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test/jdk/java/util/Collection/IteratorMicroBenchmark.java

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8200258: Improve CopyOnWriteArrayList subList code
Reviewed-by: martin, psandoz, smarks


  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /*
  25  * @test
  26  * @summary micro-benchmark correctness mode
  27  * @run main IteratorMicroBenchmark iterations=1 size=8 warmup=0
  28  */
  29 
  30 import static java.util.stream.Collectors.summingInt;
  31 import static java.util.stream.Collectors.toCollection;
  32 
  33 import java.lang.ref.WeakReference;
  34 import java.util.ArrayDeque;
  35 import java.util.ArrayList;
  36 import java.util.Collection;
  37 import java.util.Collections;
  38 import java.util.Deque;

  39 import java.util.Iterator;
  40 import java.util.LinkedList;
  41 import java.util.List;
  42 import java.util.ListIterator;
  43 import java.util.PriorityQueue;
  44 import java.util.Spliterator;
  45 import java.util.Vector;
  46 import java.util.concurrent.ArrayBlockingQueue;
  47 import java.util.concurrent.ConcurrentLinkedDeque;
  48 import java.util.concurrent.ConcurrentLinkedQueue;
  49 import java.util.concurrent.CopyOnWriteArrayList;
  50 import java.util.concurrent.LinkedBlockingDeque;
  51 import java.util.concurrent.LinkedBlockingQueue;
  52 import java.util.concurrent.LinkedTransferQueue;
  53 import java.util.concurrent.PriorityBlockingQueue;
  54 import java.util.concurrent.CountDownLatch;
  55 import java.util.concurrent.ThreadLocalRandom;
  56 import java.util.concurrent.TimeUnit;
  57 import java.util.concurrent.atomic.LongAdder;

  58 import java.util.regex.Pattern;
  59 import java.util.stream.Stream;
  60 
  61 /**
  62  * Usage: [iterations=N] [size=N] [filter=REGEXP] [warmup=SECONDS]
  63  *
  64  * To run this in micro-benchmark mode, simply run as a normal java program.
  65  * Be patient; this program runs for a very long time.
  66  * For faster runs, restrict execution using command line args.
  67  *
  68  * This is an interface based version of ArrayList/IteratorMicroBenchmark
  69  *
  70  * @author Martin Buchholz
  71  */
  72 public class IteratorMicroBenchmark {
  73     abstract static class Job {
  74         private final String name;
  75         public Job(String name) { this.name = name; }
  76         public String name() { return name; }
  77         public abstract void work() throws Throwable;







  78     }
  79 
  80     final int iterations;
  81     final int size;             // number of elements in collections
  82     final double warmupSeconds;
  83     final long warmupNanos;
  84     final Pattern nameFilter;   // select subset of Jobs to run
  85     final boolean reverse;      // reverse order of Jobs
  86     final boolean shuffle;      // randomize order of Jobs
  87 
  88     IteratorMicroBenchmark(String[] args) {
  89         iterations    = intArg(args, "iterations", 10_000);
  90         size          = intArg(args, "size", 1000);
  91         warmupSeconds = doubleArg(args, "warmup", 7.0);
  92         nameFilter    = patternArg(args, "filter");
  93         reverse       = booleanArg(args, "reverse");
  94         shuffle       = booleanArg(args, "shuffle");
  95 
  96         warmupNanos = (long) (warmupSeconds * (1000L * 1000L * 1000L));
  97     }
  98 
  99     // --------------- GC finalization infrastructure ---------------
 100 
 101     /** No guarantees, but effective in practice. */
 102     static void forceFullGc() {
 103         CountDownLatch finalizeDone = new CountDownLatch(1);
 104         WeakReference<?> ref = new WeakReference<Object>(new Object() {

