util/Collection/IteratorMicroBenchmark.java

/*
 * Copyright (c) 2007, 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
 * @summary micro-benchmark correctness mode
 * @run main IteratorMicroBenchmark iterations=1 size=8 warmup=0
 */

import static java.util.stream.Collectors.summingInt;

import java.lang.ref.WeakReference;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Deque;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import java.util.PriorityQueue;
import java.util.Spliterator;
import java.util.Vector;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.LinkedTransferQueue;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.LongAdder;
import java.util.regex.Pattern;

/**
 * Usage: [iterations=N] [size=N] [filter=REGEXP] [warmup=SECONDS]
 *
 * To run this in micro-benchmark mode, simply run as a normal java program.
 * Be patient; this program runs for a very long time.
 * For faster runs, restrict execution using command line args.
 *
 * This is an interface based version of ArrayList/IteratorMicroBenchmark
 *
 * @author Martin Buchholz
 */
public class IteratorMicroBenchmark {
    abstract static class Job {
        private final String name;
        public Job(String name) { this.name = name; }
        public String name() { return name; }
        public abstract void work() throws Throwable;
    }

    final int iterations;
    final int size;             // number of elements in collections
    final double warmupSeconds;
    final long warmupNanos;
    final Pattern filter;       // select subset of Jobs to run
    final boolean reverse;      // reverse order of Jobs
    final boolean shuffle;      // randomize order of Jobs

    IteratorMicroBenchmark(String[] args) {
        iterations    = intArg(args, "iterations", 10_000);
        size          = intArg(args, "size", 1000);
        warmupSeconds = doubleArg(args, "warmup", 7.0);
        filter        = patternArg(args, "filter");
        reverse       = booleanArg(args, "reverse");
        shuffle       = booleanArg(args, "shuffle");

        warmupNanos = (long) (warmupSeconds * (1000L * 1000L * 1000L));
    }

    // --------------- GC finalization infrastructure ---------------

    /** No guarantees, but effective in practice. */
    static void forceFullGc() {
        CountDownLatch finalizeDone = new CountDownLatch(1);
        WeakReference<?> ref = new WeakReference<Object>(new Object() {
            protected void finalize() { finalizeDone.countDown(); }});
        try {
            for (int i = 0; i < 10; i++) {
                System.gc();
                if (finalizeDone.await(1L, TimeUnit.SECONDS) && ref.get() == null) {
                    System.runFinalization(); // try to pick up stragglers
                    return;
                }
            }
        } catch (InterruptedException unexpected) {
            throw new AssertionError("unexpected InterruptedException");
        }
        throw new AssertionError("failed to do a \"full\" gc");
    }

    /**
     * Runs each job for long enough that all the runtime compilers
     * have had plenty of time to warm up, i.e. get around to
     * compiling everything worth compiling.
     * Returns array of average times per job per run.
     */
    long[] time0(List<Job> jobs) throws Throwable {
        final int size = jobs.size();
        long[] nanoss = new long[size];
        for (int i = 0; i < size; i++) {
            if (warmupNanos > 0) forceFullGc();
            Job job = jobs.get(i);
            long totalTime;
            int runs = 0;
            long startTime = System.nanoTime();
            do { job.work(); runs++; }
            while ((totalTime = System.nanoTime() - startTime) < warmupNanos);
            nanoss[i] = totalTime/runs;
        }
        return nanoss;
    }

    void time(List<Job> jobs) throws Throwable {
        if (warmupNanos > 0) time0(jobs); // Warm up run
        final int size = jobs.size();
        final long[] nanoss = time0(jobs); // Real timing run
        final long[] milliss = new long[size];
        final double[] ratios = new double[size];

        final String nameHeader   = "Method";
        final String millisHeader = "Millis";
        final String ratioHeader  = "Ratio";

        int nameWidth   = nameHeader.length();
        int millisWidth = millisHeader.length();
        int ratioWidth  = ratioHeader.length();

        for (int i = 0; i < size; i++) {
            nameWidth = Math.max(nameWidth, jobs.get(i).name().length());

            milliss[i] = nanoss[i]/(1000L * 1000L);
            millisWidth = Math.max(millisWidth,
                                   String.format("%d", milliss[i]).length());

            ratios[i] = (double) nanoss[i] / (double) nanoss[0];
            ratioWidth = Math.max(ratioWidth,
                                  String.format("%.3f", ratios[i]).length());
        }

