Intel OpenCL CPU Runtime Usage

[wjsjtu123]

After installing the Intel OpenCL CPU Runtime, how do I use it so that I can do the computation on the CPU?

[ProjectPhysX]

Hi @wjsjtu123,

once the Intel OpenCL CPU Runtime is installed, when you start FluidX3D, the CPU should appear as OpenCL device, like so:

 |----------------.------------------------------------------------------------|
 | Device ID    0 | Intel(R) Arc(TM) A750 Graphics                             |
 | Device ID    1 | Intel(R) UHD Graphics 630                                  |
+| Device ID    2 | Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz                   |
 |----------------'------------------------------------------------------------|

By default, the (fastest) dedicated GPU will be selected, here device 0. To select the CPU (here device 2) manually:

On Windows:

• open path\to\FluidX3D in Windows Explorer
• click in the folder path text field, type cmd and press Enter; the Windows CMD will open in the FluidX3D folder
• in the CMD console, type bin\FluidX3D 2 and press Enter

On Linux

• in the FluidX3D folder, to compile and run on the CPU, type .\make.sh 2 in the terminal
• to only run, without compiling, type bin/FluidX3D 2 in the terminal

You should then see that it's running on the CPU:

 |----------------.------------------------------------------------------------|
+| Device ID      | 2                                                          |
+| Device Name    | Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz                   |
+| Device Vendor  | Intel(R) Corporation                                       |
+| Device Driver  | 2023.16.6.0.28_042959 (Windows)                            |
+| OpenCL Version | OpenCL C 3.0                                               |
+| Compute Units  | 12 at 3700 MHz (6 cores, 0.710 TFLOPs/s)                   |
+| Memory, Cache  | 16250 MB, 256 KB global / 32 KB local                      |
+| Buffer Limits  | 8125 MB global, 128 KB constant                            |
 |----------------'------------------------------------------------------------|

---

Troubleshooting in case the CPU does not appear as OpenCL device when starting FluidX3D:

• the current version of the Intel CPU OpenCL Runtime on Windows (w_opencl_runtime_p_2024.0.0.49848.exe) is broken and needs a modification in registry keys
• pressWin+R, type regedit, press Enter; the Registry Editor will open
• in the path text field, enter Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Khronos\OpenCL\Vendors
  • richt click, New-->DWORD-Value (32-bit)
  • name it C:\Program Files (x86)\Common Files\Intel\Shared Libraries\bin\intelocl64.dll
  • leave its value at 0 (Hexadecimal)
• in the path text field, enter Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Khronos\OpenCL\Vendors
  • richt click, New-->DWORD-Value (32-bit)
  • name it C:\Program Files (x86)\Common Files\Intel\Shared Libraries\bin\intelocl64.dll
  • leave its value at 0 (Hexadecimal)
• in the path text field, enter Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Khronos\OpenCL\Vendors
  • richt click, New-->DWORD-Value (32-bit)
  • name it C:\Program Files (x86)\Common Files\Intel\Shared Libraries\bin32\intelocl32.dll
  • leave its value at 0 (Hexadecimal)
• close Registry Editor
• reboot
• the CPU should now show up as OpenCL device

Kind regards, Moritz