 105             protected void finalize() { finalizeDone.countDown(); }});
 106         try {
 107             for (int i = 0; i < 10; i++) {
 108                 System.gc();
 109                 if (finalizeDone.await(1L, TimeUnit.SECONDS) && ref.get() == null) {
 110                     System.runFinalization(); // try to pick up stragglers
 111                     return;
 112                 }
 113             }
 114         } catch (InterruptedException unexpected) {
 115             throw new AssertionError("unexpected InterruptedException");
 116         }
 117         throw new AssertionError("failed to do a \"full\" gc");
 118     }
 119 
 120     /**
 121      * Runs each job for long enough that all the runtime compilers
 122      * have had plenty of time to warm up, i.e. get around to
 123      * compiling everything worth compiling.
 124      * Returns array of average times per job per run.
 125      */
 126     long[] time0(List<Job> jobs) throws Throwable {
 127         final int size = jobs.size();
 128         long[] nanoss = new long[size];
 129         for (int i = 0; i < size; i++) {
 130             if (warmupNanos > 0) forceFullGc();
 131             Job job = jobs.get(i);
 132             long totalTime;
 133             int runs = 0;
 134             long startTime = System.nanoTime();
 135             do { job.work(); runs++; }
 136             while ((totalTime = System.nanoTime() - startTime) < warmupNanos);
 137             nanoss[i] = totalTime/runs;
 138         }
 139         return nanoss;
 140     }
 141 
 142     void time(List<Job> jobs) throws Throwable {
 143         if (warmupNanos > 0) time0(jobs); // Warm up run
 144         final int size = jobs.size();
 145         final long[] nanoss = time0(jobs); // Real timing run
 146         final long[] milliss = new long[size];
 147         final double[] ratios = new double[size];
 148 
 149         final String nameHeader   = "Method";
 150         final String millisHeader = "Millis";
 151         final String ratioHeader  = "Ratio";
 152 
 153         int nameWidth   = nameHeader.length();
 154         int millisWidth = millisHeader.length();
 155         int ratioWidth  = ratioHeader.length();


 194         return (val == null) ? defaultValue : Double.parseDouble(val);
 195     }
 196 
 197     private static Pattern patternArg(String[] args, String keyword) {
 198         String val = keywordValue(args, keyword);
 199         return (val == null) ? null : Pattern.compile(val);
 200     }
 201 
 202     private static boolean booleanArg(String[] args, String keyword) {
 203         String val = keywordValue(args, keyword);
 204         if (val == null || val.equals("false")) return false;
 205         if (val.equals("true")) return true;
 206         throw new IllegalArgumentException(val);
 207     }
 208 
 209     private static void deoptimize(int sum) {
 210         if (sum == 42)
 211             System.out.println("the answer");
 212     }
 213 
 214     private static <T> List<T> asSubList(List<T> list) {
 215         return list.subList(0, list.size());
 216     }
 217 
 218     private static <T> Iterable<T> backwards(final List<T> list) {
 219         return new Iterable<T>() {
 220             public Iterator<T> iterator() {
 221                 return new Iterator<T>() {
 222                     final ListIterator<T> it = list.listIterator(list.size());
 223                     public boolean hasNext() { return it.hasPrevious(); }
 224                     public T next()          { return it.previous(); }
 225                     public void remove()     {        it.remove(); }};}};
 226     }
 227 
 228     // Checks for correctness *and* prevents loop optimizations
 229     static class Check {
 230         private int sum;
 231         public void sum(int sum) {
 232             if (this.sum == 0)
 233                 this.sum = sum;
 234             if (this.sum != sum)
 235                 throw new AssertionError("Sum mismatch");
 236         }
 237     }
 238     volatile Check check = new Check();
 239 
 240     public static void main(String[] args) throws Throwable {
 241         new IteratorMicroBenchmark(args).run();
 242     }
 243 
 244     void run() throws Throwable {
 245 //         System.out.printf(
 246 //             "iterations=%d size=%d, warmup=%1g, filter=\"%s\"%n",
 247 //             iterations, size, warmupSeconds, nameFilter);




















 248 

 249         final ArrayList<Integer> al = new ArrayList<>(size);
 250 
 251         // Populate collections with random data
 252         final ThreadLocalRandom rnd = ThreadLocalRandom.current();
 253         for (int i = 0; i < size; i++)
 254             al.add(rnd.nextInt(size));
 255 
 256         final ArrayDeque<Integer> ad = new ArrayDeque<>(al);
 257         final ArrayBlockingQueue<Integer> abq = new ArrayBlockingQueue<>(al.size());
 258         abq.addAll(al);
 259 
 260         // shuffle circular array elements so they wrap
 261         for (int i = 0, n = rnd.nextInt(size); i < n; i++) {
 262             ad.addLast(ad.removeFirst());
 263             abq.add(abq.remove());
 264         }
 265 
 266         ArrayList<Job> jobs = Stream.<Collection<Integer>>of(
 267                 al, ad, abq,

 268                 new LinkedList<>(al),

 269                 new PriorityQueue<>(al),
 270                 new Vector<>(al),

