C#11 による世界最速バイナリシリアライザー「MemoryPack」の作り方

.NET Conf 2022 Recap Event Tokyo #dotnetconf

Transcript

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2. 河合 宜文 / Kawai Yoshifumi / @neuecc
   Cysharp, Inc.
   Cygames
   C#大統一理論
   C#
   

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3. #1 Binary Serializer in .NET
   https://github.com/neuecc/MessagePack-CSharp
   

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4. Zero encoding extreme fast binary serializer
   https://github.com/Cysharp/MemoryPack/
   究極的
   

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5. 1リクエストに1000回実行することはある
   

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6. バッチやクライアントアプリケーションでも
   

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7. Incremental Source Generator
   

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10. No.
    

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12. Serialize/MemoryPackWriter
    

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14. public void WriteUnmanaged(scoped in T1 value1)
    where T1 : unmanaged
    {
    var size = Unsafe.SizeOf();
    ref var spanRef = ref GetSpanReference(size);
    Unsafe.WriteUnaligned(ref spanRef, value1);
    Advance(size);
    }
    書き込み用バッファー管理
    public ref partial struct MemoryPackWriter
    where TBufferWriter : IBufferWriter
    {
    ref TBufferWriter bufferWriter;
    ref byte bufferReference;
    int bufferLength;
    ref byte GetSpanReference(int sizeHint);
    void Advance(int count);
    public MemoryPackWriter(ref TBufferWriter writer)
    }
    public interface System.Buffers.IBufferWriter
    {
    Span GetSpan(int sizeHint = 0);
    void Advance(int count);
    }
    

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15. public void WriteUnmanaged(scoped in T1 value1)
    where T1 : unmanaged
    {
    var size = Unsafe.SizeOf();
    ref var spanRef = ref GetSpanReference(size);
    Unsafe.WriteUnaligned(ref spanRef, value1);
    Advance(size);
    }
    書き込み用バッファー管理
    public ref partial struct MemoryPackWriter
    where TBufferWriter : IBufferWriter
    {
    ref TBufferWriter bufferWriter;
    ref byte bufferReference;
    int bufferLength;
    ref byte GetSpanReference(int sizeHint);
    void Advance(int count);
    public MemoryPackWriter(ref TBufferWriter writer)
    }
    public interface System.Buffers.IBufferWriter
    {
    Span GetSpan(int sizeHint = 0);
    void Advance(int count);
    }
    

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16. public void WriteUnmanaged(scoped in T1 value1)
    where T1 : unmanaged
    {
    var size = Unsafe.SizeOf();
    ref var spanRef = ref GetSpanReference(size);
    Unsafe.WriteUnaligned(ref spanRef, value1);
    Advance(size);
    }
    書き込み用バッファー管理
    public ref partial struct MemoryPackWriter
    where TBufferWriter : IBufferWriter
    {
    ref TBufferWriter bufferWriter;
    ref byte bufferReference;
    int bufferLength;
    ref byte GetSpanReference(int sizeHint);
    void Advance(int count);
    public MemoryPackWriter(ref TBufferWriter writer)
    }
    public interface System.Buffers.IBufferWriter
    {
    Span GetSpan(int sizeHint = 0);
    void Advance(int count);
    }
    

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17. public void WriteUnmanaged(scoped in T1 value1)
    where T1 : unmanaged
    {
    var size = Unsafe.SizeOf();
    ref var spanRef = ref GetSpanReference(size);
    Unsafe.WriteUnaligned(ref spanRef, value1);
    Advance(size);
    }
    書き込み用バッファー管理
    public ref partial struct MemoryPackWriter
    where TBufferWriter : IBufferWriter
    {
    ref TBufferWriter bufferWriter;
    ref byte bufferReference;
    int bufferLength;
    ref byte GetSpanReference(int sizeHint);
    void Advance(int count);
    public MemoryPackWriter(ref TBufferWriter writer)
    }
    public interface System.Buffers.IBufferWriter
    {
    Span GetSpan(int sizeHint = 0);
    void Advance(int count);
    }
    

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18. 書き込み用バッファー管理
    public ref partial struct MemoryPackWriter
    where TBufferWriter : IBufferWriter
    {
    ref TBufferWriter bufferWriter;
    ref byte bufferReference;
    int bufferLength;
    ref byte GetSpanReference(int sizeHint);
    void Advance(int count);
    public MemoryPackWriter(ref TBufferWriter writer)
    }
    

