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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/licenses/publicdomain |
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*/ |
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|
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import java.util.concurrent.*; |
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import java.util.concurrent.atomic.*; |
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import java.util.concurrent.locks.*; |
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|
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class Mutex100M { |
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public static void main(String[] args) throws Exception { |
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int x = loop((int)System.nanoTime(), 100000); |
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x = loop(x, 100000); |
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x = loop(x, 100000); |
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long start = System.nanoTime(); |
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x = loop(x, 100000000); |
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if (x == 0) System.out.print(" "); |
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long time = System.nanoTime() - start; |
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double secs = (double)time / 1000000000.0; |
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System.out.println("time: " + secs); |
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start = System.nanoTime(); |
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x = loop(x, 100000000); |
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if (x == 0) System.out.print(" "); |
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time = System.nanoTime() - start; |
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secs = (double)time / 1000000000.0; |
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System.out.println("time: " + secs); |
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|
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} |
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|
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static final Mutex100M.Mutex lock = new Mutex100M.Mutex(); |
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static int loop(int x, int iters) { |
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final Mutex100M.Mutex l = lock; |
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for (int i = iters; i > 0; --i) { |
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l.lock(); |
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x = x * 134775813 + 1; |
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l.unlock(); |
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} |
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return x; |
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} |
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|
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|
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static final class Mutex extends AbstractQueuedSynchronizer { |
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public boolean isHeldExclusively() { return getState() == 1; } |
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|
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public boolean tryAcquire(int acquires) { |
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return getState() == 0 && compareAndSetState(0, 1); |
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} |
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|
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public boolean tryRelease(int releases) { |
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setState(0); |
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return true; |
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} |
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public Condition newCondition() { return new ConditionObject(); } |
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|
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public void lock() { |
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if (!compareAndSetState(0, 1)) |
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acquire(1); |
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} |
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public boolean tryLock() { |
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return tryAcquire(1); |
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} |
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public void lockInterruptibly() throws InterruptedException { |
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acquireInterruptibly(1); |
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} |
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public boolean tryLock(long timeout, TimeUnit unit) throws InterruptedException { |
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return tryAcquireNanos(1, unit.toNanos(timeout)); |
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} |
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public void unlock() { release(1); } |
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} |
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|
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} |