        String format = String.format("%%-%ds %%%dd %%%d.3f%%n",
                                      nameWidth, millisWidth, ratioWidth);
        String headerFormat = String.format("%%-%ds %%%ds %%%ds%%n",
                                            nameWidth, millisWidth, ratioWidth);
        System.out.printf(headerFormat, "Method", "Millis", "Ratio");

        // Print out absolute and relative times, calibrated against first job
        for (int i = 0; i < size; i++)
            System.out.printf(format, jobs.get(i).name(), milliss[i], ratios[i]);
    }

    private static String keywordValue(String[] args, String keyword) {
        for (String arg : args)
            if (arg.startsWith(keyword))
                return arg.substring(keyword.length() + 1);
        return null;
    }

    private static int intArg(String[] args, String keyword, int defaultValue) {
        String val = keywordValue(args, keyword);
        return (val == null) ? defaultValue : Integer.parseInt(val);
    }

    private static double doubleArg(String[] args, String keyword, double defaultValue) {
        String val = keywordValue(args, keyword);
        return (val == null) ? defaultValue : Double.parseDouble(val);
    }

    private static Pattern patternArg(String[] args, String keyword) {
        String val = keywordValue(args, keyword);
        return (val == null) ? null : Pattern.compile(val);
    }

    private static boolean booleanArg(String[] args, String keyword) {
        String val = keywordValue(args, keyword);
        if (val == null || val.equals("false")) return false;
        if (val.equals("true")) return true;
        throw new IllegalArgumentException(val);
    }

    private static List<Job> filter(Pattern filter, List<Job> jobs) {
        if (filter == null) return jobs;
        ArrayList<Job> newJobs = new ArrayList<>();
        for (Job job : jobs)
            if (filter.matcher(job.name()).find())
                newJobs.add(job);
        return newJobs;
    }

    private static void deoptimize(int sum) {
        if (sum == 42)
            System.out.println("the answer");
    }

    private static <T> List<T> asSubList(List<T> list) {
        return list.subList(0, list.size());
    }

    private static <T> Iterable<T> backwards(final List<T> list) {
        return new Iterable<T>() {
            public Iterator<T> iterator() {
                return new Iterator<T>() {
                    final ListIterator<T> it = list.listIterator(list.size());
                    public boolean hasNext() { return it.hasPrevious(); }
                    public T next()          { return it.previous(); }
                    public void remove()     {        it.remove(); }};}};
    }

    // Checks for correctness *and* prevents loop optimizations
    class Check {
        private int sum;
        public void sum(int sum) {
            if (this.sum == 0)
                this.sum = sum;
            if (this.sum != sum)
                throw new AssertionError("Sum mismatch");
        }
    }
    volatile Check check = new Check();

    public static void main(String[] args) throws Throwable {
        new IteratorMicroBenchmark(args).run();
    }

    void run() throws Throwable {
//         System.out.printf(
//             "iterations=%d size=%d, warmup=%1g, filter=\"%s\"%n",
//             iterations, size, warmupSeconds, filter);

        final ArrayList<Integer> al = new ArrayList<>(size);

        // Populate collections with random data
        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
        for (int i = 0; i < size; i++)
            al.add(rnd.nextInt(size));

        final ArrayDeque<Integer> ad = new ArrayDeque<>(al);
        final ArrayBlockingQueue<Integer> abq = new ArrayBlockingQueue<>(al.size());
        abq.addAll(al);

        // shuffle circular array elements so they wrap
        for (int i = 0, n = rnd.nextInt(size); i < n; i++) {
            ad.addLast(ad.removeFirst());
            abq.add(abq.remove());
        }

        ArrayList<Job> jobs = new ArrayList<>(Arrays.asList());

