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.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
    static 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<>();

        List.<Collection<Integer>>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)).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:	1.27
Committed:	Sun Jan 7 20:19:00 2018 UTC (6 years, 5 months ago) by jsr166
Branch:	MAIN
Changes since 1.26:	+16 -16 lines
Log Message:	simplify c.stream().forEach to c.forEach
#	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	jsr166	1.8	import java.util.PriorityQueue;
44	jsr166	1.1	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.LinkedBlockingDeque;
50			import java.util.concurrent.LinkedBlockingQueue;
51			import java.util.concurrent.LinkedTransferQueue;
52	jsr166	1.8	import java.util.concurrent.PriorityBlockingQueue;
53	jsr166	1.1	import java.util.concurrent.CountDownLatch;
54			import java.util.concurrent.ThreadLocalRandom;
55			import java.util.concurrent.TimeUnit;
56	jsr166	1.19	import java.util.concurrent.atomic.LongAdder;
57	jsr166	1.1	import java.util.regex.Pattern;
58
59			/**
60			* Usage: [iterations=N] [size=N] [filter=REGEXP] [warmup=SECONDS]
61			*
62			* To run this in micro-benchmark mode, simply run as a normal java program.
63			* Be patient; this program runs for a very long time.
64			* For faster runs, restrict execution using command line args.
65			*
66			* This is an interface based version of ArrayList/IteratorMicroBenchmark
67			*
68			* @author Martin Buchholz
69			*/
70			public class IteratorMicroBenchmark {
71			abstract static class Job {
72			private final String name;
73			public Job(String name) { this.name = name; }
74			public String name() { return name; }
75			public abstract void work() throws Throwable;
76			}
77
78	jsr166	1.11	final int iterations;
79			final int size; // number of elements in collections
80			final double warmupSeconds;
81			final long warmupNanos;
82			final Pattern filter; // select subset of Jobs to run
83			final boolean reverse; // reverse order of Jobs
84			final boolean shuffle; // randomize order of Jobs
85
86			IteratorMicroBenchmark(String[] args) {
87			iterations = intArg(args, "iterations", 10_000);
88			size = intArg(args, "size", 1000);
89			warmupSeconds = doubleArg(args, "warmup", 7.0);
90			filter = patternArg(args, "filter");
91			reverse = booleanArg(args, "reverse");
92			shuffle = booleanArg(args, "shuffle");
93
94			warmupNanos = (long) (warmupSeconds * (1000L * 1000L * 1000L));
95			}
96	jsr166	1.1
97			// --------------- GC finalization infrastructure ---------------
98
99			/** No guarantees, but effective in practice. */
100			static void forceFullGc() {
101			CountDownLatch finalizeDone = new CountDownLatch(1);
102			WeakReference<?> ref = new WeakReference<Object>(new Object() {
103			protected void finalize() { finalizeDone.countDown(); }});
104			try {
105			for (int i = 0; i < 10; i++) {
106			System.gc();
107			if (finalizeDone.await(1L, TimeUnit.SECONDS) && ref.get() == null) {
108			System.runFinalization(); // try to pick up stragglers
109			return;
110			}
111			}
112			} catch (InterruptedException unexpected) {
113			throw new AssertionError("unexpected InterruptedException");
114			}
115			throw new AssertionError("failed to do a \"full\" gc");
116			}
117
118			/**
119			* Runs each job for long enough that all the runtime compilers
120			* have had plenty of time to warm up, i.e. get around to
121			* compiling everything worth compiling.
122			* Returns array of average times per job per run.
