Dataflow Using HLS Stream¶
This is simple example of vector addition to demonstrate Dataflow functionality of HLS. HLS Dataflow allows user to schedule multiple task together to achieve higher throughput.
KEY CONCEPTS: Task Level Parallelism
KEYWORDS: dataflow, hls::stream
This example explains how #pragma HLS dataflow
can be used to
implement task level parallelism using HLS Stream
datatype.
Usually data stored in the array is consumed or produced in a sequential
manner, a more efficient communication mechanism is to use streaming
data as specified by the STREAM
pragma, where FIFOs are used instead
of RAMs. Depth of FIFO
can be specified by depth
option in the
pragma.
#pragma HLS STREAM variable = inStream depth = 32
#pragma HLS STREAM variable = outStream depth = 32
Vector addition in kernel is divided into 3 sub-tasks(read, compute_add
and write) which are then performed concurrently using Dataflow
.
#pragma HLS dataflow
read_input(in, inStream, size);
compute_add(inStream, outStream, inc, size);
write_result(out, outStream, size);
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/adder.cpp
src/host.cpp
COMMAND LINE ARGUMENTS¶
Once the environment has been configured, the application can be executed by
./host <adder XCLBIN>