        List.of(al, ad, abq,
                new LinkedList<>(al),
                new PriorityQueue<>(al),
                new Vector<>(al),
                new ConcurrentLinkedQueue<>(al),
                new ConcurrentLinkedDeque<>(al),
                new LinkedBlockingQueue<>(al),
                new LinkedBlockingDeque<>(al),
                new LinkedTransferQueue<>(al),
                new PriorityBlockingQueue<>(al))
            .stream()
            .forEach(x -> {
                         jobs.addAll(collectionJobs(x));
                         if (x instanceof Deque)
                             jobs.addAll(dequeJobs((Deque<Integer>)x));
                     });

        if (reverse) Collections.reverse(jobs);
        if (shuffle) Collections.shuffle(jobs);

        time(filter(filter, jobs));
    }

    List<Job> collectionJobs(Collection<Integer> x) {
        String klazz = x.getClass().getSimpleName();
        return List.of(
            new Job(klazz + " iterate for loop") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        int sum = 0;
                        for (Integer n : x)
                            sum += n;
                        check.sum(sum);}}},
            new Job(klazz + " iterator().forEachRemaining()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.iterator().forEachRemaining(n -> sum[0] += n);
                        check.sum(sum[0]);}}},
            new Job(klazz + " spliterator().tryAdvance()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        Spliterator<Integer> spliterator = x.spliterator();
                        do {} while (spliterator.tryAdvance(n -> sum[0] += n));
                        check.sum(sum[0]);}}},
            new Job(klazz + " spliterator().forEachRemaining()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.spliterator().forEachRemaining(n -> sum[0] += n);
                        check.sum(sum[0]);}}},
            new Job(klazz + " removeIf") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        if (x.removeIf(n -> { sum[0] += n; return false; }))
                            throw new AssertionError();
                        check.sum(sum[0]);}}},
            new Job(klazz + " contains") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    Object y = new Object() {
                        public boolean equals(Object z) {
                            sum[0] += (int) z; return false; }};
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        if (x.contains(y)) throw new AssertionError();
                        check.sum(sum[0]);}}},
            new Job(klazz + " remove(Object)") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    Object y = new Object() {
                        public boolean equals(Object z) {
                            sum[0] += (int) z; return false; }};
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        if (x.remove(y)) throw new AssertionError();
                        check.sum(sum[0]);}}},
            new Job(klazz + " forEach") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.forEach(n -> sum[0] += n);
                        check.sum(sum[0]);}}},
            new Job(klazz + " toArray()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        for (Object o : x.toArray())
                            sum[0] += (Integer) o;
                        check.sum(sum[0]);}}},
            new Job(klazz + " toArray(a)") {
                public void work() throws Throwable {
                    Integer[] a = new Integer[x.size()];
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.toArray(a);
                        for (Object o : a)
                            sum[0] += (Integer) o;
                        check.sum(sum[0]);}}},
            new Job(klazz + " toArray(empty)") {
                public void work() throws Throwable {
                    Integer[] empty = new Integer[0];
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        for (Integer o : x.toArray(empty))
                            sum[0] += o;
                        check.sum(sum[0]);}}},
            new Job(klazz + " stream().forEach") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.stream().forEach(n -> sum[0] += n);
                        check.sum(sum[0]);}}},
            new Job(klazz + " stream().mapToInt") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        check.sum(x.stream().mapToInt(e -> e).sum());}}},
            new Job(klazz + " stream().collect") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        check.sum(x.stream()
                                  .collect(summingInt(e -> e)));}}},
            new Job(klazz + " stream()::iterator") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        for (Integer o : (Iterable<Integer>) x.stream()::iterator)
                            sum[0] += o;
                        check.sum(sum[0]);}}},
            new Job(klazz + " parallelStream().forEach") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        LongAdder sum = new LongAdder();
                        x.parallelStream().forEach(n -> sum.add(n));
                        check.sum((int) sum.sum());}}},
            new Job(klazz + " parallelStream().mapToInt") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        check.sum(x.parallelStream().mapToInt(e -> e).sum());}}},
            new Job(klazz + " parallelStream().collect") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        check.sum(x.parallelStream()
                                  .collect(summingInt(e -> e)));}}},
            new Job(klazz + " parallelStream()::iterator") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        for (Integer o : (Iterable<Integer>) x.parallelStream()::iterator)
                            sum[0] += o;
                        check.sum(sum[0]);}}});
    }

