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

[Robert Imschweiler via llvm-commits]

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@@ -1446,6 +1459,14 @@ struct GenericDeviceTy : public DeviceAllocatorTy {
   BoolEnvar OMPX_ReuseBlocksForHighTripCount =
       BoolEnvar("LIBOMPTARGET_REUSE_BLOCKS_FOR_HIGH_TRIP_COUNT", true);
 
+  /// Environment variable to trace the duration of every kernel launch.
+  BoolEnvar OMPX_KernelDurationTracing =
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ro-i wrote:

> Can we try not to add more OMPX things to the PluginInterface?

usually, I *do* try :) But in this case, I think there is a valid point for having it as a env var.
If you think that no other plugin would ever want to use it, I'll move it to the AMD plugin, no problem

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