[llvm] [OpenMP][offload] Add LIBOMPTARGET_KERNEL_EXE_TIME (PR #222105)

[Robert Imschweiler via llvm-commits]

ro-i wrote:

> Thanks for working on this. Have you checked the offload API if it provides similar functionality?

I think there is olGetEventElapsedTime, but afaict:
- this is the time between user-placed marker events and not dispatched on the kernel's own execution time
- it's in ms, not ns
- it doesn't carry the kernel information (launch id, name)

https://github.com/llvm/llvm-project/pull/222105