    List<Job> dequeJobs(Deque<Integer> x) {
        String klazz = x.getClass().getSimpleName();
        return List.of(
            new Job(klazz + " descendingIterator() loop") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        int sum = 0;
                        Iterator<Integer> it = x.descendingIterator();
                        while (it.hasNext())
                            sum += it.next();
                        check.sum(sum);}}},
            new Job(klazz + " descendingIterator().forEachRemaining()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.descendingIterator().forEachRemaining(n -> sum[0] += n);
                        check.sum(sum[0]);}}});
    }
}
Revision:	1.23
Committed:	Thu Sep 28 02:15:44 2017 UTC (6 years, 8 months ago) by jsr166
Branch:	MAIN
Changes since 1.22:	+0 -1 lines
Log Message:	removed unused imports
#	User	Rev	Content
1	jsr166	1.1	/*
2			* Copyright (c) 2007, Oracle and/or its affiliates. All rights reserved.
3			* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4			*
5			* This code is free software; you can redistribute it and/or modify it
6			* under the terms of the GNU General Public License version 2 only, as
7			* published by the Free Software Foundation.
8			*
9			* This code is distributed in the hope that it will be useful, but WITHOUT
10			* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11			* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12			* version 2 for more details (a copy is included in the LICENSE file that
13			* accompanied this code).
14			*
15			* You should have received a copy of the GNU General Public License version
16			* 2 along with this work; if not, write to the Free Software Foundation,
17			* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18			*
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	jsr166	1.12	import static java.util.stream.Collectors.summingInt;
31
32	jsr166	1.1	import java.lang.ref.WeakReference;
33			import java.util.ArrayDeque;
34			import java.util.Arrays;
35			import java.util.ArrayList;
36			import java.util.Collection;
37	jsr166	1.10	import java.util.Collections;
38	jsr166	1.1	import java.util.Deque;
39			import java.util.Iterator;
40	jsr166	1.13	import java.util.LinkedList;
41	jsr166	1.1	import java.util.List;
42			import java.util.ListIterator;
43			import java.util.Map;
44	jsr166	1.8	import java.util.PriorityQueue;
45	jsr166	1.1	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.LinkedBlockingDeque;
51			import java.util.concurrent.LinkedBlockingQueue;
52			import java.util.concurrent.LinkedTransferQueue;
53	jsr166	1.8	import java.util.concurrent.PriorityBlockingQueue;
54	jsr166	1.1	import java.util.concurrent.CountDownLatch;
55			import java.util.concurrent.ThreadLocalRandom;
56			import java.util.concurrent.TimeUnit;
57	jsr166	1.19	import java.util.concurrent.atomic.LongAdder;
58	jsr166	1.1	import java.util.regex.Pattern;
59
60			/**
61			* Usage: [iterations=N] [size=N] [filter=REGEXP] [warmup=SECONDS]
62			*
63			* To run this in micro-benchmark mode, simply run as a normal java program.
64			* Be patient; this program runs for a very long time.
65			* For faster runs, restrict execution using command line args.
66			*
67			* This is an interface based version of ArrayList/IteratorMicroBenchmark
68			*
69			* @author Martin Buchholz
70			*/
71			public class IteratorMicroBenchmark {
72			abstract static class Job {
73			private final String name;
74			public Job(String name) { this.name = name; }
75			public String name() { return name; }
76			public abstract void work() throws Throwable;
77			}
78
79	jsr166	1.11	final int iterations;
