PoGetFrequencyBucket

__int64 __fastcall PoGetFrequencyBucket(__int64 a1){
  unsigned int CurrentFrequency; 
  CurrentFrequency = PpmPerfGetCurrentFrequency(a1, 0);
  if( CurrentFrequency >= 0x4B )
    return 3;
  else
    return CurrentFrequency / 0x19;
}

Referenced by:

KiAccumulateProcessorCycleStats
KiEndDebugAccumulation