--- jsr166/src/jsr166e/ConcurrentHashMapV8.java	2011/12/05 04:50:19	1.33
+++ jsr166/src/jsr166e/ConcurrentHashMapV8.java	2012/03/04 20:34:27	1.37
@@ -20,6 +20,7 @@ import java.util.Enumeration;
 import java.util.ConcurrentModificationException;
 import java.util.NoSuchElementException;
 import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.locks.LockSupport;
 import java.io.Serializable;
 
@@ -351,7 +352,7 @@ public class ConcurrentHashMapV8<K, V>
      * Encodings for special uses of Node hash fields. See above for
      * explanation.
      */
-    static final int MOVED     = 0x80000000; // hash field for fowarding nodes
+    static final int MOVED     = 0x80000000; // hash field for forwarding nodes
     static final int LOCKED    = 0x40000000; // set/tested only as a bit
     static final int WAITING   = 0xc0000000; // both bits set/tested together
     static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash
@@ -435,11 +436,13 @@ public class ConcurrentHashMapV8<K, V>
          */
         final void tryAwaitLock(Node[] tab, int i) {
             if (tab != null && i >= 0 && i < tab.length) { // bounds check
+                int r = ThreadLocalRandom.current().nextInt(); // randomize spins
                 int spins = MAX_SPINS, h;
                 while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) {
                     if (spins >= 0) {
-                        if (--spins == MAX_SPINS >>> 1)
-                            Thread.yield();  // heuristically yield mid-way
+                        r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
+                        if (r >= 0 && --spins == 0)
+                            Thread.yield();  // yield before block
                     }
                     else if (casHash(h, h | WAITING)) {
                         synchronized (this) {
@@ -1291,7 +1294,7 @@ public class ConcurrentHashMapV8<K, V>
      *
      * At each step, the iterator snapshots the key ("nextKey") and
      * value ("nextVal") of a valid node (i.e., one that, at point of
-     * snapshot, has a nonnull user value). Because val fields can
+     * snapshot, has a non-null user value). Because val fields can
      * change (including to null, indicating deletion), field nextVal
      * might not be accurate at point of use, but still maintains the
      * weak consistency property of holding a value that was once
@@ -2237,7 +2240,7 @@ public class ConcurrentHashMapV8<K, V>
     }
 
     static final class Values<K,V> extends MapView<K,V>
-        implements Collection<V>  {
+        implements Collection<V> {
         Values(ConcurrentHashMapV8<K, V> map)   { super(map); }
         public final boolean contains(Object o) { return map.containsValue(o); }