Nothing about this is exactly new or ground breaking but few developers (enterprise) these days add proper monitoring abilities to their apps. We (now that I mostly do administration and management of other peoples apps) that has to support these things don’t come equipped with x-ray eyes or ESP pills so knowing how the the internals of ‘your’ works is an issue…

Classically developers tend to use stuff like log file, event log and so on to ‘see’ what is going on inside their apps. However, these things also pick up a lot of noise so they usually get turn off for production use but that still leaves us with the requirements that we want to know ‘what your app is doing all the time’ – when we want to track it. Ok, to make a long story shorter, there is such a thing like performance counters that can help us to know if your app is performing or not. What they are and what they can do for you you can go read up on MSDN, Google etc.

Now, it appears most developers are scared of these things – or just too lazy to implement them. I’ve created a little helper class that makes it at least a little easier to implement – without all the worries about what happens if things blow up etc. It is written is such a way that if itself ‘breaks’ it should not break the rest of the app (don’t contribute to a bigger problem).

Setting it all up.

Creating a ‘Category’ is the first step in setting up a performance counter. Once it is created you don’t have to recreate it again (unless you go and delete it which would be rather stupid). The following routine do just that.

PerformanceCounterCategory InitializeCategory(string category, CounterCreationData[] creationData, string instance = "")
        {
            PerformanceCounterCategory pcc = null;
            if (!PerformanceCounterCategory.Exists(category))
            {
                if (instance.Length > 0)
                    pcc = PerformanceCounterCategory.Create(category, category, PerformanceCounterCategoryType.MultiInstance, new CounterCreationDataCollection(creationData));
                else
                    pcc = PerformanceCounterCategory.Create(category, category, PerformanceCounterCategoryType.SingleInstance, new CounterCreationDataCollection(creationData));
            }
            else
                pcc = new PerformanceCounterCategory(category);
            return pcc;
        }

All this does is create the category for you if it doesn’t exist yet or else just returns the existing one. All you specify is the name and the definitions of the counters you want to use. Optionally you can specify an ‘instance name’ which is handy if you have multiple instances of the same set of ‘things’ you want to ‘monitor’. The default is a single instance (e.g. like a global instance). Keep in mind that a single category can only have counters of one of two types – either single instance or multi-instance counters. This cannot be changed unless the whole category is deleted and recreated again.

The next step is to create run-time ‘instances’ of the counters.

PerformanceCounter InitializePerfCounter(string categoryName, string counterName, string instanceName = "")
        {
            PerformanceCounter counter = null;
            try
            {
                if (instanceName.Length > 0)
                {
                    if (IsCategoryMultiInstance(categoryName))
                        counter = new PerformanceCounter(categoryName, counterName, instanceName, false);
                    else
                        RaiseWarningMessage(string.Format("Performance category '{0}' is not set up for multiple instances! ({1})", categoryName, counterName));
                }
                else
                {
                    if (!IsCategoryMultiInstance(categoryName))
                        counter = new PerformanceCounter(categoryName, counterName, false);
                    else
                        RaiseWarningMessage(string.Format("Performance category '{0}' is not set up for single instance use! ({1})", categoryName, counterName));
                }
                if (counter != null)
                {
                    counter.BeginInit();
                    counter.RawValue = 0;
                    counter.EndInit();
                }
            }
            catch (Exception ex)
            {
                RaiseErrorMessage(string.Format("Error initializing performance counter '{0}'!\r\n{1}", counterName, ex.ToString()));
            }
            return counter;
        }

There are a couple of sub-routines not listed yet. Please just ignore for now – they will be included in the attached sample code.

