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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. Use, modify, and |
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* redistribute this code in any way without acknowledgement. |
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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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|
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public class CachedThreadPoolLoops { |
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static final AtomicInteger remaining = new AtomicInteger(); |
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static final int maxIters = 1000000; |
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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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|
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if (args.length > 0) |
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maxThreads = Integer.parseInt(args[0]); |
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|
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int k = 1; |
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for (int i = 1; i <= maxThreads;) { |
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System.out.println("Threads:" + i); |
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oneTest(i); |
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Thread.sleep(100); |
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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 oneTest(int nThreads) throws Exception { |
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System.out.print("SynchronousQueue "); |
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oneRun(new SynchronousQueue<Runnable>(), nThreads); |
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System.out.print("SynchronousQueue(fair) "); |
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oneRun(new SynchronousQueue<Runnable>(true), nThreads); |
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} |
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|
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static final class Task implements Runnable { |
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final ThreadPoolExecutor pool; |
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final CountDownLatch done; |
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Task(ThreadPoolExecutor p, CountDownLatch d) { |
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pool = p; |
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done = d; |
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} |
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public void run() { |
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done.countDown(); |
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remaining.incrementAndGet(); |
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int n; |
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while (!Thread.interrupted() && |
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(n = remaining.get()) > 0 && |
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done.getCount() > 0) { |
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if (remaining.compareAndSet(n, n-1)) { |
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try { |
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pool.execute(this); |
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} |
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catch (RuntimeException ex) { |
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System.out.print("*"); |
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while (done.getCount() > 0) done.countDown(); |
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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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|
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static void oneRun(BlockingQueue<Runnable> q, int nThreads) throws Exception { |
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|
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ThreadPoolExecutor pool = |
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new ThreadPoolExecutor(nThreads+1, Integer.MAX_VALUE, |
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1L, TimeUnit.SECONDS, q); |
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|
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CountDownLatch done = new CountDownLatch(maxIters); |
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remaining.set(nThreads-1); |
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pool.prestartAllCoreThreads(); |
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Task t = new Task(pool, done); |
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long start = System.nanoTime(); |
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pool.execute(t); |
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done.await(); |
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long time = System.nanoTime() - start; |
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System.out.println("\t: " + LoopHelpers.rightJustify(time / maxIters) + " ns per task"); |
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pool.shutdownNow(); |
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} |
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|
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} |