80			final int size; // number of elements in collections
81			final double warmupSeconds;
82			final long warmupNanos;
83			final Pattern filter; // select subset of Jobs to run
84			final boolean reverse; // reverse order of Jobs
85			final boolean shuffle; // randomize order of Jobs
86
87			IteratorMicroBenchmark(String[] args) {
88			iterations = intArg(args, "iterations", 10_000);
89			size = intArg(args, "size", 1000);
90			warmupSeconds = doubleArg(args, "warmup", 7.0);
91			filter = patternArg(args, "filter");
92			reverse = booleanArg(args, "reverse");
93			shuffle = booleanArg(args, "shuffle");
94
95			warmupNanos = (long) (warmupSeconds * (1000L * 1000L * 1000L));
96			}
97	jsr166	1.1
98			// --------------- GC finalization infrastructure ---------------
99
100			/** No guarantees, but effective in practice. */
101			static void forceFullGc() {
102			CountDownLatch finalizeDone = new CountDownLatch(1);
103			WeakReference<?> ref = new WeakReference<Object>(new Object() {
104			protected void finalize() { finalizeDone.countDown(); }});
105			try {
106			for (int i = 0; i < 10; i++) {
107			System.gc();
108			if (finalizeDone.await(1L, TimeUnit.SECONDS) && ref.get() == null) {
109			System.runFinalization(); // try to pick up stragglers
110			return;
111			}
112			}
113			} catch (InterruptedException unexpected) {
114			throw new AssertionError("unexpected InterruptedException");
115			}
116			throw new AssertionError("failed to do a \"full\" gc");
117			}
118
119			/**
120			* Runs each job for long enough that all the runtime compilers
121			* have had plenty of time to warm up, i.e. get around to
122			* compiling everything worth compiling.
123			* Returns array of average times per job per run.
124			*/
125			long[] time0(List<Job> jobs) throws Throwable {
126			final int size = jobs.size();
127			long[] nanoss = new long[size];
128			for (int i = 0; i < size; i++) {
129			if (warmupNanos > 0) forceFullGc();
130	jsr166	1.9	Job job = jobs.get(i);
131			long totalTime;
132			int runs = 0;
133			long startTime = System.nanoTime();
134			do { job.work(); runs++; }
135			while ((totalTime = System.nanoTime() - startTime) < warmupNanos);
136			nanoss[i] = totalTime/runs;
137	jsr166	1.1	}
138			return nanoss;
139			}
140
141			void time(List<Job> jobs) throws Throwable {
142	jsr166	1.9	if (warmupNanos > 0) time0(jobs); // Warm up run
143	jsr166	1.1	final int size = jobs.size();
144			final long[] nanoss = time0(jobs); // Real timing run
145			final long[] milliss = new long[size];
146			final double[] ratios = new double[size];
147
148			final String nameHeader = "Method";
149			final String millisHeader = "Millis";
150			final String ratioHeader = "Ratio";
151
152			int nameWidth = nameHeader.length();
153			int millisWidth = millisHeader.length();
154			int ratioWidth = ratioHeader.length();
155
156			for (int i = 0; i < size; i++) {
157			nameWidth = Math.max(nameWidth, jobs.get(i).name().length());
158
159			milliss[i] = nanoss[i]/(1000L * 1000L);
160			millisWidth = Math.max(millisWidth,
161			String.format("%d", milliss[i]).length());
162
163			ratios[i] = (double) nanoss[i] / (double) nanoss[0];
164			ratioWidth = Math.max(ratioWidth,
165			String.format("%.3f", ratios[i]).length());
166			}
167
168			String format = String.format("%%-%ds %%%dd %%%d.3f%%n",
169			nameWidth, millisWidth, ratioWidth);
170			String headerFormat = String.format("%%-%ds %%%ds %%%ds%%n",
171			nameWidth, millisWidth, ratioWidth);
172			System.out.printf(headerFormat, "Method", "Millis", "Ratio");
173
174			// Print out absolute and relative times, calibrated against first job
