WaitAsync

.NET 6 has a new method added to System.Threading.Tasks.Task to wait for a task completion or timeout. WaitAsync method completes with the result of the task it is invoked on, or throws a timeout exception when the given timeout reached or throws a TaskCancelledException if the given cancellation token is set to cancelled state.

The method's primary use-case is to add cancellation or timeout ability for async methods, that inherently don't provide such capability. One use-case could be unit tests, where we explicitly want to time out and fail a test if the method invoked as the system under test is an async operation without a timeout overload. This way we can let other tests to be executed in the test suite.

Previously a poor man (woman)'s implementation for such timeout could look as:

public static async Task<T> TimeoutAfter<T>(this Task<T> task, TimeSpan timeout)
{
    if (task.IsCompleted)
        return await task;
    var cts = new CancellationTokenSource();
    if (task == await Task.WhenAny(task, Task.Delay(timeout, cts.Token)))
    {
        cts.Cancel();
        return await task;
    }
    else
    {
        throw new TimeoutException();
    }
}

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Math Sin with SIMD

Introduction

In this post I will look into how someone can implement Sin/Cosin functions with SIMD in NET 5. NET 5 does not have a wrapper on SIMD trigonometric functions, so it seems a good exercise to implement it.

Using SIMD, one may gain performance advantage on large data sets. Later in this post I will run a performance benchmark to compare the SIMD implementation with Math.Cos() and MathF.Cos() methods.

Considerations

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String Interpolation and StringBuilder in .NET6

In a previous post I have looked into what are the performance characteristics of creating interpolated string in .NET 5 and early previews of .NET 6. With .NET 6 preview 7 or better a new approach is used by the C# compiler with support from the BCL to build interpolated strings.

Fortunately the new way provides a faster approach for the most convenient ways for assembling strings, however it makes my previous post completely obsolete.

For details about the new way DefaultInterpolatedStringHandler builds strings, read: https://devblogs.microsoft.com/dotnet/string-interpolation-in-c-10-and-net-6/

Re-running the benchmarks from the previous post, shows much better memory usage:

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String Interpolation and StringBuilder

This post looks into different approaches and their performance characteristics for appendnng interpolated like strings. I use BenchmarkDotNet to benchmark the different solutions. In case of all benchmarks I have 3 string properties A, B and C each holding one of these values:

  • hello

  • world

  • how are you

The values of these variables are set in a Global setup step of BencharmarkDotNet. In all benchmarks the three string are concatenate with some punctuations.

Implementation

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Introduction to APM

In the series of these posts I will look into how we can implement an APM solution for .NET applications. Application Performance Management (APM) helps to monitor and diagnose application performance. There are numerous libraries and tools out there to solve this given problem. In this series of posts I will focus on implementing APM for .NET applications (.NET Framework 461 and above, .NET Core and NET5) with OpenTelemetry.

In the series of these posts I will look into the following topics. The current post looks into creating and recording spans.

  • W3C correlation Id specification

  • Creating and recording spans with ActivitySource

  • Using OpenTelemetry and Jaeger

OpenTelemetry

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