123			*/
124			long[] time0(List<Job> jobs) throws Throwable {
125			final int size = jobs.size();
126			long[] nanoss = new long[size];
127			for (int i = 0; i < size; i++) {
128			if (warmupNanos > 0) forceFullGc();
129	jsr166	1.9	Job job = jobs.get(i);
130			long totalTime;
131			int runs = 0;
132			long startTime = System.nanoTime();
133			do { job.work(); runs++; }
134			while ((totalTime = System.nanoTime() - startTime) < warmupNanos);
135			nanoss[i] = totalTime/runs;
136	jsr166	1.1	}
137			return nanoss;
138			}
139
140			void time(List<Job> jobs) throws Throwable {
141	jsr166	1.9	if (warmupNanos > 0) time0(jobs); // Warm up run
142	jsr166	1.1	final int size = jobs.size();
143			final long[] nanoss = time0(jobs); // Real timing run
144			final long[] milliss = new long[size];
145			final double[] ratios = new double[size];
146
147			final String nameHeader = "Method";
148			final String millisHeader = "Millis";
149			final String ratioHeader = "Ratio";
150
151			int nameWidth = nameHeader.length();
152			int millisWidth = millisHeader.length();
153			int ratioWidth = ratioHeader.length();
154
155			for (int i = 0; i < size; i++) {
156			nameWidth = Math.max(nameWidth, jobs.get(i).name().length());
157
158			milliss[i] = nanoss[i]/(1000L * 1000L);
159			millisWidth = Math.max(millisWidth,
160			String.format("%d", milliss[i]).length());
161
162			ratios[i] = (double) nanoss[i] / (double) nanoss[0];
163			ratioWidth = Math.max(ratioWidth,
164			String.format("%.3f", ratios[i]).length());
165			}
166
167			String format = String.format("%%-%ds %%%dd %%%d.3f%%n",
168			nameWidth, millisWidth, ratioWidth);
169			String headerFormat = String.format("%%-%ds %%%ds %%%ds%%n",
170			nameWidth, millisWidth, ratioWidth);
171			System.out.printf(headerFormat, "Method", "Millis", "Ratio");
172
173			// Print out absolute and relative times, calibrated against first job
174			for (int i = 0; i < size; i++)
175			System.out.printf(format, jobs.get(i).name(), milliss[i], ratios[i]);
176			}
177
178			private static String keywordValue(String[] args, String keyword) {
179			for (String arg : args)
180			if (arg.startsWith(keyword))
181			return arg.substring(keyword.length() + 1);
182			return null;
183			}
184
185			private static int intArg(String[] args, String keyword, int defaultValue) {
186			String val = keywordValue(args, keyword);
187			return (val == null) ? defaultValue : Integer.parseInt(val);
188			}
189
190			private static double doubleArg(String[] args, String keyword, double defaultValue) {
191			String val = keywordValue(args, keyword);
192			return (val == null) ? defaultValue : Double.parseDouble(val);
193			}
194
195			private static Pattern patternArg(String[] args, String keyword) {
196			String val = keywordValue(args, keyword);
197			return (val == null) ? null : Pattern.compile(val);
198			}
199
200	jsr166	1.10	private static boolean booleanArg(String[] args, String keyword) {
201			String val = keywordValue(args, keyword);
202			if (val == null \|\| val.equals("false")) return false;
203			if (val.equals("true")) return true;
204			throw new IllegalArgumentException(val);
205			}
206
207	jsr166	1.1	private static List<Job> filter(Pattern filter, List<Job> jobs) {
208			if (filter == null) return jobs;
209			ArrayList<Job> newJobs = new ArrayList<>();
210			for (Job job : jobs)
211			if (filter.matcher(job.name()).find())
212			newJobs.add(job);
213			return newJobs;
214			}
215
216			private static void deoptimize(int sum) {
217			if (sum == 42)
218			System.out.println("the answer");
219			}
220
221			private static <T> List<T> asSubList(List<T> list) {
222			return list.subList(0, list.size());
223			}
224
225			private static <T> Iterable<T> backwards(final List<T> list) {
226			return new Iterable<T>() {
227			public Iterator<T> iterator() {
228			return new Iterator<T>() {
229			final ListIterator<T> it = list.listIterator(list.size());
230			public boolean hasNext() { return it.hasPrevious(); }
231			public T next() { return it.previous(); }
232			public void remove() { it.remove(); }};}};
233			}
234
235			// Checks for correctness and prevents loop optimizations
236	jsr166	1.25	static class Check {
237	jsr166	1.1	private int sum;
238			public void sum(int sum) {