175			for (int i = 0; i < size; i++)
176			System.out.printf(format, jobs.get(i).name(), milliss[i], ratios[i]);
177			}
178
179			private static String keywordValue(String[] args, String keyword) {
180			for (String arg : args)
181			if (arg.startsWith(keyword))
182			return arg.substring(keyword.length() + 1);
183			return null;
184			}
185
186			private static int intArg(String[] args, String keyword, int defaultValue) {
187			String val = keywordValue(args, keyword);
188			return (val == null) ? defaultValue : Integer.parseInt(val);
189			}
190
191			private static double doubleArg(String[] args, String keyword, double defaultValue) {
192			String val = keywordValue(args, keyword);
193			return (val == null) ? defaultValue : Double.parseDouble(val);
194			}
195
196			private static Pattern patternArg(String[] args, String keyword) {
197			String val = keywordValue(args, keyword);
198			return (val == null) ? null : Pattern.compile(val);
199			}
200
201	jsr166	1.10	private static boolean booleanArg(String[] args, String keyword) {
202			String val = keywordValue(args, keyword);
203			if (val == null \|\| val.equals("false")) return false;
204			if (val.equals("true")) return true;
205			throw new IllegalArgumentException(val);
206			}
207
208	jsr166	1.1	private static List<Job> filter(Pattern filter, List<Job> jobs) {
209			if (filter == null) return jobs;
210			ArrayList<Job> newJobs = new ArrayList<>();
211			for (Job job : jobs)
212			if (filter.matcher(job.name()).find())
213			newJobs.add(job);
214			return newJobs;
215			}
216
217			private static void deoptimize(int sum) {
218			if (sum == 42)
219			System.out.println("the answer");
220			}
221
222			private static <T> List<T> asSubList(List<T> list) {
223			return list.subList(0, list.size());
224			}
225
226			private static <T> Iterable<T> backwards(final List<T> list) {
227			return new Iterable<T>() {
228			public Iterator<T> iterator() {
229			return new Iterator<T>() {
230			final ListIterator<T> it = list.listIterator(list.size());
231			public boolean hasNext() { return it.hasPrevious(); }
232			public T next() { return it.previous(); }
233			public void remove() { it.remove(); }};}};
234			}
235
236			// Checks for correctness and prevents loop optimizations
237			class Check {
238			private int sum;
239			public void sum(int sum) {
240			if (this.sum == 0)
241			this.sum = sum;
242			if (this.sum != sum)
243			throw new AssertionError("Sum mismatch");
244			}
245			}
246	jsr166	1.2	volatile Check check = new Check();
247	jsr166	1.1
248			public static void main(String[] args) throws Throwable {
249	jsr166	1.11	new IteratorMicroBenchmark(args).run();
250	jsr166	1.1	}
251
252	jsr166	1.11	void run() throws Throwable {
253	jsr166	1.1	// System.out.printf(
254			// "iterations=%d size=%d, warmup=%1g, filter=\"%s\"%n",
255			// iterations, size, warmupSeconds, filter);
256
257	jsr166	1.17	final ArrayList<Integer> al = new ArrayList<>(size);
258	jsr166	1.1
259			// Populate collections with random data
260			final ThreadLocalRandom rnd = ThreadLocalRandom.current();
261	jsr166	1.3	for (int i = 0; i < size; i++)
262	jsr166	1.1	al.add(rnd.nextInt(size));
263
264			final ArrayDeque<Integer> ad = new ArrayDeque<>(al);
265			final ArrayBlockingQueue<Integer> abq = new ArrayBlockingQueue<>(al.size());
266			abq.addAll(al);
267
268			// shuffle circular array elements so they wrap
269			for (int i = 0, n = rnd.nextInt(size); i < n; i++) {
270			ad.addLast(ad.removeFirst());
271			abq.add(abq.remove());
272			}
273
274			ArrayList<Job> jobs = new ArrayList<>(Arrays.asList());
275
276			List.of(al, ad, abq,