 271                 new CopyOnWriteArrayList<>(al),

 272                 new ConcurrentLinkedQueue<>(al),
 273                 new ConcurrentLinkedDeque<>(al),
 274                 new LinkedBlockingQueue<>(al),
 275                 new LinkedBlockingDeque<>(al),
 276                 new LinkedTransferQueue<>(al),
 277                 new PriorityBlockingQueue<>(al))
 278             .flatMap(x -> jobs(x))
 279             .filter(job ->
 280                 nameFilter == null || nameFilter.matcher(job.name()).find())
 281             .collect(toCollection(ArrayList::new));
 282 
 283         if (reverse) Collections.reverse(jobs);
 284         if (shuffle) Collections.shuffle(jobs);
 285 
 286         time(jobs);
 287     }
 288 
 289     @SafeVarargs @SuppressWarnings("varargs")
 290     private <T> Stream<T> concatStreams(Stream<T> ... streams) {
 291         return Stream.of(streams).flatMap(s -> s);
 292     }
 293 
 294     Stream<Job> jobs(Collection<Integer> x) {
 295         return concatStreams(
 296             collectionJobs(x),

 297             (x instanceof Deque)
 298             ? dequeJobs((Deque<Integer>)x)
 299             : Stream.empty(),

 300             (x instanceof List)
 301             ? listJobs((List<Integer>)x)
 302             : Stream.empty());
 303     }
 304 







 305     Stream<Job> collectionJobs(Collection<Integer> x) {
 306         String klazz = x.getClass().getSimpleName();
 307         return Stream.of(
 308             new Job(klazz + " iterate for loop") {
 309                 public void work() throws Throwable {
 310                     for (int i = 0; i < iterations; i++) {
 311                         int sum = 0;
 312                         for (Integer n : x)
 313                             sum += n;
 314                         check.sum(sum);}}},
 315             new Job(klazz + " iterator().forEachRemaining()") {
 316                 public void work() throws Throwable {
 317                     int[] sum = new int[1];
 318                     for (int i = 0; i < iterations; i++) {
 319                         sum[0] = 0;
 320                         x.iterator().forEachRemaining(n -> sum[0] += n);
 321                         check.sum(sum[0]);}}},
 322             new Job(klazz + " spliterator().tryAdvance()") {
 323                 public void work() throws Throwable {
 324                     int[] sum = new int[1];
 325                     for (int i = 0; i < iterations; i++) {
 326                         sum[0] = 0;


 328                         do {} while (spliterator.tryAdvance(n -> sum[0] += n));
 329                         check.sum(sum[0]);}}},
 330             new Job(klazz + " spliterator().forEachRemaining()") {
 331                 public void work() throws Throwable {
 332                     int[] sum = new int[1];
 333                     for (int i = 0; i < iterations; i++) {
 334                         sum[0] = 0;
 335                         x.spliterator().forEachRemaining(n -> sum[0] += n);
 336                         check.sum(sum[0]);}}},
 337             new Job(klazz + " removeIf") {
 338                 public void work() throws Throwable {
 339                     int[] sum = new int[1];
 340                     for (int i = 0; i < iterations; i++) {
 341                         sum[0] = 0;
 342                         if (x.removeIf(n -> { sum[0] += n; return false; }))
 343                             throw new AssertionError();
 344                         check.sum(sum[0]);}}},
 345             new Job(klazz + " contains") {
 346                 public void work() throws Throwable {
 347                     int[] sum = new int[1];
 348                     Object y = new Object() {
 349                         public boolean equals(Object z) {
 350                             sum[0] += (int) z; return false; }};







 351                     for (int i = 0; i < iterations; i++) {
 352                         sum[0] = 0;
 353                         if (x.contains(y)) throw new AssertionError();

 354                         check.sum(sum[0]);}}},
 355             new Job(klazz + " remove(Object)") {
 356                 public void work() throws Throwable {
 357                     int[] sum = new int[1];
 358                     Object y = new Object() {
 359                         public boolean equals(Object z) {
 360                             sum[0] += (int) z; return false; }};
 361                     for (int i = 0; i < iterations; i++) {
 362                         sum[0] = 0;
 363                         if (x.remove(y)) throw new AssertionError();
 364                         check.sum(sum[0]);}}},
 365             new Job(klazz + " forEach") {
 366                 public void work() throws Throwable {
 367                     int[] sum = new int[1];
 368                     for (int i = 0; i < iterations; i++) {
 369                         sum[0] = 0;
 370                         x.forEach(n -> sum[0] += n);
 371                         check.sum(sum[0]);}}},
 372             new Job(klazz + " toArray()") {
 373                 public void work() throws Throwable {
 374                     int[] sum = new int[1];
 375                     for (int i = 0; i < iterations; i++) {
 376                         sum[0] = 0;
 377                         for (Object o : x.toArray())
 378                             sum[0] += (Integer) o;
 379                         check.sum(sum[0]);}}},
 380             new Job(klazz + " toArray(a)") {
 381                 public void work() throws Throwable {
 382                     Integer[] a = new Integer[x.size()];
 383                     int[] sum = new int[1];


