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Java example source code file (ExecutionListBenchmark.java)

This example Java source code file (ExecutionListBenchmark.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

annotation, benchmark, countdownlatch, executionlistcas, executionlistwrapper, executor, guardedby, head_offset, log, logger, logging, num_threads, object, override, runnable, runnableexecutorpair, runtimeexception, threading, threads, util

The ExecutionListBenchmark.java Java example source code

/*
 * Copyright (C) 2013 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 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 com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.common.util.concurrent.AbstractFutureBenchmarks.OldAbstractFuture;

import java.util.Queue;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.annotation.Nullable;
import javax.annotation.concurrent.GuardedBy;

/**
 * Benchmarks for {@link ExecutionList}.
 */
@VmOptions({"-Xms8g", "-Xmx8g"})
public class ExecutionListBenchmark {
  private static final int NUM_THREADS = 10;  // make a param?

  // simple interface to wrap our two implementations.
  interface ExecutionListWrapper {
    void add(Runnable runnable, Executor executor);
    void execute();
    /** Returns the underlying implementation, useful for the Footprint benchmark. */
    Object getImpl();
  }

  enum Impl {
    NEW {
      @Override ExecutionListWrapper newExecutionList() {
        return new ExecutionListWrapper() {
          final ExecutionList list = new ExecutionList();
          @Override public void add(Runnable runnable, Executor executor) {
            list.add(runnable, executor);
          }

          @Override public void execute() {
            list.execute();
          }

          @Override public Object getImpl() {
            return list;
          }
        };
      }
    },
    NEW_WITH_CAS {
      @Override ExecutionListWrapper newExecutionList() {
        return new ExecutionListWrapper() {
          final ExecutionListCAS list = new ExecutionListCAS();
          @Override public void add(Runnable runnable, Executor executor) {
            list.add(runnable, executor);
          }

          @Override public void execute() {
            list.execute();
          }

          @Override public Object getImpl() {
            return list;
          }
        };
      }
    },
    NEW_WITH_QUEUE {
      @Override ExecutionListWrapper newExecutionList() {
        return new ExecutionListWrapper() {
          final NewExecutionListQueue list = new NewExecutionListQueue();
          @Override public void add(Runnable runnable, Executor executor) {
            list.add(runnable, executor);
          }

          @Override public void execute() {
            list.execute();
          }

          @Override public Object getImpl() {
            return list;
          }
        };
      }
    },
    NEW_WITHOUT_REVERSE {
      @Override ExecutionListWrapper newExecutionList() {
        return new ExecutionListWrapper() {
          final NewExecutionListWithoutReverse list = new NewExecutionListWithoutReverse();
          @Override public void add(Runnable runnable, Executor executor) {
            list.add(runnable, executor);
          }

          @Override public void execute() {
            list.execute();
          }

          @Override public Object getImpl() {
            return list;
          }
        };
      }
    },
    OLD {
      @Override ExecutionListWrapper newExecutionList() {
        return new ExecutionListWrapper() {
          final OldExecutionList list = new OldExecutionList();
          @Override public void add(Runnable runnable, Executor executor) {
            list.add(runnable, executor);
          }

          @Override public void execute() {
            list.execute();
          }

          @Override public Object getImpl() {
            return list;
          }
        };
      }
    },
    ABSTRACT_FUTURE {
      @Override ExecutionListWrapper newExecutionList() {
        return new ExecutionListWrapper() {
          final AbstractFuture<?> future = new AbstractFuture() {};
          @Override public void add(Runnable runnable, Executor executor) {
            future.addListener(runnable, executor);
          }

          @Override public void execute() {
            future.set(null);
          }

          @Override public Object getImpl() {
            return future;
          }
        };
      }
    },
    OLD_ABSTRACT_FUTURE {
      @Override ExecutionListWrapper newExecutionList() {
        return new ExecutionListWrapper() {
          final OldAbstractFuture<Object> future = new OldAbstractFuture() {};
          @Override public void add(Runnable runnable, Executor executor) {
            future.addListener(runnable, executor);
          }

