Microbenchmarks

Test.java

import java.util.concurrent.TimeUnit;

import com.comphenix.protocol.injector.StructureCache;
import com.comphenix.protocol.reflect.FieldAccessException;
import com.comphenix.protocol.reflect.StructureModifier;
import com.google.common.base.Stopwatch;

import net.minecraft.server.*;

class Test {

	public static void main(String[] args) {
		
		Packet20NamedEntitySpawn named = new Packet20NamedEntitySpawn();
		StructureModifier<Object> modifier = StructureCache.getStructure(20).withTarget(named);
		StructureModifier<Integer> intModifier = modifier.withType(int.class);
		
		Stopwatch watch = new Stopwatch();
		
		// COLD START
		reflectAdding(intModifier, 1000);
		
		named.a = 0;
		watch.start();
		
		for (int i = 0; i < 1000000; i++) {
			try {
				intModifier.write(0, intModifier.read(0) + 1);
			} catch (FieldAccessException e) {
				e.printStackTrace();
			}
		}
		
		watch.stop();
		System.out.println("A: " + named.a);
		System.out.println("Elapsed reflect (ms): " + watch.elapsedTime(TimeUnit.NANOSECONDS));
		
		named.a = 0;
		watch.reset();
		watch.start();
		
		for (int i = 0; i < 1000000; i++) {
			named.a = named.a + 1;
		}

		watch.stop();
		System.out.println("A: " + named.a);
		System.out.println("Elapsed direct (ms): " + watch.elapsedTime(TimeUnit.NANOSECONDS));
	}
	
	private static void reflectAdding(StructureModifier<Integer> intModifier, int amount) {
		for (int i = 0; i < amount; i++) {
			try {
				intModifier.write(0, intModifier.read(0) + 1);
			} catch (FieldAccessException e) {
				e.printStackTrace();
			}
		}
	}
}

That was for 100 increments. For 1000000 increments I have:

A: 1000000
Elapsed reflect (ms): 61339809
A: 1000000
Elapsed direct (ms): 4056289