HBM Large Buffers

This is a simple example of vector addition to describe how HBM pseudo-channels can be grouped to handle buffers larger than 256 MB.

KEY CONCEPTS: High Bandwidth Memory, Multiple HBM Pseudo-channel Groups

KEYWORDS: HBM

This is a simple example of vector addition to describe how HBM pseudo-channels(PC) can be grouped to handle buffers larger than 256 MB.

Compute unit interfaces are associated to fixed HBM PC groups using krnl_vadd.cfg file:

[connectivity]
sp=krnl_vadd_1.in1:HBM[0:31].15
sp=krnl_vadd_1.in2:HBM[0:31]
sp=krnl_vadd_1.out_r:HBM[0:31]

The HBM Subsystem chooses the appropriate HBM Slave AXI interface port to access memory and to maximize bandwidth and minimize latency given the pseudo channel number or a given range. However, it is also possible to indicate which Slave AXI interface to use for connecting the kernel’s Master AXI interface: this is done with the addition of an index number to the sp option (as seen above for in1).

Here, All three buffers will be created into different bank groups and the application will run and performance will be reported. Following is the real log reported while running on U50 platform :

Found Platform
Platform Name: Xilinx
INFO: Reading ./build_dir.hw.xilinx_u50_gen3x16_xdma_201920_3/krnl_vadd.xclbin
Loading: './build_dir.hw.xilinx_u50_gen3x16_xdma_201920_3/krnl_vadd.xclbin'
Trying to program device[0]: xilinx_u50_gen3x16_xdma_201920_3
Device[0]: program successful!
Running Three Separate Groups for Three Buffers
Each buffer is allocated with different HBM Group.
input 1 -> PC 0 : 31
input 2 -> PC 0 : 31
output  -> PC 0 : 31
THROUGHPUT = 39.2318 GB/s
TEST PASSED

EXCLUDED PLATFORMS:

  • Alveo U25 SmartNIC

  • Alveo U30

  • Alveo U200

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

  • All Versal Platforms, i.e vck190 etc

  • Alveo U250

  • Alveo U280

  • AWS VU9P F1

  • Samsung U.2 SmartSSD

  • All NoDMA Platforms, i.e u50 nodma etc

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/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

./hbm_large_buffers <krnl_vadd XCLBIN>