Menees.Threading 0.1.1-alpha

Threading

This repo defines some helper types for writing efficient asynchronous code.

SlimTask<TResult>

SlimTask<TResult> is an awaitable, task-like value type that does NOT capture the current synchronization context by default. It's useful to return from async library methods when results are usually available synchronously (similar to ValueTask<TResult>) but without having to call ConfigureAwait(false) everywhere.

Since it doesn't capture the synchronization context by default, it doesn't require ConfigureAwait(false). However, it supports ConfigureAwait(true) if you need the context, e.g., if your code invokes a passed-in lambda that may require the captured context.

Examples

int value = await GetValueAsync(42); // No need for .ConfigureAwait(false) with SlimTask
...
static async SlimTask<int> GetValueAsync(int value)
{
	int result = value;
	if (result % 100 == 0)
	{
		await Task.Delay(1).ConfigureAwait(false);
	}

	return result;
}

For more examples, see SlimTaskTests.cs.

Benchmarks

The Menees.Threading.Benchmarks project uses BenchmarkDotNet. Its results show that SlimTask<TResult> performs about the same as ValueTask<TResult> for timing and exactly the same for allocations.

.NET Framework 4.8.1

dotnet run -c Release --framework net48

BenchmarkDotNet v0.15.2, Windows 11 (10.0.26100.4652/24H2/2024Update/HudsonValley)
Intel Core i7-8086K CPU 4.00GHz (Max: 4.01GHz) (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
  [Host]     : .NET Framework 4.8.1 (4.8.9310.0), X64 RyuJIT VectorSize=256
  DefaultJob : .NET Framework 4.8.1 (4.8.9310.0), X64 RyuJIT VectorSize=256

| Method       | Mean     | Error   | StdDev  | Gen0   | Allocated |
|------------- |---------:|--------:|--------:|-------:|----------:|
| UseTask      | 116.2 ns | 1.74 ns | 1.45 ns | 0.0254 |     160 B |
| UseValueTask | 127.3 ns | 1.15 ns | 1.08 ns |      - |         - |
| UseSlimTask  | 120.4 ns | 0.79 ns | 0.74 ns |      - |         - |

| Method           | Mean     | Error     | StdDev    | Gen0   | Allocated |
|----------------- |---------:|----------:|----------:|-------:|----------:|
| ComputeTask      | 2.525 us | 0.0060 us | 0.0057 us | 0.2136 |   1.32 KB |
| ComputeValueTask | 2.517 us | 0.0122 us | 0.0102 us | 0.1869 |   1.17 KB |
| ComputeSlimTask  | 2.475 us | 0.0119 us | 0.0111 us | 0.1869 |   1.17 KB |

.NET 8

dotnet run -c Release --framework net8.0

BenchmarkDotNet v0.15.2, Windows 11 (10.0.26100.4652/24H2/2024Update/HudsonValley)
Intel Core i7-8086K CPU 4.00GHz (Max: 4.01GHz) (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
.NET SDK 9.0.304
  [Host]     : .NET 8.0.19 (8.0.1925.36514), X64 RyuJIT AVX2
  DefaultJob : .NET 8.0.19 (8.0.1925.36514), X64 RyuJIT AVX2

| Method       | Mean     | Error    | StdDev   | Gen0   | Allocated |
|------------- |---------:|---------:|---------:|-------:|----------:|
| UseTask      | 27.18 ns | 0.113 ns | 0.100 ns | 0.0229 |     144 B |
| UseValueTask | 16.79 ns | 0.145 ns | 0.129 ns |      - |         - |
| UseSlimTask  | 18.50 ns | 0.105 ns | 0.098 ns |      - |         - |

| Method           | Mean     | Error   | StdDev  | Gen0   | Allocated |
|----------------- |---------:|--------:|--------:|-------:|----------:|
| ComputeTask      | 651.1 ns | 3.07 ns | 2.88 ns | 0.0544 |     344 B |
| ComputeValueTask | 631.1 ns | 4.02 ns | 3.56 ns | 0.0315 |     200 B |
| ComputeSlimTask  | 662.0 ns | 8.81 ns | 7.81 ns | 0.0315 |     200 B |