| 10 |
|
import java.util.concurrent.Phaser; |
| 11 |
|
|
| 12 |
|
public class LongAdderLoops { |
| 13 |
– |
static final int ITERS = 100_000_000; |
| 14 |
– |
static final int NCPU = Runtime.getRuntime().availableProcessors(); |
| 15 |
– |
static final int MAX_THREADS = NCPU * 2; |
| 16 |
– |
|
| 17 |
– |
static final ExecutorService pool = Executors.newCachedThreadPool(); |
| 18 |
– |
|
| 13 |
|
public static void main(String[] args) { |
| 14 |
< |
for (int i = 1; i < MAX_THREADS; ++i) |
| 15 |
< |
adderTest(i, ITERS); |
| 14 |
> |
final int NCPU = Runtime.getRuntime().availableProcessors(); |
| 15 |
> |
int minThreads = 1; |
| 16 |
> |
int maxThreads = 2 * NCPU; |
| 17 |
> |
long iters = 300_000_000L; |
| 18 |
> |
nextArg: for (String arg : args) { |
| 19 |
> |
String[] fields = arg.split("="); |
| 20 |
> |
if (fields.length == 2) { |
| 21 |
> |
String prop = fields[0], val = fields[1]; |
| 22 |
> |
switch (prop) { |
| 23 |
> |
case "threads": |
| 24 |
> |
minThreads = maxThreads = Integer.valueOf(val); |
| 25 |
> |
continue nextArg; |
| 26 |
> |
case "minThreads": |
| 27 |
> |
minThreads = Integer.valueOf(val); |
| 28 |
> |
continue nextArg; |
| 29 |
> |
case "maxThreads": |
| 30 |
> |
maxThreads = Integer.valueOf(val); |
| 31 |
> |
continue nextArg; |
| 32 |
> |
case "iters": |
| 33 |
> |
iters = Long.valueOf(val); |
| 34 |
> |
continue nextArg; |
| 35 |
> |
} |
| 36 |
> |
} |
| 37 |
> |
throw new Error("Usage: LongAdderLoops minThreads=n maxThreads=n threads=n iters=n"); |
| 38 |
> |
} |
| 39 |
> |
|
| 40 |
> |
final ExecutorService pool = Executors.newCachedThreadPool(); |
| 41 |
> |
for (int i = minThreads; i <= maxThreads; i += (i+1) >>> 1) |
| 42 |
> |
adderTest(pool, i, iters); |
| 43 |
|
pool.shutdown(); |
| 44 |
|
} |
| 45 |
|
|
| 46 |
< |
static void adderTest(int nthreads, int incs) { |
| 46 |
> |
static void adderTest(ExecutorService pool, int nthreads, long iters) { |
| 47 |
|
System.out.print("LongAdder "); |
| 48 |
|
Phaser phaser = new Phaser(nthreads + 1); |
| 49 |
|
LongAdder a = new LongAdder(); |
| 50 |
|
for (int i = 0; i < nthreads; ++i) |
| 51 |
< |
pool.execute(new AdderTask(a, phaser, incs)); |
| 52 |
< |
report(nthreads, incs, timeTasks(phaser), a.sum()); |
| 51 |
> |
pool.execute(new AdderTask(a, phaser, iters)); |
| 52 |
> |
report(nthreads, iters, timeTasks(phaser), a.sum()); |
| 53 |
|
} |
| 54 |
|
|
| 55 |
< |
static void report(int nthreads, int incs, long time, long sum) { |
| 56 |
< |
long total = (long)nthreads * incs; |
| 55 |
> |
static void report(int nthreads, long iters, long time, long sum) { |
| 56 |
> |
long total = (long)nthreads * iters; |
| 57 |
|
if (sum != total) |
| 58 |
|
throw new Error(sum + " != " + total); |
| 59 |
|
double secs = (double)time / (1000L * 1000 * 1000); |
| 60 |
|
long rate = total * (1000L) / time; |
| 61 |
< |
System.out.printf("threads:%3d Time: %7.3fsec Incs per microsec: %4d\n", |
| 61 |
> |
System.out.printf("threads:%3d Time: %7.3fsec Iters per microsec: %4d\n", |
| 62 |
|
nthreads, secs, rate); |
| 63 |
|
} |
| 64 |
|
|
| 73 |
|
static final class AdderTask implements Runnable { |
| 74 |
|
final LongAdder adder; |
| 75 |
|
final Phaser phaser; |
| 76 |
< |
final int incs; |
| 76 |
> |
final long iters; |
| 77 |
|
volatile long result; |
| 78 |
< |
AdderTask(LongAdder adder, Phaser phaser, int incs) { |
| 78 |
> |
AdderTask(LongAdder adder, Phaser phaser, long iters) { |
| 79 |
|
this.adder = adder; |
| 80 |
|
this.phaser = phaser; |
| 81 |
< |
this.incs = incs; |
| 81 |
> |
this.iters = iters; |
| 82 |
|
} |
| 83 |
|
|
| 84 |
|
public void run() { |
| 85 |
|
phaser.arriveAndAwaitAdvance(); |
| 86 |
|
phaser.arriveAndAwaitAdvance(); |
| 87 |
|
LongAdder a = adder; |
| 88 |
< |
for (int i = 0; i < incs; ++i) |
| 88 |
> |
for (long i = 0; i < iters; ++i) |
| 89 |
|
a.increment(); |
| 90 |
|
result = a.sum(); |
| 91 |
|
phaser.arrive(); |
