Intel FPGA® OpenCL™ Design Example
Vector Add

This readme file for the Vector Add OpenCL Design Example contains information about the design example package. For more examples, please visit the Intel FPGA OpenCL Design Examples page.

Description

This example runs a basic OpenCL kernel that performs C = A + B where A, B and C are N-element vectors. The kernel is intentionally kept simple and not optimized to achieve maximum performance on the FPGA.

In addition to demonstrating the basic OpenCL API, this example supports partitioning the problem across multiple OpenCL devices, if available. If there are M available devices, the problem is divided so that each device operates on N/M points. The host program assumes that all devices are of the same type (that is, the same binary can be used, but the code can be generalized to support different device types easily.

Software & Hardware Requirements

Requirement Version OpenCL KernelHost Program
Hardware
Compile
Emulation
Compile
HardwareEmulation
CompileRunCompileRun
Quartus Prime Design Software (Quartus II)17.0 or later
Intel(R) FPGA SDK for OpenCL(TM)17.0 or later
(either)
(either)
(either)
(either)
Intel(R) FPGA Runtime Environment for OpenCL(TM)17.0 or later
Board Support Package17.0-compatible
Board Hardware-
gcc4.4.7 or later
GNU Make3.8.1 or later

Package Contents

Path Description
vector_add/
Makefile Makefile for host program
bin/ Host program, AOCX files
device/ OpenCL kernel files
vector_add.cl Top-level OpenCL kernel file
host/
src/ Host source files

Compiling the OpenCL Kernel

The top-level OpenCL kernel file is device/vector_add.cl.

To compile the OpenCL kernel, run:

aoc device/vector_add.cl -o bin/vector_add.aocx --board <board>

where <board> matches the board you want to target. The -o bin/vector_add.aocx argument is used to place the compiled binary in the location that the host program expects.

If you are unsure of the boards available, use the following command to list available boards:

aoc --list-boards

Compiling for Emulator

To use the emulation flow, the compilation command just needs to be modified slightly:

aoc -march=emulator device/vector_add.cl -o bin/vector_add.aocx --board <board>

Compiling the Host Program

To compile the host program, run:

make

The compiled host program will be located at bin/host.

Host Preprocessor Definitions

The host program has the following preprocessor definitions:

Define Type Default Description
-DUSE_SVM_API=<#> Optional 0 This option when set to 1 will use the OpenCL 2.0 shared virtual memory (SVM) API.

On Linux, custom values for preprocessor defines can be specified by setting the value of CPPFLAGS when invoking the Makefile.

Running the Host Program

Before running the host program, you should have compiled the OpenCL kernel and the host program. Refer to the above sections if you have not completed those steps.

To run the host program on hardware, execute:

bin/host

The output will include a wall-clock time of the OpenCL execution time and the kernel time as reported by the OpenCL event profiling API. The host program includes verification against the host CPU, printing out "PASS" when the results match.

Running with the Emulator

Prior to running the emulation flow, ensure that you have compiled the kernel for emulation. Refer to the above sections if you have not done so. Also, please set up your environment for emulation. Please see the Intel(R) FPGA SDK for OpenCL(TM) Programming Guide for more information.

For this example design, the suggested emulation command is:

CL_CONTEXT_EMULATOR_DEVICE_ALTERA=1 bin/host -n=10000

Host Parameters

The general command-line for the host program is:

bin/host [-n=<integer>]

where the one parameter is:

Parameter Type Default Description
-n=<integer> Optional 100000 Number of values to add.

OpenCL Binary Selection

The host program requires a OpenCL binary (AOCX) file to run. For this example design, OpenCL binary files should be placed in the bin directory.

By default, the host program will look for a binary file in the following order (earlier pattern matches take priority):

  1. A file named vector_add.aocx.
  2. A file named vector_add_<board>_170.aocx, where <board> is the name of the board (as passed as the --board argument to aoc).

Release History

Example Version SDK Version Date Changes
1.5 16.0 November 2016
  • Add SVM API option.
1.4 16.0 June 2016
  • Fixed makefile.
1.3 14.1 December 2014
  • New readme documentation.
  • Provide suggested emulation-specific arguments.
1.2 14.0 July 2014
  • Update documentation for 14.0 release.
1.1 13.1 January 2014
  • On Linux, fix possible compilation issues (missing include files).
1.0 13.1 December 2013
  • First release of example.

Legal

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Permission is hereby granted, free of charge, to any person obtaining a copy of this
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The above copyright notice and this permission notice shall be included in all copies or
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This agreement shall be governed in all respects by the laws of the State of California and
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Trademarks

OpenCL and the OpenCL logo are trademarks of Apple Inc. used by permission by Khronos.

Product is based on a published Khronos Specification, and has passed the Khronos Conformance Testing Process. Current conformance status can be found at www.khronos.org/conformance.

Contacting Intel

Although we have made every effort to ensure that this design example works correctly, there might be problems that we have not encountered. If you have a question or problem that is not answered by the information provided in this readme file or the example's documentation, please contact Intel support (myAltera).