Snapdragon Neural Processing Engine SDK
Reference Guide
UDO Tutorial With Weights

Overview

This tutorial describes the steps needed to run UDO with weights and execute the Alexnet model using the package. The Convolution operation has been chosen in this tutorial to demonstrate the implementation of a UDO with weights.

The SNPE SDK provides the resources for this example under

  • $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D

Information on UDO in general is available at UDO Overview.

Information on running the Alexnet network without UDO is available at Alexnet Tutorial.

Information on creating a UDO package and executing the model using the package is available at UDO Tutorial.

Prerequisites

The following tutorial assumes that general SNPE setup has been followed to support SDK environment, Caffe environment, and desired platform dependencies. For details on acquiring the Alexnet model visit Tutorials Setup.

Introduction

Here are the steps to develop and run a UDO

1.) Package Generation

2.) Framework Model Conversion to a DLC

3.) Package Implementation

4.) Package Compilation

5.) Model Execution

Steps 1-4 are run offline on the x86 host and are necessary for execution in step 5. Step 5 provides information on execution using the SNPE command-line executable snpe-net-run.

Step 1: Package Generation

Generating the Conv2DPackage package requires the snpe-udo-package-generator tool and the provided UDO plugin: Conv2D.json / Conv2DQuant.json depending on your runtime requirement. The Conv2D.json and Conv2DQuant.json gives you skeleton code for CPU(float) and DSP(uint8) implementations respectively . The plugins is located under $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/config. More information about creating a UDO plugin can be found here.

Generate the Conv2DPackage UDO package using the following:

export SNPE_UDO_ROOT=$SNPE_ROOT/share/SnpeUdo
mkdir $SNPE_ROOT/models/alexnet/ConvUdoCpu
snpe-udo-package-generator -p $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/config/Conv2D.json -o $SNPE_ROOT/models/alexnet/ConvUdoCpu

or for DSP

export SNPE_UDO_ROOT=$SNPE_ROOT/share/SnpeUdo
mkdir $SNPE_ROOT/models/alexnet/ConvUdoDsp
snpe-udo-package-generator -p $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/config/Conv2DQuant.json -o $SNPE_ROOT/models/alexnet/ConvUdoDsp

This command creates the Convolution based package at $SNPE_ROOT/models/alexnet/ConvUdoCpu/Conv2DPackage or $SNPE_ROOT/models/alexnet/ConvUdoDsp/Conv2DPackage

For more information on the snpe-udo-package-generator tool visit here.

Step 2: Framework model Conversion to a DLC

Converting the Caffe Alexnet model to DLC requires the snpe-caffe-to-dlc tool. The snpe-caffe-to-dlc tool consumes the same Conv2D.json used in package generation via the --udo command line option. In this step, <ALEXNET_PATH> refers to the path to the deploy.prototxt and bvlc_alexnet.caffemodel file. For example, after running the setup_alexnet.py script <ALEXNET_PATH> is $SNPE_ROOT/models/alexnet/caffe.

Convert Alexnet with the following:

snpe-caffe-to-dlc --input_network <ALEXNET_PATH>/deploy_batch_1.prototxt --caffe_bin <ALEXNET_PATH>/bvlc_alexnet.caffemodel --output_path $SNPE_ROOT/models/alexnet/dlc/alexnet_udo.dlc --udo $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/config/Conv2D.json

This will generate a DLC named alexnet_udo.dlc containing the Convolution as UDO at $SNPE_ROOT/models/alexnet/dlc.

Step 3: Package Implementations

The generated package creates the skeleton of the operation implementation, which must be filled by the user to create a functional UDO. Additionally, the skeleton for a user implemented validation function can be populated to validate information about the UDO passed from the SNPE runtime. The rest of the code scaffolding for compatibility with SNPE is provided by the snpe-udo-package-generator.

The UDO implementations and validation function for this tutorial are provided under $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/src.

Note: Implementing validation is user-specific and not a strict requirement for using a UDO in SNPE. Only CPU Validation is provided as example.

