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.Enumeration;
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.ConcurrentSkipListMap;
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 + " 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.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:	1.20
Committed:	Sat Apr 15 02:15:43 2017 UTC (7 years, 1 month ago) by jsr166
Branch:	MAIN
Changes since 1.19:	+17 -1 lines
Log Message:	add microbenchmarks for stream::iterator
#	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.Enumeration;
40			import java.util.Iterator;
41	jsr166	1.13	import java.util.LinkedList;
42	jsr166	1.1	import java.util.List;
43			import java.util.ListIterator;
44			import java.util.Map;
45	jsr166	1.8	import java.util.PriorityQueue;
46	jsr166	1.1	import java.util.Spliterator;
47			import java.util.Vector;
48			import java.util.concurrent.ArrayBlockingQueue;
49			import java.util.concurrent.ConcurrentLinkedDeque;
50			import java.util.concurrent.ConcurrentLinkedQueue;
51			import java.util.concurrent.LinkedBlockingDeque;
52			import java.util.concurrent.LinkedBlockingQueue;
53			import java.util.concurrent.LinkedTransferQueue;
54	jsr166	1.8	import java.util.concurrent.PriorityBlockingQueue;
55	jsr166	1.1	import java.util.concurrent.ConcurrentSkipListMap;
56			import java.util.concurrent.CountDownLatch;
57			import java.util.concurrent.ThreadLocalRandom;
58			import java.util.concurrent.TimeUnit;
59	jsr166	1.19	import java.util.concurrent.atomic.LongAdder;
60	jsr166	1.1	import java.util.regex.Pattern;
61
62			/**
63			* Usage: [iterations=N] [size=N] [filter=REGEXP] [warmup=SECONDS]
64			*
65			* To run this in micro-benchmark mode, simply run as a normal java program.
66			* Be patient; this program runs for a very long time.
67			* For faster runs, restrict execution using command line args.
68			*
69			* This is an interface based version of ArrayList/IteratorMicroBenchmark
70			*
71			* @author Martin Buchholz
72			*/
73			public class IteratorMicroBenchmark {
74			abstract static class Job {
75			private final String name;
76			public Job(String name) { this.name = name; }
77			public String name() { return name; }
78			public abstract void work() throws Throwable;
79			}
80
81	jsr166	1.11	final int iterations;
82			final int size; // number of elements in collections
83			final double warmupSeconds;
84			final long warmupNanos;
85			final Pattern filter; // select subset of Jobs to run
86			final boolean reverse; // reverse order of Jobs
87			final boolean shuffle; // randomize order of Jobs
88
89			IteratorMicroBenchmark(String[] args) {
90			iterations = intArg(args, "iterations", 10_000);
91			size = intArg(args, "size", 1000);
92			warmupSeconds = doubleArg(args, "warmup", 7.0);
93			filter = patternArg(args, "filter");
94			reverse = booleanArg(args, "reverse");
95			shuffle = booleanArg(args, "shuffle");
96
97			warmupNanos = (long) (warmupSeconds * (1000L * 1000L * 1000L));
98			}
99	jsr166	1.1
100			// --------------- GC finalization infrastructure ---------------
101
102			/** No guarantees, but effective in practice. */
103			static void forceFullGc() {
104			CountDownLatch finalizeDone = new CountDownLatch(1);
105			WeakReference<?> ref = new WeakReference<Object>(new Object() {
106			protected void finalize() { finalizeDone.countDown(); }});
107			try {
108			for (int i = 0; i < 10; i++) {
109			System.gc();
110			if (finalizeDone.await(1L, TimeUnit.SECONDS) && ref.get() == null) {
111			System.runFinalization(); // try to pick up stragglers
112			return;
113			}
114			}
115			} catch (InterruptedException unexpected) {
116			throw new AssertionError("unexpected InterruptedException");
117			}
118			throw new AssertionError("failed to do a \"full\" gc");
119			}
120
121			/**
122			* Runs each job for long enough that all the runtime compilers
123			* have had plenty of time to warm up, i.e. get around to
124			* compiling everything worth compiling.
125			* Returns array of average times per job per run.
