ladeak

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:

Null-coalescing Operator vs. Equals - Equals

I have been asked the following question over-and-over: which solution is the faster and better to use in the condition part of the if keyword, to branch based on a property which might be defined on a nullable reference type:

to use the null-coalescing operator (??)
or the equals operator (==)

To give some context let's assume that we branch our code based on a reference type's bool property:

public class SomeClass

Deep Dive in Ref Returns

In the previous post I have used Ref returns to return some data. I noticed that with slight changes we get totally different code generated by the JIT, which is can have a good or bad effect on our code.

In this post, I will dig deep (with WinDbg) in the JIT generated code. As forefront: I am using 64 bit machine, .net core 2.1 and RyuJIT.

I created a sample benchmark to showcase. I have a Point struct with 2 integer properties. I benchmark setting the values on the struct in 3 different ways, I show related IL and machine code impacting performance.

The benchmark

Ref Returns

C# has recently introduced some new features (version <7.0) one of which it is ref returns. I will use this feature in this post to further improve the performance of the Parser created in my previous post.

To refresh the Parser class looked as follows:

public class Parser 
{
 public T Parse(ReadOnlySpan input, PropertySetter[] setters) where T : struct

	using System.Diagnostics;
	using System.Threading.Tasks;
	using Microsoft.Extensions.Logging;

	namespace ConsoleApp2
	{
	public class ActivityLogWriter : IActivityWriter
	{
	private readonly ILogger<ActivityLogWriter> _logger;

	using System.Diagnostics;
	using System.Threading.Tasks;
	using Microsoft.Extensions.Logging;

	namespace ConsoleApp2
	{
	public class ActivityLogWriter : IActivityWriter
	{
	private readonly ILogger<ActivityLogWriter> _logger;

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