test/loops/ScalarLongSort.java

/*
 * 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
 */

import java.util.*;
import java.util.concurrent.*;

// Based very loosely on cilksort

class ScalarLongSort {
    static final long NPS = (1000L * 1000 * 1000); // time conversion

    static int THRESHOLD;
    static final boolean warmup = true;

    public static void main (String[] args) throws Exception {
        int n = 1 << 22;
        int sreps = 2;
        int reps = 20;
        long[] a = new long[n];

        if (warmup) {
            System.out.printf("Sorting %d longs, %d replications\n", n, 1);
            seqRandomFill(a, 0, n);
            long last = System.nanoTime();
            java.util.Arrays.sort(a);
            double elapsed = (double)(System.nanoTime() - last) / NPS;
            System.out.printf("Arrays.sort   time:  %7.3f\n", elapsed);
            checkSorted(a);
        }

        ForkJoinPool pool = new ForkJoinPool();
        // for now hardwire 8 * #CPUs leaf tasks
        THRESHOLD = 1 + ((n + 7) >>> 3) / pool.getParallelism();
        //        THRESHOLD = 1 + ((n + 15) >>> 4) / pool.getParallelism();
        //        THRESHOLD = 1 + ((n + 31) >>> 5) / pool.getParallelism();

        System.out.printf("Sorting %d longs, %d replications\n", n, reps);
        for (int i = 0; i < reps; ++i) {
            pool.invoke(new RandomFiller(a, 0, n));
            long last = System.nanoTime();
            pool.invoke(new Sorter(a, new long[n], 0, n));
            double elapsed = (double)(System.nanoTime() - last) / NPS;
            System.out.printf("Parallel sort time: %7.3f\n", elapsed);
            if (i == 0)
                checkSorted(a);
        }
        System.out.println(pool);

        System.out.printf("Sorting %d longs, %d replications\n", n, sreps);
        for (int i = 0; i < sreps; ++i) {
            pool.invoke(new RandomFiller(a, 0, n));
            long last = System.nanoTime();
            java.util.Arrays.sort(a);
            double elapsed = (double)(System.nanoTime() - last) / NPS;
            System.out.printf("Arrays.sort   time:  %7.3f\n", elapsed);
            if (i == 0)
                checkSorted(a);
        }
        System.out.println(pool);


        pool.shutdown();
    }

    static final class Sorter extends RecursiveAction {
        final long[] a; 
        final long[] w;
        final int origin; 
        final int n;
        Sorter(long[] a, long[] w, int origin, int n) {
            this.a = a; this.w = w; this.origin = origin; this.n = n;
        }

        public void compute()  {
            int l = origin;
            if (n <= THRESHOLD)
                Arrays.sort(a, l, l+n);
            else { // divide in quarters to ensure sorted array in a not w
                SubSorter rs;
                int h = n >>> 1;
                int q = n >>> 2;
                int u = h + q;
                (rs = new SubSorter
                 (new Sorter(a, w, l+h, q),
                  new Sorter(a, w, l+u, n-u),
                  new Merger(a, w, l+h, q, l+u, n-u, l+h, null))).fork();
                (new SubSorter
                 (new Sorter(a, w, l,   q),
                  new Sorter(a, w, l+q, h-q),
                  new Merger(a, w, l,   q, l+q, h-q, l, null))).compute();
                rs.join();
                new Merger(w, a, l, h, l+h, n-h, l, null).compute();
            }
        }
    }
    
    static final class SubSorter extends RecursiveAction {
        final Sorter left;
        final Sorter right;
        final Merger merger;
        SubSorter(Sorter left, Sorter right, Merger merger) {
            this.left = left; this.right = right; this.merger = merger;
        }
        public void compute() {
            right.fork();
            left.compute();
            right.join();
            merger.compute();
        }
    }

    static final class Merger extends RecursiveAction {
        final long[] a; final long[] w;
        final int lo; final int ln; final int ro; final int rn; final int wo;
        final Merger next;
        Merger(long[] a, long[] w, int lo, int ln, int ro, int rn, int wo,
               Merger next) {
            this.a = a;    this.w = w;
            this.lo = lo;  this.ln = ln;
            this.ro = ro;  this.rn = rn;
            this.wo = wo;
            this.next = next;
        }

        /**
         * Merge left and right by splitting left in half,
         * and finding index of right closest to split point.
         * Uses left-spine decomposition to generate all
         * merge tasks before bottomming out at base case.
         * 
         */
        public void compute() {
            Merger rights = null;
            int nleft = ln;
            int nright = rn;
            while (nleft > THRESHOLD) { //  && nright > (THRESHOLD >>> 3)) {
                int lh = nleft >>> 1;
                int splitIndex = lo + lh;
                long split = a[splitIndex];
                int rl = 0;
                int rh = nright;
                while (rl < rh) {
                    int mid = (rl + rh) >>> 1;
                    if (split <= a[ro + mid])
                        rh = mid;
                    else
                        rl = mid + 1;
                }
                (rights = new Merger(a, w, splitIndex, nleft-lh, ro+rh,
                                     nright-rh, wo+lh+rh, rights)).fork();
                nleft = lh;
                nright = rh;
            }

