| /* |
| * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| |
| |
| /* |
| * @test |
| * @key stress gc |
| * |
| * @summary converted from VM Testbase gc/hashcode/ExternalHashingTest. |
| * VM Testbase keywords: [gc, stress, stressopt, nonconcurrent, jrockit] |
| * VM Testbase readme: |
| * DESCRIPTION |
| * Test the possible interaction of external hashing and locking on object |
| * headers. |
| * The approach is to nearly simultaneously lock/hash a relatively small group |
| * of objects. We do this repeatedly (munging), recording all hash values |
| * collected therein. |
| * After doing this for a large number of groups, we force a garbage collection, |
| * which would change the hashCode of an object if it hasn't previously been |
| * hashed. In our case, we _know_ what the previous hashcode was, so we can |
| * recalculate all of their hashes and compare with the original value. |
| * If any of the hashCodes hash changed, we know we have a problem. |
| * |
| * COMMENTS |
| * This test was ported from JRockit test suite. |
| * |
| * @library /vmTestbase |
| * /test/lib |
| * @run driver jdk.test.lib.FileInstaller . . |
| * @run main/othervm -XX:-UseGCOverheadLimit gc.hashcode.ExternalHashingTest.ExternalHashingTest |
| */ |
| |
| package gc.hashcode.ExternalHashingTest; |
| |
| import java.text.SimpleDateFormat; |
| import java.util.Date; |
| import java.util.Random; |
| import java.util.Vector; |
| |
| /** |
| * Test the possible interaction of external hashing and locking on object |
| * headers. |
| * |
| * The approach is to nearly simultaneously lock/hash a relatively small group |
| * of objects. We do this repeatedly (munging), recording all hash values |
| * collected therein. |
| * |
| * After doing this for a large number of groups, we force a garbage collection, |
| * which would change the hashCode of an object if it hasn't previously been |
| * hashed. In our case, we _know_ what the previous hashcode was, so we can |
| * recalculate all of their hashes and compare with the original value. |
| * |
| * If any of the hashCodes hash changed, we know we have a problem. |
| */ |
| |
| public final class ExternalHashingTest { |
| |
| /** Random number generator. */ |
| static Random rand = new Random(); |
| |
| /** Goes to true when the threads should start working. */ |
| public static volatile boolean startingGun; |
| |
| /** Goes to true when the hashing thread is done. */ |
| public static volatile boolean finishHashing; |
| |
| /** Goes to true when the locking thread is done. */ |
| public static volatile boolean finishLocking; |
| |
| /** The number of objects in each batch. */ |
| private static final int BATCH_SIZE = 20; |
| |
| /** This is the global list of objects that have been hashed. */ |
| static Vector allObjects = new Vector(); |
| |
| /** This is the corresponding list of hashCodes collected. */ |
| static Vector allHashes = new Vector(); |
| |
| /** The default milliseconds to run the program. */ |
| private static final long DEFAULT_DURATION = 10000; |
| |
| /** All static */ |
| private ExternalHashingTest() {} |
| |
| /** |
| * This object holds garbage. It is a (probably unnecessary){ embellishment |
| * to increase the amount of garbage created by this benchmark. |
| * <p> |
| * It is global to discourage optimizer from removing it. |
| */ |
| public static Object[] garbageMonger; |
| |
| /** |
| * We need a fairly short pause, since we're not using a semaphore to |
| * synchronize threads. |
| */ |
| public static void pause() { |
| try { |
| // Thread.sleep(100); |
| Thread.yield(); |
| } catch (Exception e) { |
| e.printStackTrace(); |
| System.exit(1); |
| } |
| } |
| |
| /** |
| * Returns System.currentTimeMillis() in the Date format. |
| * @return String |
| */ |
| private static String getDateString() { |
| SimpleDateFormat df = new SimpleDateFormat("MMM dd, yyyy HH:mm:ss z"); |
| Date date = new Date(); |
| date.setTime(System.currentTimeMillis()); |
| return df.format(date); |
| } |
| |
| /** |
| * Main driver. |
| * @param args command line arguments aren't used. |
| */ |
| public static void main(String[] args) { |
| |
| long timeToRun = DEFAULT_DURATION;; |
| |
| try { |
| for (int i = 0; i < args.length; i++) { |
| if ("-stressTime".equals(args[i])) { |
| if (i + 1 == args.length) { |
| throw new RuntimeException("Test bug: value of -stressTime option absents"); |
| } |
| timeToRun = Long.parseLong(args[i + 1]); |
| if (timeToRun <= 0) { |
| throw new RuntimeException("Test bug: value of -stressTime option is not a positive number"); |
| } |
| break; |
| } |
| } |
| } catch (NumberFormatException e) { |
| throw new RuntimeException("Test bug: Exception occured while parsing -stressTime option's value", e); |
| } |
| |
| long startTime = System.currentTimeMillis(); |
| |
| System.out.println("[" + getDateString() + "] Test duration is: " + timeToRun + " ms"); |
| System.out.println("[" + getDateString() + "] Do munge objects..."); |
| while ((System.currentTimeMillis() - startTime) < timeToRun) { |
| for (int i = 0; i < 100; i++) { |
| mungeObjects(); |
| } |
| System.out.println("[" + getDateString() + "] The next 100 objects are munged..."); |
| } |
| |
