public static unsafe extern int FormatFromRawValue( uint dwCounterType, uint dwFormat, ref long pTimeBase, NativeMethods.PDH_RAW_COUNTER pRawValue1, NativeMethods.PDH_RAW_COUNTER pRawValue2, NativeMethods.PDH_FMT_COUNTERVALUE pFmtValue );
/// <devdoc> /// Computes the calculated value given a raw counter sample. /// </devdoc> public static float ComputeCounterValue(CounterSample oldSample, CounterSample newSample) { int newCounterType = (int)newSample.CounterType; if (oldSample.SystemFrequency == 0) { if ((newCounterType != NativeMethods.PERF_RAW_FRACTION) && (newCounterType != NativeMethods.PERF_COUNTER_RAWCOUNT) && (newCounterType != NativeMethods.PERF_COUNTER_RAWCOUNT_HEX) && (newCounterType != NativeMethods.PERF_COUNTER_LARGE_RAWCOUNT) && (newCounterType != NativeMethods.PERF_COUNTER_LARGE_RAWCOUNT_HEX) && (newCounterType != NativeMethods.PERF_COUNTER_MULTI_BASE)) { // Since oldSample has a system frequency of 0, this means the newSample is the first sample // on a two sample calculation. Since we can't do anything with it, return 0. return(0.0f); } } else if (oldSample.CounterType != newSample.CounterType) { throw new InvalidOperationException(SR.GetString(SR.MismatchedCounterTypes)); } if (newCounterType == NativeMethods.PERF_ELAPSED_TIME) { return((float)GetElapsedTime(oldSample, newSample)); } NativeMethods.PDH_RAW_COUNTER newPdhValue = new NativeMethods.PDH_RAW_COUNTER(); NativeMethods.PDH_RAW_COUNTER oldPdhValue = new NativeMethods.PDH_RAW_COUNTER(); FillInValues(oldSample, newSample, oldPdhValue, newPdhValue); LoadPerfCounterDll(); NativeMethods.PDH_FMT_COUNTERVALUE pdhFormattedValue = new NativeMethods.PDH_FMT_COUNTERVALUE(); long timeBase = newSample.SystemFrequency; int result = SafeNativeMethods.FormatFromRawValue((uint)newCounterType, NativeMethods.PDH_FMT_DOUBLE | NativeMethods.PDH_FMT_NOSCALE | NativeMethods.PDH_FMT_NOCAP100, ref timeBase, newPdhValue, oldPdhValue, pdhFormattedValue); if (result != NativeMethods.ERROR_SUCCESS) { // If the numbers go negative, just return 0. This better matches the old behavior. if (result == NativeMethods.PDH_CALC_NEGATIVE_VALUE || result == NativeMethods.PDH_CALC_NEGATIVE_DENOMINATOR || result == NativeMethods.PDH_NO_DATA) { return(0); } else { throw new Win32Exception(result, SR.GetString(SR.PerfCounterPdhError, result.ToString("x", CultureInfo.InvariantCulture))); } } return((float)pdhFormattedValue.data); }
// This method figures out which values are supposed to go into which structures so that PDH can do the // calculation for us. This was ported from Window's cutils.c private static void FillInValues(CounterSample oldSample, CounterSample newSample, NativeMethods.PDH_RAW_COUNTER oldPdhValue, NativeMethods.PDH_RAW_COUNTER newPdhValue) { int newCounterType = (int)newSample.CounterType; switch (newCounterType) { case NativeMethods.PERF_COUNTER_COUNTER: case NativeMethods.PERF_COUNTER_QUEUELEN_TYPE: case NativeMethods.PERF_SAMPLE_COUNTER: case NativeMethods.PERF_OBJ_TIME_TIMER: case NativeMethods.PERF_COUNTER_OBJ_TIME_QUEUELEN_TYPE: newPdhValue.FirstValue = newSample.RawValue; newPdhValue.SecondValue = newSample.TimeStamp; oldPdhValue.FirstValue = oldSample.RawValue; oldPdhValue.SecondValue = oldSample.TimeStamp; break; case NativeMethods.PERF_COUNTER_100NS_QUEUELEN_TYPE: newPdhValue.FirstValue = newSample.RawValue; newPdhValue.SecondValue = newSample.TimeStamp100nSec; oldPdhValue.FirstValue = oldSample.RawValue; oldPdhValue.SecondValue = oldSample.TimeStamp100nSec; break; case NativeMethods.PERF_COUNTER_TIMER: case NativeMethods.PERF_COUNTER_TIMER_INV: case NativeMethods.PERF_COUNTER_BULK_COUNT: case NativeMethods.PERF_COUNTER_LARGE_QUEUELEN_TYPE: case NativeMethods.PERF_COUNTER_MULTI_TIMER: case NativeMethods.PERF_COUNTER_MULTI_TIMER_INV: newPdhValue.FirstValue = newSample.RawValue; newPdhValue.SecondValue = newSample.TimeStamp; oldPdhValue.FirstValue = oldSample.RawValue; oldPdhValue.SecondValue = oldSample.TimeStamp; if (newCounterType == NativeMethods.PERF_COUNTER_MULTI_TIMER || newCounterType == NativeMethods.PERF_COUNTER_MULTI_TIMER_INV) { // this is to make PDH work like PERFMON for // this counter type newPdhValue.FirstValue *= (uint)newSample.CounterFrequency; if (oldSample.CounterFrequency != 0) { oldPdhValue.FirstValue *= (uint)oldSample.CounterFrequency; } } if ((newCounterType & NativeMethods.PERF_MULTI_COUNTER) == NativeMethods.PERF_MULTI_COUNTER) { newPdhValue.MultiCount = (int)newSample.BaseValue; oldPdhValue.MultiCount = (int)oldSample.BaseValue; } break; // // These counters do not use any time reference // case NativeMethods.PERF_COUNTER_RAWCOUNT: case NativeMethods.PERF_COUNTER_RAWCOUNT_HEX: case NativeMethods.PERF_COUNTER_DELTA: case NativeMethods.PERF_COUNTER_LARGE_RAWCOUNT: case NativeMethods.PERF_COUNTER_LARGE_RAWCOUNT_HEX: case NativeMethods.PERF_COUNTER_LARGE_DELTA: newPdhValue.FirstValue = newSample.RawValue; newPdhValue.SecondValue = 0; oldPdhValue.FirstValue = oldSample.RawValue; oldPdhValue.SecondValue = 0; break; // // These counters use the 100 Ns time base in thier calculation // case NativeMethods.PERF_100NSEC_TIMER: case NativeMethods.PERF_100NSEC_TIMER_INV: case NativeMethods.PERF_100NSEC_MULTI_TIMER: case NativeMethods.PERF_100NSEC_MULTI_TIMER_INV: newPdhValue.FirstValue = newSample.RawValue; newPdhValue.SecondValue = newSample.TimeStamp100nSec; oldPdhValue.FirstValue = oldSample.RawValue; oldPdhValue.SecondValue = oldSample.TimeStamp100nSec; if ((newCounterType & NativeMethods.PERF_MULTI_COUNTER) == NativeMethods.PERF_MULTI_COUNTER) { newPdhValue.MultiCount = (int)newSample.BaseValue; oldPdhValue.MultiCount = (int)oldSample.BaseValue; } break; // // These counters use two data points // case NativeMethods.PERF_SAMPLE_FRACTION: case NativeMethods.PERF_RAW_FRACTION: case NativeMethods.PERF_LARGE_RAW_FRACTION: case NativeMethods.PERF_PRECISION_SYSTEM_TIMER: case NativeMethods.PERF_PRECISION_100NS_TIMER: case NativeMethods.PERF_PRECISION_OBJECT_TIMER: case NativeMethods.PERF_AVERAGE_TIMER: case NativeMethods.PERF_AVERAGE_BULK: newPdhValue.FirstValue = newSample.RawValue; newPdhValue.SecondValue = newSample.BaseValue; oldPdhValue.FirstValue = oldSample.RawValue; oldPdhValue.SecondValue = oldSample.BaseValue; break; default: // an unidentified counter was returned so newPdhValue.FirstValue = 0; newPdhValue.SecondValue = 0; oldPdhValue.FirstValue = 0; oldPdhValue.SecondValue = 0; break; } }