Kernel Global Bandwidth

Bandwidth test of global to local memory.

This example tests global memory access bandwidth of kernel. Kernel increase the bandwidth by accessing multiple DDR banks through different interfaces.

Banks need to be specified using sp tags in respective .cfg file along with the port name and kernel name. For Ex-

[connectivity]
sp=bandwidth_1.m_axi_gmem0:DDR[0]
sp=bandwidth_1.m_axi_gmem1:DDR[1]

Following is the log reported while running the design on U200 platform:

./kernel_global ./build_dir.hw.xilinx_u200_xdma_201830_2/krnl_kernel_global.xclbin
Found Platform
Platform Name: Xilinx
Found Device=xilinx_u200_xdma_201830_2
INFO: Reading ./build_dir.hw.xilinx_u200_xdma_201830_2/krnl_kernel_global.xclbin
Loading: './build_dir.hw.xilinx_u200_xdma_201830_2/krnl_kernel_global.xclbin'
Starting kernel to read/write 1024 MB bytes from/to global memory...
Kernel Duration...66662680 ns
Kernel completed read/write 1024 MB bytes from/to global memory.
Execution time = 0.066663 (sec)
Concurrent Read and Write Throughput = 30.72 (GB/sec)
TEST PASSED

GUI Flow :

By default this example supports 1DDR execution in GUI mode for all the XSAs. To make this example to work with multi DDR XSAs please follow steps mentioned below. XSA (2DDR):

  1. Add a .cfg file in the /src folder with the following entries: [Connecttivity] sp=bandwidth_1.m_axi_gmem0:DDR[0] sp=bandwidth_1.m_axi_gmem1:DDR[1] 2. > Properties > C/C++ Build > Settings > Vitis V++ Kernel Compiler > Miscellaneous > Other flags 3.In “Other flags” box enter following

    1. –max_memory_ports all 4. > Properties > C/C++ Build > Settings > Vitis V++ Kernel Linker > Miscellaneous > Other flags –config ../src/<config_file.cfg>

XSA (3DDR):

  1. Add a .cfg file in the /src folder with the following entries: [Connecttivity] sp=bandwidth_1.m_axi_gmem0:DDR[0] sp=bandwidth_1.m_axi_gmem1:DDR[1] sp=bandwidth_1.m_axi_gmem2:DDR[2] 2. > Properties > C/C++ Build > Settings > Vitis V++ Kernel Compiler > Miscellaneous > Other flags 3.In “Other flags” box enter following

    1. –max_memory_ports all 4. > Properties > C/C++ Build > Settings > Vitis V++ Kernel Linker > Miscellaneous > Other flags –config ../src/<config_file.cfg> 5.Define NDDR_BANKS 3 in kernel “#define NDDR_BANKS 3” at the top of kernel.cl

EXCLUDED PLATFORMS:

  • Samsung U.2 SmartSSD

  • Alveo U30

  • Alveo U50

  • Alveo U55

  • Versal VCK5000

  • Alveo U250

  • Versal V70

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/kernel.cpp
src/kernel_global_bandwidth.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

./kernel_global_bandwidth <krnl_kernel_global XCLBIN>