with QNN EP's HTP backend (Python)
<palign="center"><imgwidth="100%"src="../../images/qnn_ep_quant_workflow.png"alt="Offline workflow for quantizing an ONNX model for use on QNN EP"/></p>
The QNN HTP backend only supports quantized models. Models with 32-bit floating-point activations and weights must first be quantized to use a lower integer precision (e.g., 8-bit or 16-bit integers).
This section provides instructions for quantizing a model and then running the quantized model on QNN EP's HTP backend using Python APIs. Please refer to the [quantization page](../performance/model-optimizations/quantization.md) for a broader overview of quantization concepts.
### Model requirements
QNN EP does not support models with dynamic shapes (e.g., a dynamic batch size). Dynamic shapes must be fixed to a specific value. Refer to the documentation for [making dynamic input shapes fixed](../tutorials/mobile/helpers/make-dynamic-shape-fixed.md) for more information.
Additionally, QNN EP supports a subset of ONNX operators (e.g., Loops and Ifs are not supported). Refer to the [list of supported ONNX operators](./QNN-ExecutionProvider.md#supported-onnx-operators).
### Generating a quantized model (x64)
The ONNX Runtime python package provides utilities for quantizing ONNX models via the `onnxruntime.quantization` import. The quantization utilities are currently only supported on x86_64 due to issues installing the `onnx` package on ARM64.
Therefore, it is recommended to either use an x64 machine to quantize models or, alternatively, use a separate x64 python installation on Windows ARM64 machines.
Install the nightly ONNX Runtime x64 python package.
Quantization for QNN EP requires the use of calibration input data. Using a calibration dataset that is representative of typical model inputs is crucial in generating an accurate quantized model.
The following snippet defines a sample `DataReader` class that generates random float32 input data. Note that using random input data will most likely produce an inaccurate quantized model.
Refer to the [implementation of a Resnet data reader](https://github.com/microsoft/onnxruntime-inference-examples/blob/main/quantization/image_classification/cpu/resnet50_data_reader.py) for one example of how to create a `CalibrationDataReader` that provides input from image files on disk.
```python
# data_reader.py
import numpy as np
import onnxruntime
from onnxruntime.quantization import CalibrationDataReader
# TODO: Load valid calibration input data for your model
for _ in range(10):
input_data = {inp.name : np.random.random(inp.shape).astype(np.float32) for inp in inputs}
self.data_list.append(input_data)
self.datasize = len(self.data_list)
def get_next(self):
if self.enum_data is None:
self.enum_data = iter(
self.data_list
)
return next(self.enum_data, None)
def rewind(self):
self.enum_data = None
```
The following snippet pre-processes the original model and then quantizes the pre-processed model to use `uint16` activations and `uint8` weights.
Although the quantization utilities expose the `uint8`, `int8`, `uint16`, and `int16` quantization data types, QNN operators typically support the `uint8` and `uint16` data types.
Refer to the [QNN SDK operator documentation](https://docs.qualcomm.com/bundle/publicresource/topics/80-63442-50/HtpOpDefSupplement.html) for the data type requirements of each QNN operator.
```python
# quantize_model.py
import data_reader
import numpy as np
import onnx
from onnxruntime.quantization import QuantType, quantize
from onnxruntime.quantization.execution_providers.qnn import get_qnn_qdq_config, qnn_preprocess_model
if __name__ == "__main__":
input_model_path = "model.onnx" # TODO: Replace with your actual model
output_model_path = "model.qdq.onnx" # Name of final quantized model
Running `python quantize_model.py` will generate a quantized model called `model.qdq.onnx` that can be run on Windows ARM64 devices via ONNX Runtime's QNN EP.
Refer to the following pages for more information on usage of the quantization utilities:
- [Quantization example for mobilenet on CPU EP](https://github.com/microsoft/onnxruntime-inference-examples/tree/main/quantization/image_classification/cpu)
The following assumes that the [Qualcomm AI Engine SDK (QNN SDK)](https://qpm.qualcomm.com/main/tools/details/qualcomm_ai_engine_direct) has already been downloaded and installed to a location such as `C:\Qualcomm\AIStack\QNN\2.18.0.240101`, hereafter referred to as `QNN_SDK`.