277	jsr166	1.13	new LinkedList<>(al),
278	jsr166	1.8	new PriorityQueue<>(al),
279	jsr166	1.1	new Vector<>(al),
280			new ConcurrentLinkedQueue<>(al),
281			new ConcurrentLinkedDeque<>(al),
282			new LinkedBlockingQueue<>(al),
283			new LinkedBlockingDeque<>(al),
284	jsr166	1.8	new LinkedTransferQueue<>(al),
285			new PriorityBlockingQueue<>(al))
286	jsr166	1.1	.stream()
287			.forEach(x -> {
288			jobs.addAll(collectionJobs(x));
289			if (x instanceof Deque)
290			jobs.addAll(dequeJobs((Deque<Integer>)x));
291			});
292
293	jsr166	1.11	if (reverse) Collections.reverse(jobs);
294	jsr166	1.10	if (shuffle) Collections.shuffle(jobs);
295
296	jsr166	1.1	time(filter(filter, jobs));
297			}
298
299			List<Job> collectionJobs(Collection<Integer> x) {
300			String klazz = x.getClass().getSimpleName();
301			return List.of(
302	jsr166	1.5	new Job(klazz + " iterate for loop") {
303	jsr166	1.1	public void work() throws Throwable {
304			for (int i = 0; i < iterations; i++) {
305			int sum = 0;
306			for (Integer n : x)
307			sum += n;
308			check.sum(sum);}}},
309	jsr166	1.18	new Job(klazz + " iterator().forEachRemaining()") {
310	jsr166	1.1	public void work() throws Throwable {
311			int[] sum = new int[1];
312			for (int i = 0; i < iterations; i++) {
313			sum[0] = 0;
314			x.iterator().forEachRemaining(n -> sum[0] += n);
315			check.sum(sum[0]);}}},
316	jsr166	1.18	new Job(klazz + " spliterator().tryAdvance()") {
317	jsr166	1.1	public void work() throws Throwable {
318			int[] sum = new int[1];
319			for (int i = 0; i < iterations; i++) {
320			sum[0] = 0;
321			Spliterator<Integer> spliterator = x.spliterator();
322			do {} while (spliterator.tryAdvance(n -> sum[0] += n));
323			check.sum(sum[0]);}}},
324	jsr166	1.18	new Job(klazz + " spliterator().forEachRemaining()") {
325	jsr166	1.1	public void work() throws Throwable {
326			int[] sum = new int[1];
327			for (int i = 0; i < iterations; i++) {
328			sum[0] = 0;
329			x.spliterator().forEachRemaining(n -> sum[0] += n);
330			check.sum(sum[0]);}}},
331	jsr166	1.18	new Job(klazz + " removeIf") {
332	jsr166	1.1	public void work() throws Throwable {
333			int[] sum = new int[1];
334			for (int i = 0; i < iterations; i++) {
335			sum[0] = 0;
336	jsr166	1.16	if (x.removeIf(n -> { sum[0] += n; return false; }))
337			throw new AssertionError();
338	jsr166	1.1	check.sum(sum[0]);}}},
339	jsr166	1.18	new Job(klazz + " contains") {
340	jsr166	1.14	public void work() throws Throwable {
341			int[] sum = new int[1];
342	jsr166	1.15	Object y = new Object() {
343			public boolean equals(Object z) {
344			sum[0] += (int) z; return false; }};
345	jsr166	1.14	for (int i = 0; i < iterations; i++) {
346			sum[0] = 0;
347	jsr166	1.16	if (x.contains(y)) throw new AssertionError();
348			check.sum(sum[0]);}}},
349	jsr166	1.18	new Job(klazz + " remove(Object)") {
350	jsr166	1.16	public void work() throws Throwable {
351			int[] sum = new int[1];
352			Object y = new Object() {
353			public boolean equals(Object z) {
354			sum[0] += (int) z; return false; }};
355			for (int i = 0; i < iterations; i++) {
356			sum[0] = 0;
357			if (x.remove(y)) throw new AssertionError();
358	jsr166	1.14	check.sum(sum[0]);}}},
359	jsr166	1.18	new Job(klazz + " forEach") {
360	jsr166	1.1	public void work() throws Throwable {
361			int[] sum = new int[1];
362			for (int i = 0; i < iterations; i++) {
363			sum[0] = 0;
364			x.forEach(n -> sum[0] += n);
365	jsr166	1.6	check.sum(sum[0]);}}},
366	jsr166	1.18	new Job(klazz + " toArray()") {
367	jsr166	1.6	public void work() throws Throwable {
368			int[] sum = new int[1];
369			for (int i = 0; i < iterations; i++) {
370			sum[0] = 0;
