How does LuxMark find OpenCL devices? (driver problems...)

[NotAMarmoset]

I'm evaluating a laptop (Intel i7-9850H/UHD Graphics 630, Quadro RTX 5000, Windows 10 1909).

Using the drivers it shipped with (Intel GPU driver 26.20.100.6860, NVIDIA I-forgot-to-check), LuxMark 3.1 and 4.0a show the CPU, iGPU and dGPU in the list of OpenCL devices, and can use them all. After updating the Intel drivers to 26.20.100.7810 (the latest from the manufacturer) or 27.20.100.8280 DCH (the latest from Intel directly), LuxMark no longer sees the CPU as an OpenCL device, only the iGPU and dGPU. Native C++ mode can still run. I haven't tried any other OpenCL apps, yet.

From what I can tell, the Intel GPU drivers are supposed to include OpenCL for CPU - the page for Intel's OpenCL CPU driver says so.

So, before I go chasing after Intel (and/or the manufacturer) I wanted to ask, how does LuxMark detect OpenCL devices? Any known incompatibilities with the aforementioned driver versions? Any suggestions how to check if something installed incorrectly or was misconfigured?

[Dade]

how does LuxMark detect OpenCL devices?

The list of devices is returned by OpenCL API itself.

AMD has dropped OpenCL CPU device support at some point so Intel may have done the same

There is a command line tool to list the OpenCL devices, it is called "clinfo": https://github.com/Oblomov/clinfo (bottom of the page for Windows binaries). It may provide you some information on the status of your devices.

[NotAMarmoset]

There is a command line tool to list the OpenCL devices, it is called "clinfo": https://github.com/Oblomov/clinfo (bottom of the page for Windows binaries). It may provide you some information on the status of your devices.

Hey, thanks for pointing out that tool. It clued me in that the drivers as shipped included the separate Intel OpenCL CPU driver. I must have misread or misinterpreted some information - what I said before was incorrect, and the GPU drivers don't include the CPU portion.

Now, it's still a little bizarre that the CPU driver makes you uninstall the GPU driver before it will install, and that after uninstalling the GPU driver and installing the CPU driver, you can reinstall the GPU driver (at which point OpenCL CPU support is broken again) but then re-run the CPU installer to repair itself... And it all works.

(Though LuxMark 4.0a seems to hang when trying to compile OpenCL for CPU, 3.1 runs fine.)

[Dade]

(Though LuxMark 4.0a seems to hang when trying to compile OpenCL for CPU, 3.1 runs fine.)

Try to render without the Intel GPU, they are known to have a lot of problems with large GPU computing tasks (like LuxMark). They are not really designed for this kind of stuff.