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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/publicdomain/zero/1.0/ |
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*/ |
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/* |
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* @test |
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* @summary basic safety and liveness of ReentrantLocks, and other locks based on them |
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*/ |
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|
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import java.util.concurrent.CyclicBarrier; |
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import java.util.concurrent.ExecutorService; |
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import java.util.concurrent.Executors; |
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import java.util.concurrent.Semaphore; |
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import java.util.concurrent.locks.Lock; |
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import java.util.concurrent.locks.ReentrantLock; |
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import java.util.concurrent.locks.ReentrantReadWriteLock; |
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|
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public final class CheckedLockLoops { |
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static final ExecutorService pool = Executors.newCachedThreadPool(); |
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static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom(); |
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static boolean print = false; |
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static boolean doBuiltin = true; |
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|
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public static void main(String[] args) throws Exception { |
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int maxThreads = 100; |
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int iters = 2000000; |
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if (args.length > 0) |
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maxThreads = Integer.parseInt(args[0]); |
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rng.setSeed(3122688L); |
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warmup(iters); |
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runTest(maxThreads, iters); |
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pool.shutdown(); |
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} |
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|
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static void runTest(int maxThreads, int iters) throws Exception { |
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print = true; |
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for (int k = 1, i = 1; i <= maxThreads;) { |
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System.out.println("Threads:" + i); |
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oneTest(i, iters / i); |
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if (i == k) { |
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k = i << 1; |
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i = i + (i >>> 1); |
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} |
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else |
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i = k; |
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} |
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} |
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|
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static void warmup(int iters) throws Exception { |
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print = false; |
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System.out.println("Warmup..."); |
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oneTest(1, iters); |
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oneTest(2, iters / 2); |
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} |
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|
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static void oneTest(int nthreads, int iters) throws Exception { |
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int fairIters = (nthreads <= 1) ? iters : iters/20; |
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int v = rng.next(); |
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|
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if (print) |
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System.out.print("NoLock (1 thread) "); |
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new NoLockLoop().test(v, 1, iters * nthreads); |
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Thread.sleep(10); |
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|
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if (print) |
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System.out.print("ReentrantLock "); |
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new ReentrantLockLoop().test(v, nthreads, iters); |
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Thread.sleep(10); |
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|
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if (print) |
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System.out.print("FairReentrantLock "); |
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new FairReentrantLockLoop().test(v, nthreads, fairIters); |
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Thread.sleep(10); |
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|
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if (doBuiltin) { |
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if (print) |
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System.out.print("builtin lock "); |
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new BuiltinLockLoop().test(v, nthreads, fairIters); |
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Thread.sleep(10); |
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} |
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|
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if (print) |
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System.out.print("Mutex "); |
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new MutexLoop().test(v, nthreads, iters); |
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Thread.sleep(10); |
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|
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if (print) |
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System.out.print("LongMutex "); |
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new LongMutexLoop().test(v, nthreads, iters); |
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Thread.sleep(10); |
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|
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if (print) |
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System.out.print("Semaphore "); |
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new SemaphoreLoop().test(v, nthreads, iters); |
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Thread.sleep(10); |
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|
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if (print) |
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System.out.print("FairSemaphore "); |
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new FairSemaphoreLoop().test(v, nthreads, fairIters); |
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Thread.sleep(10); |
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|
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if (print) |
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System.out.print("ReentrantWriteLock "); |
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new ReentrantWriteLockLoop().test(v, nthreads, iters); |
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Thread.sleep(10); |
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|
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if (print) |
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System.out.print("FairRWriteLock "); |
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new FairReentrantWriteLockLoop().test(v, nthreads, fairIters); |
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Thread.sleep(10); |
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|
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if (print) |
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System.out.print("ReentrantReadWriteLock"); |
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new ReentrantReadWriteLockLoop().test(v, nthreads, iters); |
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Thread.sleep(10); |
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|
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if (print) |
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System.out.print("FairRReadWriteLock "); |
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new FairReentrantReadWriteLockLoop().test(v, nthreads, fairIters); |
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Thread.sleep(10); |
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} |
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|
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abstract static class LockLoop implements Runnable { |
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int value; |
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int checkValue; |
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int iters; |
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volatile int result; |
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volatile int failures; |
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final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer(); |
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CyclicBarrier barrier; |
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|
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final int setValue(int v) { |
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checkValue = v ^ 0x55555555; |
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value = v; |
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return v; |
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} |
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|
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final int getValue() { |
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int v = value; |
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if (checkValue != ~(v ^ 0xAAAAAAAA)) |
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++failures; |
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return v; |
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} |
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|
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final void test(int initialValue, int nthreads, int iters) throws Exception { |
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setValue(initialValue); |
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this.iters = iters; |
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barrier = new CyclicBarrier(nthreads+1, timer); |
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for (int i = 0; i < nthreads; ++i) |
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pool.execute(this); |
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barrier.await(); |
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barrier.await(); |
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long time = timer.getTime(); |
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if (print) { |
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long tpi = time / (iters * nthreads); |
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System.out.print("\t" + LoopHelpers.rightJustify(tpi) + " ns per update"); |
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System.out.println(); |
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} |
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|
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if (result == 0) // avoid overoptimization |
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System.out.println("useless result: " + result); |
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if (failures != 0) |
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throw new Error("lock protection failure"); |
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} |
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|
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abstract int loop(int n); |
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public final void run() { |
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try { |
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barrier.await(); |
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result += loop(iters); |
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barrier.await(); |
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} |
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catch (Exception ie) { |
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return; |
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} |
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} |
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|
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} |
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|
