/*

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 *

 * 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.

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 * 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

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 * 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.

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/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Written by Doug Lea with assistance from members of JCP JSR-166

 * Expert Group and released to the public domain, as explained at

 * http://creativecommons.org/licenses/publicdomain

 */

/*

 * @test

 * @bug 4486658

 * @compile -source 1.5 MapLoops.java

 * @run main/timeout=4700 MapLoops

 * @summary Exercise multithreaded maps, by default ConcurrentHashMap.

 * Multithreaded hash table test.  Each thread does a random walk

 * though elements of "key" array. On each iteration, it checks if

 * table includes key.  If absent, with probability pinsert it

 * inserts it, and if present, with probability premove it removes

 * it.  (pinsert and premove are expressed as percentages to simplify

 * parsing from command line.)

 */

import java.util.*;

import java.util.concurrent.*;

public class MapLoops {

    static final int NKEYS = 100000;

    static int pinsert     = 60;

    static int premove     = 2;

    static int maxThreads  = 5;

    static int nops        = 1000000;

    static int removesPerMaxRandom;

    static int insertsPerMaxRandom;

    static final ExecutorService pool = Executors.newCachedThreadPool();

    public static void main(String[] args) throws Exception {

        Class mapClass = null;

        if (args.length > 0) {

            try {

                mapClass = Class.forName(args[0]);

            } catch(ClassNotFoundException e) {

                throw new RuntimeException("Class " + args[0] + " not found.");

            }

        }

        else

            mapClass = RWMap.class;

        if (args.length > 1)

            maxThreads = Integer.parseInt(args[1]);

        if (args.length > 2)

            nops = Integer.parseInt(args[2]);

        if (args.length > 3)

            pinsert = Integer.parseInt(args[3]);

        if (args.length > 4)

            premove = Integer.parseInt(args[4]);

        // normalize probabilities wrt random number generator

        removesPerMaxRandom = (int)(((double)premove/100.0 * 0x7FFFFFFFL));

        insertsPerMaxRandom = (int)(((double)pinsert/100.0 * 0x7FFFFFFFL));

        System.out.println("Using " + mapClass.getName());

        Random rng = new Random(315312);

        Integer[] key = new Integer[NKEYS];

        for (int i = 0; i < key.length; ++i)

            key[i] = new Integer(rng.nextInt());

        // warmup

        System.out.println("Warmup...");

        for (int k = 0; k < 2; ++k) {

            Map<Integer, Integer> map = (Map<Integer,Integer>)mapClass.newInstance();

            LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();

            CyclicBarrier barrier = new CyclicBarrier(1, timer);

            new Runner(map, key, barrier).run();

            map.clear();

            Thread.sleep(100);

        }

        for (int i = 1; i <= maxThreads; i += (i+1) >>> 1) {

            System.out.print("Threads: " + i + "\t:");

            Map<Integer, Integer> map = (Map<Integer,Integer>)mapClass.newInstance();

            LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();

            CyclicBarrier barrier = new CyclicBarrier(i+1, timer);

            for (int k = 0; k < i; ++k)

                pool.execute(new Runner(map, key, barrier));

            barrier.await();

            barrier.await();

            long time = timer.getTime();

            long tpo = time / (i * (long)nops);

            System.out.print(LoopHelpers.rightJustify(tpo) + " ns per op");

            double secs = (double)(time) / 1000000000.0;

            System.out.println("\t " + secs + "s run time");

            map.clear();

        }

        pool.shutdown();

        if (! pool.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS))

            throw new Error();

    }

    static class Runner implements Runnable {

        final Map<Integer,Integer> map;

        final Integer[] key;

        final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();

        final CyclicBarrier barrier;

        int position;

        int total;

        Runner(Map<Integer,Integer> map, Integer[] key,  CyclicBarrier barrier) {

            this.map = map;

            this.key = key;

            this.barrier = barrier;

            position = key.length / 2;

        }

        int step() {

            // random-walk around key positions,  bunching accesses

            int r = rng.next();

            position += (r & 7) - 3;

            while (position >= key.length) position -= key.length;

            while (position < 0) position += key.length;

            Integer k = key[position];

            Integer x = map.get(k);

            if (x != null) {

                if (x.intValue() != k.intValue())

                    throw new Error("bad mapping: " + x + " to " + k);

                if (r < removesPerMaxRandom) {

                    // get awy from this position

                    position = r % key.length;

                    map.remove(k);

                    return 2;

                }

                else

                    total += LoopHelpers.compute2(LoopHelpers.compute1(x.intValue()));

            }

            else {

                if (r < insertsPerMaxRandom) {

                    map.put(k, k);

                    return 2;

                }

            }

            return 1;

        }

        public void run() {

            try {

                barrier.await();

                int ops = nops;

                while (ops > 0)

                    ops -= step();

                barrier.await();

            }

            catch (Exception ex) {

                ex.printStackTrace();

            }

        }

    }

}