--- jsr166/src/test/loops/SimpleSpinLockLoops.java 2005/05/02 19:19:38 1.1 +++ jsr166/src/test/loops/SimpleSpinLockLoops.java 2014/12/31 19:21:20 1.9 @@ -1,17 +1,13 @@ /* - * @test - * @synopsis multiple threads using a spinlock - */ -/* * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain. Use, modify, and - * redistribute this code in any way without acknowledgement. + * Expert Group and released to the public domain, as explained at + * http://creativecommons.org/publicdomain/zero/1.0/ */ +import java.util.*; import java.util.concurrent.*; -import java.util.concurrent.locks.*; import java.util.concurrent.atomic.*; -import java.util.*; +import java.util.concurrent.locks.*; public final class SimpleSpinLockLoops { static final ExecutorService pool = Executors.newCachedThreadPool(); @@ -21,23 +17,22 @@ public final class SimpleSpinLockLoops { public static void main(String[] args) throws Exception { int maxThreads = 100; - if (args.length > 0) + if (args.length > 0) maxThreads = Integer.parseInt(args[0]); new LockLoop(1).test(); new LockLoop(1).test(); print = true; - int k = 1; - for (int i = 1; i <= maxThreads;) { + for (int k = 1, i = 1; i <= maxThreads;) { System.out.print("Threads: " + i); new LockLoop(i).test(); Thread.sleep(100); if (i == k) { k = i << 1; i = i + (i >>> 1); - } - else + } + else i = k; } pool.shutdown(); @@ -57,15 +52,15 @@ public final class SimpleSpinLockLoops { } final void test() throws Exception { - for (int i = 0; i < nthreads; ++i) + for (int i = 0; i < nthreads; ++i) pool.execute(this); barrier.await(); barrier.await(); if (print) { long time = timer.getTime(); - long tpi = time / ((long)iters * nthreads); + long tpi = time / ((long) iters * nthreads); System.out.print("\t" + LoopHelpers.rightJustify(tpi) + " ns per lock"); - double secs = (double)(time) / 1000000000.0; + double secs = (double) time / 1000000000.0; System.out.println("\t " + secs + "s run time"); } @@ -77,17 +72,17 @@ public final class SimpleSpinLockLoops { public final void run() { final AtomicInteger lock = this.spinlock; try { - barrier.await(); + barrier.await(); int sum = v + 1; int x = 0; int n = iters; while (n-- > 0) { - while (!lock.compareAndSet(0, 1)) ; + do {} while (!lock.compareAndSet(0, 1)); int k = (sum & 3); if (k > 0) { x = v; while (k-- > 0) - x = LoopHelpers.compute4(x); + x = LoopHelpers.compute6(x); v = x; } else x = sum + 1; @@ -95,16 +90,15 @@ public final class SimpleSpinLockLoops { if ((x += readBarrier) == 0) ++readBarrier; for (int l = x & 1; l > 0; --l) - sum += LoopHelpers.compute4(sum); - } + sum += LoopHelpers.compute6(sum); + } barrier.await(); result += sum; } - catch (Exception ie) { - return; + catch (Exception ie) { + return; } } } } -