Inference on the Ascend 910 AI processor

Overview

Users can create C++ applications and call MindSpore C++ interface to inference MindIR models.

Inference Directory Structure

Create a directory to store the inference code project, for example, /home/HwHiAiUser/mindspore_sample/ascend910_resnet50_preprocess_sample. The directory code can be obtained from the official website. The model directory stores the exported MindIR model files and the test_data directory stores the images to be classified. The directory structure of the inference code project is as follows:

└─ascend910_resnet50_preprocess_sample
    ├── CMakeLists.txt                    // Build script
    ├── README.md                         // Usage description
    ├── main.cc                           // Main function
    ├── model
    │   └── resnet50_imagenet.mindir      // MindIR model file
    └── test_data
        ├── ILSVRC2012_val_00002138.JPEG  // Input sample image 1
        ├── ILSVRC2012_val_00003014.JPEG  // Input sample image 2
        ├── ...                           // Input sample image n

Inference Code

Inference sample code: ascend310_resnet50_preprocess_sample.

Using namespace of mindspore and mindspore::dataset.

namespace ms = mindspore;
namespace ds = mindspore::dataset;

Set global context, and device target is Ascend910 and Device ID is 0:

auto context = std::make_shared<ms::Context>();
auto ascend910_info = std::make_shared<ms::Ascend910DeviceInfo>();
ascend910_info->SetDeviceID(0);
context->MutableDeviceInfo().push_back(ascend910_info);

Load model file:

// Load MindIR model
ms::Graph graph;
ms::Status ret = ms::Serialization::Load(resnet_file, ms::ModelType::kMindIR, &graph);
// Build model with graph object
ms::Model resnet50;
ret = resnet50.Build(ms::GraphCell(graph), context);

Get input information required for the model:

std::vector<ms::MSTensor> model_inputs = resnet50.GetInputs();

Load image file:

// Readfile is a function to read images
ms::MSTensor ReadFile(const std::string &file);
auto image = ReadFile(image_file);

Image preprocess:

// Create the CPU operation provided by MindData to get the function object

// Decode the input to RGB format
std::shared_ptr<ds::TensorTransform> decode(new ds::vision::Decode());
// Resize the image to the given size
std::shared_ptr<ds::TensorTransform> resize(new ds::vision::Resize({256}));
// Normalize the input
std::shared_ptr<ds::TensorTransform> normalize(new ds::vision::Normalize(
    {0.485 * 255, 0.456 * 255, 0.406 * 255}, {0.229 * 255, 0.224 * 255, 0.225 * 255}));
// Crop the input image at the center
std::shared_ptr<ds::TensorTransform> center_crop(new ds::vision::CenterCrop({224, 224}));
// shape (H, W, C) to shape (C, H, W)
std::shared_ptr<ds::TensorTransform> hwc2chw(new ds::vision::HWC2CHW());

// // Define a MindData preprocessor
ds::Execute preprocessor({decode, resize, normalize, center_crop, hwc2chw});

// Call the function object to get the processed image
ret = preprocessor(image, &image);

Execute inference:

// Create outputs vector
std::vector<ms::MSTensor> outputs;
// Create inputs vector
std::vector<ms::MSTensor> inputs;
inputs.emplace_back(model_inputs[0].Name(), model_inputs[0].DataType(), model_inputs[0].Shape(),
                    image.Data().get(), image.DataSize());
// Call the Predict function of Model for inference
ret = resnet50.Predict(inputs, &outputs);

Print the result:

// Output the maximum probability to the screen
std::cout << "Image: " << image_file << " infer result: " << GetMax(outputs[0]) << std::endl;

Introducing Building Script

The building script is used to building applications: CMakeLists.txt.

