Stream Free Running Host to Kernel(HLS C/C++)
=============================================

This is a simple streaming free running kernel that demonstrates how to interact with the host. In this design we showcase multiple stream requests in parallel.

**KEY CONCEPTS:** Free Running Kernel

**KEYWORDS:** cl_stream, CL_STREAM_EOT, CL_STREAM_NONBLOCKING


This example demonstrates how host and kernel can communicate through a
stream interface. Rather than loading the data from host to global
memory and then to consumer kernel ``increment`` we can use stream to
transfer this data directly. It reduces the latency of the application
and also reduces the memory utilization. This is a simple increment
Kernel design in which streams of kernel are directly communicating with
host using stream interfaces.

For free running kernel, user needs to specify ap_ctrl_none for return
port. This will create the kernel without AXI lite interface. Kernel
will always be in running states.

.. code:: cpp

   #pragma HLS interface ap_ctrl_none port=return

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

::

   Platform Name: Xilinx
   INFO: Reading increment.xclbin
   Loading: 'increment.xclbin'
   Trying to program device[0]: xilinx_u200_qdma_201920_1
   Device[0]: program successful!

    Writing Stream h2c_stream_a[0]
    Reading Stream c2h_stream[0]
    Writing Stream h2c_stream_a[1]
    Reading Stream c2h_stream[1]
    Writing Stream h2c_stream_a[2]
    Reading Stream c2h_stream[2]
    Writing Stream h2c_stream_a[3]
    Reading Stream c2h_stream[3]
    Writing Stream h2c_stream_a[4]
    Reading Stream c2h_stream[4]
    Writing Stream h2c_stream_a[5]
    Reading Stream c2h_stream[5]
    Writing Stream h2c_stream_a[6]
    Reading Stream c2h_stream[6]
    Writing Stream h2c_stream_a[7]
    Reading Stream c2h_stream[7]
    Writing Stream h2c_stream_a[8]
    Reading Stream c2h_stream[8]
    Writing Stream h2c_stream_a[9]
    Reading Stream c2h_stream[9]
    Writing Stream h2c_stream_a[10]
    Reading Stream c2h_stream[10]
    Writing Stream h2c_stream_a[11]
    Reading Stream c2h_stream[11]
    Writing Stream h2c_stream_a[12]
    Reading Stream c2h_stream[12]
    Writing Stream h2c_stream_a[13]
    Reading Stream c2h_stream[13]
    Writing Stream h2c_stream_a[14]
    Reading Stream c2h_stream[14]
    Writing Stream h2c_stream_a[15]
    Reading Stream c2h_stream[15]
    Writing Stream h2c_stream_a[16]
    Reading Stream c2h_stream[16]
    Writing Stream h2c_stream_a[17]
    Reading Stream c2h_stream[17]
    Writing Stream h2c_stream_a[18]
    Reading Stream c2h_stream[18]
    Writing Stream h2c_stream_a[19]
    Reading Stream c2h_stream[19]
    Writing Stream h2c_stream_a[20]
    Reading Stream c2h_stream[20]
    Writing Stream h2c_stream_a[21]
    Reading Stream c2h_stream[21]
    Writing Stream h2c_stream_a[22]
    Reading Stream c2h_stream[22]
    Writing Stream h2c_stream_a[23]
    Reading Stream c2h_stream[23]
    Writing Stream h2c_stream_a[24]
    Reading Stream c2h_stream[24]
    Writing Stream h2c_stream_a[25]
    Reading Stream c2h_stream[25]
    Writing Stream h2c_stream_a[26]
    Reading Stream c2h_stream[26]
    Writing Stream h2c_stream_a[27]
    Reading Stream c2h_stream[27]
    Writing Stream h2c_stream_a[28]
    Reading Stream c2h_stream[28]
    Writing Stream h2c_stream_a[29]
    Reading Stream c2h_stream[29]
    Writing Stream h2c_stream_a[30]
    Reading Stream c2h_stream[30]
    Writing Stream h2c_stream_a[31]
    Reading Stream c2h_stream[31]
    clPollStreams for (64) events (CU: 32, axis_in: 1, axis_out: 1)
   [ Case: 1 ] -> Throughput = 2.38802 GB/s
   TEST PASSED 

EXCLUDED PLATFORMS
------------------

Platforms containing following strings in their names are not supported for this example :

::

   u250
   zc
   vck
   xdma
   qep
   aws
   samsung

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/increment.cpp
   
COMMAND LINE ARGUMENTS
----------------------

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

::

   ./streaming_free_running_h2k -x <increment XCLBIN>