First, determine the HTP architecture version for your device by referring to the QNN SDK documentation:
For example, Snapdragon 8cx Gen 3 (SC8280X) devices have an HTP architecture value of 68, and Snapdragon 8cx Gen 4 (SC8380XP) have an HTP architecture value of 73. In the following, replace `<HTP_ARCH>` with your device's HTP architecture value.
Copy the `.so` file `QNN_SDK\lib\hexagon-v<HTP_ARCH>\unsigned\libQnnHtpV<HTP_ARCH>Skel.so` to the folder `QNN_SDK\lib\aarch64-windows-msvc\`. For example, the following terminal command copies the `libQnnHtpV73Skel.so` file:
provider_options=[{"backend_path": "QnnHtp.dll"}]) # Provide path to Htp dll in QNN SDK
# Run the model with your input.
# TODO: Use numpy to load your actual input from a file or generate random input.
input0 = np.ones((1,3,224,224), dtype=np.float32)
result = session.run(None, {"input": input0})
# Print output.
print(result)
```
Running `python run_qdq_model.py` will execute the quantized `model.qdq.onnx` model on the QNN HTP backend.
Notice that the session has been optionally configured to raise an exception if the entire model cannot be executed on the QNN HTP backend. This is useful for verifying that the quantized model is fully supported by QNN EP.
Available session configurations include:
- [session.disable_cpu_ep_fallback](https://github.com/microsoft/onnxruntime/blob/a4cfdc1c28ac95ec6fd0667e856b6a6b8dd1020c/include/onnxruntime/core/session/onnxruntime_session_options_config_keys.h#L229): Disables fallback of unsupported operators to the CPU EP.
- [ep.context_enable](https://github.com/microsoft/onnxruntime/blob/a4cfdc1c28ac95ec6fd0667e856b6a6b8dd1020c/include/onnxruntime/core/session/onnxruntime_session_options_config_keys.h#L243): [Enable QNN context cache](./QNN-ExecutionProvider.md#qnn-context-binary-cache-feature) feature to dump a cached version of the model in order to decrease session creation time.
The above snippet only specifies the `backend_path` provider option. Refer to the [Configuration options section](./QNN-ExecutionProvider.md#configuration-options) for a list of all available QNN EP provider options.
There's a QNN context which contains QNN graphs after converting, compiling, filnalizing the model. QNN can serialize the context into binary file, so that user can use it for futher inference direclty (without the QDQ model) to improve the model loading cost.
The QNN Execution Provider supports a number of session options to configure this.
### Dump QNN context binary
1. Create session option, set "ep.context_enable" to "1" to enable QNN context dump. The key "ep.context_enable" is defined as kOrtSessionOptionEpContextEnable in [onnxruntime_session_options_config_keys.h](https://github.com/microsoft/onnxruntime/blob/8931854528b1b2a3f320d012c78d37186fbbdab8/include/onnxruntime/core/session/onnxruntime_session_options_config_keys.h#L239-L252).
2. Create the session with the QDQ model using session options created in step 1, and use HTP backend
A Onnx model with QNN context binary will be created once the session is created/initialized. No need to run the session.
The QNN context binary generation can be done on the QualComm device which has HTP using Arm64 build. It can also be done on x64 machine using x64 build (not able to run it since there's no HTP device).
The generated Onnx model which has QNN context binary can be deployed to production/real device to run inference. This Onnx model is treated as a normal model by QNN Execution Provider. Inference code keeps same as inference with QDQ model on HTP backend.
The generated Onnx model with QNN context binary is default to [input_QDQ_model_path]_ctx.onnx in case user does not specify the path. User can to set the path in the session option with the key "ep.context_file_path". Example code below:
The QNN context binary content is embeded in the generated Onnx model by default. User can to disable it by setting "ep.context_embed_mode" to "0". In that case, a bin file will be generated separately. The file name looks like [ctx.onnx]_QNNExecutionProvider_QNN_[hash_id]_x_x.bin. The name is provided by Ort and tracked in the generated Onnx model. It will cause problems if any changes to the bin file. This bin file needs to sit together with the generated Onnx file.
[Image classification with Mobilenetv2 in CPP using QNN Execution Provider with QNN CPU & HTP Backend](https://github.com/microsoft/onnxruntime-inference-examples/tree/main/c_cxx/QNN_EP/mobilenetv2_classification)