Add the header file search path for the compiler:

option(MINDSPORE_PATH "mindspore install path" "")
include_directories(${MINDSPORE_PATH})
include_directories(${MINDSPORE_PATH}/include)

Search for the required dynamic library in MindSpore:

find_library(MS_LIB libmindspore.so ${MINDSPORE_PATH}/lib)
file(GLOB_RECURSE MD_LIB ${MINDSPORE_PATH}/_c_dataengine*)

Use the source files to generate the target executable file, and link the MindSpore libraries for the executable file:

add_executable(resnet50_sample main.cc)
target_link_libraries(resnet50_sample ${MS_LIB} ${MD_LIB})

Building Inference Code

Go to the project directory ascend910_resnet50_preprocess_sample and set the following environment variables:

# control log level. 0-DEBUG, 1-INFO, 2-WARNING, 3-ERROR, 4-CRITICAL, default level is WARNING.
export GLOG_v=2

# Conda environmental options
LOCAL_ASCEND=/usr/local/Ascend # the root directory of run package

# lib libraries that the run package depends on
export LD_LIBRARY_PATH=${LOCAL_ASCEND}/ascend-toolkit/latest/lib64:${LOCAL_ASCEND}/driver/lib64/common:${LOCAL_ASCEND}/driver/lib64/driver:${LOCAL_ASCEND}/ascend-toolkit/latest/opp/op_impl/built-in/ai_core/tbe/op_tiling:${LD_LIBRARY_PATH}

# lib libraries that the mindspore depends on, modify "pip3" according to the actual situation
export LD_LIBRARY_PATH=`pip3 show mindspore | grep Location | awk '{print $2"/mindspore/lib"}' | xargs realpath`:${LD_LIBRARY_PATH}

# Environment variables that must be configured
export TBE_IMPL_PATH=${LOCAL_ASCEND}/ascend-toolkit/latest/opp/op_impl/built-in/ai_core/tbe            # TBE operator implementation tool path
export ASCEND_OPP_PATH=${LOCAL_ASCEND}/ascend-toolkit/latest/opp                                       # OPP path
export PATH=${LOCAL_ASCEND}/ascend-toolkit/latest/compiler/ccec_compiler/bin/:${PATH}                  # TBE operator compilation tool path
export PYTHONPATH=${TBE_IMPL_PATH}:${PYTHONPATH}                                                       # Python library that TBE implementation depends on

Run the cmake command, and modify pip3 according to the actual situation:

cmake . -DMINDSPORE_PATH=`pip3 show mindspore | grep Location | awk '{print $2"/mindspore"}' | xargs realpath`

Run the make command for building.

make

After building, the executable file is generated in ascend910_resnet50_preprocess_sample.

Performing Inference and Viewing the Result

Log in to the Ascend 910 server, and create the model directory for storing the MindIR file resnet50_imagenet.mindir, for example, /home/HwHiAiUser/mindspore_sample/ascend910_resnet50_preprocess_sample/model. Create the test_data directory to store images, for example, /home/HwHiAiUser/mindspore_sample/ascend910_resnet50_preprocess_sample/test_data. Then, perform the inference.

./resnet50_sample

Inference is performed on all images stored in the test_data directory. For example, if there are 9 images whose label is 0 in the ImageNet2012 validation set, the inference result is as follows:

Image: ./test_data/ILSVRC2012_val_00002138.JPEG infer result: 0
Image: ./test_data/ILSVRC2012_val_00003014.JPEG infer result: 0
Image: ./test_data/ILSVRC2012_val_00006697.JPEG infer result: 0
Image: ./test_data/ILSVRC2012_val_00007197.JPEG infer result: 0
Image: ./test_data/ILSVRC2012_val_00009111.JPEG infer result: 0
Image: ./test_data/ILSVRC2012_val_00009191.JPEG infer result: 0
Image: ./test_data/ILSVRC2012_val_00009346.JPEG infer result: 0
Image: ./test_data/ILSVRC2012_val_00009379.JPEG infer result: 0
Image: ./test_data/ILSVRC2012_val_00009396.JPEG infer result: 0