            // Base case -- merge left and right
            int l = lo;
            int lFence = lo + nleft;
            int r = ro;
            int rFence = ro + nright;
            int k = wo;
            while (l < lFence && r < rFence) {
                long al = a[l];
                long ar = a[r];
                long t;
                if (al <= ar) { ++l; t = al; } else { ++r; t = ar; }
                w[k++] = t;
            }
            while (l < lFence)
                w[k++] = a[l++];
            while (r < rFence)
                w[k++] = a[r++];
            
            while (rights != null) {
                rights.join();
                rights = rights.next;
            }
        }

    }

    static void checkSorted (long[] a)  {
        int n = a.length;
        for (int i = 0; i < n - 1; i++) {
            if (a[i] > a[i+1]) {
                throw new Error("Unsorted at " + i + ": " + 
                                a[i] + " / " + a[i+1]);
            }
        }
    }

    static void seqRandomFill(long[] array, int lo, int hi) {
        ThreadLocalRandom rng = ThreadLocalRandom.current();
        for (int i = lo; i < hi; ++i)
            array[i] = rng.nextLong();
    }

    static final class RandomFiller extends RecursiveAction {
        final long[] array;
        final int lo, hi;
        RandomFiller(long[] array, int lo, int hi) {
            this.array = array; this.lo = lo; this.hi = hi;
        }
        public void compute() {
            if (hi - lo <= THRESHOLD)
                seqRandomFill(array, lo, hi);
            else {
                int mid = (lo + hi) >>> 1;
                RandomFiller r = new RandomFiller(array, mid, hi);
                r.fork();
                (new RandomFiller(array, lo, mid)).compute();
                r.join();
            }
        }
    }


