How to measure the execution time using PostSharp

Knowing the execution time of a method helps analyze performance issues. While you can use performance profilers like RedGate ANTS, JetBrains dotTrace, and Telerik Just Trace, PostSharp also enables you to measure execution time programmatically through its AOP capabilities.

Programmatically Measuring Execution Time

To measure the execution time of a method programmatically, you can use the Stopwatch class from the System.Diagnostics namespace. It allows you to track elapsed time for a single or multiple intervals.

For example, how you can use the Stopwatch class to measure execution time:

var timer = System.Diagnostics.Stopwatch.StartNew();

// Write your code here

timer.Stop();
var elapsedMilliseconds = timer.ElapsedMilliseconds;

Additionally, the Stopwatch class has a useful IsHighResolution property that informs you whether the system's hardware and operating system support high-resolution timing.

Measuring Execution Time Using PostSharp

PostSharp can simplify measuring execution time by reducing boilerplate code and offering compile-time weaving for cleaner method profiling. PostSharp is a popular library for implementing Aspect-Oriented Programming (AOP) in .NET applications.

First, install the PostSharp library via NuGet. Then, you can create a custom aspect that logs execution time by extending the OnMethodBoundaryAspect class.

[Serializable]
[AttributeUsage(AttributeTargets.Method)]
public sealed class LogExecutionTimeAttribute : OnMethodBoundaryAspect
{
    private static readonly Stopwatch timer = new Stopwatch();

    public override void OnEntry(MethodExecutionArgs args)
    {
        timer.Start();
    }

    public override void OnExit(MethodExecutionArgs args)
    {
        var elapsedMilliseconds = timer.ElapsedMilliseconds;
        timer.Stop();
        // Add code to store elapsed time, e.g., in a log or database
    }
}

This attribute, marked with [Serializable], can be applied to methods as defined by AttributeTargets.Method. You can also apply it to classes or interfaces if desired.

To apply this aspect to a method, just annotate it as follows:

static void Main(string[] args)
{
    TestMethod();
}

[LogExecutionTimeAttribute]
static void TestMethod()
{
    for (int i = 0; i < 100000; i++) ;
}

In the OnEntry method, we start the stopwatch, and in the OnExit method, we retrieve and store the elapsed time. You can customize the aspect further to handle logging or set thresholds to flag slow methods.