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 |
|
|
|
8 |
|
|
import jsr166y.*; |
9 |
|
|
import extra166y.*; |
10 |
|
|
import static extra166y.Ops.*; |
11 |
|
|
import java.util.*; |
12 |
|
|
import java.util.concurrent.*; |
13 |
|
|
|
14 |
|
|
public class LongCumulateDemo { |
15 |
|
|
static final int NCPU = Runtime.getRuntime().availableProcessors(); |
16 |
|
|
/** for time conversion */ |
17 |
|
|
static final long NPS = (1000L * 1000 * 1000); |
18 |
|
|
|
19 |
|
|
static final boolean reportSteals = false; |
20 |
|
|
|
21 |
|
|
public static void main(String[] args) throws Exception { |
22 |
|
|
int n = 1 << 19; |
23 |
|
|
int reps = 1 << 8; |
24 |
|
|
int tests = 2; |
25 |
|
|
long[] array = new long[n]; |
26 |
|
|
long last, now; |
27 |
|
|
double elapsed; |
28 |
|
|
|
29 |
|
|
for (int j = 0; j < tests; ++j) { |
30 |
|
|
seqFill(array); |
31 |
|
|
last = System.nanoTime(); |
32 |
|
|
for (int k = 0; k < reps; ++k) { |
33 |
|
|
seqCumulate(array); |
34 |
|
|
if (j == 0 && k == 0) |
35 |
|
|
check(array); |
36 |
|
|
} |
37 |
|
|
now = System.nanoTime(); |
38 |
|
|
elapsed = (double)(now - last) / (NPS); |
39 |
|
|
System.out.printf("seq : %9.5f\n", elapsed); |
40 |
|
|
} |
41 |
|
|
|
42 |
|
|
ForkJoinPool fjp = new ForkJoinPool(2); |
43 |
|
|
for (int sweeps = 0; sweeps < 2; ++sweeps) { |
44 |
|
|
for (int i = 2; i <= NCPU; i <<= 1) { |
45 |
|
|
fjp.setParallelism(i); |
46 |
|
|
oneRun(fjp, array, i, reps, tests); |
47 |
|
|
} |
48 |
|
|
for (int i = NCPU; i >= 1; i >>>= 1) { |
49 |
|
|
fjp.setParallelism(i); |
50 |
|
|
oneRun(fjp, array, i, reps, tests); |
51 |
|
|
} |
52 |
|
|
} |
53 |
|
|
fjp.shutdown(); |
54 |
|
|
} |
55 |
|
|
|
56 |
|
|
static void oneRun(ForkJoinPool fjp, |
57 |
|
|
long[] array, int nthreads, |
58 |
|
|
int reps, int tests) throws Exception { |
59 |
|
|
ParallelLongArray pa = ParallelLongArray.createUsingHandoff(array, fjp); |
60 |
|
|
long last, now; |
61 |
|
|
long steals = fjp.getStealCount(); |
62 |
|
|
// long syncs = fjp.getSyncCount(); |
63 |
|
|
for (int j = 0; j < tests; ++j) { |
64 |
|
|
pa.replaceWithValue(1); |
65 |
|
|
last = System.nanoTime(); |
66 |
|
|
for (int k = 0; k < reps; ++k) { |
67 |
|
|
pa.cumulateSum(); |
68 |
|
|
if (j == 0 && k == 0) |
69 |
|
|
check(array); |
70 |
|
|
} |
71 |
|
|
now = System.nanoTime(); |
72 |
|
|
double elapsed = (double)(now - last) / (NPS); |
73 |
|
|
last = now; |
74 |
|
|
System.out.printf("ps %2d: %9.5f", nthreads, elapsed); |
75 |
|
|
if (reportSteals) { |
76 |
|
|
long sc = fjp.getStealCount(); |
77 |
|
|
long scount = (sc - steals) / reps; |
78 |
|
|
steals = sc; |
79 |
|
|
System.out.printf(" Steals:%6d", scount); |
80 |
|
|
} |
81 |
|
|
System.out.println(); |
82 |
|
|
} |
83 |
|
|
Thread.sleep(100); |
84 |
|
|
} |
85 |
|
|
|
86 |
|
|
static void check(long[] array) { |
87 |
|
|
for (int i = 0; i < array.length; ++i) { |
88 |
|
|
long sum = i + 1; |
89 |
|
|
if (array[i] != sum) { |
90 |
|
|
System.out.println("i: " + i + " sum: " + sum + " element:" + array[i]); |
91 |
|
|
throw new Error(); |
92 |
|
|
} |
93 |
|
|
} |
94 |
|
|
} |
95 |
|
|
|
96 |
|
|
static void seqFill(long[] array) { |
97 |
|
|
for (int i = 0; i < array.length; ++i) |
98 |
|
|
array[i] = 1; |
99 |
|
|
} |
100 |
|
|
|
101 |
|
|
static long seqCumulate(long[] array) { |
102 |
|
|
long sum = 0; |
103 |
|
|
for (int i = 0; i < array.length; ++i) |
104 |
|
|
sum = array[i] += sum; |
105 |
|
|
return sum; |
106 |
|
|
} |
107 |
|
|
} |