branch-2.0.4-alpha/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestMultiThreadedHflush.java - hadoop - Git at Google

 /**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you 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 org.apache.hadoop.hdfs;

 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;

 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.conf.Configured;
 import org.apache.hadoop.fs.CommonConfigurationKeys;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.metrics2.util.Quantile;
 import org.apache.hadoop.metrics2.util.SampleQuantiles;
 import org.apache.hadoop.util.Tool;
 import org.apache.hadoop.util.ToolRunner;
 import org.junit.Test;

 import com.google.common.base.Stopwatch;

 /**
  * This class tests hflushing concurrently from many threads.
  */
 public class TestMultiThreadedHflush {
   static final int blockSize = 1024*1024;

   private static final int NUM_THREADS = 10;
   private static final int WRITE_SIZE = 517;
   private static final int NUM_WRITES_PER_THREAD = 1000;

   private byte[] toWrite = null;

   private final SampleQuantiles quantiles = new SampleQuantiles(
       new Quantile[] {
         new Quantile(0.50, 0.050),
         new Quantile(0.75, 0.025), new Quantile(0.90, 0.010),
         new Quantile(0.95, 0.005), new Quantile(0.99, 0.001) });

   /*
    * creates a file but does not close it
    */
   private FSDataOutputStream createFile(FileSystem fileSys, Path name, int repl)
     throws IOException {
     FSDataOutputStream stm = fileSys.create(name, true, fileSys.getConf()
         .getInt(CommonConfigurationKeys.IO_FILE_BUFFER_SIZE_KEY, 4096),
         (short) repl, blockSize);
     return stm;
   }

   private void initBuffer(int size) {
     long seed = AppendTestUtil.nextLong();
     toWrite = AppendTestUtil.randomBytes(seed, size);
   }

   private class WriterThread extends Thread {
     private final FSDataOutputStream stm;
     private final AtomicReference<Throwable> thrown;
     private final int numWrites;
     private final CountDownLatch countdown;

     public WriterThread(FSDataOutputStream stm,
       AtomicReference<Throwable> thrown,
       CountDownLatch countdown, int numWrites) {
       this.stm = stm;
       this.thrown = thrown;
       this.numWrites = numWrites;
       this.countdown = countdown;
     }

     @Override
     public void run() {
       try {
         countdown.await();
         for (int i = 0; i < numWrites && thrown.get() == null; i++) {
           doAWrite();
         }
       } catch (Throwable t) {
         thrown.compareAndSet(null, t);
       }
     }

     private void doAWrite() throws IOException {
       Stopwatch sw = new Stopwatch().start();
       stm.write(toWrite);
       stm.hflush();
       long micros = sw.elapsedTime(TimeUnit.MICROSECONDS);
       quantiles.insert(micros);
     }
   }


   /**
    * Test case where a bunch of threads are both appending and flushing.
    * They all finish before the file is closed.
    */
   @Test
   public void testMultipleHflushersRepl1() throws Exception {
     doTestMultipleHflushers(1);
   }

   @Test
   public void testMultipleHflushersRepl3() throws Exception {
     doTestMultipleHflushers(3);
   }

   private void doTestMultipleHflushers(int repl) throws Exception {
     Configuration conf = new Configuration();
     MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
         .numDataNodes(repl)
         .build();

     FileSystem fs = cluster.getFileSystem();
     Path p = new Path("/multiple-hflushers.dat");
     try {
       doMultithreadedWrites(conf, p, NUM_THREADS, WRITE_SIZE,
           NUM_WRITES_PER_THREAD, repl);
       System.out.println("Latency quantiles (in microseconds):\n" +
           quantiles);
     } finally {
       fs.close();
       cluster.shutdown();
     }
   }

   /**
    * Test case where a bunch of threads are continuously calling hflush() while another
    * thread appends some data and then closes the file.
    *
    * The hflushing threads should eventually catch an IOException stating that the stream
    * was closed -- and not an NPE or anything like that.
    */
   @Test
   public void testHflushWhileClosing() throws Throwable {
     Configuration conf = new Configuration();
     MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).build();
     FileSystem fs = cluster.getFileSystem();
     Path p = new Path("/hflush-and-close.dat");

     final FSDataOutputStream stm = createFile(fs, p, 1);


