How to use AverageTimer32 and AverageBase performa

问题:

When I execute the following program and look at the performance counter the results don't make sense to me. The average value is zero and the min/max values are ~0.4 when I would expect ~0.1 or ~100.

What is my problem?

Code

class Program
{
    const string CategoryName = "____Test Category";
    const string CounterName = "Average Operation Time";
    const string BaseCounterName = "Average Operation Time Base";

    static void Main(string[] args)
    {
        if (PerformanceCounterCategory.Exists(CategoryName))
            PerformanceCounterCategory.Delete(CategoryName);

        var counterDataCollection = new CounterCreationDataCollection();

        var avgOpTimeCounter = new CounterCreationData()
        {
            CounterName = CounterName,
            CounterHelp = "Average Operation Time Help",
            CounterType = PerformanceCounterType.AverageTimer32
        };
        counterDataCollection.Add(avgOpTimeCounter);

        var avgOpTimeBaseCounter = new CounterCreationData()
        {
            CounterName = BaseCounterName,
            CounterHelp = "Average Operation Time Base Help",
            CounterType = PerformanceCounterType.AverageBase
        };
        counterDataCollection.Add(avgOpTimeBaseCounter);

        PerformanceCounterCategory.Create(CategoryName, "Test Perf Counters", PerformanceCounterCategoryType.SingleInstance, counterDataCollection);

        var counter = new PerformanceCounter(CategoryName, CounterName, false);
        var baseCounter = new PerformanceCounter(CategoryName, BaseCounterName, false);

        for (int i = 0; i < 500; i++)
        {
            var sw = Stopwatch.StartNew();
            Thread.Sleep(100);
            sw.Stop();

            Console.WriteLine(string.Format("t({0}) ms({1})", sw.Elapsed.Ticks, sw.Elapsed.TotalMilliseconds));
            counter.IncrementBy(sw.Elapsed.Ticks);
            baseCounter.Increment();
        }

        Console.Read();
    }
}

Performance Counter Screenshot Performance Counter Screenshot http://friendfeed-media.com/50028bb6a0016931a3af5122774b56f93741bb5c

回答1:

The System.Diagnostics API contains a pretty subtle source of great confusion: System.Diagnostics 'ticks' are not the same as DateTime or TimeSpan 'ticks'!

If you use StopWatch.ElapsedTicks instead of StopWatch.Elapsed.Ticks, it should work.

The documentation contains more information about this.

回答2:

Mark Seemann explained the confusing source of the problem but I would like to provide a little bit of additional information.

If you want to set your AverageTimer32 performance counter from a TimeSpan and not a Stopwatch you can perform the following conversion:

var performanceCounterTicks = timeSpan.Ticks*Stopwatch.Frequency/TimeSpan.TicksPerSecond;
averageTimerCounter.IncrementBy(performanceCounterTicks);
averageTimerCounterBase.Increment();

回答3:

This is an old thread, but I thought I'd chime in. I was told by someone from Microsoft that I shouldn't use TimeSpan, StopWatch, or DateTime when working with Performance Counters. Instead, he recommended adding the following native method to my project:

internal static class NativeMethods
{
    [DllImport("Kernel32.dll")]
    public static extern void QueryPerformanceCounter(ref long ticks); 
}

When incrementing a counter, he recommended doing so like this:

public void Foo()
{
    var beginTicks = 0L;

    var endTicks = 0L;

    NativeMethods.QueryPerformanceCounter(ref beginTicks);

    // Do stuff

    NativeMethods.QueryPerformanceCounter(ref endTicks);

    this.Counter.IncrementBy(endTicks - beginTicks);
    this.BaseCounter.Increment();
}