239			if (this.sum == 0)
240			this.sum = sum;
241			if (this.sum != sum)
242			throw new AssertionError("Sum mismatch");
243			}
244			}
245	jsr166	1.2	volatile Check check = new Check();
246	jsr166	1.1
247			public static void main(String[] args) throws Throwable {
248	jsr166	1.11	new IteratorMicroBenchmark(args).run();
249	jsr166	1.1	}
250
251	jsr166	1.11	void run() throws Throwable {
252	jsr166	1.1	// System.out.printf(
253			// "iterations=%d size=%d, warmup=%1g, filter=\"%s\"%n",
254			// iterations, size, warmupSeconds, filter);
255
256	jsr166	1.17	final ArrayList<Integer> al = new ArrayList<>(size);
257	jsr166	1.1
258			// Populate collections with random data
259			final ThreadLocalRandom rnd = ThreadLocalRandom.current();
260	jsr166	1.3	for (int i = 0; i < size; i++)
261	jsr166	1.1	al.add(rnd.nextInt(size));
262
263			final ArrayDeque<Integer> ad = new ArrayDeque<>(al);
264			final ArrayBlockingQueue<Integer> abq = new ArrayBlockingQueue<>(al.size());
265			abq.addAll(al);
266
267			// shuffle circular array elements so they wrap
268			for (int i = 0, n = rnd.nextInt(size); i < n; i++) {
269			ad.addLast(ad.removeFirst());
270			abq.add(abq.remove());
271			}
272
273	jsr166	1.26	ArrayList<Job> jobs = new ArrayList<>();
274	jsr166	1.1
275	jsr166	1.27	List.<Collection<Integer>>of(
276			al, ad, abq,
277			new LinkedList<>(al),
278			new PriorityQueue<>(al),
279			new Vector<>(al),
280			new ConcurrentLinkedQueue<>(al),
281			new ConcurrentLinkedDeque<>(al),
282			new LinkedBlockingQueue<>(al),
283			new LinkedBlockingDeque<>(al),
284			new LinkedTransferQueue<>(al),
285			new PriorityBlockingQueue<>(al)).forEach(
286			x -> {
287			jobs.addAll(collectionJobs(x));
288			if (x instanceof Deque)
289			jobs.addAll(dequeJobs((Deque<Integer>)x));
290			});
291	jsr166	1.1
292	jsr166	1.11	if (reverse) Collections.reverse(jobs);
293	jsr166	1.10	if (shuffle) Collections.shuffle(jobs);
294
295	jsr166	1.1	time(filter(filter, jobs));
296			}
297
298			List<Job> collectionJobs(Collection<Integer> x) {
299			String klazz = x.getClass().getSimpleName();
300			return List.of(
301	jsr166	1.5	new Job(klazz + " iterate for loop") {
302	jsr166	1.1	public void work() throws Throwable {
303			for (int i = 0; i < iterations; i++) {
304			int sum = 0;
305			for (Integer n : x)
306			sum += n;
307			check.sum(sum);}}},
308	jsr166	1.18	new Job(klazz + " iterator().forEachRemaining()") {
309	jsr166	1.1	public void work() throws Throwable {
310			int[] sum = new int[1];
311			for (int i = 0; i < iterations; i++) {
312			sum[0] = 0;
313			x.iterator().forEachRemaining(n -> sum[0] += n);
314			check.sum(sum[0]);}}},
315	jsr166	1.18	new Job(klazz + " spliterator().tryAdvance()") {
316	jsr166	1.1	public void work() throws Throwable {
317			int[] sum = new int[1];
318			for (int i = 0; i < iterations; i++) {
319			sum[0] = 0;
320			Spliterator<Integer> spliterator = x.spliterator();
321			do {} while (spliterator.tryAdvance(n -> sum[0] += n));
322			check.sum(sum[0]);}}},
323	jsr166	1.18	new Job(klazz + " spliterator().forEachRemaining()") {
324	jsr166	1.1	public void work() throws Throwable {
325			int[] sum = new int[1];
326			for (int i = 0; i < iterations; i++) {
327			sum[0] = 0;
328			x.spliterator().forEachRemaining(n -> sum[0] += n);
329			check.sum(sum[0]);}}},
330	jsr166	1.18	new Job(klazz + " removeIf") {
331	jsr166	1.1	public void work() throws Throwable {
332			int[] sum = new int[1];
333			for (int i = 0; i < iterations; i++) {
334			sum[0] = 0;
335	jsr166	1.16	if (x.removeIf(n -> { sum[0] += n; return false; }))
336			throw new AssertionError();
337	jsr166	1.1	check.sum(sum[0]);}}},
338	jsr166	1.18	new Job(klazz + " contains") {
339	jsr166	1.14	public void work() throws Throwable {
340			int[] sum = new int[1];
341	jsr166	1.15	Object y = new Object() {
342			public boolean equals(Object z) {
343			sum[0] += (int) z; return false; }};
344	jsr166	1.14	for (int i = 0; i < iterations; i++) {
345			sum[0] = 0;
346	jsr166	1.16	if (x.contains(y)) throw new AssertionError();
347			check.sum(sum[0]);}}},
348	jsr166	1.18	new Job(klazz + " remove(Object)") {
349	jsr166	1.16	public void work() throws Throwable {
350			int[] sum = new int[1];
351			Object y = new Object() {
352			public boolean equals(Object z) {
