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Reduce allocations #342

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merged 3 commits into from
Oct 1, 2017
Merged

Reduce allocations #342

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4c4baf6
Update Benchmark runtime to .NET 4.7.
bgrainger Sep 30, 2017
88c13ac
Remove local function allocation.
bgrainger Sep 30, 2017
978129e
Reduce allocations by making Packet a struct.
bgrainger Sep 30, 2017
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22 changes: 11 additions & 11 deletions src/MySqlConnector/MySqlClient/Results/ResultSet.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -167,17 +167,17 @@ private ValueTask<Row> ScanRowAsync(IOBehavior ioBehavior, Row row, Cancellation
{
// if we've already read past the end of this resultset, Read returns false
if (BufferState == ResultSetState.HasMoreData || BufferState == ResultSetState.NoMoreData || BufferState == ResultSetState.None)
return new ValueTask<Row>((Row)null);
return new ValueTask<Row>((Row) null);

using (Command.RegisterCancel(cancellationToken))
{
var payloadValueTask = Session.ReceiveReplyAsync(ioBehavior, CancellationToken.None);
return payloadValueTask.IsCompletedSuccessfully
? new ValueTask<Row>(ScanRowAsyncRemainder(payloadValueTask.Result))
: new ValueTask<Row>(ScanRowAsyncAwaited(payloadValueTask.AsTask(), cancellationToken));
? new ValueTask<Row>(ScanRowAsyncRemainder(payloadValueTask.Result, row))
: new ValueTask<Row>(ScanRowAsyncAwaited(payloadValueTask.AsTask(), row, cancellationToken));
}

async Task<Row> ScanRowAsyncAwaited(Task<PayloadData> payloadTask, CancellationToken token)
async Task<Row> ScanRowAsyncAwaited(Task<PayloadData> payloadTask, Row row_, CancellationToken token)
{
PayloadData payloadData;
try
Expand All @@ -191,10 +191,10 @@ async Task<Row> ScanRowAsyncAwaited(Task<PayloadData> payloadTask, CancellationT
token.ThrowIfCancellationRequested();
throw;
}
return ScanRowAsyncRemainder(payloadData);
return ScanRowAsyncRemainder(payloadData, row_);
}

Row ScanRowAsyncRemainder(PayloadData payload)
Row ScanRowAsyncRemainder(PayloadData payload, Row row_)
{
if (payload.HeaderByte == EofPayload.Signature)
{
Expand Down Expand Up @@ -223,12 +223,12 @@ Row ScanRowAsyncRemainder(PayloadData payload)
reader.Offset += m_dataLengths[column];
}

if (row == null)
row = new Row(this);
row.SetData(m_dataLengths, m_dataOffsets, payload.ArraySegment);
m_rowBuffered = row;
if (row_ == null)
row_ = new Row(this);
row_.SetData(m_dataLengths, m_dataOffsets, payload.ArraySegment);
m_rowBuffered = row_;
m_hasRows = true;
return row;
return row_;
}
}

Expand Down
8 changes: 3 additions & 5 deletions src/MySqlConnector/Protocol/Serialization/Packet.cs
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Original file line number Diff line number Diff line change
@@ -1,16 +1,14 @@
using System;
using System;

namespace MySql.Data.Protocol.Serialization
{
internal class Packet
internal struct Packet
{
public Packet(int sequenceNumber, ArraySegment<byte> contents)
public Packet(ArraySegment<byte> contents)
{
SequenceNumber = sequenceNumber;
Contents = contents;
}

public int SequenceNumber { get; }
public ArraySegment<byte> Contents { get; }
}
}
23 changes: 8 additions & 15 deletions src/MySqlConnector/Protocol/Serialization/ProtocolUtility.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
using System;
using System;
using System.Buffers;
using System.IO;
using System.Threading.Tasks;
Expand Down Expand Up @@ -45,16 +45,16 @@ private static ValueTask<Packet> ReadPacketAfterHeader(ArraySegment<byte> header

var payloadBytesTask = bufferedByteReader.ReadBytesAsync(byteHandler, payloadLength, ioBehavior);
if (payloadBytesTask.IsCompleted)
return CreatePacketFromPayload(payloadBytesTask.Result, payloadLength, packetSequenceNumber, protocolErrorBehavior);
return AddContinuation(payloadBytesTask, payloadLength, packetSequenceNumber, protocolErrorBehavior);
return CreatePacketFromPayload(payloadBytesTask.Result, payloadLength, protocolErrorBehavior);
return AddContinuation(payloadBytesTask, payloadLength, protocolErrorBehavior);

