Counter of type RateOfCountsPerSecond32 always shows 0

问题

I have a windows service that serves messages of some virtual queue via a WCF service interface. I wanted to expose two performance counters -

The number of items on the queue
The number of items removed from the queue per second

The first one works fine, the second one always shows as 0 in PerfMon.exe, despite the RawValue appearing to be correct.

I'm creating the counters as such -

    internal const string PERF_COUNTERS_CATEGORY = "HRG.Test.GDSSimulator";
    internal const string PERF_COUNTER_ITEMSINQUEUE_COUNTER = "# Messages on queue";
    internal const string PERF_COUNTER_PNR_PER_SECOND_COUNTER = "# Messages read / sec";

if (!PerformanceCounterCategory.Exists(PERF_COUNTERS_CATEGORY))
{
    System.Diagnostics.Trace.WriteLine("Creating performance counter category: " + PERF_COUNTERS_CATEGORY);
    CounterCreationDataCollection counters = new CounterCreationDataCollection();

    CounterCreationData numberOfMessagesCounter = new CounterCreationData();
    numberOfMessagesCounter.CounterHelp = "This counter provides the number of messages exist in each simulated queue";
    numberOfMessagesCounter.CounterName = PERF_COUNTER_ITEMSINQUEUE_COUNTER;
    numberOfMessagesCounter.CounterType = PerformanceCounterType.NumberOfItems32;
    counters.Add(numberOfMessagesCounter);

    CounterCreationData messagesPerSecondCounter= new CounterCreationData();
    messagesPerSecondCounter.CounterHelp = "This counter provides the number of messages read from the queue per second";
    messagesPerSecondCounter.CounterName = PERF_COUNTER_PNR_PER_SECOND_COUNTER;
    messagesPerSecondCounter.CounterType = PerformanceCounterType.RateOfCountsPerSecond32;
    counters.Add(messagesPerSecondCounter);

    PerformanceCounterCategory.Create(PERF_COUNTERS_CATEGORY, "HRG Queue Simulator performance counters", PerformanceCounterCategoryType.MultiInstance,counters);
}

Then, on each service call, I increment the relevant counter, for the per/sec counter this currently looks like this -

messagesPerSecCounter = new PerformanceCounter();
messagesPerSecCounter.CategoryName = QueueSimulator.PERF_COUNTERS_CATEGORY;
messagesPerSecCounter.CounterName = QueueSimulator.PERF_COUNTER_PNR_PER_SECOND_COUNTER;
messagesPerSecCounter.MachineName = ".";
messagesPerSecCounter.InstanceName = this.ToString().ToLower();
messagesPerSecCounter.ReadOnly = false;

messagesPerSecCounter.Increment();

As mentioned - if I put a breakpoint after the call to increment I can see the RawValue constantly increasing, in consistence with the calls to the service (fairly frequently, more than once a second, I would think) But the performance counter itself stays on 0.

The performance counter providing the count of items on the 'queue', which is implemented in the same way (although I assign the RawValue, rather than call Increment) works just fine.

What am I missing?

回答1:

I also initially had problems with this counter. MSDN has a full working example that helped me a lot:

http://msdn.microsoft.com/en-us/library/4bcx21aa.aspx

As their example was fairly long winded, I boiled it down to a single method to demonstrate the bare essentials. When run, I see the expected value of 10 counts per second in PerfMon.

public static void Test()
{
    var ccdc = new CounterCreationDataCollection();

    // add the counter
    const string counterName = "RateOfCountsPerSecond64Sample";
    var rateOfCounts64 = new CounterCreationData
    {
        CounterType = PerformanceCounterType.RateOfCountsPerSecond64,
        CounterName = counterName
    };
    ccdc.Add(rateOfCounts64);

    // ensure category exists
    const string categoryName = "RateOfCountsPerSecond64SampleCategory";
    if (PerformanceCounterCategory.Exists(categoryName))
    {
        PerformanceCounterCategory.Delete(categoryName);
    }
    PerformanceCounterCategory.Create(categoryName, "",
        PerformanceCounterCategoryType.SingleInstance, ccdc);

    // create the counter
    var pc = new PerformanceCounter(categoryName, counterName, false);

    // send some sample data - roughly ten counts per second
    while (true)
    {
        pc.IncrementBy(10);
        System.Threading.Thread.Sleep(1000);
    }
}

I hope this helps someone.

回答2:

When you are working with Average type Performance Counters there are two components - a numerator and a denominator. Because you are working with an average the counter is calculated as 'x instances per y instances'. In your case you are working out 'number items' per 'number of seconds'. In other words, you need to count both how many items you take out of the queue and how many seconds they take to be removed.

The Average type Performance Counters actually create two counters - a numerator component called {name} and a denominator component called {name}Base. If you go to the Performance Counter snap-in you can view all the categories and counters; you can check the name of the Base counter. When the queue processing process is started, you should

begin a stopwatch
remove item(s) from the queue
stop the stopwatch
increment the {name} counter by the number of items removed from the queue
increment the {name}Base counter by the number of ticks on the stopwatch

The counter is supposed to automatically know to divide the first counter by the second to give the average rate. Check CodeProject for a good example of how this works.

It's quite likely that you don't want this type of counter. These Average counters are used to determine how many instances happen per second of operation; e.g. the average number of seconds it takes to complete an order, or to do some complex transaction or process. What you may want is an average number of instances in 'real' time as opposed to processing time.

Consider if you had 1 item in your queue, and it took 1ms to remove, that's a rate of 1000 items per second. But after one second you have only removed 1 item (because that's all there is) and so you are processing 1 item per second in 'real' time. Similarly, if there are a million items in the queue but you've only processed one because your server is busy doing some other work, do you want to see 1000 items / second theoretical or 1 item / second real?

If you want this 'real' figure, as opposed to the theoretical throughput figure, then this scenario isn't really suited to performance counters - instead you need to know a start time, and end time, and a number of items processed. It can't really be done with a simple 'counter'. Instead you would store a system startup time somewhere, and calculate (number of items) / (now - startup time).

回答3:

I had the same problem. In my testing, I believe I was seeing the issue was some combination of multi instance and rate of count per second. If I used single instance or a number of items counter it worked. Something about that combination of multi instance and rate per second caused it to be always zero.

As Performance counter of type RateOfCountsPerSecond64 has always the value 0 mentions, a reboot may do the trick. Worked for me anyway.

Another thing that worked for me was this initializing the counter in a block like this:

counter.BeginInit();
counter.RawValue = 0;
counter.EndInit();

回答4:

I think you need some way to persist the counter. It appears to me that each time the service call is initiated then the counter is recreated.

So you could save the counter to a DB, flat file, or perhaps even a session variable if you wanted it unique to a user.

来源：https://stackoverflow.com/questions/2238212/counter-of-type-rateofcountspersecond32-always-shows-0

标签

performancecounter