Next step is just how to use them – setting the values. I tend to only use two types of counters – a ‘rate of’ and absolute values. The ‘rate of’ type of counters are typically used to track the number of events or sum of something per second while absolute values track the actual value of something as it is ‘now’ at that moment of tracking – e.g. CPU % usage.

void SetCounterValue(PerformanceCounter counter, long value)
        {
            try
            {
                if (counter == null)
                {
                    RaiseWarningMessage("Performance counter not set up or installed!");
                }
                else
                {
                    counter.RawValue = value;
                }
            }
            catch (Exception ex)
            {
                RaiseErrorMessage(string.Format("Increment performance counter error! : {0}\r\n{1}", counter.CounterName, ex.ToString()));
            }
        }
void IncrementCounter(PerformanceCounter counter)
        {
            IncrementCounterBy(counter, 1);
        }
void IncrementCounterBy(PerformanceCounter counter, long incBy)
        {
            try
            {
                if (counter == null)
                {
                    RaiseWarningMessage("Performance counter not set up or installed!");
                }
                else
                {
                    counter.IncrementBy(incBy);
                }
            }
            catch (Exception ex)
            {
                RaiseErrorMessage(string.Format("Increment performance counter error! : {0}\r\n{1}", counter.CounterName, ex.ToString()));
            }
        }

Events
In order to provide all this functionality without ‘breaking’ anything else I make use of ‘events’ e.g. RaiseWarningMessage and RaiseErrorMessage. The calling class/code don’t have to make use of the events but of course that would make troubleshooting a bit harder if needed. The code for this is fairly simple:

        public event MessageRaisedDelegate ErrorRaised;
        internal void RaiseErrorMessage(string message)
        {
            if (ErrorRaised != null)
            {
                ErrorRaised(message);
            }
        }
        public event MessageRaisedDelegate WarningRaised;
        internal void RaiseWarningMessage(string message)
        {
            if (WarningRaised != null)
            {
                WarningRaised(message);
            }
        }

Implementation
It is possible to use the utility class ‘as is’ but I would recommend doing the following to provide ‘cleaner’ code. Inheriting from the class ‘PerfCounterUtilBase’ (not shown in above code) and implementing all the specific performance counter functionality ‘you’ need is a better way to so it. The following is just example code to initialize the performance counter category and counters you want to use:

void InitializePerformanceCounters()
        {
            string lastErr = "Create performance counter category error!: {0}";
            try
            {
                CounterCreationData[] creationData = new CounterCreationData[]
                    {
                        new CounterCreationData("Clicks/Sec", "Clicks per second", PerformanceCounterType.RateOfCountsPerSecond32),
                        new CounterCreationData("Total X value/Sec", "Sum of X values per second", PerformanceCounterType.RateOfCountsPerSecond32),
                        new CounterCreationData("Total Y value/Sec", "Sum of Y values per second", PerformanceCounterType.RateOfCountsPerSecond32),
                        new CounterCreationData("Last X value", "Last X value", PerformanceCounterType.NumberOfItems32),
                        new CounterCreationData("Last Y value", "Last Y value", PerformanceCounterType.NumberOfItems32)
                    };
                InitializeCategory(Category, creationData, Instance);

                lastErr = "Initialize performance counter(s) error!: {0}";
                clicksPerSecond = InitializePerfCounter(Category, "Clicks/Sec", Instance);
                xValuePerSecond = InitializePerfCounter(Category, "Total X value/Sec", Instance);
                yValuePerSecond = InitializePerfCounter(Category, "Total Y value/Sec", Instance);
                lastXValue = InitializePerfCounter(Category, "Last X value", Instance);
                lastYValue = InitializePerfCounter(Category, "Last Y value", Instance);
            }
            catch (Exception ex)
            {
                RaiseErrorMessage(string.Format(lastErr, ex.Message));
            }
        }

Then you can simply have specific methods like these to use in your own code:

public void IncClicks()
        {
            IncrementCounter(clicksPerSecond);
        }
        public void IncXValues(long value)
        {
            IncrementCounterBy(xValuePerSecond, value);
        }
...

In ‘your’ code you simply do this then:

pcu = new PerfCounterExampleImplemetation();
pcu.ErrorRaised += new MessageRaisedDelegate(pcu_ErrorRaised);
pcu.WarningRaised += new MessageRaisedDelegate(pcu_WarningRaised);
pcu.Category = txtCategory.Text;
pcu.Instance = txtInstance.Text;
pcu.InitializePerformanceCounters();
...
void pcu_ErrorRaised(string message)
        {
            MessageBox.Show(message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }

void SomeMethod()
        {
            long val = GetSomeValue();

            if (pcu != null)
            {
                pcu.IncClicks();
                pcu.IncXValues(val);
                ...
            }
        }

Now go have fun…

Example code: ShowPerfCounterUtils