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/* |
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* @test %I% %E% |
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* @bug 4486658 |
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* @compile -source 1.5 ConcurrentQueueLoops.java |
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* @run main/timeout=230 ConcurrentQueueLoops |
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* @summary Checks that a set of threads can repeatedly get and modify items |
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*/ |
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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.*; |
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import java.util.concurrent.*; |
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import java.util.concurrent.locks.*; |
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import java.util.concurrent.atomic.*; |
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|
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public class ConcurrentQueueLoops { |
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static final ExecutorService pool = Executors.newCachedThreadPool(); |
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static boolean print = false; |
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static final Integer zero = new Integer(0); |
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static final Integer one = new Integer(1); |
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static int workMask; |
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static final long RUN_TIME_NANOS = 5 * 1000L * 1000L * 1000L; |
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static final int BATCH_SIZE = 8; |
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|
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public static void main(String[] args) throws Exception { |
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int maxStages = 100; |
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int work = 1024; |
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Class klass = null; |
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if (args.length > 0) { |
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try { |
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klass = Class.forName(args[0]); |
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} catch(ClassNotFoundException e) { |
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throw new RuntimeException("Class " + args[0] + " not found."); |
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} |
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} |
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|
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if (args.length > 1) |
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maxStages = Integer.parseInt(args[1]); |
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|
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if (args.length > 2) |
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work = Integer.parseInt(args[2]); |
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|
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workMask = work - 1; |
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System.out.print("Class: " + klass.getName()); |
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System.out.print(" stages: " + maxStages); |
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System.out.println(" work: " + work); |
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|
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print = false; |
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System.out.println("Warmup..."); |
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// oneRun(klass, 4); |
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// |
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Thread.sleep(100); |
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oneRun(klass, 1); |
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Thread.sleep(100); |
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print = true; |
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|
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int k = 1; |
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for (int i = 1; i <= maxStages;) { |
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oneRun(klass, 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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pool.shutdown(); |
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} |
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|
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static final class Stage implements Callable<Integer> { |
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final Queue<Integer> queue; |
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final CyclicBarrier barrier; |
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final int nthreads; |
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Stage (Queue<Integer> q, CyclicBarrier b, int nthreads) { |
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queue = q; |
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barrier = b; |
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this.nthreads = nthreads; |
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} |
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|
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static int compute(int l) { |
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if (l == 0) |
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return (int)System.nanoTime(); |
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int nn = (l >>> 7) & workMask; |
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while (nn-- > 0) |
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l = LoopHelpers.compute6(l); |
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return l; |
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} |
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|
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public Integer call() { |
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try { |
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barrier.await(); |
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long now = System.nanoTime(); |
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long stopTime = now + RUN_TIME_NANOS; |
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int l = (int)now; |
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int takes = 0; |
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int misses = 0; |
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int lmask = 1; |
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for (;;) { |
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l = compute(l); |
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Integer item = queue.poll(); |
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if (item != null) { |
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++takes; |
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if (item == one) |
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l = LoopHelpers.compute6(l); |
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} else if ((misses++ & 255) == 0 && |
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System.nanoTime() >= stopTime) { |
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return new Integer(takes); |
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} else { |
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for (int i = 0; i < BATCH_SIZE; ++i) { |
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queue.offer(((l & lmask)== 0)? zero : one); |
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if ((lmask <<= 1) == 0) lmask = 1; |
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if (i != 0) l = compute(l); |
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} |
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} |
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} |
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} |
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catch (Exception ie) { |
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ie.printStackTrace(); |
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throw new Error("Call loop failed"); |
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} |
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} |
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} |
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|
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static void oneRun(Class klass, int n) throws Exception { |
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Queue<Integer> q = (Queue<Integer>)klass.newInstance(); |
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LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer(); |
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CyclicBarrier barrier = new CyclicBarrier(n + 1, timer); |
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ArrayList<Future<Integer>> results = new ArrayList<Future<Integer>>(n); |
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for (int i = 0; i < n; ++i) |
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results.add(pool.submit(new Stage(q, barrier, n))); |
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|
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if (print) |
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System.out.print("Threads: " + n + "\t:"); |
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barrier.await(); |
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int total = 0; |
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for (int i = 0; i < n; ++i) { |
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Future<Integer> f = results.get(i); |
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Integer r = f.get(); |
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total += r.intValue(); |
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} |
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long endTime = System.nanoTime(); |
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long time = endTime - timer.startTime; |
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long ips = 1000000000L * total / time; |
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|
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if (print) |
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System.out.print(LoopHelpers.rightJustify(ips) + " items per sec"); |
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if (print) |
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System.out.println(); |
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} |
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|
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} |