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19. public static partial class MemoryPackSerializer
    {
    public static void Serialize(in TBufferWriter bufferWriter, in T? value)
    public static byte[] Serialize(in T? value)
    public static ValueTask SerializeAsync(Stream stream, T? value)
    }
    var writer = new MemoryPackWriter(ref bufferWriter);
    writer.WriteValue(value);
    writer.Flush();
    

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20. public static partial class MemoryPackSerializer
    {
    public static void Serialize(in TBufferWriter bufferWriter, in T? value)
    public static byte[] Serialize(in T? value)
    public static ValueTask SerializeAsync(Stream stream, T? value)
    }
    var bufferWriter = ReusableLinkedArrayBufferWriterPool.Rent();
    var writer = new MemoryPackWriter(ref bufferWriter);
    writer.WriteValue(value);
    writer.Flush();
    await bufferWriter.WriteToAndResetAsync(stream);
    return bufferWriter.ToArrayAndReset();
    

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21. byte[] byte[] byte[]
    ArrayPool.Shared.Rent
    GetSpan()
    public sealed class ReusableLinkedArrayBufferWriter : IBufferWriter
    {
    List buffers;
    }
    struct BufferSegment
    {
    byte[] buffer;
    int written;
    }
    

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22. IBufferWriterを優先する
    

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23. Deserialize/MemoryPackReader
    

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25. public ref partial struct MemoryPackReader
    {
    ReadOnlySequence bufferSource;
    ref byte bufferReference;
    int bufferLength;
    ref byte GetSpanReference(int sizeHint);
    void Advance(int count);
    public MemoryPackReader(in ReadOnlySequence bufferSource)
    public MemoryPackReader(ReadOnlySpan buffer)
    }
    読み込み用バッファー管理
    

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26. 連結されたbyte[]、のようなもの
    

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27. 性能は同期バッファと非同期読み書きで決まる
    Streaming処理は別の機構で行う
    

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28. Optimize for All Types
    

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29. C#の配列は要素がunmanaged型(参照型を含まな
    いstruct)の場合、全て直列に並ぶ
    var srcLength = Unsafe.SizeOf() * value.Length;
    var allocSize = srcLength + 4;
    ref var dest = ref GetSpanReference(allocSize);
    ref var src = ref Unsafe.As(ref GetArrayDataReference(value));
    Unsafe.WriteUnaligned(ref dest, value.Length);
    Unsafe.CopyBlockUnaligned(ref Unsafe.Add(ref dest, 4), ref src, (uint)srcLength);
    Advance(allocSize);
    

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30. Vector3[]など複合型になればなるほど有利
    

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31. public sealed class ListFormatter : MemoryPackFormatter>
    {
    public override void Serialize(
    ref MemoryPackWriter writer, scoped ref List? value)
    {
    if (value == null)
    {
    writer.WriteNullCollectionHeader();
    return;
    }
    var span = CollectionsMarshal.AsSpan(value);
    var formatter = GetFormatter();
    WriteCollectionHeader(span.Length);
    for (int i = 0; i < span.Length; i++)
    {
    formatter.Serialize(ref this, ref span[i]);
    }
    }
    }
    

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32. public override void Deserialize(ref MemoryPackReader reader, scoped ref List? value)
    {
    if (!reader.TryReadCollectionHeader(out var length))
    {
    value = null;
    return;
    }
    value = new List(length);
    var span = CollectionsMarshalEx.CreateSpan(value, length);
    var formatter = GetFormatter();
    for (int i = 0; i < length; i++)
    {
    formatter.Deserialize(ref this, ref span[i]);
    }
    }
    internal static class CollectionsMarshalEx
    {
    public static Span CreateSpan(
    List list, int length)
    {
    list.EnsureCapacity(length);
    ref var view = ref Unsafe.As,
    ListView>(ref list);
    view._size = length;
    return view._items.AsSpan(0, length);
    }
    }
    internal sealed class ListView
    {
    public T[] _items;
    public int _size;
    public int _version;
    }
    

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33. Conclusion
    

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34. 究極のシリアライザーを作る
    MemoryPack
    https://github.com/Cysharp/MemoryPack/
    

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