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The base Stream class implements these overloads by renting a buffer,
creating a ReadWriteTask, and copying data as necessary.

Instead, ConsoleStreams can just override these Async methods and synchronously
call the underlying OS API.

Benchmark

public class ConsoleStreamsBenchmark
{
    static byte[] _bytes = Encoding.ASCII.GetBytes("Hello, World!");
    static Stream _stream = Console.OpenStandardOutput();

    static NativeMemoryManager _nativeMemoryManager = CreateNativeMemory();

    private unsafe static NativeMemoryManager CreateNativeMemory()
    {
        byte* mem = (byte*)NativeMemory.Alloc((nuint)_bytes.Length);
        _bytes.AsSpan().CopyTo(new Span<byte>(mem, _bytes.Length));
        return new NativeMemoryManager(mem, _bytes.Length);
    }

    [Benchmark]
    public async Task WriteToStream()
    {
        await _stream.WriteAsync(_bytes);
    }

    [Benchmark]
    public async Task WriteNativeMemoryToStream()
    {
        await _stream.WriteAsync(_nativeMemoryManager.Memory);
    }

    unsafe class NativeMemoryManager : MemoryManager<byte>
    {
        private byte* _pointer;
        private int _length;
        internal NativeMemoryManager(byte* pointer, int length)
        {
            _pointer = pointer;
            _length = length;
        }

        public override Span<byte> GetSpan() => new Span<byte>(_pointer, _length);
        public override MemoryHandle Pin(int elementIndex = 0) => default;
        public override void Unpin() { }
        protected override void Dispose(bool disposing) { }
    }
}

Results

Method Job Toolchain Mean Error StdDev Ratio RatioSD
WriteToStream Job-AMXSLA \main\corerun.exe 6.221 us 0.6849 us 0.7888 us 1.00 0.00
WriteToStream Job-CRTAYW \pr\corerun.exe 4.602 us 0.6634 us 0.7374 us 0.74 0.08
WriteNativeMemoryToStream Job-AMXSLA \main\corerun.exe 6.549 us 0.8117 us 0.8685 us 1.00 0.00
WriteNativeMemoryToStream Job-CRTAYW \pr\corerun.exe 4.575 us 0.6448 us 0.7426 us 0.69 0.07

The base Stream class implements these overloads by renting a buffer,
creating a ReadWriteTask, and copying data as necessary.

Instead, ConsoleStreams can just override these Async methods and synchronously
call the underlying OS API.

Add tests to verify that input and output console streams behave correctly.
@ghost ghost added the area-System.Console label Jul 11, 2022
@ghost ghost assigned eerhardt Jul 11, 2022
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ghost commented Jul 11, 2022

Tagging subscribers to this area: @dotnet/area-system-console
See info in area-owners.md if you want to be subscribed.

Issue Details

The base Stream class implements these overloads by renting a buffer,
creating a ReadWriteTask, and copying data as necessary.

Instead, ConsoleStreams can just override these Async methods and synchronously
call the underlying OS API.

Benchmark

public class ConsoleStreamsBenchmark
{
    static byte[] _bytes = Encoding.ASCII.GetBytes("Hello, World!");
    static Stream _stream = Console.OpenStandardOutput();

    static NativeMemoryManager _nativeMemoryManager = CreateNativeMemory();

    private unsafe static NativeMemoryManager CreateNativeMemory()
    {
        byte* mem = (byte*)NativeMemory.Alloc((nuint)_bytes.Length);
        _bytes.AsSpan().CopyTo(new Span<byte>(mem, _bytes.Length));
        return new NativeMemoryManager(mem, _bytes.Length);
    }

    [Benchmark]
    public async Task WriteToStream()
    {
        await _stream.WriteAsync(_bytes);
    }

    [Benchmark]
    public async Task WriteNativeMemoryToStream()
    {
        await _stream.WriteAsync(_nativeMemoryManager.Memory);
    }

    unsafe class NativeMemoryManager : MemoryManager<byte>
    {
        private byte* _pointer;
        private int _length;
        internal NativeMemoryManager(byte* pointer, int length)
        {
            _pointer = pointer;
            _length = length;
        }

        public override Span<byte> GetSpan() => new Span<byte>(_pointer, _length);
        public override MemoryHandle Pin(int elementIndex = 0) => default;
        public override void Unpin() { }
        protected override void Dispose(bool disposing) { }
    }
}

Results

Method Job Toolchain Mean Error StdDev Ratio RatioSD
WriteToStream Job-AMXSLA \main\corerun.exe 6.221 us 0.6849 us 0.7888 us 1.00 0.00
WriteToStream Job-CRTAYW \pr\corerun.exe 4.602 us 0.6634 us 0.7374 us 0.74 0.08
WriteNativeMemoryToStream Job-AMXSLA \main\corerun.exe 6.549 us 0.8117 us 0.8685 us 1.00 0.00
WriteNativeMemoryToStream Job-CRTAYW \pr\corerun.exe 4.575 us 0.6448 us 0.7426 us 0.69 0.07
Author: eerhardt
Assignees: -
Labels:

area-System.Console

Milestone: -

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@stephentoub stephentoub left a comment

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Thanks.

@eerhardt
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The new "OpenStandardInput" tests need to be skipped on platforms that don't support standard input - like wasm, ios, and android. Fixing...

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LGTM, thank you @eerhardt !

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/azp list

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@adamsitnik
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/azp run runtime-extra-platforms

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Azure Pipelines successfully started running 1 pipeline(s).

@eerhardt
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All the runtime-extra-platforms failures are unrelated to System.Console.

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3 participants