1 |
/* |
2 |
* @test %I% %E% |
3 |
* @bug 4486658 |
4 |
* @compile -source 1.5 ConcurrentDequeLoops.java |
5 |
* @run main/timeout=230 ConcurrentDequeLoops |
6 |
* @summary Checks that a set of threads can repeatedly get and modify items |
7 |
*/ |
8 |
/* |
9 |
* Written by Doug Lea with assistance from members of JCP JSR-166 |
10 |
* Expert Group and released to the public domain. Use, modify, and |
11 |
* redistribute this code in any way without acknowledgement. |
12 |
*/ |
13 |
|
14 |
import java.util.*; |
15 |
import java.util.concurrent.*; |
16 |
import java.util.concurrent.atomic.*; |
17 |
import java.util.concurrent.locks.*; |
18 |
|
19 |
public class ConcurrentDequeLoops { |
20 |
static final ExecutorService pool = Executors.newCachedThreadPool(); |
21 |
static AtomicInteger totalItems; |
22 |
static boolean print = false; |
23 |
|
24 |
public static void main(String[] args) throws Exception { |
25 |
int maxStages = 8; |
26 |
int items = 1000000; |
27 |
|
28 |
Class klass = null; |
29 |
if (args.length > 0) { |
30 |
try { |
31 |
klass = Class.forName(args[0]); |
32 |
} catch(ClassNotFoundException e) { |
33 |
throw new RuntimeException("Class " + args[0] + " not found."); |
34 |
} |
35 |
} |
36 |
else |
37 |
throw new Error(); |
38 |
|
39 |
if (args.length > 1) |
40 |
maxStages = Integer.parseInt(args[1]); |
41 |
|
42 |
System.out.print("Class: " + klass.getName()); |
43 |
System.out.println(" stages: " + maxStages); |
44 |
|
45 |
print = false; |
46 |
System.out.println("Warmup..."); |
47 |
oneRun(klass, 1, items); |
48 |
Thread.sleep(100); |
49 |
oneRun(klass, 1, items); |
50 |
Thread.sleep(100); |
51 |
print = true; |
52 |
|
53 |
int k = 1; |
54 |
for (int i = 1; i <= maxStages;) { |
55 |
oneRun(klass, i, items); |
56 |
if (i == k) { |
57 |
k = i << 1; |
58 |
i = i + (i >>> 1); |
59 |
} |
60 |
else |
61 |
i = k; |
62 |
} |
63 |
pool.shutdown(); |
64 |
} |
65 |
|
66 |
static class Stage implements Callable<Integer> { |
67 |
final Deque<Integer> queue; |
68 |
final CyclicBarrier barrier; |
69 |
final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom(); |
70 |
int items; |
71 |
Stage (Deque<Integer> q, CyclicBarrier b, int items) { |
72 |
queue = q; |
73 |
barrier = b; |
74 |
this.items = items; |
75 |
} |
76 |
|
77 |
public Integer call() { |
78 |
// Repeatedly take something from queue if possible, |
79 |
// transform it, and put back in. |
80 |
try { |
81 |
barrier.await(); |
82 |
int l = (int)System.nanoTime(); |
83 |
int takes = 0; |
84 |
for (;;) { |
85 |
Integer item; |
86 |
int rnd = rng.next(); |
87 |
if ((rnd & 1) == 0) |
88 |
item = queue.pollFirst(); |
89 |
else |
90 |
item = queue.pollLast(); |
91 |
if (item != null) { |
92 |
++takes; |
93 |
l += LoopHelpers.compute2(item.intValue()); |
94 |
} |
95 |
else if (takes != 0) { |
96 |
totalItems.getAndAdd(-takes); |
97 |
takes = 0; |
98 |
} |
99 |
else if (totalItems.get() <= 0) |
100 |
break; |
101 |
l = LoopHelpers.compute1(l); |
102 |
if (items > 0) { |
103 |
--items; |
104 |
Integer res = new Integer(l); |
105 |
if ((rnd & 16) == 0) |
106 |
queue.addFirst(res); |
107 |
else |
108 |
queue.addLast(res); |
109 |
} |
110 |
else { // spinwait |
111 |
for (int k = 1 + (l & 15); k != 0; --k) |
112 |
l = LoopHelpers.compute1(LoopHelpers.compute2(l)); |
113 |
if ((l & 3) == 3) { |
114 |
Thread.sleep(1); |
115 |
} |
116 |
} |
117 |
} |
118 |
return new Integer(l); |
119 |
} |
120 |
catch (Exception ie) { |
121 |
ie.printStackTrace(); |
122 |
throw new Error("Call loop failed"); |
123 |
} |
124 |
} |
125 |
} |
126 |
|
127 |
static void oneRun(Class klass, int n, int items) throws Exception { |
128 |
Deque<Integer> q = (Deque<Integer>)klass.newInstance(); |
129 |
LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer(); |
130 |
CyclicBarrier barrier = new CyclicBarrier(n + 1, timer); |
131 |
totalItems = new AtomicInteger(n * items); |
132 |
ArrayList<Future<Integer>> results = new ArrayList<Future<Integer>>(n); |
133 |
for (int i = 0; i < n; ++i) |
134 |
results.add(pool.submit(new Stage(q, barrier, items))); |
135 |
|
136 |
if (print) |
137 |
System.out.print("Threads: " + n + "\t:"); |
138 |
barrier.await(); |
139 |
int total = 0; |
140 |
for (int i = 0; i < n; ++i) { |
141 |
Future<Integer> f = results.get(i); |
142 |
Integer r = f.get(); |
143 |
total += r.intValue(); |
144 |
} |
145 |
long endTime = System.nanoTime(); |
146 |
long time = endTime - timer.startTime; |
147 |
if (print) |
148 |
System.out.println(LoopHelpers.rightJustify(time / (items * n)) + " ns per item"); |
149 |
if (total == 0) // avoid overoptimization |
150 |
System.out.println("useless result: " + total); |
151 |
|
152 |
} |
153 |
} |