Page Comparison

Background:

• -rtl: Tells the compiler to stop after report generation.

• -v: Shows more details during the generation

• -board=p520_max_sg280l: Specifies the target FPGA board (Bittware 520N with Intel Stratix 10 GX 2800).

• -board-package=/opt/software/FPGA/IntelFPGA/opencl_sdk/20.4.0/hld/board/bittware_pcie/s10_hpc_default: Specifies the BSP in the correct version. Normally this argument is not required as the compiler uses the environment variable AOCL_BOARD_PACKAGE_ROOT. Only if you you intentionally want to generate a report on an FPGA node allocated with a different constraint, this argument is needed.

• device/vector_add.cl: Kernel file for vector_add written in OpenCL.

• -o vector_add_report: Output directory.

In order to inspect the report, you may want to copy the report to your local file system or mount your working directory, for more information refer to [Noctua2-FileSystems]. For example you can compress the report on Noctua 2:

tar -caf vector_add_report.tar.gz vector_add_report/reports

Then copy and decompress it from your local command line (e.g. Linux, MacOS, or Windows Subsystem for Linux):

TBD
rsync -azv -e 'ssh -J <your-username>@fe.noctuanoctua2.pc2.uni-paderborn.de' <your-username>@ln-0001username>@n2login2:/scratch/<DIRECTORY_ASSIGNED_TO_YOUR_PROJECT>/getting_started_with_fpgas/vector_add/vector_add_report.tar.gz .

tar -xzf vectorfpga_addcompile_report.tar.gz

Open and inspect fpga_compile_report.prj/reports/report.html in your browser. The whole analysis contains little information, since the example is very simple. The main blocks of the report are

• Throughput Analysis -> Loop Analysis: displays information about all loops and their optimization status (is it pipelined? what is the initiation interval (II) of the loop?, …).

• Area Analysis (of System): details about the area utilization with architectural details into the generated hardware.

• Views -> System Viewer: gives an overall overview of your kernels, their connections between each other and to external resources like memory.

• Views -> Kernel Memory Viewer: displays the data movement and synchronization in your code.

• Views -> Schedule Viewer: shows the scheduling of the generated instructions with corresponding latencies.

• Bottleneck Viewer: identifies bottlenecks that reduce the performance of the design (lower maximum clock frequency of the design (F_max), increases the initiation interval (II), …).

Open and inspect vector_add_report/reports/report.html in your browser. The throughput analysis contains little information, since the example is very simple and ND-Range kernels as the one used in this example yield less details in the report than Single Work Item Kernels. The area analysis shows that the kernel system uses at most 1% of the available resources, much more complex or parallel kernels could fit on the FPGA. The system viewer shows two 32-bit Burst-coalesced load and one 32-bit Burst-coalesced store operations. Refer to Intel's documentation (in particular Programming and Best Practice guides) about the Intel FPGA for OpenCL to learn more about the properties and optimization goals in the report.

#!/bin/sh

# synthesis_script.sh script

module reset
module load intelFPGA_profpga
module load bittwareintel/opencl_520nsdk
module load toolchainbittware/gompi520n

aoc -board=p520_max_sg280l -board-package=/opt/software/FPGA/IntelFPGA/opencl_sdk/20.4.0/hld/board/bittware_pcie/s10_hpc_default device/vector_add.cl -o bin/vector_add.aocx

In order to still use the slurm workload manager, we use a modified batch script copy_pre-synthesed_design_script.sh and submit it.

#!/bin/sh

# copy_pre-synthesed_design_script.sh

# Instead of starting the actual synthesis we use pre-synthezed results.
mv bin/vector_add_fpga.aocx bin/vector_add.aocx

Then, we submit the copy_pre-synthesed_design_script.sh to the slurm workload manager:

sbatch --partition=allnormal -A <your_project_acronym> -t 00:10:00 ./copy_pre-synthesed_design_script.sh

• We submit into --partition=allnormal.

• With -t 00:10:00, we allocate a small amount of time to this file copy job.

• You can check the progress of your job via squeue and after the job completes, check the complete job output in slurm-<jobid>.out.

Please notice that the compiled kernel has the same name for emulation and FPGA execution (that is vector_add.aocx). If you override the pre-synthesized design accidentally, you can submit the script again.

module reset
module load intelFPGA_profpga
module load bittwareintel/opencl_520nsdk
module load toolchainbittware/gompi520n

./bin/host