1 |
dl |
1.1 |
/* |
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 jsr166y.*; |
8 |
|
|
import extra166y.*; |
9 |
|
|
import java.util.*; |
10 |
|
|
import java.util.concurrent.*; |
11 |
|
|
|
12 |
|
|
public class ApplyDemo { |
13 |
|
|
static final int NCPU = Runtime.getRuntime().availableProcessors(); |
14 |
|
|
/** |
15 |
|
|
* Sequential version, for performance comparison |
16 |
|
|
*/ |
17 |
|
|
static <T> void seqApply(T[] array, Ops.Procedure<T> f) { |
18 |
|
|
int n = array.length; |
19 |
jsr166 |
1.2 |
for (int i = 0; i < n; ++i) |
20 |
dl |
1.1 |
f.op(array[i]); |
21 |
|
|
} |
22 |
|
|
|
23 |
|
|
/** |
24 |
|
|
* A sample procedure to apply |
25 |
|
|
*/ |
26 |
|
|
static final class Proc implements Ops.Procedure<Rand> { |
27 |
jsr166 |
1.2 |
public void op(Rand x) { |
28 |
dl |
1.1 |
for (int k = 0; k < (1 << 10); ++k) |
29 |
|
|
x.next(); |
30 |
|
|
} |
31 |
|
|
} |
32 |
|
|
|
33 |
|
|
/** for time conversion */ |
34 |
|
|
static final long NPS = (1000L * 1000 * 1000); |
35 |
|
|
|
36 |
|
|
public static void main(String[] args) throws Exception { |
37 |
|
|
test(); |
38 |
|
|
test(); |
39 |
|
|
} |
40 |
|
|
|
41 |
|
|
public static void test() throws Exception { |
42 |
|
|
int n = 1 << 18; |
43 |
|
|
Rand[] array = new Rand[n]; |
44 |
jsr166 |
1.2 |
for (int i = 0; i < n; ++i) |
45 |
dl |
1.1 |
array[i] = new Rand(i); |
46 |
|
|
final Proc proc = new Proc(); |
47 |
|
|
long last, now; |
48 |
|
|
double elapsed; |
49 |
|
|
last = System.nanoTime(); |
50 |
|
|
for (int k = 0; k < 2; ++k) { |
51 |
|
|
for (int j = 0; j < (1 << 3); ++j) |
52 |
|
|
seqApply(array, proc); |
53 |
|
|
now = System.nanoTime(); |
54 |
|
|
elapsed = (double)(now - last) / NPS; |
55 |
|
|
last = now; |
56 |
|
|
System.out.printf("seq: %7.3f\n", elapsed); |
57 |
|
|
} |
58 |
|
|
for (int i = 1; i <= NCPU; i <<= 1) { |
59 |
|
|
ForkJoinPool fjp = new ForkJoinPool(i); |
60 |
|
|
ParallelArray pa = ParallelArray.createUsingHandoff(array, fjp); |
61 |
|
|
last = System.nanoTime(); |
62 |
|
|
for (int k = 0; k < 2; ++k) { |
63 |
|
|
for (int j = 0; j < (1 << 3); ++j) |
64 |
|
|
pa.apply(proc); |
65 |
|
|
now = System.nanoTime(); |
66 |
|
|
elapsed = (double)(now - last) / NPS; |
67 |
|
|
last = now; |
68 |
|
|
System.out.printf("ps %2d: %7.3f\n", fjp.getParallelism(), elapsed); |
69 |
|
|
} |
70 |
|
|
fjp.shutdownNow(); |
71 |
|
|
fjp.awaitTermination(1, TimeUnit.SECONDS); |
72 |
|
|
Thread.sleep(10); |
73 |
|
|
} |
74 |
|
|
int sum = 0; |
75 |
|
|
for (int i = 0; i < array.length; ++i) sum += array[i].seed; |
76 |
|
|
if (sum == 0) |
77 |
|
|
System.out.print(" "); |
78 |
|
|
} |
79 |
|
|
|
80 |
|
|
/** |
81 |
|
|
* Unsynchronized version of java.util.Random algorithm. |
82 |
|
|
*/ |
83 |
|
|
static final class Rand { |
84 |
|
|
final static long multiplier = 0x5DEECE66DL; |
85 |
|
|
final static long addend = 0xBL; |
86 |
|
|
final static long mask = (1L << 48) - 1; |
87 |
|
|
long seed; |
88 |
|
|
|
89 |
|
|
Rand(long s) { |
90 |
|
|
seed = s; |
91 |
|
|
} |
92 |
|
|
public int next() { |
93 |
|
|
long nextseed = (seed * multiplier + addend) & mask; |
94 |
|
|
seed = nextseed; |
95 |
|
|
return ((int)(nextseed >>> 17)) & 0x7FFFFFFF; |
96 |
|
|
} |
97 |
|
|
} |
98 |
|
|
|
99 |
|
|
} |