Stream Kernel to Kernel Memory Mapped XRT (XRT Native API’s)

This is a simple kernel to kernel streaming Vector Add and Vector Multiply C Kernel design with 2 memory mapped input to kernel 1, 1 Stream output from kernel 1 to input of kernel 2, 1 memory mapped input to kernel 2, and 1 memory mapped output that demonstrates on how to process a stream of data for computation between two kernels using XRT Native APIs. This design also illustrates how to set FIFO depth for AXIS connections i.e. for the stream connecting the two kernels

KEY CONCEPTS: Read/Write Stream, Create/Release Stream, AXIS FIFO depth

KEYWORDS: stream_connect

This example demonstrates how kernels can have memory mapped inputs along with stream interface from one kernel to another.

kernel_stream_vadd has two memory mapped inputs and one stream output. kernel_stream_vmult has one memory mapped input along with kernel to kernel stream from kernel_stream_vadd which acts as its second input.

Kernel arguments are not required to be setup in host code for kernel to kernel streaming interfaces. Argument 2 for kernel_vadd and argument 1 for kernel_vmult are not declared.

run.set_arg(0,bo0);
run.set_arg(1,bo1);
run.set_arg(3,DATA_SIZE);

run1.set_arg(0,bo2);
run1.set_arg(2,bo_out);
run1.set_arg(3,DATA_SIZE);

Producer kernel stream output port must be connected to consumer kernel stream input port during the v++ linking stage.

--config krnl_stream_vadd_vmult.cfg

Content of krnl_stream_vadd_vmult.cfg file is below:

[connectivity]
stream_connect=krnl_stream_vadd_1.out:krnl_stream_vmult_1.in2:64

Above specify that out port of krnl_stream_vadd_1 kernel is connected to in2 port of krnl_stream_vmult_1. The FIFO depth of this stream is 64.

EXCLUDED PLATFORMS:

  • Samsung SmartSSD Computation Storage Drive

  • Samsung U.2 SmartSSD

  • Versal VCK190

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

  • 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_stream_vadd.cpp
src/krnl_stream_vmult.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

./streaming_k2k_mm_xrt -x <krnl_stream_vadd_vmult XCLBIN>