CPU Implementations (Android and x86)

The files in the package that need to be implemented for CPU are

  • ConvUdoCpu/Conv2DPackage/jni/src/CPU/ConvolutionImplLibCpu.cpp
  • ConvUdoCpu/Conv2DPackage/jni/src/reg/Conv2DPackageCpuImplValidationFunctions.cpp

The provided example implementations for these files are at the locations

  • $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/src/CPU/ConvolutionImplLibCpu.cpp
  • $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/src/reg/Conv2DPackageCpuImplValidationFunctions.cpp

Copy the provided implementations to the package:

cp -f $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/src/CPU/ConvolutionImplLibCpu.cpp $SNPE_ROOT/models/alexnet/ConvUdoCpu/Conv2DPackage/jni/src/CPU/
cp -f $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/src/reg/Conv2DPackageCpuImplValidationFunctions.cpp $SNPE_ROOT/models/alexnet/ConvUdoCpu/Conv2DPackage/jni/src/reg/

Dsp Implementations (Android)

The files in the package that need to be implemented for DSP are

  • ConvUdoDsp/Conv2DPackage/jni/src/DSP/ConvolutionImplLibDsp.c
  • ConvUdoDsp/Conv2DPackage/include/ConvolutionImplLibDsp.h

The provided example implementations for these files are at the locations

  • $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/src/DSP/Conv2DInt8Impl/ConvolutionImplLibDsp.c
  • $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/src/DSP/Conv2DInt8Impl/ConvolutionImplLibDsp.h

Copy the provided implementations to the package:

cp -f $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/src/DSP/Conv2DInt8Impl/ConvolutionImplLibDsp.c $SNPE_ROOT/models/alexnet/ConvUdoDsp/Conv2DPackage/jni/src/DSP/
cp -f $SNPE_ROOT/examples/NativeCpp/UdoExample/Conv2D/src/DSP/Conv2DInt8Impl/ConvolutionImplLibDsp.h $SNPE_ROOT/models/alexnet/ConvUdoDsp/Conv2DPackage/include/

Optionally, the user can provide their own implementations in the package.

Step 4: Package Compilation

x86 Host Compilation

Compiling on x86 host uses the make build system. Compile the CPU implementations with the following:

cd $SNPE_ROOT/models/alexnet/ConvUdoCpu/Conv2DPackage
make cpu_x86

The expected artifacts after compiling for CPU on x86 host are

  • ConvUdoCpu/Conv2DPackage/libs/x86-64_linux_clang/libUdoConv2DPackageImplCpu.so
  • ConvUdoCpu/Conv2DPackage/libs/x86-64_linux_clang/libUdoConv2DPackageReg.so

Android CPU Runtime Compilation

Compilation for the CPU runtime on Android uses Android NDK. The ANDROID_NDK_ROOT environment variable must be set to the directory containing ndk-build in order to compile the package.

export ANDROID_NDK_ROOT=<path_to_android_ndk>

It is suggested to add ANDROID_NDK_ROOT to the PATH environment variable to access ndk-build.

export PATH=$ANDROID_NDK_ROOT:$PATH

Target architecture must also be specified when compiling the package.

export UDO_APP_ABI=<target_architecture>

This tutorial uses arm64-v8a architectures - it is recommended but not required to use arm64-v8a as the target architecture for the remainder of the tutorial. If no target architecture is supplied both arm64-v8a and armeabi-v7a are targeted.

Once the ANDROID_NDK_ROOT is part of PATH, compile the package for Android CPU target:

cd $SNPE_ROOT/models/alexnet/ConvUdoCpu/Conv2DPackage
make cpu_android PLATFORM=$UDO_APP_ABI

The expected artifacts after compiling for Android CPU are

  • ConvUdoCpu/Conv2DPackage/libs/<target_architecture>/libUdoConv2DPackageImplCpu.so
  • ConvUdoCpu/Conv2DPackage/libs/<target_architecture>/libUdoConv2DPackageReg.so
  • ConvUdoCpu/Conv2DPackage/libs/<target_architecture>/libc++_shared.so

Hexagon DSP Runtime Compilation

Compilation for the DSP runtime makes use of the make system. In order to build the DSP implementation libraries, Hexagon-SDK needs to be installed and set up. For details, follow the setup instructions on $HEXAGON_SDK_ROOT/docs/readme.html page, where HEXAGON_SDK_ROOT is the location of your Hexagon-SDK installation.

Note: This SNPE release supports building UDO DSP implementation libraries using Hexagon-SDK 3.5.1/3.5.2.

