typedef struct 
{
     ULONG Count;
     ULONG MaxFrequency;
     ULONG MaxPerfState;
     ULONG MinPerfState;
     ULONG LowestPState;
     ULONG IncreaseTime;
     ULONG DecreaseTime;
     UCHAR BusyAdjThreshold;
     UCHAR Reserved;
     UCHAR ThrottleStatesOnly;
     UCHAR PolicyType;
     ULONG TimerInterval;
     ULONG Flags;
     ULONG TargetProcessors;
     LONG * PStateHandler;
     ULONG PStateContext;
     LONG * TStateHandler;
     ULONG TStateContext;
     LONG unsigned * FeedbackHandler;
     PPM_PERF_STATE State[1];
} PPM_PERF_STATES, *PPPM_PERF_STATES;

Windows Vista Kernel Structures