--- jsr166/src/test/loops/DynamicLeftSpineFib.java	2009/11/14 20:58:11	1.7
+++ jsr166/src/test/loops/DynamicLeftSpineFib.java	2015/09/12 18:26:21	1.17
@@ -1,7 +1,7 @@
 /*
  * Written by Doug Lea with assistance from members of JCP JSR-166
  * Expert Group and released to the public domain, as explained at
- * http://creativecommons.org/licenses/publicdomain
+ * http://creativecommons.org/publicdomain/zero/1.0/
  */
 
 import java.util.*;
@@ -9,12 +9,11 @@ import java.util.concurrent.*;
 
 public final class DynamicLeftSpineFib extends RecursiveAction {
 
-    // Performance-tuning constant:
     static long lastStealCount;
-  
+
     public static void main(String[] args) throws Exception {
         int procs = 0;
-        int num = 43;
+        int num = 45;
         try {
             if (args.length > 0)
                 procs = Integer.parseInt(args[0]);
@@ -26,16 +25,20 @@ public final class DynamicLeftSpineFib e
             return;
         }
 
-        
         for (int reps = 0; reps < 2; ++reps) {
-            ForkJoinPool g = procs == 0? new ForkJoinPool() :
+            ForkJoinPool g = (procs == 0) ? ForkJoinPool.commonPool() :
                 new ForkJoinPool(procs);
             lastStealCount = g.getStealCount();
-            for (int i = 0; i < 10; ++i) {
+            for (int i = 0; i < 20; ++i) {
                 test(g, num);
             }
             System.out.println(g);
-            g.shutdown();
+            if (g != ForkJoinPool.commonPool()) {
+                g.shutdown();
+                if (!g.awaitTermination(10, TimeUnit.SECONDS))
+                    throw new Error();
+            }
+            Thread.sleep(1000);
         }
     }
 
@@ -57,54 +60,67 @@ public final class DynamicLeftSpineFib e
         System.out.println();
     }
 
-
     // Initialized with argument; replaced with result
     int number;
     DynamicLeftSpineFib next;
 
-    DynamicLeftSpineFib(int n, DynamicLeftSpineFib nxt) { 
-        number = n; next = nxt; 
+    DynamicLeftSpineFib(int n, DynamicLeftSpineFib nxt) {
+        number = n; next = nxt;
     }
 
     int getAnswer() {
         return number;
     }
 
-    public final void compute() {
-        int n = number;
-        if (n > 1) {
-            int r = 0;
-            DynamicLeftSpineFib rt = null;
-            while (getSurplusQueuedTaskCount() <= 3) {
-                int m = n - 2;
-                n -= 1;
-                if (m <= 1) {
-                    r += m;
-                    if (n > 1) {
-                        r += n - 2;
-                        n -= 1;
-                    }
-                    break;
-                }
+    public void compute() {
+        number = fib(number);
+    }
+
+    static final int fib(int n) {
+        if (n <= 1)
+            return n;
+        int r = 0;
+        DynamicLeftSpineFib rt = null;
+        while (getSurplusQueuedTaskCount() <= 3) {
+            int m = n - 2;
+            if (m <= 1)
+                r += m;
+            else
                 (rt = new DynamicLeftSpineFib(m, rt)).fork();
-            }
-            r += seqFib(n);
-            while (rt != null) {
-                if (rt.tryUnfork()) rt.compute(); else rt.helpJoin();
+            if (--n <= 1)
+                break;
+        }
+        r += n <= 1 ? n : seqFib(n);
+        if (rt != null)
+            r += collectRights(rt);
+        return r;
+    }
+
+
+    static final int collectRights(DynamicLeftSpineFib rt) {
+        int r = 0;
+        while (rt != null) {
+            DynamicLeftSpineFib rn = rt.next;
+            rt.next = null;
+            if (rt.tryUnfork())
+                r += fib(rt.number);
+            else {
+                rt.join();
                 r += rt.number;
-                rt = rt.next;
             }
-            number = r;
+            rt = rn;
         }
+        return r;
     }
 
     // Sequential version for arguments less than threshold
-    static int seqFib(int n) {
-        if (n <= 1) 
-            return n;
-        else 
-            return seqFib(n-1) + seqFib(n-2);
+    static final int seqFib(int n) { // unroll left only
+        int r = 1;
+        do {
+            int m = n - 2;
+            r += m <= 1 ? m : seqFib(m);
+        } while (--n > 1);
+        return r;
     }
-    
-}
 
+}