 429             new Job(klazz + " parallelStream().mapToInt") {
 430                 public void work() throws Throwable {
 431                     for (int i = 0; i < iterations; i++) {
 432                         check.sum(x.parallelStream().mapToInt(e -> e).sum());}}},
 433             new Job(klazz + " parallelStream().collect") {
 434                 public void work() throws Throwable {
 435                     for (int i = 0; i < iterations; i++) {
 436                         check.sum(x.parallelStream()
 437                                   .collect(summingInt(e -> e)));}}},
 438             new Job(klazz + " parallelStream()::iterator") {
 439                 public void work() throws Throwable {
 440                     int[] sum = new int[1];
 441                     for (int i = 0; i < iterations; i++) {
 442                         sum[0] = 0;
 443                         for (Integer o : (Iterable<Integer>) x.parallelStream()::iterator)
 444                             sum[0] += o;
 445                         check.sum(sum[0]);}}});
 446     }
 447 
 448     Stream<Job> dequeJobs(Deque<Integer> x) {
 449         String klazz = x.getClass().getSimpleName();
 450         return Stream.of(
 451             new Job(klazz + " descendingIterator() loop") {
 452                 public void work() throws Throwable {
 453                     for (int i = 0; i < iterations; i++) {
 454                         int sum = 0;
 455                         Iterator<Integer> it = x.descendingIterator();
 456                         while (it.hasNext())
 457                             sum += it.next();
 458                         check.sum(sum);}}},
 459             new Job(klazz + " descendingIterator().forEachRemaining()") {
 460                 public void work() throws Throwable {
 461                     int[] sum = new int[1];
 462                     for (int i = 0; i < iterations; i++) {
 463                         sum[0] = 0;
 464                         x.descendingIterator().forEachRemaining(n -> sum[0] += n);
 465                         check.sum(sum[0]);}}});
 466     }
 467 
 468     Stream<Job> listJobs(List<Integer> x) {
 469         String klazz = x.getClass().getSimpleName();
 470         return Stream.of(
 471             new Job(klazz + " subList toArray()") {
 472                 public void work() throws Throwable {
 473                     int size = x.size();
 474                     for (int i = 0; i < iterations; i++) {
 475                         int total = Stream.of(x.subList(0, size / 2),
 476                                               x.subList(size / 2, size))
 477                             .mapToInt(subList -> {
 478                                 int sum = 0;
 479                                 for (Object o : subList.toArray())
 480                                     sum += (Integer) o;
 481                                 return sum; })
 482                             .sum();
 483                         check.sum(total);}}},
 484             new Job(klazz + " subList toArray(a)") {
 485                 public void work() throws Throwable {
 486                     int size = x.size();
 487                     for (int i = 0; i < iterations; i++) {
 488                         int total = Stream.of(x.subList(0, size / 2),
 489                                               x.subList(size / 2, size))
 490                             .mapToInt(subList -> {
 491                                 int sum = 0;
 492                                 Integer[] a = new Integer[subList.size()];
 493                                 for (Object o : subList.toArray(a))
 494                                     sum += (Integer) o;
 495                                 return sum; })
 496                             .sum();
 497                         check.sum(total);}}},
 498             new Job(klazz + " subList toArray(empty)") {
 499                 public void work() throws Throwable {
 500                     int size = x.size();
 501                     Integer[] empty = new Integer[0];
 502                     for (int i = 0; i < iterations; i++) {
 503                         int total = Stream.of(x.subList(0, size / 2),
 504                                               x.subList(size / 2, size))
 505                             .mapToInt(subList -> {
 506                                 int sum = 0;
 507                                 for (Object o : subList.toArray(empty))
 508                                     sum += (Integer) o;
 509                                 return sum; })
 510                             .sum();
 511                         check.sum(total);}}});


