353			sum[0] += (int) z; return false; }};
354			for (int i = 0; i < iterations; i++) {
355			sum[0] = 0;
356			if (x.remove(y)) throw new AssertionError();
357	jsr166	1.14	check.sum(sum[0]);}}},
358	jsr166	1.18	new Job(klazz + " forEach") {
359	jsr166	1.1	public void work() throws Throwable {
360			int[] sum = new int[1];
361			for (int i = 0; i < iterations; i++) {
362			sum[0] = 0;
363			x.forEach(n -> sum[0] += n);
364	jsr166	1.6	check.sum(sum[0]);}}},
365	jsr166	1.18	new Job(klazz + " toArray()") {
366	jsr166	1.6	public void work() throws Throwable {
367			int[] sum = new int[1];
368			for (int i = 0; i < iterations; i++) {
369			sum[0] = 0;
370			for (Object o : x.toArray())
371			sum[0] += (Integer) o;
372			check.sum(sum[0]);}}},
373	jsr166	1.18	new Job(klazz + " toArray(a)") {
374	jsr166	1.6	public void work() throws Throwable {
375			Integer[] a = new Integer[x.size()];
376			int[] sum = new int[1];
377			for (int i = 0; i < iterations; i++) {
378			sum[0] = 0;
379			x.toArray(a);
380			for (Object o : a)
381			sum[0] += (Integer) o;
382	jsr166	1.7	check.sum(sum[0]);}}},
383	jsr166	1.18	new Job(klazz + " toArray(empty)") {
384	jsr166	1.7	public void work() throws Throwable {
385			Integer[] empty = new Integer[0];
386			int[] sum = new int[1];
387			for (int i = 0; i < iterations; i++) {
388			sum[0] = 0;
389			for (Integer o : x.toArray(empty))
390			sum[0] += o;
391	jsr166	1.12	check.sum(sum[0]);}}},
392	jsr166	1.19	new Job(klazz + " stream().forEach") {
393			public void work() throws Throwable {
394			int[] sum = new int[1];
395			for (int i = 0; i < iterations; i++) {
396			sum[0] = 0;
397			x.stream().forEach(n -> sum[0] += n);
398			check.sum(sum[0]);}}},
399			new Job(klazz + " stream().mapToInt") {
400			public void work() throws Throwable {
401			for (int i = 0; i < iterations; i++) {
402			check.sum(x.stream().mapToInt(e -> e).sum());}}},
403	jsr166	1.18	new Job(klazz + " stream().collect") {
404	jsr166	1.12	public void work() throws Throwable {
405			for (int i = 0; i < iterations; i++) {
406			check.sum(x.stream()
407			.collect(summingInt(e -> e)));}}},
408	jsr166	1.21	new Job(klazz + " stream()::iterator") {
409	jsr166	1.20	public void work() throws Throwable {
410			int[] sum = new int[1];
411			for (int i = 0; i < iterations; i++) {
412			sum[0] = 0;
413			for (Integer o : (Iterable<Integer>) x.stream()::iterator)
414			sum[0] += o;
415			check.sum(sum[0]);}}},
416	jsr166	1.19	new Job(klazz + " parallelStream().forEach") {
417			public void work() throws Throwable {
418			for (int i = 0; i < iterations; i++) {
419			LongAdder sum = new LongAdder();
420			x.parallelStream().forEach(n -> sum.add(n));
421			check.sum((int) sum.sum());}}},
422			new Job(klazz + " parallelStream().mapToInt") {
423			public void work() throws Throwable {
424			for (int i = 0; i < iterations; i++) {
425			check.sum(x.parallelStream().mapToInt(e -> e).sum());}}},
426	jsr166	1.18	new Job(klazz + " parallelStream().collect") {
427	jsr166	1.12	public void work() throws Throwable {
428			for (int i = 0; i < iterations; i++) {
429			check.sum(x.parallelStream()
430	jsr166	1.20	.collect(summingInt(e -> e)));}}},
431	jsr166	1.21	new Job(klazz + " parallelStream()::iterator") {
432	jsr166	1.20	public void work() throws Throwable {
433			int[] sum = new int[1];
434			for (int i = 0; i < iterations; i++) {
435			sum[0] = 0;
436			for (Integer o : (Iterable<Integer>) x.parallelStream()::iterator)
437			sum[0] += o;
438			check.sum(sum[0]);}}});
439	jsr166	1.1	}
440
441			List<Job> dequeJobs(Deque<Integer> x) {
442			String klazz = x.getClass().getSimpleName();
443			return List.of(
444	jsr166	1.18	new Job(klazz + " descendingIterator() loop") {
445	jsr166	1.1	public void work() throws Throwable {
446			for (int i = 0; i < iterations; i++) {
447			int sum = 0;
448			Iterator<Integer> it = x.descendingIterator();
449			while (it.hasNext())
450			sum += it.next();
451			check.sum(sum);}}},
452	jsr166	1.18	new Job(klazz + " descendingIterator().forEachRemaining()") {
453	jsr166	1.1	public void work() throws Throwable {
454			int[] sum = new int[1];
455			for (int i = 0; i < iterations; i++) {
456			sum[0] = 0;
457			x.descendingIterator().forEachRemaining(n -> sum[0] += n);
458			check.sum(sum[0]);}}});
459			}
460			}