126			*/
127			long[] time0(List<Job> jobs) throws Throwable {
128			final int size = jobs.size();
129			long[] nanoss = new long[size];
130			for (int i = 0; i < size; i++) {
131			if (warmupNanos > 0) forceFullGc();
132	jsr166	1.9	Job job = jobs.get(i);
133			long totalTime;
134			int runs = 0;
135			long startTime = System.nanoTime();
136			do { job.work(); runs++; }
137			while ((totalTime = System.nanoTime() - startTime) < warmupNanos);
138			nanoss[i] = totalTime/runs;
139	jsr166	1.1	}
140			return nanoss;
141			}
142
143			void time(List<Job> jobs) throws Throwable {
144	jsr166	1.9	if (warmupNanos > 0) time0(jobs); // Warm up run
145	jsr166	1.1	final int size = jobs.size();
146			final long[] nanoss = time0(jobs); // Real timing run
147			final long[] milliss = new long[size];
148			final double[] ratios = new double[size];
149
150			final String nameHeader = "Method";
151			final String millisHeader = "Millis";
152			final String ratioHeader = "Ratio";
153
154			int nameWidth = nameHeader.length();
155			int millisWidth = millisHeader.length();
156			int ratioWidth = ratioHeader.length();
157
158			for (int i = 0; i < size; i++) {
159			nameWidth = Math.max(nameWidth, jobs.get(i).name().length());
160
161			milliss[i] = nanoss[i]/(1000L * 1000L);
162			millisWidth = Math.max(millisWidth,
163			String.format("%d", milliss[i]).length());
164
165			ratios[i] = (double) nanoss[i] / (double) nanoss[0];
166			ratioWidth = Math.max(ratioWidth,
167			String.format("%.3f", ratios[i]).length());
168			}
169
170			String format = String.format("%%-%ds %%%dd %%%d.3f%%n",
171			nameWidth, millisWidth, ratioWidth);
172			String headerFormat = String.format("%%-%ds %%%ds %%%ds%%n",
173			nameWidth, millisWidth, ratioWidth);
174			System.out.printf(headerFormat, "Method", "Millis", "Ratio");
175
176			// Print out absolute and relative times, calibrated against first job
177			for (int i = 0; i < size; i++)
178			System.out.printf(format, jobs.get(i).name(), milliss[i], ratios[i]);
179			}
180
181			private static String keywordValue(String[] args, String keyword) {
182			for (String arg : args)
183			if (arg.startsWith(keyword))
184			return arg.substring(keyword.length() + 1);
185			return null;
186			}
187
188			private static int intArg(String[] args, String keyword, int defaultValue) {
189			String val = keywordValue(args, keyword);
190			return (val == null) ? defaultValue : Integer.parseInt(val);
191			}
192
193			private static double doubleArg(String[] args, String keyword, double defaultValue) {
194			String val = keywordValue(args, keyword);
195			return (val == null) ? defaultValue : Double.parseDouble(val);
196			}
197
198			private static Pattern patternArg(String[] args, String keyword) {
199			String val = keywordValue(args, keyword);
200			return (val == null) ? null : Pattern.compile(val);
201			}
202
203	jsr166	1.10	private static boolean booleanArg(String[] args, String keyword) {
204			String val = keywordValue(args, keyword);
205			if (val == null \|\| val.equals("false")) return false;
206			if (val.equals("true")) return true;
207			throw new IllegalArgumentException(val);
208			}
209
210	jsr166	1.1	private static List<Job> filter(Pattern filter, List<Job> jobs) {
211			if (filter == null) return jobs;
212			ArrayList<Job> newJobs = new ArrayList<>();
213			for (Job job : jobs)
214			if (filter.matcher(job.name()).find())
215			newJobs.add(job);
216			return newJobs;
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> List<T> asSubList(List<T> list) {
225			return list.subList(0, list.size());
226			}
227
228			private static <T> Iterable<T> backwards(final List<T> list) {
229			return new Iterable<T>() {
230			public Iterator<T> iterator() {
231			return new Iterator<T>() {
232			final ListIterator<T> it = list.listIterator(list.size());
233			public boolean hasNext() { return it.hasPrevious(); }
234			public T next() { return it.previous(); }
235			public void remove() { it.remove(); }};}};
236			}
237
238			// Checks for correctness and prevents loop optimizations
239			class Check {
240			private int sum;
241			public void sum(int sum) {
242			if (this.sum == 0)
243			this.sum = sum;