// NOTE: use a local function (with no captures) to defer creation of lambda objects
ValueTask<Packet> AddContinuation(ValueTask<ArraySegment<byte>> payloadBytesTask_, int payloadLength_, int packetSequenceNumber_, ProtocolErrorBehavior protocolErrorBehavior_)
=> payloadBytesTask_.ContinueWith(x => CreatePacketFromPayload(x, payloadLength_, packetSequenceNumber_, protocolErrorBehavior_));
ValueTask<Packet> AddContinuation(ValueTask<ArraySegment<byte>> payloadBytesTask_, int payloadLength_, ProtocolErrorBehavior protocolErrorBehavior_)
=> payloadBytesTask_.ContinueWith(x => CreatePacketFromPayload(x, payloadLength_, protocolErrorBehavior_));
}

private static ValueTask<Packet> CreatePacketFromPayload(ArraySegment<byte> payloadBytes, int payloadLength, int packetSequenceNumber, ProtocolErrorBehavior protocolErrorBehavior) =>
payloadBytes.Count >= payloadLength ? new ValueTask<Packet>(new Packet(packetSequenceNumber, payloadBytes)) :
private static ValueTask<Packet> CreatePacketFromPayload(ArraySegment<byte> payloadBytes, int payloadLength, ProtocolErrorBehavior protocolErrorBehavior) =>
payloadBytes.Count >= payloadLength ? new ValueTask<Packet>(new Packet(payloadBytes)) :
protocolErrorBehavior == ProtocolErrorBehavior.Throw ? ValueTaskExtensions.FromException<Packet>(new EndOfStreamException()) :
default(ValueTask<Packet>);

Expand All @@ -69,8 +69,7 @@ private static ValueTask<ArraySegment<byte>> DoReadPayloadAsync(BufferedByteRead
var readPacketTask = ReadPacketAsync(bufferedByteReader, byteHandler, getNextSequenceNumber, protocolErrorBehavior, ioBehavior);
while (readPacketTask.IsCompleted)
{
ValueTask<ArraySegment<byte>> result;
if (HasReadPayload(previousPayloads, readPacketTask.Result, protocolErrorBehavior, out result))
if (HasReadPayload(previousPayloads, readPacketTask.Result, protocolErrorBehavior, out var result))
return result;

readPacketTask = ReadPacketAsync(bufferedByteReader, byteHandler, getNextSequenceNumber, protocolErrorBehavior, ioBehavior);
Expand All @@ -89,12 +88,6 @@ ValueTask<ArraySegment<byte>> AddContinuation(ValueTask<Packet> readPacketTask_,

private static bool HasReadPayload(ArraySegmentHolder<byte> previousPayloads, Packet packet, ProtocolErrorBehavior protocolErrorBehavior, out ValueTask<ArraySegment<byte>> result)
{
if (packet == null && protocolErrorBehavior == ProtocolErrorBehavior.Ignore)
{
result = default(ValueTask<ArraySegment<byte>>);
return true;
}
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packet will never be null now, because I made it a struct. OTOH, I'm not sure if it was ever null before, because it's dereferenced later in the method without a null check. (If it was possible that default(Packet) could come through, then packet.Contents.Array might throw a NullReferenceException later in the method.)


if (previousPayloads.Count == 0 && packet.Contents.Count < MaxPacketSize)
{
result = new ValueTask<ArraySegment<byte>>(packet.Contents);
Expand Down
2 changes: 1 addition & 1 deletion tests/Benchmark/Benchmark.csproj
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFrameworks>netcoreapp1.1;net462;netcoreapp2.0</TargetFrameworks>
<TargetFrameworks>netcoreapp1.1;net47;netcoreapp2.0</TargetFrameworks>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="BenchmarkDotNet" Version="0.10.8" />
Expand Down
4 changes: 2 additions & 2 deletions tests/Benchmark/Program.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
using System;
using System;
using System.Data.Common;
using System.Threading.Tasks;
using BenchmarkDotNet.Attributes;
Expand All @@ -24,7 +24,7 @@ static void Main()
.With(JitOptimizationsValidator.FailOnError)
.With(MemoryDiagnoser.Default)
.With(StatisticColumn.AllStatistics)
.With(Job.Default.With(Runtime.Clr).With(Jit.RyuJit).With(Platform.X64).With(CsProjClassicNetToolchain.Net462).WithId("net462"))
.With(Job.Default.With(Runtime.Clr).With(Jit.RyuJit).With(Platform.X64).With(CsProjClassicNetToolchain.Net47).WithId("net47"))
.With(Job.Default.With(Runtime.Core).With(CsProjCoreToolchain.NetCoreApp11).WithId("netcore11"))
.With(Job.Default.With(Runtime.Core).With(CsProjCoreToolchain.NetCoreApp20).WithId("netcore20"))
.With(DefaultExporters.Csv);
Expand Down