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private static class NoLockLoop extends LockLoop { |
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private volatile int readBarrier; |
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final int loop(int n) { |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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int r1 = readBarrier; |
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x = setValue(LoopHelpers.compute1(getValue())); |
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int r2 = readBarrier; |
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if (r1 == r2 && x == r1) |
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++readBarrier; |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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|
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private static class BuiltinLockLoop extends LockLoop { |
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final int loop(int n) { |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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synchronized (this) { |
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x = setValue(LoopHelpers.compute1(getValue())); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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|
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private static class ReentrantLockLoop extends LockLoop { |
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private final ReentrantLock lock = new ReentrantLock(); |
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final int loop(int n) { |
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final ReentrantLock lock = this.lock; |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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lock.lock(); |
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try { |
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x = setValue(LoopHelpers.compute1(getValue())); |
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} |
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finally { |
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lock.unlock(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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|
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private static class MutexLoop extends LockLoop { |
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private final Mutex lock = new Mutex(); |
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final int loop(int n) { |
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final Mutex lock = this.lock; |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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lock.lock(); |
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try { |
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x = setValue(LoopHelpers.compute1(getValue())); |
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} |
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finally { |
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lock.unlock(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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|
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private static class LongMutexLoop extends LockLoop { |
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private final LongMutex lock = new LongMutex(); |
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final int loop(int n) { |
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final LongMutex lock = this.lock; |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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lock.lock(); |
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try { |
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x = setValue(LoopHelpers.compute1(getValue())); |
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} |
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finally { |
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lock.unlock(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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|
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private static class FairReentrantLockLoop extends LockLoop { |
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private final ReentrantLock lock = new ReentrantLock(true); |
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final int loop(int n) { |
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final ReentrantLock lock = this.lock; |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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lock.lock(); |
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try { |
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x = setValue(LoopHelpers.compute1(getValue())); |
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} |
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finally { |
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lock.unlock(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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|
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private static class ReentrantWriteLockLoop extends LockLoop { |
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private final Lock lock = new ReentrantReadWriteLock().writeLock(); |
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final int loop(int n) { |
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final Lock lock = this.lock; |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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lock.lock(); |
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try { |
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x = setValue(LoopHelpers.compute1(getValue())); |
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} |
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finally { |
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lock.unlock(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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|
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private static class FairReentrantWriteLockLoop extends LockLoop { |
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final Lock lock = new ReentrantReadWriteLock(true).writeLock(); |
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final int loop(int n) { |
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final Lock lock = this.lock; |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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lock.lock(); |
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try { |
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x = setValue(LoopHelpers.compute1(getValue())); |
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} |
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finally { |
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lock.unlock(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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|
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private static class SemaphoreLoop extends LockLoop { |
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private final Semaphore sem = new Semaphore(1, false); |
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final int loop(int n) { |
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final Semaphore sem = this.sem; |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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sem.acquireUninterruptibly(); |
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try { |
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x = setValue(LoopHelpers.compute1(getValue())); |
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} |
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finally { |
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sem.release(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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private static class FairSemaphoreLoop extends LockLoop { |
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private final Semaphore sem = new Semaphore(1, true); |
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final int loop(int n) { |
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final Semaphore sem = this.sem; |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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sem.acquireUninterruptibly(); |
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try { |
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x = setValue(LoopHelpers.compute1(getValue())); |
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} |
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finally { |
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sem.release(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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return sum; |
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} |
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} |
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|
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private static class ReentrantReadWriteLockLoop extends LockLoop { |
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private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(); |
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final int loop(int n) { |
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final Lock rlock = lock.readLock(); |
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final Lock wlock = lock.writeLock(); |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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if ((n & 16) != 0) { |
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rlock.lock(); |
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try { |
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x = LoopHelpers.compute1(getValue()); |
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x = LoopHelpers.compute2(x); |
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} |
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finally { |
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rlock.unlock(); |
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} |
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} |
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else { |
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wlock.lock(); |
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try { |
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setValue(x); |
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} |
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finally { |
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wlock.unlock(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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} |
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return sum; |
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} |
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|
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} |
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|
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private static class FairReentrantReadWriteLockLoop extends LockLoop { |
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private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true); |
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final int loop(int n) { |
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final Lock rlock = lock.readLock(); |
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final Lock wlock = lock.writeLock(); |
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int sum = 0; |
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int x = 0; |
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while (n-- > 0) { |
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if ((n & 16) != 0) { |
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rlock.lock(); |
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try { |
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x = LoopHelpers.compute1(getValue()); |
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x = LoopHelpers.compute2(x); |
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} |
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finally { |
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rlock.unlock(); |
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} |
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} |
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else { |
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wlock.lock(); |
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try { |
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setValue(x); |
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} |
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finally { |
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wlock.unlock(); |
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} |
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sum += LoopHelpers.compute2(x); |
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} |
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} |
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return sum; |
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} |
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|
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} |
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} |