Building and Running ExecuTorch with Qualcomm AI Engine Direct Backend¶
In this tutorial we will walk you through the process of getting setup to build ExecuTorch for Qualcomm AI Engine Direct and running a model on it.
Qualcomm AI Engine Direct is also referred to as QNN in the source and documentation.
In this tutorial you will learn how to lower and deploy a model for Qualcomm AI Engine Direct.
What’s Qualcomm AI Engine Direct?¶
Qualcomm AI Engine Direct is designed to provide unified, low-level APIs for AI development.
Developers can interact with various accelerators on Qualcomm SoCs with these set of APIs, including Kryo CPU, Adreno GPU, and Hexagon processors. More details can be found here.
Currently, this ExecuTorch Backend can delegate AI computations to Hexagon processors through Qualcomm AI Engine Direct APIs.
Prerequsites (Hardware and Software)¶
Host OS¶
The Linux host operating system that QNN Backend is verified with is Ubuntu 20.04 LTS x64.
However, because Qualcomm Package Manager(QPM) used to download necessary SDK (see below) only support Ubuntu, we recommend users to exercise this tutorial exacly on Ubuntu 20.04.
Hardware:¶
You will need an Android smartphone with adb-connected running on one of below Qualcomm SoCs:
SM8450 (Snapdragon 8 Gen 1)
SM8475 (Snapdragon 8 Gen 1+)
SM8550 (Snapdragon 8 Gen 2)
This example is verified with SM8550 and SM8450.
Software:¶
Follow ExecuTorch recommneded Python version.
A compiler to compile AOT parts. GCC 9.4 come with Ubuntu20.04 is verified.
Android NDK. This example is verified with NDK 25c.
-
Follow the download button. After logging in, search Qualcomm AI Stack at the Tool panel.
You can find Qualcomm AI Engine Direct SDK under the AI Stack group.
Please download the Linux version, and follow instructions on the page to extract the file.
The SDK should be installed to somewhere
/opt/qcom/aistack/qnnby default.It’s also OK to place it somewhere else. We don’t have assumption about the absolute path of the SDK.
This example is verified with version 2.12.0.
The directory with installed Qualcomm AI Engine Direct SDK looks like:
$ tree -L 1 /opt/qcom/aistack/qnn/<version>/
/opt/qcom/aistack/qnn/<version>/
├── benchmarks
├── bin
├── docs
├── examples
├── include
├── lib
├── LICENSE.pdf
├── QNN_NOTICE.txt
├── QNN_README.txt
├── QNN_ReleaseNotes.txt
├── share
└── Uninstall
Setting up your developer environment¶
Conventions¶
$QNN_SDK_ROOT refers to the root of Qualcomm AI Engine Direct SDK,
i.e., the directory containing QNN_README.txt.
$ANDROID_NDK refers to the root of Android NDK.
$EXECUTORCH_ROOT refers to the root of executorch git repository.
Setup environment variables¶
We set LD_LIBRARY_PATH to make sure the dynamic linker can find QNN libraries.
Further, we set PYTHONPATH because it’s easier to develop and import ExecuTorch
Pytho APIs.
export LD_LIBRARY_PATH=$QNN_SDK_ROOT/lib/x86_64-linux-clang/:$LD_LIBRARY_PATH
export PYTHONPATH=$EXECUTORCH_ROOT/..
Build¶
An example script for below building instructions is here.
AOT (Ahead-of-time) components:¶
Python APIs on x64 are required to compile models to Qualcomm AI Engine Direct binary.
cd $EXECUTORCH_ROOT
mkdir build_x86_64
cd build_x86_64
cmake .. -DEXECUTORCH_BUILD_QNN=ON -DQNN_SDK_ROOT=${QNN_SDK_ROOT}
cmake --build . -t "PyQnnManagerAdaptor" "PyQnnWrapperAdaptor" -j8
# install Python APIs to correct import path
# The filename might vary depending on your Python and host version.
cp -f backends/qualcomm/PyQnnManagerAdaptor.cpython-310-x86_64-linux-gnu.so $EXECUTORCH_ROOT/backends/qualcomm/python
cp -f backends/qualcomm/PyQnnWrapperAdaptor.cpython-310-x86_64-linux-gnu.so $EXECUTORCH_ROOT/backends/qualcomm/python
Runtime:¶
A example qnn_executor_runner executable would be used to run the compiled pte model.
