1 |
jsr166 |
1.1 |
/** |
2 |
|
|
* Misc utilities in JSR166 performance tests |
3 |
|
|
*/ |
4 |
|
|
|
5 |
|
|
import java.util.concurrent.*; |
6 |
|
|
import java.util.concurrent.atomic.*; |
7 |
|
|
|
8 |
|
|
class LoopHelpers { |
9 |
|
|
|
10 |
|
|
static final SimpleRandom staticRNG = new SimpleRandom(); |
11 |
|
|
|
12 |
|
|
// Some mindless computation to do between synchronizations... |
13 |
|
|
|
14 |
|
|
/** |
15 |
|
|
* generates 32 bit pseudo-random numbers. |
16 |
|
|
* Adapted from http://www.snippets.org |
17 |
|
|
*/ |
18 |
|
|
public static int compute1(int x) { |
19 |
|
|
int lo = 16807 * (x & 0xFFFF); |
20 |
|
|
int hi = 16807 * (x >>> 16); |
21 |
|
|
lo += (hi & 0x7FFF) << 16; |
22 |
|
|
if ((lo & 0x80000000) != 0) { |
23 |
|
|
lo &= 0x7fffffff; |
24 |
|
|
++lo; |
25 |
|
|
} |
26 |
|
|
lo += hi >>> 15; |
27 |
|
|
if (lo == 0 || (lo & 0x80000000) != 0) { |
28 |
|
|
lo &= 0x7fffffff; |
29 |
|
|
++lo; |
30 |
|
|
} |
31 |
|
|
return lo; |
32 |
|
|
} |
33 |
|
|
|
34 |
|
|
/** |
35 |
|
|
* Computes a linear congruential random number a random number |
36 |
|
|
* of times. |
37 |
|
|
*/ |
38 |
|
|
public static int compute2(int x) { |
39 |
|
|
int loops = (x >>> 4) & 7; |
40 |
|
|
while (loops-- > 0) { |
41 |
|
|
x = (x * 2147483647) % 16807; |
42 |
|
|
} |
43 |
|
|
return x; |
44 |
|
|
} |
45 |
|
|
|
46 |
|
|
public static int compute3(int x) { |
47 |
|
|
int t = (x % 127773) * 16807 - (x / 127773) * 2836; |
48 |
|
|
return (t > 0)? t : t + 0x7fffffff; |
49 |
|
|
} |
50 |
|
|
|
51 |
|
|
/** |
52 |
|
|
* An actually useful random number generator, but unsynchronized. |
53 |
|
|
* Basically same as java.util.Random. |
54 |
|
|
*/ |
55 |
|
|
public static class SimpleRandom { |
56 |
|
|
private final static long multiplier = 0x5DEECE66DL; |
57 |
|
|
private final static long addend = 0xBL; |
58 |
|
|
private final static long mask = (1L << 48) - 1; |
59 |
|
|
static final AtomicLong seq = new AtomicLong(1); |
60 |
|
|
private long seed = System.nanoTime() + seq.getAndIncrement(); |
61 |
|
|
|
62 |
|
|
public void setSeed(long s) { |
63 |
|
|
seed = s; |
64 |
|
|
} |
65 |
|
|
|
66 |
|
|
public int next() { |
67 |
|
|
long nextseed = (seed * multiplier + addend) & mask; |
68 |
|
|
seed = nextseed; |
69 |
|
|
return ((int)(nextseed >>> 17)) & 0x7FFFFFFF; |
70 |
|
|
} |
71 |
|
|
} |
72 |
|
|
|
73 |
|
|
public static class BarrierTimer implements Runnable { |
74 |
|
|
public volatile long startTime; |
75 |
|
|
public volatile long endTime; |
76 |
|
|
public void run() { |
77 |
|
|
long t = System.nanoTime(); |
78 |
|
|
if (startTime == 0) |
79 |
|
|
startTime = t; |
80 |
|
|
else |
81 |
|
|
endTime = t; |
82 |
|
|
} |
83 |
|
|
public void clear() { |
84 |
|
|
startTime = 0; |
85 |
|
|
endTime = 0; |
86 |
|
|
} |
87 |
|
|
public long getTime() { |
88 |
|
|
return endTime - startTime; |
89 |
|
|
} |
90 |
|
|
} |
91 |
|
|
|
92 |
|
|
public static String rightJustify(long n) { |
93 |
|
|
// There's probably a better way to do this... |
94 |
|
|
String field = " "; |
95 |
|
|
String num = Long.toString(n); |
96 |
|
|
if (num.length() >= field.length()) |
97 |
|
|
return num; |
98 |
|
|
StringBuffer b = new StringBuffer(field); |
99 |
|
|
b.replace(b.length()-num.length(), b.length(), num); |
100 |
|
|
return b.toString(); |
101 |
|
|
} |
102 |
|
|
|
103 |
|
|
} |