          @Override public void execute() {
            future.set(null);
          }

          @Override public Object getImpl() {
            return future;
          }
        };
      }
    };
    abstract ExecutionListWrapper newExecutionList();
  }

  private ThreadPoolExecutor executorService;
  private CountDownLatch listenerLatch;
  private ExecutionListWrapper list;

  @Param Impl impl;
  @Param({"1", "5", "10"}) int numListeners;

  private final Runnable listener = new Runnable() {
    @Override public void run() {
      listenerLatch.countDown();
    }
  };

  @BeforeExperiment void setUp() throws Exception {
    executorService = new ThreadPoolExecutor(NUM_THREADS,
        NUM_THREADS,
        Long.MAX_VALUE,
        TimeUnit.SECONDS,
        new ArrayBlockingQueue<Runnable>(1000));
    executorService.prestartAllCoreThreads();
    final AtomicInteger integer = new AtomicInteger();
    // Execute a bunch of tasks to ensure that our threads are allocated and hot
    for (int i = 0; i < NUM_THREADS * 10; i++) {
      executorService.submit(new Runnable() {
        @Override public void run() {
          integer.getAndIncrement();
        }
      });
    }
  }

  @AfterExperiment void tearDown() throws Exception {
    executorService.shutdown();
  }

  @Footprint(exclude = {Runnable.class, Executor.class})
  public Object measureSize() {
    list = impl.newExecutionList();
    for (int i = 0; i < numListeners; i++) {
      list.add(listener, directExecutor());
    }
    return list.getImpl();
  }

  @Benchmark int addThenExecute_singleThreaded(int reps) {
    int returnValue = 0;
    for (int i = 0; i < reps; i++) {
      list = impl.newExecutionList();
      listenerLatch = new CountDownLatch(numListeners);
      for (int j = 0; j < numListeners; j++) {
        list.add(listener, directExecutor());
        returnValue += listenerLatch.getCount();
      }
      list.execute();
      returnValue += listenerLatch.getCount();
    }
    return returnValue;
  }

  @Benchmark int executeThenAdd_singleThreaded(int reps) {
    int returnValue = 0;
    for (int i = 0; i < reps; i++) {
      list = impl.newExecutionList();
      list.execute();
      listenerLatch = new CountDownLatch(numListeners);
      for (int j = 0; j < numListeners; j++) {
        list.add(listener, directExecutor());
        returnValue += listenerLatch.getCount();
      }
      returnValue += listenerLatch.getCount();
    }
    return returnValue;
  }

  private final Runnable executeTask = new Runnable() {
    @Override public void run() {
      list.execute();
    }
  };

  @Benchmark int addThenExecute_multiThreaded(final int reps) throws InterruptedException {
    Runnable addTask = new Runnable() {
      @Override public void run() {
        for (int i = 0; i < numListeners; i++) {
          list.add(listener, directExecutor());
        }
      }
    };
    int returnValue = 0;
    for (int i = 0; i < reps; i++) {
      list = impl.newExecutionList();
      listenerLatch = new CountDownLatch(numListeners * NUM_THREADS);
      for (int j = 0; j < NUM_THREADS; j++) {
        executorService.submit(addTask);
      }
      executorService.submit(executeTask);
      returnValue += (int) listenerLatch.getCount();
      listenerLatch.await();
    }
    return returnValue;
  }

  @Benchmark int executeThenAdd_multiThreaded(final int reps) throws InterruptedException {
    Runnable addTask = new Runnable() {
      @Override public void run() {
        for (int i = 0; i < numListeners; i++) {
          list.add(listener, directExecutor());
        }
      }
    };
    int returnValue = 0;
    for (int i = 0; i < reps; i++) {
      list = impl.newExecutionList();
      listenerLatch = new CountDownLatch(numListeners * NUM_THREADS);
      executorService.submit(executeTask);
      for (int j = 0; j < NUM_THREADS; j++) {
        executorService.submit(addTask);
      }
      returnValue += (int) listenerLatch.getCount();
      listenerLatch.await();
    }
    return returnValue;
  }

