Reflection benchmark

ReflectionBenchmark.cs

using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using TMPro;
using UnityEngine;
using Debug = UnityEngine.Debug;

public class ReflectionBenchmark : MonoBehaviour
{
	TextMeshProUGUI label;

	int n = 1000000;

	class Animal
	{
		public string habitat;
		public string biome;
		public bool ambassador;
	}
	

	IEnumerator Start ()
	{
		label = GetComponent<TextMeshProUGUI>();
		
		yield return new WaitForSeconds(1f);

		Animal instance = new Animal
		{
			habitat = "",
			ambassador =  false,
			biome = "",
		};
		string[] fieldNames = { "habitat", "ambassador", "biome"};

		string result = $"n: {n}\n";
		
		var watch = new Stopwatch();
		
		watch.Start();
		Normal(instance);
		result += $"instance.field: {watch.ElapsedMilliseconds}ms\n";
		watch.Restart();

		SimpleReflection(fieldNames, instance);
		result += $"Full refelction: {watch.ElapsedMilliseconds}ms\n";
		watch.Restart();
		
		CacheField(fieldNames, instance);
		result += $"Cache GetField() in dict: {watch.ElapsedMilliseconds}ms\n";
		watch.Restart();
		
		CacheValue(fieldNames, instance);
		result += $"Cache GetValue() in dict: {watch.ElapsedMilliseconds}ms\n";
		watch.Restart();
		
		CacheValueArray(fieldNames, instance);
		result += $"Cache GetValue() in array: {watch.ElapsedMilliseconds}ms\n";
		watch.Stop();

		label.text = result;
	}

	void Normal(Animal instance)
	{
		int sumNormal = 0;
		for (int i = 0; i < n; i++)
		{
			sumNormal += instance.habitat.ToString().Length;
			sumNormal += instance.ambassador.ToString().Length;
			sumNormal += instance.biome.ToString().Length;
		}
		
		Debug.Log("Control Sum " + sumNormal);
	}

	void SimpleReflection(string[] fieldNames, Animal instance)
	{
		int sumReflection = 0;
		for (int i = 0; i < n; i++)
		{
			foreach (var fieldName in fieldNames)
			{
				var field = instance.GetType().GetField(fieldName);
				sumReflection += field.GetValue(instance).ToString().Length;
			}
		}
		
		Debug.Log("Control Sum " + sumReflection);
	}

	void CacheField(string[] fieldNames, Animal instance)
	{
		int sumCached = 0;
		var dict = new Dictionary<string, FieldInfo>();

		foreach (var fieldName in fieldNames)
			dict[fieldName] = instance.GetType().GetField(fieldName);

		for (int i = 0; i < n; i++)
		{
			foreach (var fieldName in fieldNames)
				sumCached += dict[fieldName].GetValue(instance).ToString().Length;
		}
		
		Debug.Log("Control Sum " + sumCached);
	}
	
	void CacheValue(string[] fieldNames, Animal instance)
	{
		int sumCached = 0;
		var dict = new Dictionary<string, object>();

		foreach (var fieldName in fieldNames)
			dict[fieldName] = instance.GetType().GetField(fieldName).GetValue(instance);

		for (int i = 0; i < n; i++)
		{
			foreach (var fieldName in fieldNames)
				sumCached += dict[fieldName].ToString().Length;
		}
		
		Debug.Log("Control Sum " + sumCached);
	}
	
	void CacheValueArray(string[] fieldNames, Animal instance)
	{
		int sumCached = 0;
		var array = new KeyValuePair<string, object>[fieldNames.Length];

		for (var i = 0; i < fieldNames.Length; i++)
			array[i] = new KeyValuePair<string, object>(fieldNames[i],
				instance.GetType().GetField(fieldNames[i]).GetValue(instance));

		for (int i = 0; i < n; i++)
		{
			for (var j = 0; j < fieldNames.Length; j++)
				sumCached += array[j].Value.ToString().Length;
		}

		Debug.Log("Control Sum " + sumCached);
	}
}

result.markdown

Result on Samsung S6 edge (scripting backend Mono)

testcase	time
instance.field	162ms
Full reflection	18516ms
Cache GetField() in dict	4729ms
Cache GetValue() in dict	736ms
Cache GetValue() in array	90ms