Make sure that HEXAGON_SDK_ROOT, HEXAGON_TOOLS_ROOT and SDK_SETUP_ENV=Done is set.

export HEXAGON_SDK_ROOT=<path to hexagon sdk installation>
export HEXAGON_TOOLS_ROOT=$HEXAGON_SDK_ROOT/tools/HEXAGON_Tools/8.3.07
export SDK_SETUP_ENV=Done

With the environment set up, compile for DSP with the following:

cd $SNPE_ROOT/models/alexnet/ConvUdoDsp/Conv2DPackage
make dsp PLATFORM=$UDO_ABI

The expected artifacts after compiling for Hexagon DSP are

  • ConvUdoDsp/Conv2DPackage/libs/dsp/libUdoConv2DPackageImplDsp.so
  • ConvUdoDsp/Conv2DPackage/libs/$UDO_APP_ABI/libUdoConv2DPackageReg.so

Note: For DSP, PLATFORM will only determine the ABI of the registration library.

Model Execution

Execution using snpe-net-run

Executing Inception-V3 for UDO is largely the same as use of snpe-net-run without UDO.

The SNPE SDK provides Linux and Android binaries of snpe-net-run under

  • $SNPE_ROOT/bin/x86_64-linux-clang
  • $SNPE_ROOT/bin/arm-android-clang6.0
  • $SNPE_ROOT/bin/aarch64-android-clang6.0
  • $SNPE_ROOT/bin/aarch64-linux-gcc4.9
  • $SNPE_ROOT/bin/arm-linux-gcc4.9sf
  • $SNPE_ROOT/bin/aarch64-oe-linux-gcc6.4
  • $SNPE_ROOT/bin/arm-oe-linux-gcc6.4hf

For UDO, snpe-net-run consumes the registration library through the --udo_package_path option. LD_LIBRARY_PATH must also be updated to include the runtime-specific artifacts generated from package compilation.

x86 Host Execution

To execute the network on x86 host, run:

cd $SNPE_ROOT/models/alexnet
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$SNPE_ROOT/models/alexnet/ConvUdoCpu/Conv2DPackage/libs/x86-64_linux_clang/
snpe-net-run --container dlc/alexnet_udo.dlc --input_list data/cropped/raw_list.txt --udo_package_path ConvUdoCpu/Conv2DPackage/libs/x86-64_linux_clang/libUdoConv2DPackageReg.so

Android Target Execution

The tutorial for execution on Android targets will use the arm64-v8a architecture. This portion of the tutorial is generic to all runtimes (CPU, DSP).

# architecture: arm64-v8a - compiler: clang - STL: libc++
export SNPE_TARGET_ARCH=aarch64-android-clang6.0
export SNPE_TARGET_STL=libc++_shared.so

Then, push SNPE binaries and libraries to the target device:

adb shell "mkdir -p /data/local/tmp/snpeexample/$SNPE_TARGET_ARCH/bin"
adb shell "mkdir -p /data/local/tmp/snpeexample/$SNPE_TARGET_ARCH/lib"

adb push $SNPE_ROOT/lib/$SNPE_TARGET_ARCH/$SNPE_TARGET_STL \
      /data/local/tmp/snpeexample/$SNPE_TARGET_ARCH/lib
adb push $SNPE_ROOT/lib/$SNPE_TARGET_ARCH/*.so \
      /data/local/tmp/snpeexample/$SNPE_TARGET_ARCH/lib
adb push $SNPE_ROOT/bin/$SNPE_TARGET_ARCH/snpe-net-run \
      /data/local/tmp/snpeexample/$SNPE_TARGET_ARCH/bin

Next, update environment variables on the target device to include the SNPE libraries and binaries:

adb shell
export SNPE_TARGET_ARCH=aarch64-android-clang6.0
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/data/local/tmp/snpeexample/$SNPE_TARGET_ARCH/lib
export PATH=$PATH:/data/local/tmp/snpeexample/$SNPE_TARGET_ARCH/bin

Lastly, push the Alexnet UDO model and input data to the device:

cd $SNPE_ROOT/models/alexnet
mkdir data/rawfiles && cp data/cropped/*.raw data/rawfiles/
adb shell "mkdir -p /data/local/tmp/alexnet_udo"
adb push data/rawfiles /data/local/tmp/alexnet_udo/cropped
adb push data/target_raw_list.txt /data/local/tmp/alexnet_udo
adb push dlc/alexnet_udo.dlc /data/local/tmp/alexnet_udo
rm -rf data/rawfiles

