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Posted to commits@hbase.apache.org by st...@apache.org on 2014/03/25 00:51:32 UTC
svn commit: r1581141 -
/hbase/trunk/hbase-common/src/main/java/org/apache/hadoop/hbase/util/Counter.java
Author: stack
Date: Mon Mar 24 23:51:31 2014
New Revision: 1581141
URL: http://svn.apache.org/r1581141
Log:
HBASE-10822 Thread local addendum to HBASE-10656 Counter
Modified:
hbase/trunk/hbase-common/src/main/java/org/apache/hadoop/hbase/util/Counter.java
Modified: hbase/trunk/hbase-common/src/main/java/org/apache/hadoop/hbase/util/Counter.java
URL: http://svn.apache.org/viewvc/hbase/trunk/hbase-common/src/main/java/org/apache/hadoop/hbase/util/Counter.java?rev=1581141&r1=1581140&r2=1581141&view=diff
==============================================================================
--- hbase/trunk/hbase-common/src/main/java/org/apache/hadoop/hbase/util/Counter.java (original)
+++ hbase/trunk/hbase-common/src/main/java/org/apache/hadoop/hbase/util/Counter.java Mon Mar 24 23:51:31 2014
@@ -31,7 +31,6 @@ import org.apache.hadoop.classification.
@InterfaceStability.Evolving
public class Counter {
private static final int MAX_CELLS_LENGTH = 1 << 20;
- private static final int SUFFERABLE_SPIN_COUNT = 2;
private static class Cell {
// Pads are added around the value to avoid cache-line contention with
@@ -57,18 +56,6 @@ public class Counter {
return value;
}
- boolean addAndIsCongested(long delta) {
- for(int i = 0; i < SUFFERABLE_SPIN_COUNT; i++) {
- if(add(delta)) {
- return false;
- }
- }
-
- while(! add(delta)) {}
-
- return true;
- }
-
boolean add(long delta) {
long current = value;
return valueUpdater.compareAndSet(this, current, current + delta);
@@ -109,16 +96,53 @@ public class Counter {
}
private static int hash() {
- return (int) Thread.currentThread().getId();
+ // The logic is borrowed from high-scale-lib's ConcurrentAutoTable.
+
+ int h = System.identityHashCode(Thread.currentThread());
+ // You would think that System.identityHashCode on the current thread
+ // would be a good hash fcn, but actually on SunOS 5.8 it is pretty lousy
+ // in the low bits.
+
+ h ^= (h >>> 20) ^ (h >>> 12); // Bit spreader, borrowed from Doug Lea
+ h ^= (h >>> 7) ^ (h >>> 4);
+ return h;
+ }
+
+ private static class IndexHolder {
+ int index = hash();
}
+ private final ThreadLocal<IndexHolder> indexHolderThreadLocal =
+ new ThreadLocal<IndexHolder>() {
+ @Override
+ protected IndexHolder initialValue() {
+ return new IndexHolder();
+ }
+ };
+
public void add(long delta) {
Container container = containerRef.get();
Cell[] cells = container.cells;
- int index = hash() & (cells.length - 1);
- Cell cell = cells[index];
+ int mask = cells.length - 1;
+
+ IndexHolder indexHolder = indexHolderThreadLocal.get();
+ int baseIndex = indexHolder.index;
+ if(cells[baseIndex & mask].add(delta)) {
+ return;
+ }
+
+ int index = baseIndex + 1;
+ while(true) {
+ if(cells[index & mask].add(delta)) {
+ break;
+ }
+ index++;
+ }
+
+ indexHolder.index = index;
- if(cell.addAndIsCongested(delta) && cells.length < MAX_CELLS_LENGTH &&
+ if(index - baseIndex >= cells.length &&
+ cells.length < MAX_CELLS_LENGTH &&
container.demoted.compareAndSet(false, true)) {
if(containerRef.get() == container) {