     ArrayList<Thread> flushers = new ArrayList<Thread>();
     final AtomicReference<Throwable> thrown = new AtomicReference<Throwable>();
     try {
       for (int i = 0; i < 10; i++) {
         Thread flusher = new Thread() {
             @Override
             public void run() {
               try {
                 while (true) {
                   try {
                     stm.hflush();
                   } catch (IOException ioe) {
                     if (!ioe.toString().contains("DFSOutputStream is closed")) {
                       throw ioe;
                     } else {
                       return;
                     }
                   }
                 }
               } catch (Throwable t) {
                 thrown.set(t);
               }
             }
           };
         flusher.start();
         flushers.add(flusher);
       }

       // Write some data
       for (int i = 0; i < 10000; i++) {
         stm.write(1);
       }

       // Close it while the flushing threads are still flushing
       stm.close();

       // Wait for the flushers to all die.
       for (Thread t : flushers) {
         t.join();
       }

       // They should have all gotten the expected exception, not anything
       // else.
       if (thrown.get() != null) {
         throw thrown.get();
       }

     } finally {
       fs.close();
       cluster.shutdown();
     }
   }

   public void doMultithreadedWrites(
       Configuration conf, Path p, int numThreads, int bufferSize, int numWrites,
       int replication) throws Exception {
     initBuffer(bufferSize);

     // create a new file.
     FileSystem fs = p.getFileSystem(conf);
     FSDataOutputStream stm = createFile(fs, p, replication);
     System.out.println("Created file simpleFlush.dat");

     // There have been a couple issues with flushing empty buffers, so do
     // some empty flushes first.
     stm.hflush();
     stm.hflush();
     stm.write(1);
     stm.hflush();
     stm.hflush();

     CountDownLatch countdown = new CountDownLatch(1);
     ArrayList<Thread> threads = new ArrayList<Thread>();
     AtomicReference<Throwable> thrown = new AtomicReference<Throwable>();
     for (int i = 0; i < numThreads; i++) {
       Thread t = new WriterThread(stm, thrown, countdown, numWrites);
       threads.add(t);
       t.start();
     }

     // Start all the threads at the same time for maximum raciness!
     countdown.countDown();

     for (Thread t : threads) {
       t.join();
     }
     if (thrown.get() != null) {
       throw new RuntimeException("Deferred", thrown.get());
     }
     stm.close();
     System.out.println("Closed file.");
   }

   public static void main(String args[]) throws Exception {
     System.exit(ToolRunner.run(new CLIBenchmark(), args));
   }

   private static class CLIBenchmark extends Configured implements Tool {
     public int run(String args[]) throws Exception {
       if (args.length != 1) {
         System.err.println(
           "usage: " + TestMultiThreadedHflush.class.getSimpleName() +
           " <path to test file> ");
         System.err.println(
             "Configurations settable by -D options:\n" +
             "  num.threads [default 10] - how many threads to run\n" +
             "  write.size [default 511] - bytes per write\n" +
             "  num.writes [default 50000] - how many writes to perform");
         System.exit(1);
       }
       TestMultiThreadedHflush test = new TestMultiThreadedHflush();
       Configuration conf = getConf();
       Path p = new Path(args[0]);

       int numThreads = conf.getInt("num.threads", 10);
       int writeSize = conf.getInt("write.size", 511);
       int numWrites = conf.getInt("num.writes", 50000);
       int replication = conf.getInt(DFSConfigKeys.DFS_REPLICATION_KEY,
           DFSConfigKeys.DFS_REPLICATION_DEFAULT);

       Stopwatch sw = new Stopwatch().start();
       test.doMultithreadedWrites(conf, p, numThreads, writeSize, numWrites,
           replication);
       sw.stop();

