Java example source code file (MoreExecutorsDirectExecutorBenchmark.java)

This example Java source code file (MoreExecutorsDirectExecutorBenchmark.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

afterexperiment, atomicinteger, beforeexperiment, benchmark, countingrunnable, executor, footprint, impl, moreexecutorsdirectexecutorbenchmark, object, override, set, thread, threading, threads, util, xms12g

The MoreExecutorsDirectExecutorBenchmark.java Java example source code

/*
 * Copyright (C) 2014 The Guava Authors
 *
 * 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 com.google.common.util.concurrent;

import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
import static com.google.common.util.concurrent.MoreExecutors.newDirectExecutorService;

import com.google.caliper.AfterExperiment;
import com.google.caliper.BeforeExperiment;
import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import com.google.caliper.api.Footprint;
import com.google.caliper.api.VmOptions;

import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * A benchmark comparing the {@link MoreExecutors#newDirectExecutorService()} to
 * {@link MoreExecutors#directExecutor}.
 */
@VmOptions({"-Xms12g", "-Xmx12g", "-d64"})
public class MoreExecutorsDirectExecutorBenchmark {
  enum Impl {
    EXECUTOR_SERVICE {
      @Override Executor executor() {
        return newDirectExecutorService();
      }
    },
    EXECUTOR {
      @Override Executor executor() {
        return directExecutor();
      }
    };
    abstract Executor executor();
  }

  @Param Impl impl;
  Executor executor;

  static final class CountingRunnable implements Runnable {
    AtomicInteger integer = new AtomicInteger();
    @Override public void run() {
      integer.incrementAndGet();
    }
  }

  CountingRunnable countingRunnable = new CountingRunnable();

  Set<Thread> threads = new HashSet();

  @BeforeExperiment void before() {
    executor = impl.executor();
    for (int i = 0; i < 4; i++) {
      Thread thread = new Thread() {
        @Override public void run() {
          CountingRunnable localRunnable = new CountingRunnable();
          while (!isInterrupted()) {
            executor.execute(localRunnable);
          }
          countingRunnable.integer.addAndGet(localRunnable.integer.get());
        }
      };
      threads.add(thread);
    }
  }

  @AfterExperiment void after() {
    for (Thread thread : threads) {
      thread.interrupt();  // try to get them to exit
    }
    threads.clear();
  }

  @Footprint Object measureSize() {
    return executor;
  }

  @Benchmark int timeUncontendedExecute(int reps) {
    final Executor executor = this.executor;
    final CountingRunnable countingRunnable = this.countingRunnable;
    for (int i = 0; i < reps; i++) {
      executor.execute(countingRunnable);
    }
    return countingRunnable.integer.get();
  }

  @Benchmark int timeContendedExecute(int reps) {
    final Executor executor = this.executor;
    for (Thread thread : threads) {
      if (!thread.isAlive()) {
        thread.start();
      }
    }
    final CountingRunnable countingRunnable = this.countingRunnable;
    for (int i = 0; i < reps; i++) {
      executor.execute(countingRunnable);
    }
    return countingRunnable.integer.get();
  }
}