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/* |
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* Written by Bill Scherer and Doug Lea with assistance from members |
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* of JCP JSR-166 Expert Group and released to the public domain, as |
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* explained at http://creativecommons.org/publicdomain/zero/1.0/ |
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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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public class ExchangeLoops { |
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static final int NCPUS = Runtime.getRuntime().availableProcessors(); |
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|
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static final int DEFAULT_THREADS = NCPUS + 2; |
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static final long DEFAULT_TRIAL_MILLIS = 10000; |
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|
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public static void main(String[] args) throws Exception { |
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int maxThreads = DEFAULT_THREADS; |
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long trialMillis = DEFAULT_TRIAL_MILLIS; |
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int nReps = 3; |
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|
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// Parse and check args |
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int argc = 0; |
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while (argc < args.length) { |
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String option = args[argc++]; |
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if (option.equals("-t")) |
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trialMillis = Integer.parseInt(args[argc]); |
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else if (option.equals("-r")) |
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nReps = Integer.parseInt(args[argc]); |
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else |
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maxThreads = Integer.parseInt(option); |
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argc++; |
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} |
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|
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// Display runtime parameters |
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System.out.print("ExchangeTest"); |
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System.out.print(" -t " + trialMillis); |
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System.out.print(" -r " + nReps); |
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System.out.print(" max threads " + maxThreads); |
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System.out.println(); |
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long warmupTime = 2000; |
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long sleepTime = 100; |
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int nw = (maxThreads >= 3) ? 3 : 2; |
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|
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System.out.println("Warmups.."); |
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oneRun(3, warmupTime); |
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Thread.sleep(sleepTime); |
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|
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for (int i = maxThreads; i >= 2; i -= 1) { |
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oneRun(i, warmupTime++); |
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// System.gc(); |
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Thread.sleep(sleepTime); |
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} |
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|
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/* |
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for (int i = maxThreads; i >= 2; i -= 1) { |
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oneRun(i, warmupTime++); |
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} |
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*/ |
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|
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for (int j = 0; j < nReps; ++j) { |
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System.out.println("Trial: " + j); |
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for (int i = 2; i <= maxThreads; i += 2) { |
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oneRun(i, trialMillis); |
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// System.gc(); |
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Thread.sleep(sleepTime); |
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} |
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for (int i = maxThreads; i >= 2; i -= 2) { |
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oneRun(i, trialMillis); |
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// System.gc(); |
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Thread.sleep(sleepTime); |
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} |
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Thread.sleep(sleepTime); |
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} |
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|
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} |
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|
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static void oneRun(int nThreads, long trialMillis) throws Exception { |
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System.out.printf("%4d threads", nThreads); |
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Exchanger x = new Exchanger(); |
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Runner[] runners = new Runner[nThreads]; |
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Thread[] threads = new Thread[nThreads]; |
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for (int i = 0; i < nThreads; ++i) { |
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runners[i] = new Runner(x); |
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threads[i] = new Thread(runners[i]); |
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// int h = System.identityHashCode(threads[i]); |
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// h ^= h << 1; |
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// h ^= h >>> 3; |
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// h ^= h << 10; |
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// System.out.printf("%10x\n", h); |
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} |
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|
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long startTime = System.nanoTime(); |
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for (int i = 0; i < nThreads; ++i) { |
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threads[i].start(); |
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} |
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Thread.sleep(trialMillis); |
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for (int i = 0; i < nThreads; ++i) |
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threads[i].interrupt(); |
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long elapsed = System.nanoTime() - startTime; |
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for (int i = 0; i < nThreads; ++i) |
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threads[i].join(); |
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int iters = 1; |
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// System.out.println(); |
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for (int i = 0; i < nThreads; ++i) { |
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int ipr = runners[i].iters; |
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// System.out.println(ipr); |
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iters += ipr; |
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} |
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long rate = iters * 1000L * 1000L * 1000L / elapsed; |
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long npt = elapsed / iters; |
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System.out.printf("%9dms", elapsed / (1000L * 1000L)); |
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System.out.printf("%9d it/s ", rate); |
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System.out.printf("%9d ns/it", npt); |
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System.out.println(); |
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// x.printStats(); |
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} |
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|
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static final class Runner implements Runnable { |
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final Exchanger exchanger; |
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final Object mine = new Integer(2688); |
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volatile int iters; |
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Runner(Exchanger x) { this.exchanger = x; } |
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|
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public void run() { |
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Exchanger x = exchanger; |
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Object m = mine; |
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int i = 0; |
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try { |
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for (;;) { |
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Object e = x.exchange(m); |
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if (e == null || e == m) |
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throw new Error(); |
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m = e; |
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++i; |
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} |
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} catch (InterruptedException ie) { |
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iters = i; |
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} |
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} |
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} |
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} |
