Sqrt Xilinx OpenCL C Kernel

This repository is used to test the built-in sqrt() OpenCL C function inside a kernel targeting a Xilinx Alveo U250 FPGA.

This repository shows a linking issue for testing built in OpenCL C functions using sw_emu and a work around to fix the issue. If you try to run build_and_run_sw_emu.sh you will get a undefined symbols in the kernel error. However, if you add /opt/Xilinx/Vitis/2020.1/lib/lnx64.o to the path, then build_and_run_sw_emu.sh will run correctly. I have also included build_and_run_sw_emu_fixed.sh which changes LD_LIBRARY_PATH to the minimal directories required to successfully run sw_emu. These directories are /opt/Xilinx/Vitis/2020.1/lib/lnx64.o and /opt/xilinx/xrt/lib. /opt/xilinx/xrt/lib is already added automatically by source /opt/xilinx/xrt/setup.sh.

To run the SW EMU test

Run the bash script build_and_run_sw_emu.sh after sourcing the Vitis tool chain.

The expected result is an error loading the kernel:

$ ./build_and_run_sw_emu.sh
Grab build target from argv
arg_idx = 3
argv[3] = sw_emu
Build tgt was found to be sw_emu
argc now = 3
Grab kernel version number
arg_idx = 2
argv[2] = v1
Using version 1
argc now = 2
XRT build version: 2.7.766
Build hash: 19bc791a7d9b54ecc23644649c3ea2c2ea31821c
Build date: 2020-08-17 23:51:58
Git branch: 2020.1_PU1
PID: 46385
UID: 40412
[Mon Jan 25 23:01:37 2021 GMT]
HOST: pcie
EXE: /home/7ry/Data/xilinx/sqrt_xilinx/sqrt
[XRT] WARNING: The data_transfer_trace setting of coarse is not supported in emulation. Fine will be used.
Found Platform
Platform Name: Xilinx
hi starting cmd q
0
hi done with cmd q
my_kernel_name = ./sw_emu/sqrt_kernel_v1
binary_name = ./sw_emu/sqrt_kernel_v1.xclbin
INFO: Reading ./sw_emu/sqrt_kernel_v1.xclbin
Loading: './sw_emu/sqrt_kernel_v1.xclbin'
ERROR: dlopen of /home/7ry/Data/xilinx/sqrt_xilinx/.run/46385/sw_emu/device0/binary_0/dltmp is failed. Please check undefined symbols in the kernel
[XRT] ERROR: Failed to load xclbin.
cv_opencl.cpp:47 Error calling cl::Program program(ctx, devices, bins, NULL, &err), error code is: -44

After updating LD_LIBRARY_PATH the simulation will run correctly.

$ export LD_LIBRARY_PATH=/opt/Xilinx/Vitis/2020.1/lib/lnx64.o:$LD_LIBRARY_PATH
$ ./build_and_run_sw_emu.sh
make: Nothing to be done for `all'.
Grab build target from argv
arg_idx = 3
argv[3] = sw_emu
Build tgt was found to be sw_emu
argc now = 3
Grab kernel version number
arg_idx = 2
argv[2] = v1
Using version 1
argc now = 2
XRT build version: 2.7.766
Build hash: 19bc791a7d9b54ecc23644649c3ea2c2ea31821c
Build date: 2020-08-17 23:51:58
Git branch: 2020.1_PU1
PID: 84146
UID: 40412
[Fri Jan 29 22:32:45 2021 GMT]
HOST: pcie
EXE: /home/7ry/Data/xilinx/sqrt_xilinx/sqrt
[XRT] WARNING: The data_transfer_trace setting of coarse is not supported in emulation. Fine will be used.
Found Platform
Platform Name: Xilinx
hi starting cmd q
0
hi done with cmd q
my_kernel_name = ./sw_emu/sqrt_kernel_v1
binary_name = ./sw_emu/sqrt_kernel_v1.xclbin
INFO: Reading ./sw_emu/sqrt_kernel_v1.xclbin
Loading: './sw_emu/sqrt_kernel_v1.xclbin'
Starting...
Computation Duration: 0.00198501 s
Result: sqrt(25) = 5
Saving solution...
Saved solution to results.txt...
Done...

Alternatively, running build_and_run_sw_emu_fixed.sh also works as expected, since I explicitly set LD_LIBRARY_PATH in the script.

$ ./build_and_run_sw_emu_fixed.sh
make: Nothing to be done for `all'.
/opt/Xilinx/Vitis/2020.1/lib/lnx64.o:/opt/xilinx/xrt/lib
Grab build target from argv
arg_idx = 3
argv[3] = sw_emu
Build tgt was found to be sw_emu
argc now = 3
Grab kernel version number
arg_idx = 2
argv[2] = v1
Using version 1
argc now = 2
XRT build version: 2.7.766
Build hash: 19bc791a7d9b54ecc23644649c3ea2c2ea31821c
Build date: 2020-08-17 23:51:58
Git branch: 2020.1_PU1
PID: 85432
UID: 40412
[Fri Jan 29 22:36:06 2021 GMT]
HOST: pcie
EXE: /home/7ry/Data/xilinx/sqrt_xilinx/sqrt
[XRT] WARNING: The data_transfer_trace setting of coarse is not supported in emulation. Fine will be used.
Found Platform
Platform Name: Xilinx
hi starting cmd q
0
hi done with cmd q
my_kernel_name = ./sw_emu/sqrt_kernel_v1
binary_name = ./sw_emu/sqrt_kernel_v1.xclbin
INFO: Reading ./sw_emu/sqrt_kernel_v1.xclbin
Loading: './sw_emu/sqrt_kernel_v1.xclbin'
Starting...
Computation Duration: 0.00191534 s
Result: sqrt(25) = 5
Saving solution...
Saved solution to results.txt...
Done...

To run the HW test

Run the bash script build_and_run_hw.sh after sourcing the Vitis tool chain.

The expected result is a successful run:

$ ./build_and_run_hw.sh
Grab build target from argv
arg_idx = 3
argv[3] = hw
Build tgt was found to be hw
argc now = 3
Grab kernel version number
arg_idx = 2
argv[2] = v1
Using version 1
argc now = 2
Found Platform
Platform Name: Xilinx
hi starting cmd q
0
hi done with cmd q
my_kernel_name = ./hw/sqrt_kernel_v1
binary_name = ./hw/sqrt_kernel_v1.xclbin
INFO: Reading ./hw/sqrt_kernel_v1.xclbin
Loading: './hw/sqrt_kernel_v1.xclbin'
XRT build version: 2.7.766
Build hash: 19bc791a7d9b54ecc23644649c3ea2c2ea31821c
Build date: 2020-08-17 23:51:58
Git branch: 2020.1_PU1
PID: 42650
UID: 40412
[Mon Jan 25 22:56:23 2021 GMT]
HOST: pcie
EXE: /home/7ry/Data/xilinx/sqrt_xilinx/sqrt
[XRT] WARNING: unaligned host pointer '0xe78cc0' detected, this leads to extra memcpy
Starting...
Computation Duration: 0.000568077 s
Result: sqrt(25) = 5
Saving solution...
Saved solution to results.txt...
Done...

Geekdude / sqrt_xilinx

Sqrt Xilinx OpenCL C Kernel

To run the SW EMU test

To run the HW test

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