 512     }
 513 }


  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /*
  25  * @test
  26  * @summary micro-benchmark correctness mode
  27  * @run main IteratorMicroBenchmark iterations=1 size=8 warmup=0
  28  */
  29 
  30 import static java.util.stream.Collectors.summingInt;
  31 import static java.util.stream.Collectors.toCollection;
  32 
  33 import java.lang.ref.WeakReference;
  34 import java.util.ArrayDeque;
  35 import java.util.ArrayList;
  36 import java.util.Collection;
  37 import java.util.Collections;
  38 import java.util.Deque;
  39 import java.util.HashMap;
  40 import java.util.Iterator;
  41 import java.util.LinkedList;
  42 import java.util.List;
  43 import java.util.ListIterator;
  44 import java.util.PriorityQueue;
  45 import java.util.Spliterator;
  46 import java.util.Vector;
  47 import java.util.concurrent.ArrayBlockingQueue;
  48 import java.util.concurrent.ConcurrentLinkedDeque;
  49 import java.util.concurrent.ConcurrentLinkedQueue;
  50 import java.util.concurrent.CopyOnWriteArrayList;
  51 import java.util.concurrent.LinkedBlockingDeque;
  52 import java.util.concurrent.LinkedBlockingQueue;
  53 import java.util.concurrent.LinkedTransferQueue;
  54 import java.util.concurrent.PriorityBlockingQueue;
  55 import java.util.concurrent.CountDownLatch;
  56 import java.util.concurrent.ThreadLocalRandom;
  57 import java.util.concurrent.TimeUnit;
  58 import java.util.concurrent.atomic.LongAdder;
  59 import java.util.function.UnaryOperator;
  60 import java.util.regex.Pattern;
  61 import java.util.stream.Stream;
  62 
  63 /**
  64  * Usage: [iterations=N] [size=N] [filter=REGEXP] [warmup=SECONDS]
  65  *
  66  * To run this in micro-benchmark mode, simply run as a normal java program.
  67  * Be patient; this program runs for a very long time.
  68  * For faster runs, restrict execution using command line args.
  69  *
  70  * This is an interface based version of ArrayList/IteratorMicroBenchmark
  71  *
  72  * @author Martin Buchholz
  73  */
  74 public class IteratorMicroBenchmark {
  75     abstract static class Job {
  76         private final String name;
  77         public Job(String name) { this.name = name; }
  78         public String name() { return name; }
  79         public abstract void work() throws Throwable;
  80         public void run() {
  81             try { work(); }
  82             catch (Throwable ex) {
  83                 // current job cannot always be deduced from stacktrace.
  84                 throw new RuntimeException("Job failed: " + name(), ex);
  85             }
  86         }
  87     }
  88 
  89     final int iterations;
  90     final int size;             // number of elements in collections
  91     final double warmupSeconds;
  92     final long warmupNanos;
  93     final Pattern nameFilter;   // select subset of Jobs to run
  94     final boolean reverse;      // reverse order of Jobs
  95     final boolean shuffle;      // randomize order of Jobs
  96 
  97     IteratorMicroBenchmark(String[] args) {
  98         iterations    = intArg(args, "iterations", 10_000);
  99         size          = intArg(args, "size", 1000);
 100         warmupSeconds = doubleArg(args, "warmup", 7.0);
 101         nameFilter    = patternArg(args, "filter");
 102         reverse       = booleanArg(args, "reverse");
 103         shuffle       = booleanArg(args, "shuffle");
 104 
 105         warmupNanos = (long) (warmupSeconds * (1000L * 1000L * 1000L));
 106     }
 107 
 108     // --------------- GC finalization infrastructure ---------------
 109 
 110     /** No guarantees, but effective in practice. */
 111     static void forceFullGc() {
 112         CountDownLatch finalizeDone = new CountDownLatch(1);
 113         WeakReference<?> ref = new WeakReference<Object>(new Object() {
 114             @SuppressWarnings("deprecation")
 115             protected void finalize() { finalizeDone.countDown(); }});
 116         try {
 117             for (int i = 0; i < 10; i++) {
 118                 System.gc();
 119                 if (finalizeDone.await(1L, TimeUnit.SECONDS) && ref.get() == null) {
 120                     System.runFinalization(); // try to pick up stragglers
 121                     return;
 122                 }
 123             }
 124         } catch (InterruptedException unexpected) {
 125             throw new AssertionError("unexpected InterruptedException");
 126         }
 127         throw new AssertionError("failed to do a \"full\" gc");
 128     }
 129 
 130     /**
 131      * Runs each job for long enough that all the runtime compilers
 132      * have had plenty of time to warm up, i.e. get around to
 133      * compiling everything worth compiling.
 134      * Returns array of average times per job per run.
 135      */
 136     long[] time0(List<Job> jobs) {
 137         final int size = jobs.size();
 138         long[] nanoss = new long[size];
 139         for (int i = 0; i < size; i++) {
 140             if (warmupNanos > 0) forceFullGc();
 141             Job job = jobs.get(i);
 142             long totalTime;
 143             int runs = 0;
 144             long startTime = System.nanoTime();
 145             do { job.run(); runs++; }
 146             while ((totalTime = System.nanoTime() - startTime) < warmupNanos);
 147             nanoss[i] = totalTime/runs;
 148         }
 149         return nanoss;
 150     }
 151 
 152     void time(List<Job> jobs) throws Throwable {
 153         if (warmupNanos > 0) time0(jobs); // Warm up run
 154         final int size = jobs.size();
 155         final long[] nanoss = time0(jobs); // Real timing run
 156         final long[] milliss = new long[size];
 157         final double[] ratios = new double[size];
 158 
 159         final String nameHeader   = "Method";
 160         final String millisHeader = "Millis";
 161         final String ratioHeader  = "Ratio";
 162 
 163         int nameWidth   = nameHeader.length();
 164         int millisWidth = millisHeader.length();
 165         int ratioWidth  = ratioHeader.length();


