Host Memory Copy Kernel

This is a Host Memory Example to describe how data can be copied between host-only buffer and device-only buffer using User Copy Kernel.

KEY CONCEPTS: host memory

KEYWORDS: XCL_MEM_EXT_HOST_ONLY, CL_MEM_HOST_NO_ACCESS, enqueueMapBuffer

Here a user copy kernel is instantiated inside container which copies data between host and device memory.

Host only buffer is created using XCL_MEM_EXT_HOST_ONLY flag whereas device only buffer is created using CL_MEM_HOST_NO_ACCESS flag. The following data transfers take place in the example -

  1. Enqueue kernel copy_kernel to copy the HOST_ONLY input buffer buffer_in_host into DEVICE_ONLY input buffer buffer_in_dev.

  2. Enqueue kernel krnl_vadd to do computations on DEVICE_ONLY input buffer buffer_in_dev and put output in DEVICE_ONLY output buffer buffer_out_dev.

  3. Enqueue kernel copy_kernel to copy the DEVICE_ONLY output buffer buffer_out_dev into HOST_ONLY output buffer buffer_out_host.

EXCLUDED PLATFORMS:

  • Alveo U25 SmartNIC

  • Alveo U30

  • Alveo U50lv

  • Alveo U50 gen3x4

  • All Embedded Zynq Platforms, i.e zc702, zcu102 etc

  • All Versal Platforms, i.e vck190 etc

  • All Platforms with 2019 Version

  • All Platforms with 2018 Version

  • Samsung U.2 SmartSSD

DESIGN FILES

Application code is located in the src directory. Accelerator binary files will be compiled to the xclbin directory. The xclbin directory is required by the Makefile and its contents will be filled during compilation. A listing of all the files in this example is shown below

src/copy_kernel.cpp
src/host.cpp
src/krnl_vadd.cpp

Access these files in the github repo by clicking here.

COMMAND LINE ARGUMENTS

Once the environment has been configured, the application can be executed by

./host_memory_copy_kernel.exe <krnl_vadd XCLBIN>