| // Force a GC (so that objects move their position) |
| System.out.println("[" + getDateString() + "] Force a GC..."); |
| garbageMonger = null; |
| System.gc(); |
| |
| // Now, to check to see if hashes are correct |
| System.out.println("[" + getDateString() + "] Check hash codes..."); |
| for (int i = 0; i < allObjects.size(); i++) { |
| Object o = allObjects.elementAt(i); |
| int hash = ((Integer) allHashes.elementAt(i)).intValue(); |
| |
| if (o.hashCode() != hash) { |
| System.out.println("Inconsistent hash code found (Object " |
| + i + " out of " + allObjects.size()); |
| System.out.println("Object = " + o.toString() + "; hashCode = 0x" |
| + Integer.toHexString(o.hashCode()) |
| + "; expected = 0x" + Integer.toHexString(hash)); |
| System.exit(1); |
| } |
| } |
| |
| System.exit(95 /* PASSED */); |
| } |
| |
| /** |
| * Add a single batch of objects to the mix. |
| * <p> |
| * It prepares a list of candidate objects, and presents them to a |
| * LockerThread and a HasherThread in randomized orders. |
| * <p> |
| * The two threads are launched, and control is returned to the caller after |
| * they have finished their processing. |
| */ |
| private static void mungeObjects() { |
| |
| startingGun = false; |
| finishHashing = false; |
| finishLocking = false; |
| |
| /* Create the list of victims. */ |
| Object[] candidates = new Object[BATCH_SIZE]; |
| for (int i = 0; i < candidates.length; i++) { |
| candidates[i] = new Object(); |
| } |
| |
| Object[] lockedList = randomize(candidates); |
| Object[] hashedList = randomize(candidates); |
| int[] foundHashes = new int[BATCH_SIZE]; |
| |
| // Launch the child threads |
| LockerThread locker = new LockerThread(lockedList); |
| Thread lockerThread = new Thread(locker); |
| Thread hasherThread = new Thread(new HasherThread(hashedList, |
| foundHashes)); |
| lockerThread.start(); |
| hasherThread.start(); |
| startingGun = true; |
| |
| while (!finishLocking || !finishHashing) { |
| pause(); |
| } |
| |
| garbageMonger = new Object[BATCH_SIZE]; |
| for (int i = 0; i < BATCH_SIZE; i++) { |
| /* Add all of the results of this pass to the global list. */ |
| allObjects.add(hashedList[i]); |
| allHashes.add(new Integer(foundHashes[i])); |
| |
| /* Create even more garbage for the GC to find */ |
| garbageMonger[i] = new Object(); |
| } |
| |
| // just some noise to make sure that do-nothing code is not optimized |
| // away. |
| if (locker.getCount() != BATCH_SIZE) { |
| throw new InternalError("should not get here"); |
| } |
| } |
| |
| /** |
| * Return the list of objects in random order |
| */ |
| private static Object[] randomize(Object[] list) { |
| |
| Vector v = new Vector(); |
| for (int i = 0; i < list.length; i++) { |
| v.add(list[i]); |
| } |
| |
| Object[] result = new Object[list.length]; |
| for (int i = 0; i < list.length; i++) { |
| int pos = rand.nextInt(list.length - i); |
| result[i] = v.remove(pos); |
| } |
| return result; |
| } |
| } |
| |
| /** |
| * This helper thread locks all objects in a list in a given order before |
| * returning. |
| */ |
| |
| class LockerThread implements Runnable { |
| |
| /** The list of objects to be locked. */ |
| Object[] theList; |
| |
| /** |
| * This junk counter is an attempt to cause the contents of the synchronized |
| * block not to be completely optimized away. |
| */ |
| int count; |
| |
| /** |
| * Construct a LockerThread and provide a list of objects to work with. |
| * @param list the objects to lock. |
| */ |
| LockerThread(Object[] list) { |
| theList = list; |
| count = 0; |
| } |
| |
| /** |
| * Proceed to lock the objects... |
| */ |
| public void run() { |
| // Synchronize. Wait for caller to say all is go. |
| while (!ExternalHashingTest.startingGun) { |
| ExternalHashingTest.pause(); |
| } |
| |
| // Perform the locking |
| for (int i = 0; i < theList.length; i++) { |
| synchronized (theList[i]) { |
| count++; |
| } |
| } |
| |
| // Tell the caller we are done. |
| ExternalHashingTest.finishLocking = true; |
| } |
| |
| /** |
| * Discourage compiler from removing do-nothing count field. |
| * @return the number of objects locked. |
| */ |
| public int getCount() { |
| return count; |
| } |
| } |
| |
| /** |
| * This helper thread hashes all objects in a list in a given order before |
| * returning. |
| */ |
| |
| class HasherThread implements Runnable { |
| |
| /** The list of objects to be hashed. */ |
| Object[] theList; |
| |
| /** The list of hash codes. */ |
| int[] theHashes; |
| |
| /** |
| * Construct a HasherThread and provide a list of objects to work with. |
| * @param list the objects to hash. |
| * @param hashes for storing the hash values. |
| */ |
| HasherThread(Object[] list, int[] hashes) { |
| theList = list; |
| theHashes = hashes; |
| } |
| |
| /** |
| * Proceed to hash the objects. |
| */ |
| public void run() { |
| // Synchronize. Wait for caller to say all is go. |
| while (!ExternalHashingTest.startingGun) { |
| ExternalHashingTest.pause(); |
| } |
| |
| // Perform the hashing (collect for the caller) |
| for (int i = 0; i < theList.length; i++) { |
| theHashes[i] = theList[i].hashCode(); |
| } |
| // Tell the caller we are done. |
| ExternalHashingTest.finishHashing = true; |
| } |
| } |