 204         return (val == null) ? defaultValue : Double.parseDouble(val);
 205     }
 206 
 207     private static Pattern patternArg(String[] args, String keyword) {
 208         String val = keywordValue(args, keyword);
 209         return (val == null) ? null : Pattern.compile(val);
 210     }
 211 
 212     private static boolean booleanArg(String[] args, String keyword) {
 213         String val = keywordValue(args, keyword);
 214         if (val == null || val.equals("false")) return false;
 215         if (val.equals("true")) return true;
 216         throw new IllegalArgumentException(val);
 217     }
 218 
 219     private static void deoptimize(int sum) {
 220         if (sum == 42)
 221             System.out.println("the answer");
 222     }
 223 




 224     private static <T> Iterable<T> backwards(final List<T> list) {
 225         return new Iterable<T>() {
 226             public Iterator<T> iterator() {
 227                 return new Iterator<T>() {
 228                     final ListIterator<T> it = list.listIterator(list.size());
 229                     public boolean hasNext() { return it.hasPrevious(); }
 230                     public T next()          { return it.previous(); }
 231                     public void remove()     {        it.remove(); }};}};
 232     }
 233 
 234     // Checks for correctness *and* prevents loop optimizations
 235     static class Check {
 236         private int sum;
 237         public void sum(int sum) {
 238             if (this.sum == 0)
 239                 this.sum = sum;
 240             if (this.sum != sum)
 241                 throw new AssertionError("Sum mismatch");
 242         }
 243     }
 244     volatile Check check = new Check();
 245 
 246     public static void main(String[] args) throws Throwable {
 247         new IteratorMicroBenchmark(args).run();
 248     }
 249 
 250     HashMap<Class<?>, String> goodClassName = new HashMap<>();
 251 
 252     String goodClassName(Class<?> klazz) {
 253         return goodClassName.computeIfAbsent(
 254             klazz,
 255             k -> {
 256                 String simple = k.getSimpleName();
 257                 return (simple.equals("SubList")) // too simple!
 258                     ? k.getName().replaceFirst(".*\\.", "")
 259                     : simple;
 260             });
 261     }
 262 
 263     static List<Integer> makeSubList(List<Integer> list) {
 264         final ThreadLocalRandom rnd = ThreadLocalRandom.current();
 265         int size = list.size();
 266         if (size <= 2) return list.subList(0, size);
 267         List<Integer> subList = list.subList(rnd.nextInt(0, 2),
 268                                              size - rnd.nextInt(0, 2));
 269         List<Integer> copy = new ArrayList<>(list);
 270         subList.clear();
 271         subList.addAll(copy);
 272         return subList;
 273     }
 274 
 275     void run() throws Throwable {
 276         final ArrayList<Integer> al = new ArrayList<>(size);
 277 
 278         // Populate collections with random data
 279         final ThreadLocalRandom rnd = ThreadLocalRandom.current();
 280         for (int i = 0; i < size; i++)
 281             al.add(rnd.nextInt(size));
 282 
 283         final ArrayDeque<Integer> ad = new ArrayDeque<>(al);
 284         final ArrayBlockingQueue<Integer> abq = new ArrayBlockingQueue<>(al.size());
 285         abq.addAll(al);
 286 
 287         // shuffle circular array elements so they wrap
 288         for (int i = 0, n = rnd.nextInt(size); i < n; i++) {
 289             ad.addLast(ad.removeFirst());
 290             abq.add(abq.remove());
 291         }
 292 
 293         ArrayList<Job> jobs = Stream.<Collection<Integer>>of(
 294                 al, ad, abq,
 295                 makeSubList(new ArrayList<>(al)),
 296                 new LinkedList<>(al),
 297                 makeSubList(new LinkedList<>(al)),
 298                 new PriorityQueue<>(al),
 299                 new Vector<>(al),
 300                 makeSubList(new Vector<>(al)),
 301                 new CopyOnWriteArrayList<>(al),
 302                 makeSubList(new CopyOnWriteArrayList<>(al)),
 303                 new ConcurrentLinkedQueue<>(al),
 304                 new ConcurrentLinkedDeque<>(al),
 305                 new LinkedBlockingQueue<>(al),
 306                 new LinkedBlockingDeque<>(al),
 307                 new LinkedTransferQueue<>(al),
 308                 new PriorityBlockingQueue<>(al))
 309             .flatMap(x -> jobs(x))
 310             .filter(job ->
 311                 nameFilter == null || nameFilter.matcher(job.name()).find())
 312             .collect(toCollection(ArrayList::new));
 313 
 314         if (reverse) Collections.reverse(jobs);
 315         if (shuffle) Collections.shuffle(jobs);
 316 
 317         time(jobs);
 318     }
 319 
 320     @SafeVarargs @SuppressWarnings("varargs")
 321     private <T> Stream<T> concatStreams(Stream<T> ... streams) {
 322         return Stream.of(streams).flatMap(s -> s);
 323     }
 324 
 325     Stream<Job> jobs(Collection<Integer> x) {
 326         return concatStreams(
 327             collectionJobs(x),
 328 
 329             (x instanceof Deque)
 330             ? dequeJobs((Deque<Integer>)x)
 331             : Stream.empty(),
 332 
 333             (x instanceof List)
 334             ? listJobs((List<Integer>)x)
 335             : Stream.empty());
 336     }
 337 
 338     Object sneakyAdder(int[] sneakySum) {
 339         return new Object() {
 340             public int hashCode() { throw new AssertionError(); }
 341             public boolean equals(Object z) {
 342                 sneakySum[0] += (int) z; return false; }};
 343     }
 344 
 345     Stream<Job> collectionJobs(Collection<Integer> x) {
 346         final String klazz = goodClassName(x.getClass());
 347         return Stream.of(
 348             new Job(klazz + " iterate for loop") {
 349                 public void work() throws Throwable {
 350                     for (int i = 0; i < iterations; i++) {
 351                         int sum = 0;
 352                         for (Integer n : x)
 353                             sum += n;
 354                         check.sum(sum);}}},
 355             new Job(klazz + " iterator().forEachRemaining()") {
 356                 public void work() throws Throwable {
 357                     int[] sum = new int[1];
 358                     for (int i = 0; i < iterations; i++) {
 359                         sum[0] = 0;
 360                         x.iterator().forEachRemaining(n -> sum[0] += n);
 361                         check.sum(sum[0]);}}},
 362             new Job(klazz + " spliterator().tryAdvance()") {
 363                 public void work() throws Throwable {
 364                     int[] sum = new int[1];
 365                     for (int i = 0; i < iterations; i++) {
 366                         sum[0] = 0;