244			if (this.sum != sum)
245			throw new AssertionError("Sum mismatch");
246			}
247			}
248	jsr166	1.2	volatile Check check = new Check();
249	jsr166	1.1
250			public static void main(String[] args) throws Throwable {
251	jsr166	1.11	new IteratorMicroBenchmark(args).run();
252	jsr166	1.1	}
253
254	jsr166	1.11	void run() throws Throwable {
255	jsr166	1.1	// System.out.printf(
256			// "iterations=%d size=%d, warmup=%1g, filter=\"%s\"%n",
257			// iterations, size, warmupSeconds, filter);
258
259	jsr166	1.17	final ArrayList<Integer> al = new ArrayList<>(size);
260	jsr166	1.1
261			// Populate collections with random data
262			final ThreadLocalRandom rnd = ThreadLocalRandom.current();
263	jsr166	1.3	for (int i = 0; i < size; i++)
264	jsr166	1.1	al.add(rnd.nextInt(size));
265
266			final ArrayDeque<Integer> ad = new ArrayDeque<>(al);
267			final ArrayBlockingQueue<Integer> abq = new ArrayBlockingQueue<>(al.size());
268			abq.addAll(al);
269
270			// shuffle circular array elements so they wrap
271			for (int i = 0, n = rnd.nextInt(size); i < n; i++) {
272			ad.addLast(ad.removeFirst());
273			abq.add(abq.remove());
274			}
275
276			ArrayList<Job> jobs = new ArrayList<>(Arrays.asList());
277
278			List.of(al, ad, abq,
279	jsr166	1.13	new LinkedList<>(al),
280	jsr166	1.8	new PriorityQueue<>(al),
281	jsr166	1.1	new Vector<>(al),
282			new ConcurrentLinkedQueue<>(al),
283			new ConcurrentLinkedDeque<>(al),
284			new LinkedBlockingQueue<>(al),
285			new LinkedBlockingDeque<>(al),
286	jsr166	1.8	new LinkedTransferQueue<>(al),
287			new PriorityBlockingQueue<>(al))
288	jsr166	1.1	.stream()
289			.forEach(x -> {
290			jobs.addAll(collectionJobs(x));
291			if (x instanceof Deque)
292			jobs.addAll(dequeJobs((Deque<Integer>)x));
293			});
294
295	jsr166	1.11	if (reverse) Collections.reverse(jobs);
296	jsr166	1.10	if (shuffle) Collections.shuffle(jobs);
297
298	jsr166	1.1	time(filter(filter, jobs));
299			}
300
301			List<Job> collectionJobs(Collection<Integer> x) {
302			String klazz = x.getClass().getSimpleName();
303			return List.of(
304	jsr166	1.5	new Job(klazz + " iterate for loop") {
305	jsr166	1.1	public void work() throws Throwable {
306			for (int i = 0; i < iterations; i++) {
307			int sum = 0;
308			for (Integer n : x)
309			sum += n;
310			check.sum(sum);}}},
311	jsr166	1.18	new Job(klazz + " iterator().forEachRemaining()") {
312	jsr166	1.1	public void work() throws Throwable {
313			int[] sum = new int[1];
314			for (int i = 0; i < iterations; i++) {
315			sum[0] = 0;
316			x.iterator().forEachRemaining(n -> sum[0] += n);
317			check.sum(sum[0]);}}},
318	jsr166	1.18	new Job(klazz + " spliterator().tryAdvance()") {
319	jsr166	1.1	public void work() throws Throwable {
320			int[] sum = new int[1];
321			for (int i = 0; i < iterations; i++) {
322			sum[0] = 0;
323			Spliterator<Integer> spliterator = x.spliterator();
324			do {} while (spliterator.tryAdvance(n -> sum[0] += n));
325			check.sum(sum[0]);}}},
326	jsr166	1.18	new Job(klazz + " spliterator().forEachRemaining()") {
327	jsr166	1.1	public void work() throws Throwable {
328			int[] sum = new int[1];
329			for (int i = 0; i < iterations; i++) {
330			sum[0] = 0;
331			x.spliterator().forEachRemaining(n -> sum[0] += n);
332			check.sum(sum[0]);}}},
333	jsr166	1.18	new Job(klazz + " removeIf") {
334	jsr166	1.1	public void work() throws Throwable {
335			int[] sum = new int[1];
336			for (int i = 0; i < iterations; i++) {
337			sum[0] = 0;
338	jsr166	1.16	if (x.removeIf(n -> { sum[0] += n; return false; }))
339			throw new AssertionError();
340	jsr166	1.1	check.sum(sum[0]);}}},
341	jsr166	1.18	new Job(klazz + " contains") {
342	jsr166	1.14	public void work() throws Throwable {
343			int[] sum = new int[1];
344	jsr166	1.15	Object y = new Object() {
345			public boolean equals(Object z) {
346			sum[0] += (int) z; return false; }};
347	jsr166	1.14	for (int i = 0; i < iterations; i++) {
348			sum[0] = 0;
349	jsr166	1.16	if (x.contains(y)) throw new AssertionError();
350			check.sum(sum[0]);}}},
351	jsr166	1.18	new Job(klazz + " remove(Object)") {
352	jsr166	1.16	public void work() throws Throwable {
353			int[] sum = new int[1];
354			Object y = new Object() {
