C# Serialization Performance - Part I

[WilliamWhispell]

What version of protobuf and what language are you using?
Version: master
Language: C#

What operating system (Linux, Windows, ...) and version?
Linux, Windows

What runtime / compiler are you using (e.g., python version or gcc version)
MSBUILD 15

bool, double and float should be marked as fixed size. In FieldCodec.cs we create the codecs used by RepeatedField.cs. Having these not be fixed means that on large repeated fields for these fixed length primitives, we will call the size calculator each time, for every single data point (inside CalculatePackedDataSize). I've seen about 40% serialization improvement on repeated fields for these types when they are marked as fixed.

Straight forward fix is to rename ComputeBoolSize to ComputeFixedBoolSize, ComputeFloatSize to ComputeFixedFloatSize and ComputeDoubleSize to ComputeFixedDoubleSize, then we should change ForBool, ForFloat and ForDouble to send in a dummy value to the computesize functions when creating the codec (we will set the FixedSize attribute to the result).

[jtattermusch]

@WilliamWhispell FTR, you might want to look at the ongoing planning for protobuf performance optimization in grpc/grpc-dotnet#30.

[WilliamWhispell]

@jtattermusch - Had a quick read through. Sounds exciting. I looked over the pull request for the benchmark code the other day and I'm looking forward to its release.