 368                         do {} while (spliterator.tryAdvance(n -> sum[0] += n));
 369                         check.sum(sum[0]);}}},
 370             new Job(klazz + " spliterator().forEachRemaining()") {
 371                 public void work() throws Throwable {
 372                     int[] sum = new int[1];
 373                     for (int i = 0; i < iterations; i++) {
 374                         sum[0] = 0;
 375                         x.spliterator().forEachRemaining(n -> sum[0] += n);
 376                         check.sum(sum[0]);}}},
 377             new Job(klazz + " removeIf") {
 378                 public void work() throws Throwable {
 379                     int[] sum = new int[1];
 380                     for (int i = 0; i < iterations; i++) {
 381                         sum[0] = 0;
 382                         if (x.removeIf(n -> { sum[0] += n; return false; }))
 383                             throw new AssertionError();
 384                         check.sum(sum[0]);}}},
 385             new Job(klazz + " contains") {
 386                 public void work() throws Throwable {
 387                     int[] sum = new int[1];
 388                     Object sneakyAdder = sneakyAdder(sum);
 389                     for (int i = 0; i < iterations; i++) {
 390                         sum[0] = 0;
 391                         if (x.contains(sneakyAdder)) throw new AssertionError();
 392                         check.sum(sum[0]);}}},
 393             new Job(klazz + " containsAll") {
 394                 public void work() throws Throwable {
 395                     int[] sum = new int[1];
 396                     Collection<Object> sneakyAdderCollection =
 397                         Collections.singleton(sneakyAdder(sum));
 398                     for (int i = 0; i < iterations; i++) {
 399                         sum[0] = 0;
 400                         if (x.containsAll(sneakyAdderCollection))
 401                             throw new AssertionError();
 402                         check.sum(sum[0]);}}},
 403             new Job(klazz + " remove(Object)") {
 404                 public void work() throws Throwable {
 405                     int[] sum = new int[1];
 406                     Object sneakyAdder = sneakyAdder(sum);