355			public boolean equals(Object z) {
356			sum[0] += (int) z; return false; }};
357			for (int i = 0; i < iterations; i++) {
358			sum[0] = 0;
359			if (x.remove(y)) throw new AssertionError();
360	jsr166	1.14	check.sum(sum[0]);}}},
361	jsr166	1.18	new Job(klazz + " forEach") {
362	jsr166	1.1	public void work() throws Throwable {
363			int[] sum = new int[1];
364			for (int i = 0; i < iterations; i++) {
365			sum[0] = 0;
366			x.forEach(n -> sum[0] += n);
367	jsr166	1.6	check.sum(sum[0]);}}},
368	jsr166	1.18	new Job(klazz + " toArray()") {
369	jsr166	1.6	public void work() throws Throwable {
370			int[] sum = new int[1];
371			for (int i = 0; i < iterations; i++) {
372			sum[0] = 0;
373			for (Object o : x.toArray())
374			sum[0] += (Integer) o;
375			check.sum(sum[0]);}}},
376	jsr166	1.18	new Job(klazz + " toArray(a)") {
377	jsr166	1.6	public void work() throws Throwable {
378			Integer[] a = new Integer[x.size()];
379			int[] sum = new int[1];
380			for (int i = 0; i < iterations; i++) {
381			sum[0] = 0;
382			x.toArray(a);
383			for (Object o : a)
384			sum[0] += (Integer) o;
385	jsr166	1.7	check.sum(sum[0]);}}},
386	jsr166	1.18	new Job(klazz + " toArray(empty)") {
387	jsr166	1.7	public void work() throws Throwable {
388			Integer[] empty = new Integer[0];
389			int[] sum = new int[1];
390			for (int i = 0; i < iterations; i++) {
391			sum[0] = 0;
392			for (Integer o : x.toArray(empty))
393			sum[0] += o;
394	jsr166	1.12	check.sum(sum[0]);}}},
395	jsr166	1.19	new Job(klazz + " stream().forEach") {
396			public void work() throws Throwable {
397			int[] sum = new int[1];
398			for (int i = 0; i < iterations; i++) {
399			sum[0] = 0;
400			x.stream().forEach(n -> sum[0] += n);
401			check.sum(sum[0]);}}},
402			new Job(klazz + " stream().mapToInt") {
403			public void work() throws Throwable {
404			for (int i = 0; i < iterations; i++) {
405			check.sum(x.stream().mapToInt(e -> e).sum());}}},
406	jsr166	1.18	new Job(klazz + " stream().collect") {
407	jsr166	1.12	public void work() throws Throwable {
408			for (int i = 0; i < iterations; i++) {
409			check.sum(x.stream()
410			.collect(summingInt(e -> e)));}}},
411	jsr166	1.20	new Job(klazz + " stream().iterator()") {
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			for (Integer o : (Iterable<Integer>) x.stream()::iterator)
417			sum[0] += o;
418			check.sum(sum[0]);}}},
419	jsr166	1.19	new Job(klazz + " parallelStream().forEach") {
420			public void work() throws Throwable {
421			for (int i = 0; i < iterations; i++) {
422			LongAdder sum = new LongAdder();
423			x.parallelStream().forEach(n -> sum.add(n));
424			check.sum((int) sum.sum());}}},
425			new Job(klazz + " parallelStream().mapToInt") {
426			public void work() throws Throwable {
427			for (int i = 0; i < iterations; i++) {
428			check.sum(x.parallelStream().mapToInt(e -> e).sum());}}},
429	jsr166	1.18	new Job(klazz + " parallelStream().collect") {
430	jsr166	1.12	public void work() throws Throwable {
431			for (int i = 0; i < iterations; i++) {
432			check.sum(x.parallelStream()
433	jsr166	1.20	.collect(summingInt(e -> e)));}}},
434			new Job(klazz + " stream().iterator()") {
435			public void work() throws Throwable {
436			int[] sum = new int[1];
437			for (int i = 0; i < iterations; i++) {
438			sum[0] = 0;
439			for (Integer o : (Iterable<Integer>) x.parallelStream()::iterator)
440			sum[0] += o;
441			check.sum(sum[0]);}}});
442	jsr166	1.1	}
443
444			List<Job> dequeJobs(Deque<Integer> x) {
445			String klazz = x.getClass().getSimpleName();
446			return List.of(
447	jsr166	1.18	new Job(klazz + " descendingIterator() loop") {
448	jsr166	1.1	public void work() throws Throwable {
449			for (int i = 0; i < iterations; i++) {
450			int sum = 0;
451			Iterator<Integer> it = x.descendingIterator();
452			while (it.hasNext())
453			sum += it.next();
454			check.sum(sum);}}},
455	jsr166	1.18	new Job(klazz + " descendingIterator().forEachRemaining()") {
456	jsr166	1.1	public void work() throws Throwable {
457			int[] sum = new int[1];
458			for (int i = 0; i < iterations; i++) {
459			sum[0] = 0;
460			x.descendingIterator().forEachRemaining(n -> sum[0] += n);
461			check.sum(sum[0]);}}});
462			}
463			}