Android CPU Execution

Once the model and data have been placed on the device, place the UDO libraries on the device:

cd $SNPE_ROOT/models/alexnet/ConvUdoCpu
adb shell "mkdir -p /data/local/tmp/alexnet_udo/cpu"
adb push Conv2DPackage/libs/arm64-v8a/libUdoConv2DUdoPackageImplCpu.so /data/local/tmp/alexnet_udo/cpu
adb push Conv2DPackage/libs/arm64-v8a/libUdoConv2DUdoPackageReg.so /data/local/tmp/alexnet_udo/cpu
adb push Conv2DPackage/libs/arm64-v8a/libc++_shared.so /data/local/tmp/alexnet_udo/cpu

Now set required environment variables and run snpe-net-run on device:

adb shell
cd /data/local/tmp/alexnet_udo/
export LD_LIBRARY_PATH=/data/local/tmp/alexnet_udo/cpu/:$LD_LIBRARY_PATH
snpe-net-run --container alexnet_udo.dlc --input_list target_raw_list.txt --udo_package_path cpu/libUdoConv2DPackageReg.so

Hexagon DSP Execution

The procedure for execution on device for DSP is largely the same as CPU and GPU. However, the DSP runtime requires quantized network parameters. While DSP allows unquantized DLCs, it is generally recommended to quantize DLCs for improved performance. The tutorial will use a quantized DLC as an illustrative example. Quantizing the DLC requires the snpe-dlc-quantize tool.

To quantize the DLC for use on DSP:

cd $SNPE_ROOT/models/alexnet/
snpe-dlc-quantize --input_dlc dlc/alexnet_udo.dlc --input_list data/cropped/raw_list.txt --udo_package_path ConvUdoCpu/Conv2DPackage/libs/x86-64_linux_clang/libUdoConv2DPackageReg.so --output_dlc dlc/alexnet_udo_quantized.dlc

For more information on snpe-dlc-quantize visit quantization. For information on UDO-specific quantization visit Quantizing a DLC with UDO. For information on DSP runtime visit DSP Runtime.

Now push the quantized model to device:

adb push dlc/alexnet_udo_quantized.dlc /data/local/tmp/alexnet_udo

Before executing on the DSP, push the SNPE libraries for DSP to device:

adb shell "mkdir -p /data/local/tmp/snpeexample/dsp/lib"
adb push $SNPE_ROOT/lib/dsp/*.so \
      /data/local/tmp/snpeexample/dsp/lib

Now push DSP-specific UDO libraries to device:

cd $SNPE_ROOT/models/alexnet/ConvUdoDsp
adb shell "mkdir -p /data/local/tmp/alexnet_udo/dsp"
adb push Conv2DPackage/libs/dsp/*.so /data/local/tmp/alexnet_udo/dsp
adb push Conv2DPackage/libs/arm64-v8a/libUdoConv2DPackageReg.so /data/local/tmp/alexnet_udo/dsp # Pushes reg lib

Then set required environment variables and run snpe-net-run on device:

adb shell
cd /data/local/tmp/alexnet_udo/
export LD_LIBRARY_PATH=/data/local/tmp/alexnet_udo/dsp/:$LD_LIBRARY_PATH
export ADSP_LIBRARY_PATH="/data/local/tmp/alexnet_udo/dsp/;/data/local/tmp/snpeexample/dsp/lib;/system/lib/rfsa/adsp;/system/vendor/lib/rfsa/adsp;/dsp"
snpe-net-run --container alexnet_udo_quantized.dlc --input_list target_raw_list.txt --udo_package_path dsp/libUdoConv2DPackageReg.so --use_dsp

To verify classification results run the following on your host cpu machine .

cd $SNPE_ROOT/models/alexnet/
adb pull /data/local/tmp/alexnet_udo/output .
python3 $SNPE_ROOT/models/alexnet/scripts/show_alexnet_classifications.py -i data/cropped/raw_list.txt \
                                                                         -o output/ \
                                                                         -l data/ilsvrc_2012_labels.txt

The output should look like the following, showing classification results for all the images.

Classification results
<input_files_dir>/trash_bin.raw     0.949348 412 ashcan, trash can, garbage can,
                                                 wastebin, ash bin, ash-bin, ashbin,
                                                 dustbin, trash barrel, trash bin

<input_files_dir>/plastic_cup.raw   0.749104 647 measuring cup
<input_files_dir>/chairs.raw        0.365685 831 studio couch, day bed
<input_files_dir>/notice_sign.raw   0.722708 458 brass, memorial tablet, plaque