 407                     for (int i = 0; i < iterations; i++) {
 408                         sum[0] = 0;
 409                         if (x.remove(sneakyAdder)) throw new AssertionError();
 410                         check.sum(sum[0]);}}},
 411             new Job(klazz + " forEach") {
 412                 public void work() throws Throwable {
 413                     int[] sum = new int[1];
 414                     for (int i = 0; i < iterations; i++) {
 415                         sum[0] = 0;
 416                         x.forEach(n -> sum[0] += n);
 417                         check.sum(sum[0]);}}},
 418             new Job(klazz + " toArray()") {
 419                 public void work() throws Throwable {
 420                     int[] sum = new int[1];
 421                     for (int i = 0; i < iterations; i++) {
 422                         sum[0] = 0;
 423                         for (Object o : x.toArray())
 424                             sum[0] += (Integer) o;
 425                         check.sum(sum[0]);}}},
 426             new Job(klazz + " toArray(a)") {
 427                 public void work() throws Throwable {
 428                     Integer[] a = new Integer[x.size()];
 429                     int[] sum = new int[1];


 475             new Job(klazz + " parallelStream().mapToInt") {
 476                 public void work() throws Throwable {
 477                     for (int i = 0; i < iterations; i++) {
 478                         check.sum(x.parallelStream().mapToInt(e -> e).sum());}}},
 479             new Job(klazz + " parallelStream().collect") {
 480                 public void work() throws Throwable {
 481                     for (int i = 0; i < iterations; i++) {
 482                         check.sum(x.parallelStream()
 483                                   .collect(summingInt(e -> e)));}}},
 484             new Job(klazz + " parallelStream()::iterator") {
 485                 public void work() throws Throwable {
 486                     int[] sum = new int[1];
 487                     for (int i = 0; i < iterations; i++) {
 488                         sum[0] = 0;
 489                         for (Integer o : (Iterable<Integer>) x.parallelStream()::iterator)
 490                             sum[0] += o;
 491                         check.sum(sum[0]);}}});
 492     }
 493 
 494     Stream<Job> dequeJobs(Deque<Integer> x) {
 495         String klazz = goodClassName(x.getClass());
 496         return Stream.of(
 497             new Job(klazz + " descendingIterator() loop") {
 498                 public void work() throws Throwable {
 499                     for (int i = 0; i < iterations; i++) {
 500                         int sum = 0;
 501                         Iterator<Integer> it = x.descendingIterator();
 502                         while (it.hasNext())
 503                             sum += it.next();
 504                         check.sum(sum);}}},
 505             new Job(klazz + " descendingIterator().forEachRemaining()") {
 506                 public void work() throws Throwable {
 507                     int[] sum = new int[1];
 508                     for (int i = 0; i < iterations; i++) {
 509                         sum[0] = 0;
 510                         x.descendingIterator().forEachRemaining(n -> sum[0] += n);
 511                         check.sum(sum[0]);}}});
 512     }
 513 
 514     Stream<Job> listJobs(List<Integer> x) {
 515         final String klazz = goodClassName(x.getClass());
 516         return Stream.of(
 517             new Job(klazz + " listIterator forward loop") {
 518                 public void work() throws Throwable {

 519                     for (int i = 0; i < iterations; i++) {



 520                         int sum = 0;
 521                         ListIterator<Integer> it = x.listIterator();
 522                         while (it.hasNext())
 523                             sum += it.next();
 524                         check.sum(sum);}}},
 525             new Job(klazz + " listIterator backward loop") {















 526                 public void work() throws Throwable {


 527                     for (int i = 0; i < iterations; i++) {



 528                         int sum = 0;
 529                         ListIterator<Integer> it = x.listIterator(x.size());
 530                         while (it.hasPrevious())
 531                             sum += it.previous();
 532                         check.sum(sum);}}},
 533             new Job(klazz + " indexOf") {
 534                 public void work() throws Throwable {
 535                     int[] sum = new int[1];
 536                     Object sneakyAdder = sneakyAdder(sum);
 537                     for (int i = 0; i < iterations; i++) {
 538                         sum[0] = 0;
 539                         if (x.indexOf(sneakyAdder) != -1)
 540                             throw new AssertionError();
 541                         check.sum(sum[0]);}}},
 542             new Job(klazz + " lastIndexOf") {
 543                 public void work() throws Throwable {
 544                     int[] sum = new int[1];
 545                     Object sneakyAdder = sneakyAdder(sum);
 546                     for (int i = 0; i < iterations; i++) {
 547                         sum[0] = 0;
 548                         if (x.lastIndexOf(sneakyAdder) != -1)
 549                             throw new AssertionError();
 550                         check.sum(sum[0]);}}},
 551             new Job(klazz + " replaceAll") {
 552                 public void work() throws Throwable {
 553                     int[] sum = new int[1];
 554                     UnaryOperator<Integer> sneakyAdder =
 555                         x -> { sum[0] += x; return x; };
 556                     for (int i = 0; i < iterations; i++) {
 557                         sum[0] = 0;
 558                         x.replaceAll(sneakyAdder);
 559                         check.sum(sum[0]);}}});
 560     }
 561 }
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