       System.out.println("Finished in " + sw.elapsedMillis() + "ms");
       System.out.println("Latency quantiles (in microseconds):\n" +
           test.quantiles);
       return 0;
     }
   }
 }
	/**
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you 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 org.apache.hadoop.hdfs;

	import java.io.IOException;
	import java.util.ArrayList;
	import java.util.concurrent.CountDownLatch;
	import java.util.concurrent.TimeUnit;
	import java.util.concurrent.atomic.AtomicReference;

	import org.apache.hadoop.conf.Configuration;
	import org.apache.hadoop.conf.Configured;
	import org.apache.hadoop.fs.CommonConfigurationKeys;
	import org.apache.hadoop.fs.FSDataOutputStream;
	import org.apache.hadoop.fs.FileSystem;
	import org.apache.hadoop.fs.Path;
	import org.apache.hadoop.metrics2.util.Quantile;
	import org.apache.hadoop.metrics2.util.SampleQuantiles;
	import org.apache.hadoop.util.Tool;
	import org.apache.hadoop.util.ToolRunner;
	import org.junit.Test;

	import com.google.common.base.Stopwatch;

	/**
	* This class tests hflushing concurrently from many threads.
	*/
	public class TestMultiThreadedHflush {
	static final int blockSize = 1024*1024;

	private static final int NUM_THREADS = 10;
	private static final int WRITE_SIZE = 517;
	private static final int NUM_WRITES_PER_THREAD = 1000;

	private byte[] toWrite = null;

	private final SampleQuantiles quantiles = new SampleQuantiles(
	new Quantile[] {
	new Quantile(0.50, 0.050),
	new Quantile(0.75, 0.025), new Quantile(0.90, 0.010),
	new Quantile(0.95, 0.005), new Quantile(0.99, 0.001) });

	/*
	* creates a file but does not close it
	*/
	private FSDataOutputStream createFile(FileSystem fileSys, Path name, int repl)
	throws IOException {
	FSDataOutputStream stm = fileSys.create(name, true, fileSys.getConf()
	.getInt(CommonConfigurationKeys.IO_FILE_BUFFER_SIZE_KEY, 4096),
	(short) repl, blockSize);
	return stm;
	}

	private void initBuffer(int size) {
	long seed = AppendTestUtil.nextLong();
	toWrite = AppendTestUtil.randomBytes(seed, size);
	}

	private class WriterThread extends Thread {
	private final FSDataOutputStream stm;
	private final AtomicReference<Throwable> thrown;
	private final int numWrites;
	private final CountDownLatch countdown;

	public WriterThread(FSDataOutputStream stm,
	AtomicReference<Throwable> thrown,
	CountDownLatch countdown, int numWrites) {
	this.stm = stm;
	this.thrown = thrown;
	this.numWrites = numWrites;
	this.countdown = countdown;
	}

	@Override
	public void run() {
	try {
	countdown.await();
	for (int i = 0; i < numWrites && thrown.get() == null; i++) {
	doAWrite();
	}
	} catch (Throwable t) {
	thrown.compareAndSet(null, t);
	}
	}

	private void doAWrite() throws IOException {
	Stopwatch sw = new Stopwatch().start();
	stm.write(toWrite);
	stm.hflush();
	long micros = sw.elapsedTime(TimeUnit.MICROSECONDS);
	quantiles.insert(micros);
	}
	}


	/**
	* Test case where a bunch of threads are both appending and flushing.
	* They all finish before the file is closed.
	*/
	@Test
	public void testMultipleHflushersRepl1() throws Exception {
	doTestMultipleHflushers(1);
	}

	@Test
	public void testMultipleHflushersRepl3() throws Exception {
	doTestMultipleHflushers(3);
	}

	private void doTestMultipleHflushers(int repl) throws Exception {
	Configuration conf = new Configuration();
	MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
	.numDataNodes(repl)
	.build();

	FileSystem fs = cluster.getFileSystem();
	Path p = new Path("/multiple-hflushers.dat");
	try {
	doMultithreadedWrites(conf, p, NUM_THREADS, WRITE_SIZE,
	NUM_WRITES_PER_THREAD, repl);
	System.out.println("Latency quantiles (in microseconds):\n" +
	quantiles);
	} finally {
	fs.close();
	cluster.shutdown();
	}
	}

