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import java.util.concurrent.Phaser; |
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public class LongAdderLoops { |
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static final int ITERS = 100_000_000; |
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static final int NCPU = Runtime.getRuntime().availableProcessors(); |
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static final int MAX_THREADS = NCPU * 2; |
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static final ExecutorService pool = Executors.newCachedThreadPool(); |
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public static void main(String[] args) { |
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for (int i = 1; i < MAX_THREADS; ++i) |
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adderTest(i, ITERS); |
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final int NCPU = Runtime.getRuntime().availableProcessors(); |
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int minThreads = 1; |
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int maxThreads = 2 * NCPU; |
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long iters = 300_000_000L; |
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nextArg: for (String arg : args) { |
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String[] fields = arg.split("="); |
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if (fields.length == 2) { |
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String prop = fields[0], val = fields[1]; |
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switch (prop) { |
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case "threads": |
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minThreads = maxThreads = Integer.valueOf(val); |
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continue nextArg; |
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case "minThreads": |
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minThreads = Integer.valueOf(val); |
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continue nextArg; |
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case "maxThreads": |
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maxThreads = Integer.valueOf(val); |
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continue nextArg; |
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case "iters": |
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iters = Long.valueOf(val); |
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continue nextArg; |
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} |
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} |
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throw new Error("Usage: LongAdderLoops minThreads=n maxThreads=n threads=n iters=n"); |
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} |
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|
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final ExecutorService pool = Executors.newCachedThreadPool(); |
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for (int i = minThreads; i <= maxThreads; i += (i+1) >>> 1) |
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adderTest(pool, i, iters); |
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pool.shutdown(); |
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} |
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static void adderTest(int nthreads, int incs) { |
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static void adderTest(ExecutorService pool, int nthreads, long iters) { |
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System.out.print("LongAdder "); |
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Phaser phaser = new Phaser(nthreads + 1); |
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LongAdder a = new LongAdder(); |
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for (int i = 0; i < nthreads; ++i) |
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pool.execute(new AdderTask(a, phaser, incs)); |
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report(nthreads, incs, timeTasks(phaser), a.sum()); |
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pool.execute(new AdderTask(a, phaser, iters)); |
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report(nthreads, iters, timeTasks(phaser), a.sum()); |
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} |
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static void report(int nthreads, int incs, long time, long sum) { |
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long total = (long)nthreads * incs; |
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static void report(int nthreads, long iters, long time, long sum) { |
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long total = (long)nthreads * iters; |
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if (sum != total) |
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throw new Error(sum + " != " + total); |
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double secs = (double)time / (1000L * 1000 * 1000); |
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long rate = total * (1000L) / time; |
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System.out.printf("threads:%3d Time: %7.3fsec Incs per microsec: %4d\n", |
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System.out.printf("threads:%3d Time: %7.3fsec Iters per microsec: %4d\n", |
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nthreads, secs, rate); |
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} |
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static final class AdderTask implements Runnable { |
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final LongAdder adder; |
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final Phaser phaser; |
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final int incs; |
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final long iters; |
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volatile long result; |
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< |
AdderTask(LongAdder adder, Phaser phaser, int incs) { |
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> |
AdderTask(LongAdder adder, Phaser phaser, long iters) { |
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this.adder = adder; |
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this.phaser = phaser; |
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this.incs = incs; |
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> |
this.iters = iters; |
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} |
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public void run() { |
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phaser.arriveAndAwaitAdvance(); |
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phaser.arriveAndAwaitAdvance(); |
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LongAdder a = adder; |
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for (int i = 0; i < incs; ++i) |
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> |
for (long i = 0; i < iters; ++i) |
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a.increment(); |
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result = a.sum(); |
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phaser.arrive(); |