package com.bellsw.yield;

import static java.util.concurrent.TimeUnit.*;
import static org.openjdk.jmh.annotations.Mode.*;
import static org.openjdk.jmh.annotations.Scope.*;
import static org.openjdk.jmh.annotations.Level.*;
import org.openjdk.jmh.infra.Control;

import org.openjdk.jmh.annotations.*;

@BenchmarkMode(Throughput)
@Warmup(iterations = 5, time = 1, timeUnit = SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = SECONDS)//, batchSize = 1000)
@Fork(5)
@OutputTimeUnit(MICROSECONDS)
@State(Group)
public class SpinWaitBench {

	@State(Scope.Thread)
	@AuxCounters(AuxCounters.Type.OPERATIONS)
	public static class Spins {
		public long totalSpins = 0;
	}
    
    public volatile long spinData; // even: ready to produce; odd: ready to consume; -3: terminate
    
    @Setup(Iteration)
    public void initSpins() {
    	spinData = 0;
    }
	
    @Benchmark
    @Group("pong")
    @GroupThreads(1)
    public void produce(Control cnt, Spins aux) {
        long spins = 0;
        while ((spinData & 0x1) == 1 && !cnt.stopMeasurement) {
            // busy spin until ready to produce
            java.lang.Thread.onSpinWait();
            spins++;
        }
        spinData++; // produce
        aux.totalSpins += spins;
    }

    @Benchmark
    @Group("pong")
    @GroupThreads(1)
    public void consume(Control cnt) {
        while ((spinData & 0x1) == 0 && !cnt.stopMeasurement) {
            // busy spin until ready to consume
            java.lang.Thread.onSpinWait();
        }
        spinData++; // consume
    }
}