airbreather
commented
5 years ago Appendix 1
MyArrayFactory.cs
using System;
using Itinero;
using Reminiscence.Arrays;
public sealed class MyArrayFactory : IArrayFactory
{
public ArrayBase<T> CreateMemoryBackedArray<T>(long size) => ArrayCreatorCache<T>.CreateNewArray(size);
private sealed class ArrayCreatorCache<T>
{
public static readonly Func<long, ArrayBase<T>> CreateNewArray = Create();
private static Func<long, ArrayBase<T>> Create()
{
if (typeof(T) == typeof(byte) ||
typeof(T) == typeof(sbyte) ||
typeof(T) == typeof(short) ||
typeof(T) == typeof(ushort) ||
typeof(T) == typeof(int) ||
typeof(T) == typeof(uint) ||
typeof(T) == typeof(long) ||
typeof(T) == typeof(ulong) ||
typeof(T) == typeof(float) ||
typeof(T) == typeof(double))
{
var types = new[] { typeof(IUnmanagedMemoryAllocator), typeof(long) };
var ctor = typeof(NativeMemoryArray<>).MakeGenericType(typeof(T)).GetConstructor(types);
var allocator = DefaultUnmanagedMemoryAllocator.Instance;
return x => (ArrayBase<T>)ctor.Invoke(new object[] { allocator, x });
}
return x => new MemoryArray<T>(x);
}
}
}
xivk
According to my testing, I/O for serializing / deserializing Itinero objects is significantly faster with this, to the extent that I'm satisfied that this is worth pursuing on that basis alone.
There are occasionally some other places that see speedups as well, primarily during the initial build and contraction hierarchy creation (which is what I was targeting with these improvements), but these are very minor (presumably because
netcoreapp2.2has a much smarter JIT thannetcoreapp2.0, which is what I was originally targeting when I embarked on this roughly a year and a half ago).I just did one run for each row because the times can be so long. All files were entirely served from the filesystem cache for these tests. Timings were captured on
netcoreapp2.2with server GC. The only difference between "vanilla" and "new array" is whether or not the test injected a customIArrayFactoryimplementation.denmark-latest.osm.pbf(2019-01-19) (from here)RouterDb.LoadOsmDatadenmark-latest.osm.pbf(2019-01-19) (from here)RouterDb.AddContracted(Profile)RouterDb.Deserialize(Stream)RouterDb.DeserializeAndAddContracted(Stream)I did not observe any differences in timings for actual calculations worth discussing.