private static void LazyCreatePerformanceCounter(PerformanceCounterHolder holder, TelemetryData data)
{
if (holder.Counter != null)
{
return;
}
// If counter does not exist then it's probably an installation problem:
// * counters have not been created and TelemetrySession.Start did it but OS didn't refresh them yet;
// * category already existed but a new version added more counters and old category has not been properly uninstalled.
if (!PerformanceCounterCategory.CounterExists(data.Name, data.Category))
{
holder.IsDisabled = true;
return;
}
holder.Counter = new PerformanceCounter(data.Category, data.Name, false);
if (data.CounterType == TelemetryDataType.AverageCount)
{
// Base PC name convention: keep in sync with code in WpcTelemetrySessionInstaller
holder.Base = new PerformanceCounter(data.Category, data.Name + "Base", false);
holder.Counter.RawValue = 0;
holder.Base.RawValue = 0;
}
}
public bool TryGetValue(TelemetryData data, out PerformanceCounterHolder value)
{
if (!_telemetryData.TryGetValue(data, out value))
{
return(false);
}
// PerformanceCounterHolder exists but it's disabled, there is no need to
// (try to) create an instance of its associated PC(s).
if (value.IsDisabled)
{
return(true);
}
// If caller requested this PerformanceCounterHolder then it will use it,
// it's the right moment to (lazy) create required instances. Note that
// in this way performance penality for this operation is spanned across program
// execution, it's a drawback but it speed-up initialization time (especially if there are
// many mostly unused PCs).
LazyCreatePerformanceCounter(value, data);
return(true);
}