371			for (Object o : x.toArray())
372			sum[0] += (Integer) o;
373			check.sum(sum[0]);}}},
374	jsr166	1.18	new Job(klazz + " toArray(a)") {
375	jsr166	1.6	public void work() throws Throwable {
376			Integer[] a = new Integer[x.size()];
377			int[] sum = new int[1];
378			for (int i = 0; i < iterations; i++) {
379			sum[0] = 0;
380			x.toArray(a);
381			for (Object o : a)
382			sum[0] += (Integer) o;
383	jsr166	1.7	check.sum(sum[0]);}}},
384	jsr166	1.18	new Job(klazz + " toArray(empty)") {
385	jsr166	1.7	public void work() throws Throwable {
386			Integer[] empty = new Integer[0];
387			int[] sum = new int[1];
388			for (int i = 0; i < iterations; i++) {
389			sum[0] = 0;
390			for (Integer o : x.toArray(empty))
391			sum[0] += o;
392	jsr166	1.12	check.sum(sum[0]);}}},
393	jsr166	1.19	new Job(klazz + " stream().forEach") {
394			public void work() throws Throwable {
395			int[] sum = new int[1];
396			for (int i = 0; i < iterations; i++) {
397			sum[0] = 0;
398			x.stream().forEach(n -> sum[0] += n);
399			check.sum(sum[0]);}}},
400			new Job(klazz + " stream().mapToInt") {
401			public void work() throws Throwable {
402			for (int i = 0; i < iterations; i++) {
403			check.sum(x.stream().mapToInt(e -> e).sum());}}},
404	jsr166	1.18	new Job(klazz + " stream().collect") {
405	jsr166	1.12	public void work() throws Throwable {
406			for (int i = 0; i < iterations; i++) {
407			check.sum(x.stream()
408			.collect(summingInt(e -> e)));}}},
409	jsr166	1.21	new Job(klazz + " stream()::iterator") {
410	jsr166	1.20	public void work() throws Throwable {
411			int[] sum = new int[1];
412			for (int i = 0; i < iterations; i++) {
413			sum[0] = 0;
414			for (Integer o : (Iterable<Integer>) x.stream()::iterator)
415			sum[0] += o;
416			check.sum(sum[0]);}}},
417	jsr166	1.19	new Job(klazz + " parallelStream().forEach") {
418			public void work() throws Throwable {
419			for (int i = 0; i < iterations; i++) {
420			LongAdder sum = new LongAdder();
421			x.parallelStream().forEach(n -> sum.add(n));
422			check.sum((int) sum.sum());}}},
423			new Job(klazz + " parallelStream().mapToInt") {
424			public void work() throws Throwable {
425			for (int i = 0; i < iterations; i++) {
426			check.sum(x.parallelStream().mapToInt(e -> e).sum());}}},
427	jsr166	1.18	new Job(klazz + " parallelStream().collect") {
428	jsr166	1.12	public void work() throws Throwable {
429			for (int i = 0; i < iterations; i++) {
430			check.sum(x.parallelStream()
431	jsr166	1.20	.collect(summingInt(e -> e)));}}},
432	jsr166	1.21	new Job(klazz + " parallelStream()::iterator") {
433	jsr166	1.20	public void work() throws Throwable {
434			int[] sum = new int[1];
435			for (int i = 0; i < iterations; i++) {
436			sum[0] = 0;
437			for (Integer o : (Iterable<Integer>) x.parallelStream()::iterator)
438			sum[0] += o;
439			check.sum(sum[0]);}}});
440	jsr166	1.1	}
441
442			List<Job> dequeJobs(Deque<Integer> x) {
443			String klazz = x.getClass().getSimpleName();
444			return List.of(
445	jsr166	1.18	new Job(klazz + " descendingIterator() loop") {
446	jsr166	1.1	public void work() throws Throwable {
447			for (int i = 0; i < iterations; i++) {
448			int sum = 0;
449			Iterator<Integer> it = x.descendingIterator();
450			while (it.hasNext())
451			sum += it.next();
452			check.sum(sum);}}},
453	jsr166	1.18	new Job(klazz + " descendingIterator().forEachRemaining()") {
454	jsr166	1.1	public void work() throws Throwable {
455			int[] sum = new int[1];
456			for (int i = 0; i < iterations; i++) {
457			sum[0] = 0;
458			x.descendingIterator().forEachRemaining(n -> sum[0] += n);
459			check.sum(sum[0]);}}});
460			}
461			}