	/**
	* Test case where a bunch of threads are continuously calling hflush() while another
	* thread appends some data and then closes the file.
	*
	* The hflushing threads should eventually catch an IOException stating that the stream
	* was closed -- and not an NPE or anything like that.
	*/
	@Test
	public void testHflushWhileClosing() throws Throwable {
	Configuration conf = new Configuration();
	MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).build();
	FileSystem fs = cluster.getFileSystem();
	Path p = new Path("/hflush-and-close.dat");

	final FSDataOutputStream stm = createFile(fs, p, 1);


	ArrayList<Thread> flushers = new ArrayList<Thread>();
	final AtomicReference<Throwable> thrown = new AtomicReference<Throwable>();
	try {
	for (int i = 0; i < 10; i++) {
	Thread flusher = new Thread() {
	@Override
	public void run() {
	try {
	while (true) {
	try {
	stm.hflush();
	} catch (IOException ioe) {
	if (!ioe.toString().contains("DFSOutputStream is closed")) {
	throw ioe;
	} else {
	return;
	}
	}
	}
	} catch (Throwable t) {
	thrown.set(t);
	}
	}
	};
	flusher.start();
	flushers.add(flusher);
	}

	// Write some data
	for (int i = 0; i < 10000; i++) {
	stm.write(1);
	}

	// Close it while the flushing threads are still flushing
	stm.close();

	// Wait for the flushers to all die.
	for (Thread t : flushers) {
	t.join();
	}

	// They should have all gotten the expected exception, not anything
	// else.
	if (thrown.get() != null) {
	throw thrown.get();
	}

	} finally {
	fs.close();
	cluster.shutdown();
	}
	}

	public void doMultithreadedWrites(
	Configuration conf, Path p, int numThreads, int bufferSize, int numWrites,
	int replication) throws Exception {
	initBuffer(bufferSize);

	// create a new file.
	FileSystem fs = p.getFileSystem(conf);
	FSDataOutputStream stm = createFile(fs, p, replication);
	System.out.println("Created file simpleFlush.dat");

	// There have been a couple issues with flushing empty buffers, so do
	// some empty flushes first.
	stm.hflush();
	stm.hflush();
	stm.write(1);
	stm.hflush();
	stm.hflush();

	CountDownLatch countdown = new CountDownLatch(1);
	ArrayList<Thread> threads = new ArrayList<Thread>();
	AtomicReference<Throwable> thrown = new AtomicReference<Throwable>();
	for (int i = 0; i < numThreads; i++) {
	Thread t = new WriterThread(stm, thrown, countdown, numWrites);
	threads.add(t);
	t.start();
	}

	// Start all the threads at the same time for maximum raciness!
	countdown.countDown();

	for (Thread t : threads) {
	t.join();
	}
	if (thrown.get() != null) {
	throw new RuntimeException("Deferred", thrown.get());
	}
	stm.close();
	System.out.println("Closed file.");
	}

	public static void main(String args[]) throws Exception {
	System.exit(ToolRunner.run(new CLIBenchmark(), args));
	}

	private static class CLIBenchmark extends Configured implements Tool {
	public int run(String args[]) throws Exception {
	if (args.length != 1) {
	System.err.println(
	"usage: " + TestMultiThreadedHflush.class.getSimpleName() +
	" <path to test file> ");
	System.err.println(
	"Configurations settable by -D options:\n" +
	" num.threads [default 10] - how many threads to run\n" +
	" write.size [default 511] - bytes per write\n" +
	" num.writes [default 50000] - how many writes to perform");
	System.exit(1);
	}
	TestMultiThreadedHflush test = new TestMultiThreadedHflush();
	Configuration conf = getConf();
	Path p = new Path(args[0]);

	int numThreads = conf.getInt("num.threads", 10);
	int writeSize = conf.getInt("write.size", 511);
	int numWrites = conf.getInt("num.writes", 50000);
	int replication = conf.getInt(DFSConfigKeys.DFS_REPLICATION_KEY,
	DFSConfigKeys.DFS_REPLICATION_DEFAULT);

	Stopwatch sw = new Stopwatch().start();
	test.doMultithreadedWrites(conf, p, numThreads, writeSize, numWrites,
	replication);
	sw.stop();

	System.out.println("Finished in " + sw.elapsedMillis() + "ms");
	System.out.println("Latency quantiles (in microseconds):\n" +
	test.quantiles);
	return 0;
	}
	}
	}