gistfile1.txt

package org.openjdk;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;

import org.openjdk.jmh.annotations.*;
import org.openjdk.jmh.infra.Blackhole;

/**
 * <code>
 * -XX:BiasedLockingStartupDelay=0 -XX:+UseBiasedLocking
 * </code>
 */
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Fork(1)
@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 10, time = 1, timeUnit = TimeUnit.SECONDS)
@Threads(1)
@State(Scope.Benchmark)
public class BiasedLockingPerfTest {

    public static class Counter {
        private long count = 0L;
        private volatile long atomic = 0L;

        static final AtomicLongFieldUpdater<Counter> UP =
                AtomicLongFieldUpdater.newUpdater(Counter.class, "atomic");

        public synchronized long incAndGet() {
            return ++count;
        }
        public long incAndGet_Atomic() {
            return UP.incrementAndGet(this);
        }
    }

    Counter counter, counterWithSysIdHashCode;

    @Setup
    public void setup(Blackhole bh) {
        counter = new Counter();
        counterWithSysIdHashCode = new Counter();
        bh.consume(System.identityHashCode(counterWithSysIdHashCode));
    }

    @Benchmark
    public long sync() {
        return counter.incAndGet();
    }

    @Benchmark
    public long sync_ihc() {
        return counterWithSysIdHashCode.incAndGet();
    }

    @Benchmark
    public long atomic() {
        return counter.incAndGet_Atomic();
    }

    @Benchmark
    public long atomic_ihc() {
        return counterWithSysIdHashCode.incAndGet_Atomic();
    }

}