Adding ILA Triggers Before Starting Kernels - 2021.2 English

Vitis Unified Software Platform Documentation: Application Acceleration Development (UG1393)

Document ID
UG1393
ft:locale
English (United States)
Release Date
2021-12-15
Version
2021.2 English

Pausing the host program can be accomplished through the use of a pause, or wait step in the code, such as the wait_for_enter function used in the RTL Kernel example on GitHub. The function is defined in the src/host.cpp code as follows:

void wait_for_enter(const std::string &msg) {
    std::cout << msg << std::endl;
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
}

The wait_for_enter function is used in the main function as follows:

....
    std::string binaryFile = xcl::find_binary_file(device_name,"vadd");
	
    cl::Program::Binaries bins = xcl::import_binary_file(binaryFile);
    devices.resize(1);
    cl::Program program(context, devices, bins);
    cl::Kernel krnl_vadd(program,"krnl_vadd_rtl");


     wait_for_enter("\nPress ENTER to continue after setting up ILA trigger...");

    //Allocate Buffer in Global Memory
    std::vector<cl::Memory> inBufVec, outBufVec;
    cl::Buffer buffer_r1(context,CL_MEM_USE_HOST_PTR | CL_MEM_READ_ONLY, 
            vector_size_bytes, source_input1.data());
    ...

    //Copy input data to device global memory
    q.enqueueMigrateMemObjects(inBufVec,0/* 0 means from host*/);

    //Set the Kernel Arguments
    ...

    //Launch the Kernel
    q.enqueueTask(krnl_vadd);

The use of the wait_for_enter function pauses the host program to give you time to set up the required ILA triggers and prepare to capture data from the kernel. After the Vivado hardware manager is set up and configured, press Enter to continue running the application.

  • For C++ host code, add a pause after the creation of the cl::Kernel object, as shown in the example above.
  • For C-language host code, add a pause after the clCreateKernel() function call: