[slurm-users] Selecting OpenCL GPU reliably

[Valerio Bellizzomi]

It is now possible for programs to do a precise and reliable selection
of the GPU by first issuing a query to OpenCL with the
clGetDeviceInfo() function with the param_name parameter set to
cl_khr_pci_bus_info. This extension is available starting from OpenCL
3.0.7

References:

- 
https://github.com/KhronosGroup/OpenCL-Registry/blob/master/specs/3.0-unified/pdf/OpenCL_Ext.pdf
Chapter 39. PCI Bus Information Query

- 
https://www.khronos.org/registry/OpenCL/sdk/1.0/docs/man/xhtml/clGetDeviceInfo.html

- 
https://www.khronos.org/registry/OpenCL/sdk/1.0/docs/man/xhtml/clGetDeviceIDs.html

- 
https://www.khronos.org/registry/OpenCL/sdk/1.0/docs/man/xhtml/clGetPlatformIDs.html