}
Revision:	1.1
Committed:	Tue Mar 16 11:42:46 2010 UTC (14 years, 2 months ago) by dl
Branch:	MAIN
Log Message:	Add sorting demo
#	Content
1	/*
2	* Written by Doug Lea with assistance from members of JCP JSR-166
3	* Expert Group and released to the public domain, as explained at
4	* http://creativecommons.org/licenses/publicdomain
5	*/
6
7	import java.util.*;
8	import java.util.concurrent.*;
9
10	// Based very loosely on cilksort
11
12	class ScalarLongSort {
13	static final long NPS = (1000L * 1000 * 1000); // time conversion
14
15	static int THRESHOLD;
16	static final boolean warmup = true;
17
18	public static void main (String[] args) throws Exception {
19	int n = 1 << 22;
20	int sreps = 2;
21	int reps = 20;
22	long[] a = new long[n];
23
24	if (warmup) {
25	System.out.printf("Sorting %d longs, %d replications\n", n, 1);
26	seqRandomFill(a, 0, n);
27	long last = System.nanoTime();
28	java.util.Arrays.sort(a);
29	double elapsed = (double)(System.nanoTime() - last) / NPS;
30	System.out.printf("Arrays.sort time: %7.3f\n", elapsed);
31	checkSorted(a);
32	}
33
34	ForkJoinPool pool = new ForkJoinPool();
35	// for now hardwire 8 * #CPUs leaf tasks
36	THRESHOLD = 1 + ((n + 7) >>> 3) / pool.getParallelism();
37	// THRESHOLD = 1 + ((n + 15) >>> 4) / pool.getParallelism();
38	// THRESHOLD = 1 + ((n + 31) >>> 5) / pool.getParallelism();
39
40	System.out.printf("Sorting %d longs, %d replications\n", n, reps);
41	for (int i = 0; i < reps; ++i) {
42	pool.invoke(new RandomFiller(a, 0, n));
43	long last = System.nanoTime();
44	pool.invoke(new Sorter(a, new long[n], 0, n));
45	double elapsed = (double)(System.nanoTime() - last) / NPS;
46	System.out.printf("Parallel sort time: %7.3f\n", elapsed);
47	if (i == 0)
48	checkSorted(a);
49	}
50	System.out.println(pool);
51
52	System.out.printf("Sorting %d longs, %d replications\n", n, sreps);
53	for (int i = 0; i < sreps; ++i) {
54	pool.invoke(new RandomFiller(a, 0, n));
55	long last = System.nanoTime();
56	java.util.Arrays.sort(a);
57	double elapsed = (double)(System.nanoTime() - last) / NPS;
58	System.out.printf("Arrays.sort time: %7.3f\n", elapsed);
59	if (i == 0)
60	checkSorted(a);
61	}
62	System.out.println(pool);
63
64
65	pool.shutdown();
66	}
67
68	static final class Sorter extends RecursiveAction {
69	final long[] a;
70	final long[] w;
71	final int origin;
72	final int n;
73	Sorter(long[] a, long[] w, int origin, int n) {
74	this.a = a; this.w = w; this.origin = origin; this.n = n;
75	}
76
77	public void compute() {
78	int l = origin;
79	if (n <= THRESHOLD)
80	Arrays.sort(a, l, l+n);
81	else { // divide in quarters to ensure sorted array in a not w
82	SubSorter rs;
83	int h = n >>> 1;
84	int q = n >>> 2;
85	int u = h + q;
86	(rs = new SubSorter
87	(new Sorter(a, w, l+h, q),
88	new Sorter(a, w, l+u, n-u),
89	new Merger(a, w, l+h, q, l+u, n-u, l+h, null))).fork();
90	(new SubSorter
91	(new Sorter(a, w, l, q),
92	new Sorter(a, w, l+q, h-q),
93	new Merger(a, w, l, q, l+q, h-q, l, null))).compute();
94	rs.join();
95	new Merger(w, a, l, h, l+h, n-h, l, null).compute();
96	}
97	}
98	}
99
100	static final class SubSorter extends RecursiveAction {
101	final Sorter left;
102	final Sorter right;
103	final Merger merger;
104	SubSorter(Sorter left, Sorter right, Merger merger) {
105	this.left = left; this.right = right; this.merger = merger;
106	}
107	public void compute() {
108	right.fork();
109	left.compute();
110	right.join();
111	merger.compute();
112	}
113	}
114
115	static final class Merger extends RecursiveAction {
116	final long[] a; final long[] w;
117	final int lo; final int ln; final int ro; final int rn; final int wo;
118	final Merger next;
119	Merger(long[] a, long[] w, int lo, int ln, int ro, int rn, int wo,
120	Merger next) {
121	this.a = a; this.w = w;
122	this.lo = lo; this.ln = ln;
123	this.ro = ro; this.rn = rn;
124	this.wo = wo;
125	this.next = next;
126	}
127
128	/**
129	* Merge left and right by splitting left in half,
130	* and finding index of right closest to split point.
131	* Uses left-spine decomposition to generate all
132	* merge tasks before bottomming out at base case.
133	*
134	*/
135	public void compute() {
136	Merger rights = null;
137	int nleft = ln;
138	int nright = rn;
139	while (nleft > THRESHOLD) { // && nright > (THRESHOLD >>> 3)) {
140	int lh = nleft >>> 1;
141	int splitIndex = lo + lh;
142	long split = a[splitIndex];
143	int rl = 0;
144	int rh = nright;
145	while (rl < rh) {
146	int mid = (rl + rh) >>> 1;
147	if (split <= a[ro + mid])
148	rh = mid;
149	else
150	rl = mid + 1;
151	}
152	(rights = new Merger(a, w, splitIndex, nleft-lh, ro+rh,
153	nright-rh, wo+lh+rh, rights)).fork();
154	nleft = lh;
155	nright = rh;
156	}
157
158	// Base case -- merge left and right
159	int l = lo;
160	int lFence = lo + nleft;
161	int r = ro;
162	int rFence = ro + nright;
163	int k = wo;
164	while (l < lFence && r < rFence) {
165	long al = a[l];
166	long ar = a[r];
167	long t;
168	if (al <= ar) { ++l; t = al; } else { ++r; t = ar; }
169	w[k++] = t;
170	}
171	while (l < lFence)
172	w[k++] = a[l++];
173	while (r < rFence)
174	w[k++] = a[r++];
175
176	while (rights != null) {
177	rights.join();
178	rights = rights.next;
179	}
180	}
181
182	}
183
184	static void checkSorted (long[] a) {
185	int n = a.length;
186	for (int i = 0; i < n - 1; i++) {
187	if (a[i] > a[i+1]) {
188	throw new Error("Unsorted at " + i + ": " +
189	a[i] + " / " + a[i+1]);
190	}
191	}
192	}
193
194	static void seqRandomFill(long[] array, int lo, int hi) {
195	ThreadLocalRandom rng = ThreadLocalRandom.current();
196	for (int i = lo; i < hi; ++i)
197	array[i] = rng.nextLong();
198	}
199
200	static final class RandomFiller extends RecursiveAction {
201	final long[] array;
202	final int lo, hi;
203	RandomFiller(long[] array, int lo, int hi) {
204	this.array = array; this.lo = lo; this.hi = hi;
205	}
206	public void compute() {
207	if (hi - lo <= THRESHOLD)
208	seqRandomFill(array, lo, hi);
209	else {
210	int mid = (lo + hi) >>> 1;
211	RandomFiller r = new RandomFiller(array, mid, hi);
212	r.fork();
213	(new RandomFiller(array, lo, mid)).compute();
214	r.join();
215	}
216	}
217	}
218
219
220	}