This readme file for the Matrix Multiplication OpenCL Design Example contains information about the design example package. For more examples, please visit the Intel FPGA OpenCL Design Examples page.
This example provides a kernel that implements the standard matrix multiplication operation C = A × B, where
The kernel uses the standard loop tiling optimization to take advantage of data reuse among different output values. Each tile has the dimensions of BLOCK_SIZE × BLOCK_SIZE, where the value of BLOCK_SIZE is fixed at kernel compilation time.
| Requirement | Version | OpenCL Kernel | Host Program | ||||
|---|---|---|---|---|---|---|---|
| Hardware Compile | Emulation Compile | Hardware | Emulation | ||||
| Compile | Run | Compile | Run | ||||
| Quartus Prime Design Software (Quartus II) | 16.1 or later | ✓ | ✓ | ||||
| Intel(R) FPGA SDK for OpenCL(TM) | 16.1 or later | ✓ | ✓ | ✓ (either) | ✓ (either) | ✓ (either) | ✓ (either) |
| Intel(R) FPGA Runtime Environment for OpenCL(TM) | 16.1 or later | ||||||
| Board Support Package | 16.1-compatible | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Board Hardware | - | ✓ | |||||
| gcc | 4.4.7 or later | ✓ | ✓ | ✓ | ✓ | ||
| GNU Make | 3.8.1 or later | ✓ | ✓ | ||||
| Path | Description |
|---|---|
| matrix_mult/ | |
| Makefile | Makefile for host program |
| bin/ | Host program, AOCX files |
| device/ | OpenCL kernel files |
| matrix_mult.cl | Top-level OpenCL kernel file |
| host/ | |
| inc/ | Host include files |
| src/ | Host source files |
The top-level OpenCL kernel file is device/matrix_mult.cl.
To compile the OpenCL kernel, run:
where <board> matches the board you want to target. The -o bin/matrix_mult.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:
To use the emulation flow, the compilation command just needs to be modified slightly:
The kernel has the following preprocessor definitions:
| Define | Type | Default | Description |
|---|---|---|---|
| -DBLOCK_SIZE=<#> | Optional | 64 | The OpenCL kernel is a blocked matrix multiplication with a block size of BLOCK_SIZE × BLOCK_SIZE. The value of BLOCK_SIZE affects the amount of on-chip memory used and the performance of the kernel. Higher values lead to higher performance. The same value must be used for kernel and host compilation. |
| -DSIMD_WORK_ITEMS=<#> | Optional | 4 | This controls the num_simd_work_items kernel attribute. The value should be set based on available resources on the FPGA device. Higher values lead to higher performance. |
To compile the host program, run:
The compiled host program will be located at bin/host.
The host program has the following preprocessor definitions:
| Define | Type | Default | Description |
|---|---|---|---|
| -DBLOCK_SIZE=<#> | Optional | 64 | This value must be the same as the one used when compiling the kernel. |
| -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
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:
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:
The general command-line for the host program is:
where the parameters are:
| Parameter | Type | Default | Description |
|---|---|---|---|
| -ah=<#> | Optional | 32 × BLOCK_SIZE | Height of matrix A. Must be a multiple of BLOCK_SIZE. |
| -aw=<#> | Optional | 16 × BLOCK_SIZE | Width of matrix A. Must be a multiple of BLOCK_SIZE. |
| -bw=<#> | Optional | 16 × BLOCK_SIZE | Width of matrix B. Must be a multiple of BLOCK_SIZE. |
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):
| Example Version | SDK Version | Date | Changes |
|---|---|---|---|
| 1.5 | 16.0 | November 2016 |
|
| 1.4 | 16.0 | June 2016 |
|
| 1.3 | 14.1 | December 2014 |
|
| 1.2 | 14.0 | July 2014 |
|
| 1.1 | 13.1 | January 2014 |
|
| 1.0 | 13.1 | December 2013 |
|
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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.
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).