  // This is the old implementation of ExecutionList using a LinkedList.
  private static final class OldExecutionList {
    static final Logger log = Logger.getLogger(OldExecutionList.class.getName());
    final Queue<OldExecutionList.RunnableExecutorPair> runnables = Lists.newLinkedList();
    boolean executed = false;

    public void add(Runnable runnable, Executor executor) {
      Preconditions.checkNotNull(runnable, "Runnable was null.");
      Preconditions.checkNotNull(executor, "Executor was null.");

      boolean executeImmediate = false;

      synchronized (runnables) {
        if (!executed) {
          runnables.add(new RunnableExecutorPair(runnable, executor));
        } else {
          executeImmediate = true;
        }
      }

      if (executeImmediate) {
        new RunnableExecutorPair(runnable, executor).execute();
      }
    }

    public void execute() {
      synchronized (runnables) {
        if (executed) {
          return;
        }
        executed = true;
      }

      while (!runnables.isEmpty()) {
        runnables.poll().execute();
      }
    }

    private static class RunnableExecutorPair {
      final Runnable runnable;
      final Executor executor;

      RunnableExecutorPair(Runnable runnable, Executor executor) {
        this.runnable = runnable;
        this.executor = executor;
      }

      void execute() {
        try {
          executor.execute(runnable);
        } catch (RuntimeException e) {
          log.log(Level.SEVERE, "RuntimeException while executing runnable "
              + runnable + " with executor " + executor, e);
        }
      }
    }
  }

  // A version of the execution list that doesn't reverse the stack in execute().
  private static final class NewExecutionListWithoutReverse {
    static final Logger log = Logger.getLogger(NewExecutionListWithoutReverse.class.getName());

    @GuardedBy("this")
    private RunnableExecutorPair runnables;
    @GuardedBy("this")
    private boolean executed;

    public void add(Runnable runnable, Executor executor) {
      Preconditions.checkNotNull(runnable, "Runnable was null.");
      Preconditions.checkNotNull(executor, "Executor was null.");

      synchronized (this) {
        if (!executed) {
          runnables = new RunnableExecutorPair(runnable, executor, runnables);
          return;
        }
      }
      executeListener(runnable, executor);
    }

    public void execute() {
      RunnableExecutorPair list;
      synchronized (this) {
        if (executed) {
          return;
        }
        executed = true;
        list = runnables;
        runnables = null;  // allow GC to free listeners even if this stays around for a while.
      }
      while (list != null) {
        executeListener(list.runnable, list.executor);
        list = list.next;
      }
    }

    private static void executeListener(Runnable runnable, Executor executor) {
      try {
        executor.execute(runnable);
      } catch (RuntimeException e) {
        log.log(Level.SEVERE, "RuntimeException while executing runnable "
            + runnable + " with executor " + executor, e);
      }
    }

    private static final class RunnableExecutorPair {
      final Runnable runnable;
      final Executor executor;
      @Nullable RunnableExecutorPair next;

      RunnableExecutorPair(Runnable runnable, Executor executor, RunnableExecutorPair next) {
        this.runnable = runnable;
        this.executor = executor;
        this.next = next;
      }
    }
  }

  // A version of the ExecutionList that uses an explicit tail pointer to keep the nodes in order
  // rather than flipping the stack in execute().
  private static final class NewExecutionListQueue {
    static final Logger log = Logger.getLogger(NewExecutionListQueue.class.getName());

    @GuardedBy("this")
    private RunnableExecutorPair head;
    @GuardedBy("this")
    private RunnableExecutorPair tail;
    @GuardedBy("this")
    private boolean executed;

    public void add(Runnable runnable, Executor executor) {
      Preconditions.checkNotNull(runnable, "Runnable was null.");
      Preconditions.checkNotNull(executor, "Executor was null.");

      synchronized (this) {
        if (!executed) {
          RunnableExecutorPair newTail = new RunnableExecutorPair(runnable, executor);
          if (head == null) {
            head = newTail;
            tail = newTail;
          } else {
            tail.next = newTail;
            tail = newTail;
          }
          return;
        }
      }
      executeListener(runnable, executor);
    }

    public void execute() {
      RunnableExecutorPair list;
      synchronized (this) {
        if (executed) {
          return;
        }
        executed = true;
        list = head;
        head = null;  // allow GC to free listeners even if this stays around for a while.
        tail = null;
      }
      while (list != null) {
        executeListener(list.runnable, list.executor);
        list = list.next;
      }
    }

    private static void executeListener(Runnable runnable, Executor executor) {
      try {
        executor.execute(runnable);
      } catch (RuntimeException e) {
        log.log(Level.SEVERE, "RuntimeException while executing runnable "
            + runnable + " with executor " + executor, e);
      }
    }

    private static final class RunnableExecutorPair {
      Runnable runnable;
      Executor executor;
      @Nullable RunnableExecutorPair next;

