Xeon E5-2690 v3 doesn't report correct OpenCL Max Compute Units

allanmac1 · ‎11-04-2016

Here's a puzzling situation.

Different drivers and architectures (x86 vs. x64) report a different "max compute units" value on a dual Xeon E6-2690 v3 workstation (2 x HyperThreaded 12-core Xeons).

The new Visual Studio Code-Builder "Platform Info Tree" reports 32 compute units on both the 1.2 and 2.1 devices (incorrect).

The older standalone _x86_ Code-Builder reports 32 on both the 1.2 and 2.1 devices (incorrect).

The _x64_ Code-Builder reports 48 on both the 1.2 and 2.1 devices (correct).

The Nsight OpenCL System Info window reports 48 on both devices (correct).

Jeffrey_M_Intel1 · ‎11-04-2016

Thanks for this report. Some questions:

We've just released a new SDK (R3). Do you still see the problem in the Visual Studio code-builder plugin with the latest R3 SDK version?
What version of Visual Studio are you using?
What info do you get from clGetDeviceInfo for CL_DEVICE_MAX_COMPUTE_UNITS? (You can check with the Capsbasic sample. Should be correct, but it will be helpful to verify.)

allanmac1 · ‎11-05-2016

Jeffrey M. (Intel) wrote:

Thanks for this report. Some questions:

We've just released a new SDK (R3). Do you still see the problem in the Visual Studio code-builder plugin with the latest R3 SDK version?

What version of Visual Studio are you using?

What info do you get from clGetDeviceInfo for CL_DEVICE_MAX_COMPUTE_UNITS? (You can check with the Capsbasic sample. Should be correct, but it will be helpful to verify.)

This was with R3 installed. The VS2015 code builder plugin only reports 32 compute units. The EOL'd standalone Code Builder x86 also only reports 32 compute units.
VS2015 Pro
CL_DEVICE_MAX_COMPUTE_UNITS is what the Nsight System Info panel uses and it reports 48 units ... but is this related to x64 vs. x86?

Jeffrey_M_Intel1 · ‎11-06-2016

Thanks for the additional info. Not sure if there is a relationship to x64 vs x86, but I've got this filed as a potential bug so we can continue looking from here. Thank you for your help with making our tools even better.