Commands to build qnn_executor_runner for Android:
cd $EXECUTORCH_ROOT
mkdir build_android
cd build_android
cmake .. -DQNN_SDK_ROOT=$QNN_SDK_ROOT \
-DEXECUTORCH_BUILD_QNN=ON \
-DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake \
-DANDROID_ABI='arm64-v8a' \
-DANDROID_NATIVE_API_LEVEL=23 \
-DBUCK2=buck2
cmake --build . -j8
You can find qnn_executor_runner under build_android/examples/qualcomm/.
Deploying and running on device¶
AOT compile a model¶
You can refer to this script for the exact flow. We use deeplab-v3-resnet101 as an example in this tutorial. Run below commands to compile:
cd $EXECUTORCH_ROOT
python -m examples.qualcomm.scripts.deeplab_v3 -b build_android -m SM8550 --compile_only --download
You might see something like below:
[INFO][Qnn ExecuTorch] Destroy Qnn context
[INFO][Qnn ExecuTorch] Destroy Qnn device
[INFO][Qnn ExecuTorch] Destroy Qnn backend
opcode name target args kwargs
------------- ------------------------ --------------------------- ----------------------------- --------
placeholder arg684_1 arg684_1 () {}
get_attr lowered_module_0 lowered_module_0 () {}
call_function executorch_call_delegate executorch_call_delegate (lowered_module_0, arg684_1) {}
call_function getitem <built-in function getitem> (executorch_call_delegate, 0) {}
call_function getitem_1 <built-in function getitem> (executorch_call_delegate, 1) {}
output output output ([getitem_1, getitem],) {}
The compiled model is ./deeplab_v3/dlv3_qnn.pte.
Run model Inference on an Android smartphone with Qualcomm SoCs¶
Step 1. We need to push required QNN libraries to the device.
# make sure you have write-permission on below path.
DEVICE_DIR=/data/local/tmp/executorch_qualcomm_tutorial/
adb shell "mkdir -p ${DEVICE_DIR}"
adb push ${QNN_SDK_ROOT}/lib/aarch64-android/libQnnHtp.so ${DEVICE_DIR}
adb push ${QNN_SDK_ROOT}/lib/aarch64-android/libQnnHtpV69Stub.so ${DEVICE_DIR}
adb push ${QNN_SDK_ROOT}/lib/aarch64-android/libQnnHtpV73Stub.so ${DEVICE_DIR}
adb push ${QNN_SDK_ROOT}/lib/aarch64-android/libQnnSystem.so ${DEVICE_DIR}
adb push ${QNN_SDK_ROOT}/lib/hexagon-v69/unsigned/libQnnHtpV69Skel.so ${DEVICE_DIR}
adb push ${QNN_SDK_ROOT}/lib/hexagon-v73/unsigned/libQnnHtpV73Skel.so ${DEVICE_DIR}
Step 2. We also need to indicate dynamic linkers on Android and Hexagon
where to find these libraries by setting ADSP_LIBRARY_PATH and LD_LIBRARY_PATH.
So, we can run qnn_executor_runner like
adb push ./deeplab_v3/dlv3_qnn.pte ${DEVICE_DIR}
adb push ${EXECUTORCH_ROOT}/build_android/examples/qualcomm/qnn_executor_runner ${DEVICE_DIR}
adb shell "cd ${DEVICE_DIR} \
&& export LD_LIBRARY_PATH=${DEVICE_DIR} \
&& export ADSP_LIBRARY_PATH=${DEVICE_DIR} \
&& ./qnn_executor_runner --model_path ./dlv3_qnn.pte"
You should see something like below:
I 00:00:01.835706 executorch:qnn_executor_runner.cpp:298] 100 inference took 1096.626000 ms, avg 10.966260 ms
[INFO][Qnn ExecuTorch] Destroy Qnn backend parameters
[INFO][Qnn ExecuTorch] Destroy Qnn context
[INFO][Qnn ExecuTorch] Destroy Qnn device
[INFO][Qnn ExecuTorch] Destroy Qnn backend
Running a model via ExecuTorch’s android demo-app¶
An Android demo-app using Qualcomm AI Engine Direct Backend can be found in
examples. Please refer to android demo app tutorial.
What is coming?¶
An example using quantized mobilebert to solve multi-class text classification.
More Qualcomm AI Engine Direct accelerators, e.g., GPU.
FAQ¶
If you encounter any issues while reproducing the tutorial, please file a github
issue on ExecuTorch repo and tag use #qcom_aisw tag
