Fix for AMD OpenCL Devices Showing Up as the Same Name

I’ve been experimenting with OpenCL via pyopencl recently. They provide a nice interface for enumerating available devices and getting information about them, and then using them to run OpenCL code:

>>> import pyopencl as cl
>>> platform = cl.get_platforms()[0]
>>> platform.get_devices()
[
  <pyopencl.Device 'gfx1100' on 'AMD Accelerated Parallel Processing' at 0x56353125bd70>,
  <pyopencl.Device 'gfx1036' on 'AMD Accelerated Parallel Processing' at 0x5635312ec670>
]
>>>

There are two devices for me because I have one discrete 7900 XTX GPU as well as an integrated GPU on my 7950X CPU. gfx1100 is the Shader ISA for the 7900 XTX, and gfx1036 is for the iGPU.

The Problem⌗

At some point, pyopencl started returning gfx1100 as the name for both of my devices:

>>> import pyopencl as cl
>>> platform = cl.get_platforms()[0]
>>> platform.get_devices()
[
  <pyopencl.Device 'gfx1100' on 'AMD Accelerated Parallel Processing' at 0x555cc5a8ed60>,
  <pyopencl.Device 'gfx1100' on 'AMD Accelerated Parallel Processing' at 0x555cc5b1f5f0>
]
>>> [d.hashable_model_and_version_identifier for d in platform.get_devices()]
[
  ('v1', 'Advanced Micro Devices, Inc.', 4098, 'gfx1100', 'OpenCL 2.0 '),
  ('v1', 'Advanced Micro Devices, Inc.', 4098, 'gfx1100', 'OpenCL 2.0 ')
]
>>>

There was no way to tell them apart. I needed my code to only run on my 7900 XTX and not on the iGPU, and this caused the filtering my code was doing on device.name to not work since I had no way to tell the devices apart.

The Cause + The Fix⌗

It turns out that I had exported the environment variable HSA_OVERRIDE_GFX_VERSION=11.0.0. I did this to support building a custom TensorFlow package that works on the 7900 XTX with ROCm 5.5.

It turns out that setting that environment variable causes some driver in the stack to pretend that all the devices support gfx1100 and changes their names as well.

For this OpenCL code, I wasn’t using TensorFlow and so didn’t need to export that anymore. I expect that in the near future, that hack won’t be necessary anymore anyway.

unsetting that environment variable fixed the problem, and my cards are now properly identified by OpenCL again.