      RunnableExecutorPair(Runnable runnable, Executor executor) {
        this.runnable = runnable;
        this.executor = executor;
      }
    }
  }

  // A version of the list that uses compare and swap to manage the stack without locks.
  private static final class ExecutionListCAS {
    static final Logger log = Logger.getLogger(ExecutionListCAS.class.getName());

    private static final sun.misc.Unsafe UNSAFE;
    private static final long HEAD_OFFSET;

    /**
     * A special instance of {@link RunnableExecutorPair} that is used as a sentinel value for the
     * bottom of the stack.
     */
    private static final RunnableExecutorPair NULL_PAIR = new RunnableExecutorPair(null, null);

    static {
      try {
        UNSAFE = getUnsafe();
        HEAD_OFFSET = UNSAFE.objectFieldOffset(ExecutionListCAS.class.getDeclaredField("head"));
      } catch (Exception ex) {
        throw new Error(ex);
      }
    }

    /**
     * TODO(lukes):  This was copied verbatim from Striped64.java... standardize this?
     */
    private static sun.misc.Unsafe getUnsafe() {
        try {
            return sun.misc.Unsafe.getUnsafe();
        } catch (SecurityException tryReflectionInstead) {}
        try {
            return java.security.AccessController.doPrivileged
            (new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
                @Override public sun.misc.Unsafe run() throws Exception {
                    Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
                    for (java.lang.reflect.Field f : k.getDeclaredFields()) {
                        f.setAccessible(true);
                        Object x = f.get(null);
                        if (k.isInstance(x))
                            return k.cast(x);
                    }
                    throw new NoSuchFieldError("the Unsafe");
                }});
        } catch (java.security.PrivilegedActionException e) {
            throw new RuntimeException("Could not initialize intrinsics",
                                       e.getCause());
        }
    }
    private volatile RunnableExecutorPair head = NULL_PAIR;

    public void add(Runnable runnable, Executor executor) {
      Preconditions.checkNotNull(runnable, "Runnable was null.");
      Preconditions.checkNotNull(executor, "Executor was null.");

      RunnableExecutorPair newHead = new RunnableExecutorPair(runnable, executor);
      RunnableExecutorPair oldHead;
      do {
        oldHead = head;
        if (oldHead == null) {
          // If runnables == null then execute() has been called so we should just execute our
          // listener immediately.
          newHead.execute();
          return;
        }
        // Try to make newHead the new head of the stack at runnables.
        newHead.next = oldHead;
      } while (!UNSAFE.compareAndSwapObject(this, HEAD_OFFSET, oldHead, newHead));
    }

    public void execute() {
      RunnableExecutorPair stack;
      do {
        stack = head;
        if (stack == null) {
          // If head == null then execute() has been called so we should just return
          return;
        }
        // try to swap null into head.
      } while (!UNSAFE.compareAndSwapObject(this, HEAD_OFFSET, stack, null));

      RunnableExecutorPair reversedStack = null;
      while (stack != NULL_PAIR) {
        RunnableExecutorPair head = stack;
        stack = stack.next;
        head.next = reversedStack;
        reversedStack = head;
      }
      stack = reversedStack;
      while (stack != null) {
        stack.execute();
        stack = stack.next;
      }
    }

    private static class RunnableExecutorPair {
      final Runnable runnable;
      final Executor executor;
      // Volatile because this is written on one thread and read on another with no synchronization.
      @Nullable volatile RunnableExecutorPair next;

      RunnableExecutorPair(Runnable runnable, Executor executor) {
        this.runnable = runnable;
        this.executor = executor;
      }

      void execute() {
        try {
          executor.execute(runnable);
        } catch (RuntimeException e) {
          log.log(Level.SEVERE, "RuntimeException while executing runnable "
              + runnable + " with executor " + executor, e);
        }
      }
    }
  }
}




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