content: /*
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package io.airlift.concurrent;
  
  import com.google.common.util.concurrent.ListenableFuture;
  import com.google.common.util.concurrent.SettableFuture;
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.BenchmarkMode;
  import org.openjdk.jmh.annotations.Fork;
  import org.openjdk.jmh.annotations.Measurement;
  import org.openjdk.jmh.annotations.Mode;
  import org.openjdk.jmh.annotations.OutputTimeUnit;
  import org.openjdk.jmh.annotations.Param;
  import org.openjdk.jmh.annotations.Scope;
  import org.openjdk.jmh.annotations.State;
  import org.openjdk.jmh.annotations.Warmup;
  import org.openjdk.jmh.runner.Runner;
  import org.openjdk.jmh.runner.RunnerException;
  import org.openjdk.jmh.runner.options.Options;
  import org.openjdk.jmh.runner.options.OptionsBuilder;
  import org.openjdk.jmh.runner.options.VerboseMode;
  
  import java.util.ArrayList;
  import java.util.concurrent.Semaphore;
  import java.util.concurrent.TimeUnit;
  
  import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
  import static io.airlift.concurrent.MoreFutures.whenAnyCompleteCancelOthers;
  
  @State(Scope.Thread)
  @OutputTimeUnit(TimeUnit.NANOSECONDS)
  @Fork(2)
  @Warmup(iterations = 5, time = 500, timeUnit = TimeUnit.MILLISECONDS)
  @Measurement(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
  @BenchmarkMode(Mode.AverageTime)
  public class BenchmarkWhenAnyCompleteCancelOthers
  {
      //        with optimization in ExtendedSettableFuture.setAsync    without
      // 300                    32.7 +/- 1.7 us                     810.6 +/- 31 us
      // 1000                  106.2 +/- 3.0 us                    2813.5 +/- 121 us
  
      @Param({"300", "1000"})
      private int futureCount;
  
      @Benchmark
      public void benchmark()
              throws Exception
      {
          Semaphore semaphore = new Semaphore(futureCount);
  
          ArrayList<SettableFuture<?>> futures = new ArrayList<>();
          for (int i = 0; i < futureCount; i++) {
              SettableFuture<?> future = SettableFuture.create();
              future.addListener(() -> semaphore.release(1), directExecutor());
              futures.add(future);
          }
          ListenableFuture<?> anyComplete = whenAnyCompleteCancelOthers(futures);
          futures.get(futureCount / 2).set(null);
          semaphore.acquireUninterruptibly(futureCount);
          anyComplete.get();
      }
  
      public static void main(String[] args)
              throws RunnerException
      {
          Options options = new OptionsBuilder()
                  .verbosity(VerboseMode.NORMAL)
                  .include(".*" + BenchmarkWhenAnyCompleteCancelOthers.class.getSimpleName() + ".*")
                  .build();
  
          new Runner(options).run();
      }
  }
  