SHORT GPU utilization

EVENTSET
ROCM0 ROCP_GRBM_COUNT
ROCM1 ROCP_GRBM_GUI_ACTIVE


METRICS
GPU utilization 100*ROCM1/ROCM0


LONG
Formulas:
GPU utilization = 100*ROCP_GRBM_GUI_ACTIVE/ROCP_GRBM_COUNT
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This group reassembles the 'GPUBusy' metric provided by RocProfiler.
We should add, that we can select the GPUBusy metric directly and the
calculations are done internally in case the metric formula changes.
