--- jsr166/src/main/java/util/ArrayPrefixHelpers.java	2015/09/20 15:33:12	1.7
+++ jsr166/src/main/java/util/ArrayPrefixHelpers.java	2015/09/20 17:42:24	1.9
@@ -7,6 +7,7 @@
 package java.util;
 
 import java.util.concurrent.CountedCompleter;
+import java.util.concurrent.ForkJoinPool;
 import java.util.function.BinaryOperator;
 import java.util.function.DoubleBinaryOperator;
 import java.util.function.IntBinaryOperator;
@@ -72,14 +73,27 @@ class ArrayPrefixHelpers {
     /** The smallest subtask array partition size to use as threshold */
     static final int MIN_PARTITION = 16;
 
-    private static final class CumulateTask<T>
-            extends CountedCompleter<Void> {
+    static final class CumulateTask<T> extends CountedCompleter<Void> {
         final T[] array;
         final BinaryOperator<T> function;
         CumulateTask<T> left, right;
         T in, out;
         final int lo, hi, origin, fence, threshold;
 
+        /** Root task constructor */
+        public CumulateTask(CumulateTask<T> parent,
+                            BinaryOperator<T> function,
+                            T[] array, int lo, int hi) {
+            super(parent);
+            this.function = function; this.array = array;
+            this.lo = this.origin = lo; this.hi = this.fence = hi;
+            int p;
+            this.threshold =
+                (p = (hi - lo) / (ForkJoinPool.getCommonPoolParallelism() << 3))
+                <= MIN_PARTITION ? MIN_PARTITION : p;
+        }
+
+        /** Subtask constructor */
         CumulateTask(CumulateTask<T> parent, BinaryOperator<T> function,
                      T[] array, int origin, int fence, int threshold,
                      int lo, int hi) {
@@ -211,14 +225,27 @@ class ArrayPrefixHelpers {
         private static final long serialVersionUID = 5293554502939613543L;
     }
 
-    private static final class LongCumulateTask
-            extends CountedCompleter<Void> {
+    static final class LongCumulateTask extends CountedCompleter<Void> {
         final long[] array;
         final LongBinaryOperator function;
         LongCumulateTask left, right;
         long in, out;
         final int lo, hi, origin, fence, threshold;
 
+        /** Root task constructor */
+        public LongCumulateTask(LongCumulateTask parent,
+                                LongBinaryOperator function,
+                                long[] array, int lo, int hi) {
+            super(parent);
+            this.function = function; this.array = array;
+            this.lo = this.origin = lo; this.hi = this.fence = hi;
+            int p;
+            this.threshold =
+                (p = (hi - lo) / (ForkJoinPool.getCommonPoolParallelism() << 3))
+                <= MIN_PARTITION ? MIN_PARTITION : p;
+        }
+
+        /** Subtask constructor */
         LongCumulateTask(LongCumulateTask parent, LongBinaryOperator function,
                          long[] array, int origin, int fence, int threshold,
                          int lo, int hi) {
@@ -348,14 +375,27 @@ class ArrayPrefixHelpers {
         private static final long serialVersionUID = -5074099945909284273L;
     }
 
-    private static final class DoubleCumulateTask
-            extends CountedCompleter<Void> {
+    static final class DoubleCumulateTask extends CountedCompleter<Void> {
         final double[] array;
         final DoubleBinaryOperator function;
         DoubleCumulateTask left, right;
         double in, out;
         final int lo, hi, origin, fence, threshold;
 
+        /** Root task constructor */
+        public DoubleCumulateTask(DoubleCumulateTask parent,
+                                  DoubleBinaryOperator function,
+                                  double[] array, int lo, int hi) {
+            super(parent);
+            this.function = function; this.array = array;
+            this.lo = this.origin = lo; this.hi = this.fence = hi;
+            int p;
+            this.threshold =
+                (p = (hi - lo) / (ForkJoinPool.getCommonPoolParallelism() << 3))
+                <= MIN_PARTITION ? MIN_PARTITION : p;
+        }
+
+        /** Subtask constructor */
         DoubleCumulateTask(DoubleCumulateTask parent, DoubleBinaryOperator function,
                            double[] array, int origin, int fence, int threshold,
                            int lo, int hi) {
@@ -485,14 +525,27 @@ class ArrayPrefixHelpers {
         private static final long serialVersionUID = -586947823794232033L;
     }
 
-    private static final class IntCumulateTask
-            extends CountedCompleter<Void> {
+    static final class IntCumulateTask extends CountedCompleter<Void> {
         final int[] array;
         final IntBinaryOperator function;
         IntCumulateTask left, right;
         int in, out;
         final int lo, hi, origin, fence, threshold;
 
+        /** Root task constructor */
+        public IntCumulateTask(IntCumulateTask parent,
+                               IntBinaryOperator function,
+                               int[] array, int lo, int hi) {
+            super(parent);
+            this.function = function; this.array = array;
+            this.lo = this.origin = lo; this.hi = this.fence = hi;
+            int p;
+            this.threshold =
+                (p = (hi - lo) / (ForkJoinPool.getCommonPoolParallelism() << 3))
+                <= MIN_PARTITION ? MIN_PARTITION : p;
+        }
+
+        /** Subtask constructor */
         IntCumulateTask(IntCumulateTask parent, IntBinaryOperator function,
                         int[] array, int origin, int fence, int threshold,
                         int lo, int hi) {