| 13 |
|
final static int iters = 1000000; |
| 14 |
|
static AtomicReference turn = new AtomicReference(); |
| 15 |
|
public static void main(String[] args) throws Exception { |
| 16 |
+ |
test(); |
| 17 |
+ |
test(); |
| 18 |
+ |
test(); |
| 19 |
+ |
} |
| 20 |
+ |
|
| 21 |
+ |
static void test() throws Exception { |
| 22 |
|
MyThread a = new MyThread(); |
| 23 |
|
MyThread b = new MyThread(); |
| 24 |
|
a.other = b; |
| 31 |
|
b.join(); |
| 32 |
|
long endTime = System.nanoTime(); |
| 33 |
|
int np = a.nparks + b.nparks; |
| 34 |
< |
System.out.println((endTime - startTime) / np); |
| 35 |
< |
} |
| 36 |
< |
|
| 31 |
< |
private static int nextRandom(int x) { |
| 32 |
< |
int t = (x % 127773) * 16807 - (x / 127773) * 2836; |
| 33 |
< |
return (t > 0)? t : t + 0x7fffffff; |
| 34 |
> |
System.out.println("Average time: " + |
| 35 |
> |
((endTime - startTime) / np) + |
| 36 |
> |
"ns"); |
| 37 |
|
} |
| 38 |
|
|
| 39 |
|
static final class MyThread extends Thread { |
| 40 |
|
volatile Thread other; |
| 41 |
|
volatile int nparks; |
| 39 |
– |
volatile int result; |
| 42 |
|
|
| 43 |
|
public void run() { |
| 44 |
< |
int x = 17; |
| 44 |
> |
final AtomicReference t = turn; |
| 45 |
> |
final Thread other = this.other; |
| 46 |
> |
if (turn == null || other == null) |
| 47 |
> |
throw new NullPointerException(); |
| 48 |
|
int p = 0; |
| 49 |
|
for (int i = 0; i < iters; ++i) { |
| 50 |
< |
while (!turn.compareAndSet(other, this)) { |
| 50 |
> |
while (!t.compareAndSet(other, this)) { |
| 51 |
|
LockSupport.park(); |
| 52 |
|
++p; |
| 53 |
|
} |
| 49 |
– |
x = nextRandom(x); |
| 54 |
|
LockSupport.unpark(other); |
| 55 |
|
} |
| 56 |
|
LockSupport.unpark(other); |
| 57 |
|
nparks = p; |
| 54 |
– |
result = x; |
| 58 |
|
System.out.println("parks: " + p); |
| 59 |
|
|
| 60 |
|
} |
